Bob_H

Have you rolled your fenders yet? The tires hitting the fender is a common problem with a very easy fix. You can fit a 245 under there with some fancy backspacing work. You are only rolling the fender from about the 11 o'clock position to the 1 o'clock position. You can take a baseball bat, or a "professional device" to to this. I actually used a hammer. What you are doing is taking that lip behind the fender edge and pounding/pushing it up to a near vertical position. It will gain you almost an inch of clearance in some cases. (When I say almost, I mean like 3/4 of an inch). And 2.08's aren't bad for cheap-o radials as you say. I managed the same on 195 cheap-o radials, so you aren't far off. How serious are you for track stuff? If you aren't running in the real low 13's or faster, I just don't think drag radials are called for. Have you seen a honda running high 14's with DR's? Yea, it helps their time, but come-on! DR's on a 14 sec car!? Don't take that the wrong way. As I said, 2.08 is pretty good for crappy street tires. If you really want DR's, I would say go with the Nitto's. They stick good and are still a decent street tire. (i.e. no swaping back and forth). Remember, once you start to get it to hook, things start breaking.... -Bob

Hey Dan, What is your upcoming track schedule? This year is likely the only time we can be on the track at the same time. I guess the big question is are you heading down to Summit Point again, or somewhere near there? There is a NASA event at Beaver Run, somewhere in PA, which I might go to. I think Oct time frame. I'm checking into that one. I also found a group called tracktime, which is often at Watkins Glen, but that is a serious 500 mi drive for me. Point me to your clubs website and their schedule. I obviously won't be at the Canada and NHIS events... The only benefit for me with same size all around is I can take them off the rear rims and put them on the front rims. Front and rear require a unique offset. We are talking about a 40mm difference. No, spacers in the rear are not an option,(I need something like a 43mm offset in front, and 0 in the rear). And it looks goofy with a high offset FWD type rim in the rear. Looks are worth up to a second a lap you know! Something to do with others gazing at your car as you zing by them on the straightaway... And spares? They don't exist in the M coupe. I have what is called the "M mobility kit" A glorified fix a flat can, but with an airpump. I dunno... How does your car compare to the 88-91 M3's? They don't even compare to the M coupe. (Puts up armor for M3 types) When the M coupe is fully setup for track it competes against the likes of Corvette and Porsche. While the Z car is usually down a class or two. Regardless of the age, I'm sure if it could be made competitive, it would be classed as such. So I think as a 100% track car, the BMW wins again. There is a M coupe currently competing in GT type racing, and was blowing the doors off the 911's and the other M3's. There was an article in Roundel about it. It was the first true track car made from a M coupe. If I start stripping out stuff, and put in a cage and race seats, I drop down to about 2800 lbs or less- or less than the Honda S2000,(talking about dual purpose car, not dedicated track rat) . Each seat is almost 100 lbs stock! (like 85 lbs -but man, heated seats are awesome!). I can get the 3.2L BMW motor up to 350 hp,(euro or new motor trim), which compares favorably to about 250-270 in the Z and its weight,(not talking about all out race motors). For a realistic 240Z race car,(full cage, minimal interior, decent seats, etc..), It is in the 2200 lb range. Even John is having a hard time getting down below 2100, and he is contemplating CF hoods and such. We could go back and forth, but neither has driven the other car in a track environment, so we are both guessing. And I'm not sold on the chapman being "superior". A great design, absolutely. But superior starts to sound like saying the P series is best...(ok, cheap blow on my part). And as for cost, my purchase is long gone, so that is out of the equation. I can spend another 5-10k on the BMW, or spend 5-10k on the Datsun. Both end up fairly close. I still think, for equal aftermarket parts work, the BMW will be faster. And you say M coupes are more prevelant up there! wow. I'll put it this way: In nearly every town I have lived in since I bought the car, I am the only one in town, maybe one other. They have sold more Factory Five Cobra kits than M coupes sold in the U.S.! But the rarity is no the overriding reason. I am still split and will be for at least 3-6 months. Which one I sell will be a tough choice. Now Rick: You suggested a stiffer spring in the rear. Yes, if I was bottoming out the spring. However, that is not the case. But more important, when I switch to the Koni DA shocks in the rear, they are slightly shorter,(designed for the reduced ride height), vice the SA's I have now which are designed for stock ride heights or a tad less. I switched to a barrel type spring, which allows the coils to "lay down next to" each other. That may not make much sense, but they are shaped like an old barrel, and allow more travel before binding. And I don't hit the bump stops at all under braking or any other time,(have checked the rears as well, already trimmed them once). So all that leaves is the rubber bump stop internal to the rear shock. It is when I am full tilt cornering and hit some undulation mid corner, I feel it load up. Next, my car is 50-50 from the factory. As per Dan and my discussion,(and some reading up on it in Race Car Dynamics), I am not going to screw that up, only the cross weighting. So with that in mind, I am running fairly close to equal front and rear. It turns out I misquoted my actual rate, and it is 450 up front. I am running 525 in the rear. Some have run as high as 650 in the rear. But they did that for two reasons. One, the barrel spring was not available, so they had to up the rate to keep the coils from binding. We are limited in the spring length to one length,(6 inches). Any longer and it sits higher than stock at full down adjustment. Any shorter and it bottoms all the time. The barrel spring was a godsend for our suspensions,(spring is located inside of wheel towards pivot on trailing arm). I have tried softer front springs, didn't like them. I can only jump up in 50 lb increments for the front. So 500 would be the next jump. Also, I don't know how your suspension is setup, but that can make a huge difference in what rates you must run. B/C of the spring location on a SN95 Mustang,(the newer ones), they run on the order of 800-1000lbs or more in track setups. When they change to a coil over setup which moves the spring location, it drops to 350-400 for the same effective wheel rate. I don't know the relationship for your car vs. mine. Wheel rate is what is important, not spring rate. I can dive further into that if you want, but it will take some research on my part. I feel I am fine tuning the car right now, and am past springs. I like the way it rides and don't want to monkey with that too much. Remember, I drive this nearly every day. So that puts me at sway bars and shocks. But more importantly, checking tire temps and corner weighting for now. And establishing exactly what the baseline is that I have now. I agree with the order and premise of what you say, but fell I am ready for the next step, after establishing a better knowledge on the baseline. -Bob

Well, actually my distributor is driven directly from the front tires. So it is all moot for me. I am kidding. (he deadpans) In reference to your comment, yes, ignition timing is independent, however, comma... With the valve even timing significantly off,(as was mine), sparking at xx degrees before TDC assumed I had a certain amount of compression built up, which I had a different amount. So in my case, on the chassis dyno, it turned out to cost me nearly 20 hp till I could get it correct. That was a combination of BOTH ignition timing being off, (I had it off one tooth), and the cam timing being off. Not a good place to start. My first pull with it all screwed up was 138 hp. (this motor had already proved itself at 170 before, so it was my screwed up install of the cam) Ended up with 178. Got it up to about 160 by fixing the timing. Then got up to 178 with the camshaft correctly degreed,(was off the aformentioned one link). That was the point I found out heat was a major problem and that is my next assignment, a heat shield. That is what timing and retarded camshafts can get you. One last point on the ignition timing related to the camshaft timing. I don't have a dial gauge to get exact TDC, so I was putting it pretty close, then looking at the camshaft to see where the lobes were. Oops. Didn't exactly help. Ironically, on some of the chassis dyno pulls,(not talking about the above set, but my first set when I first built the engine), with the cam on the #1 hole, I made the most torque down low. When I advanced it to #2, more power, and better overall torque/power. So it would lead me to believe that a retarded cam could actually feel faster than a correctly set one, b/c of the increased power down low. But that is all conjecture, not actual experience. I never drove it like that. -Bob

Alright, this is going to be fun. I feel a little better being backed up on my thoughts. However, some more responses: JohnC said: Thank's John. I am skeptical w/o actually seeing it though, for my above mentioned reasons. I bruised too many ego's with my full frontal attack, so I softened the blow for that one. Second, Mine can hit 9k, for a brief glorious second when not in gear. I'm not about to try it either. 7k is my self imposted limit, mainly b/c of the stroker crank and pistons speeds. But this subject is dead already. I would be skeptical of the igntion as well, but you already pulled the head, so the discussion is moot. Next. yo2001: I'm sure there is as well, but why? Titanium is just not used in a metal on metal contact point. They don't use it in F1, so I don't see why it would be used for high rpm in this application. Of course, they don't use nickel iron blocks in F1 either! I seriously doubt it is a titanium liner. If anything, it is titanium parts in the valvetrain such as retainers. Next. DAW: HA! yup. Actually, we were ignoring you! I'll respond. First, I don't think it is the "best" head for a 2.8. I think it is the "best" head for a 2.4 or 2.6 motor. The rather extensive work required to get decent airflow through that head lowers its value to the "backyard" enthusiast, i.e. one w/o the knowledge to port and unshroud and such. Either the intake or the exhaust,(I forget off hand), has to be increased in size to match the stock valve sizes in the N series heads,(Z heads). Second, the combustion chamber has been measured to be in the 39-40cc range for that head. With a stock gasket, you are talking 10.7:1 with flat tops. When you switch to dished pistons,(depending on which ones), you lose some of the advantage of that "quench" or "squish" design of the chamber, as it won't push that mixture tumbling towards the center as the piston approaches TDC. However, with mods to unshroud the valves,(stock Z size valves), and some minor bowl work, it is a great head for a 2.8 motor. And with those chamber mods to unshroud the intake, you increase the chamber volume, and approach the more resonable CR. However, how accurate can you be to ensure each chamber is close to the same size? It is for those reasons that I don't think it is the best plug and play head. But it does offer great potential. I don't think it is overlooked, but rather, people shy away from the mods it does require to work on a 2.8L. But as a bolt on to a 2.4L, wow, that would be great! edit: You mentioned "not as extensive as shaving .080". I think monkeying with the chamber,(unshrouding) in any way is "extensive", and much more so than shaving the head. But others may not think so. /edit Next. Back and forth btw Tim and Lockjaw..... Personal note/experience on shaved head and retarted timing. In my P-90 what was shaved about 20 thou, the number one hole retarted the timing and fixing that alone,(going to the second hole), made almost a 15 hp difference. And about 5-10 hp throughout the range. So it is not insignificant,(and mine is a street motor, not a "race" motor). And degreeing a cam shows more than it is what the manafacturer said it is and where it is. That last part is huge. Degreeing a cam will show you if it is retarded or not. See above power claim with retarded camshaft. On a higher powered car than mine, the effect can be larger,(turbo/race). And on a head that is shaved more, it might take to the third hole to get it where the manafacturer said it should be. As a reference, my head is shaved about .35 thou right now and the cam had to be in the second hole to get it degreed properly,(btw, hydraulic heads are a PITA to degree, the dang lifters bleed down after a few min!) When the cam timing is off, so is your ignition. I chased that on my last re-assemble of the head. The camshaft was retarded on link in that case, which wrecked havoc on the timing and power. One link can be similar to shaving the head a significant amount and retarding the camshaft. I offer that up as a reference. I'm not stepping in the middle of this one. It is doing exactly what I wanted, good discussion back and forth. -Bob resident jackass

2 events! Man, esp. for a lightweight car like the Z! That reminds me of the EBC greenstuff pads. They worked great, but were gone in no time flat on the track. That is almost borderline unacceptable for me. John, you know I run the Performance Friction pads. I run the 93 compound. They work fine on the street and when cold, great when hot, a very high CF, but have some issues. Obviously, they will still squeal. Second, they dust like crazy, and when subjected to water, it actually rusts, (the dust does). But if you were willing to swap the pads out for each track day, the 93's are great for the track, and you can run the Z compound on the street. However, I am not a fan of the Z compound, as they have a very low CF and require a fair amount of pedal pressure. I have heard great things about the Carbotech pads on the track, but that XP one Dan is talking about seems to have a very low life on the track. I would call Carbotech as Dan suggests and tell them your application and what you want. Something similar to the Hawk pad you were talking about. I am not a fan of Hawk pads b/c they are hell on rotors. Any new Carbon/Kevlar type pad is much eaiser on the rotor and offers great stopping and wear. Again, call them, and good luck with the rear swap! -Bob

First, John, yes I did get your e-mail. I was having so much fun with the webber/head debacle that I haven't responded,(note, that is not actually true...) I will respond though. Doesn't look like I will make it to Lowes, for I think I may try for VIR that weekend with I believe the Alfa club. I can get info for you if you wish. I have been trying hard to make it to VIR. Lowes and hitting 130+ doesn't really strike me as fun. That long speedway is merely a connection to the road course.. And I quote Dan: Nuts! I figured it might be something like that, and 18 inches is reasonable. It might higher, but it is still negligeble in the overall scheme of things. As for the stock tires: they were Pilot Sports, so the actual size was 24.8F and 24.7R, so they are pretty close to equal stock, something I hand't checked till you brought up the diameters... I'll have to check into the E-30 M3's. They run close to the same suspension,(a few improvements), but equal tires around. I think part of the reason for bigger tires in the rear was the significantly more power than the E30 M3. Hmmm... I'll think that one through. For now, 235 is as big as I can go up front on the stock rim,(7.5in and that is actually .5 in under the reccommended width). I may be able to downsize to 245 in the rear. Time to do some more research. 245/255 does sound like a good combo. If I pick up a set of SSR Comps, I can do that. And I have never experienced snap oversteer in the BMW. You know, they are both called the Z btw... But I digress. Some others have, but mostly when they do something stupid like chop the throttle mid corner when they were full power and at the limit. The Z would do a nice spin as well under those condtions. I have some serious decisions to make in the next few months. Up till last month, I had all but decided to sell the M coupe and keep the Z as the 100% track car. However, the BMW can be driven every day, is much more rare, and holds similar status as my first car like the Z does. The Z can be a daily driver and such, but it will never be as refined, as quiet. (ack! what am I saying!). It is a tough decision which one will be sold, but the reality is I just can't keep both. I need to fix the Z's tranny and take it to some track days. Then I can make a judgement as to which one I like better on the track. One or the other will end up with a roll cage, race seats, and still see duty as a semi-daily driver. Just think of what $12k+ could do for mods to the BMW...can you say Turbo? BTW, that figure is from the sale of my car in a completed state. Ultimately, I want a car that will be the quickest wherever it goes. I can dump all kinds of money into both cars to help that,(assume the driver has the skill, work with me, it is a fantasy..). It is hard for me to say, but I think the BMW has more ultimate potential as a track car. Its suspension is 20 years newer and more sophisticated and refined,(in spite of the trailing arms, which work quite well). To an extent, it is also more forgiving, but that is second hand info, for I haven't taken the Z on track yet, only autocross with a close to stock suspension. If I stay with the Z, it will end up like JohnC's with FI and some form of Sunbelt head and high 200 hp range. If I get skippy, I might turbo it. If I keep my BMW, I will contiunue to refine the suspension,(it is fairly close right now, in spite of my complaints), and likely put a turbo on it. That one or two seconds a lap I am slower than a Z06/Viper just can't be made up all in the corners, (talking competent driver in the z06). On a short course, it is not as dramatic, but on long courses like TWS, it starts to show. I can't hit 150+ on the front straightaway. And there is a limit there as well. How comfortable are you at the greatly increased speeds? I am a little more than mosts, but that stems from the luxury of my job. Each day, I go back and forth. For now, I have commited to putting the T5 in the Z, and taking it to some track days and see how I like it. That will play a large role in which one I keep. I am very comfortable with the handling characteristics of the BMW and it is clearly more unique than the Z. Very tough call. -Bob now if I could just stop breaking camshafts...

Yes, there are too many variables. However, the current setup has been that way since March,(with no change in shock settings either). My real complaint about the current setup is the bottoming out of something in the rear occasionally, (I think I am hitting the shock bump stops - for the coil's aren't hitting anymore - still chasing that one), and the slight understeer problem. I like your approach, but every time the crew wears purple shirts, I lose 2 seconds a lap! Wait! Crew!? I am a one man operation here with my track day car, not racing against others for time. I guess I need to buy more beer! (can you buy friends?) I do need to find a one day event where I can do just what you are suggesting. Up till now, I instruct at every event, so that takes up a fair amount of time. I'll see what I can do to find someone to take temps for me. So until I can do just what you suggested, I'll change one thing at a time for each event and see how it goes. First though, the car needs to have its corner weights checked to make sure I'm not way out in left field. Then I'll find some gopher, I mean "crew member" to help me check tire temps. -Bob

Mike, thanks for the reply. And I quoth myself: Never doubted you got to 9k. It was the power produced with stock SU's and the titanium sleeves that I questioned. The rest about asking on your crank and such was to determine if anything else helped you get to 9k, not determine if you got to 9k.Revving to 9k, and actually producing power up there are two totally seperate things. I rest. -Bob edit: spelling, man I suck! /edit

Datto, Thanks for the info, but it just doesn't sound right. Are you running a 240 crank and huge pistons? That would then support a high rev limit like you say. with a 2.8L crank,(or a stroker crank for that matter), you start to get into serious piston speeds at 9k rpm, F1 type piston speeds, and that doesn't include the crank resonance at that rpm. The full blown race motors I am familiar with only turn to the mid 8's. I don't doubt the numbers you claim as far as power, or reving to 9k, but two areas just seem way out of wack for me. 1: Titanium anything as a wear surface. You may have titanium rods, or titanium spring retainers, or something else, but titanium is just not used in a cylinder as a wear surface. Let me put it this way, (and don't take this wrong, I just think you are mixing up something), but I was at the carwash yesterday. The "resident" or the crony who goes around and empties the trash, makes sure the stuff is working, etc.. started asking me about my car,(the BMW), we'll just call him Genius for now. I started talking to him about my road racing,(instructing with NASA), and he then made the following set of comments: Genius: Yea, I would ask you to race, but I bet its pointless. Me- well, I don't really race except on the track, but it can hold its own. Genius - yea, well I have a CRX with a twin turbo V6 with nitrous so its pretty fast, but i'll bet you could beat it. (more comments followed, I wasn't about to egg him on). I did press the v6 issue, but dropped it when I realized he didn't know what he was talking about. My point? The v6 only came in the Accord with an automatic. There is no twin turbo kit out there, unless you have serious cash and want to completely fab one, plus fab a serious adapter to mate the engine to a manual tranny. And to fit all this in a CRX to boot. Now obviously this guy was a moron, and that is not what I am saying about you Datto, but when you say a titanium sleeve, it sounds as far fetched as a twin turbo v6 accord motor in a CRX with a manual tranny. I have seen steel inserts, iron inserts, and even carbon and silicon inserts, but never titanium,(let me clarify see, meaning I know of, or have read about, I have seen only normal sleeves). Again, I am not relating you in any way to Genius, but rather showing you how crazy it sounds to me. I also realize it is what you were told, so you have no way to know otherwise. #2 -Using SU's that aren't modified for that kind of revolutions and power. Again, not saying I don't believe, but stock SU's and even SU's with SM needles, or aftermarket needles won't support that kind of power or rpm. They need to be bored out and custom needles made or very seriously modifed. I have done airflow testing on Z SU carbs, and even Z therapy modified shaft carbs,(He lent me the carbs for the project). They are designed to have full piston opening, (at top of carb), when the 2.4L motor was at a theoretical 100% VE and 7000 rpm. Which worked out to be about 150 cfm per carb,(just under 300 cfm - the sheets aren't right here, but you can calculate it quick if you need - it was within a few %). For a 9000 rpm 2.9L motor, assuming 75% VE,(reasonable for that rpm), it needs 363 fcm. Remember, that ~300 cfm was for 100% VE at 7k. Its actual VE is closer to 70%. That is why many who build strokers or 2.8L and put SU's on them have problems once they get over about 5-6000 rpm, the carb is maxed out. You can change the dashpot spring, and the needle, but that is some serious tuning. I'm not going to get too detailed, but when the dashpot is maxed out, you start increasing the velocity/pressure drop over the bridge,(where the needle and seat are), which will pull more fuel out, but it is no longer metered the same as it was when the needle was moving. So I am not saying you are wrong, but those two points stand out. Lastly, 100 over is a inches reference. You are talking about 88.5 mm pistons, to get your 2916cc's or 2.9L. I have a hard time refering to english when talking about a metric motor. So we are dealing with a 2.5mm overbore We would appreciate if the guy who built your motor could elaborate. I will also end with this: While waiting at a Z recycler in the morining for some parts, I met a guy with another Z. We started talking about our motors,(I had recently finished the 3.1L). He told me that his 2.8L with webers was putting out "Just over 500 hp". Needless to say, that gave me pause. I was nice to the guy and probed him further and found out that is what his engine builder had told him. I discussed with him full out race L6's and what power they really put out,(low 300's), and told him I'm sorry, but your car just won't put out that kind of power. He was very nice about it, and a little mad at his engine builder. His repsonse was his builder said that is what it put out on the dyno, and had told him such. Unfortunatly, that is unethical and sad. But in spite of the false power claims, the guy loved his car and the motor, even if it only put out 200 hp vice just over 500. That encounter, coupled with some "edjumacation" about dyno's and how you can play with the output from my builder I am wary of anyones power claims. (he showed me how my motor could suddenly put out "400 hp!", vice the actual 230 hp - you just play with the baseline/correction factor). This is not to say their cars aren't fast... but I know the power mine puts out, and cars like Norms I know what time it is capable of in the 1/4 mi. The best strokers and some of the true race cars taken to the tracks break into the 12's. To go faster requires serious work,(oh, and nitrous!). It helps weed through b.s. claims. Again, not saying this about you Datto. However, your information is second hand from your friend who built the motor, (as I understand). Because of that, I take it with a grain of salt. That being said, I would love a ride in it though! It is a great looking car, and you have done a good job with it. -Bob ever present skeptic

A couple of notes. First, I can't adjust camber to any small degree and caster is not adjustable. Right now, all I can do is swap the upper strut mounts left to right, going from stock camber to about 2.5-3 degress negative. I put it back to stock after the track day,(occasionally if it is a short time btw track days I will leave it). Until Ground control comes out with a street adjustable upper mount, I am stuck with stock ones. Speed into corners shouldn't be an issue, as I am significantly slower into corners than others, mainly b/c I run street tires and they run Kumho's, etc.. I do have to trail brake into the corners for rotation, so I am sure that is contributing. I'll take that under advisement and play with that next time at the track. And I don't think the rears are coming up into the temp range. As per my cc.com commments,(see first post for link), I am using the "calibrated palm" method. About as accurate as my butt dyno. Also, I don't have pyrometer, so I'll have to see if I can steal someone elses, (uuhh, I mean "borrow" ). What do you think about shock/spring tuning questions? For them, lets assume I am getting even temp spread across the tires and camber is optimized. Also assume that I am entering the corners properly, (yea idealistic!), and that is not an issue. To give you and idea of the speed I am running, I ran 1:59 at TWS on a different setup than I am running now, i.e. aftermarket stock style springs and Koni SA all the way around with the eibach bars. Brian Provost ran 2:02 with his high powered '95 LWT at the same weight. Of course, with a 500+ hp GT-2 Porsche he turned 1:49...so.... You know, I just thought of something. I my response to Dan, I said I had the stiff coilover setup when I ran the 1:59 at TWS. Not true, I didn't buy that strut assy. until I was in Mississippi, replacing the bent front set of struts.. Oops, my bad - getting old. So the fastest TWS time was H&R sport springs and Koni SA struts up front with the eibach bar... Anyways, interested in your suspension thoughts, ignoring driving style.

Dan, Did you get a chance to read the other posts at CC.com? Yes, I could change the roll stiffness, but I am working up towards that limit right now,(of what I want for a dual purpose car). This car has a short wheelbase, high power, and a trailing arm rear suspension. That is why BMW went with a a larger rear tire. And with the dramatically different suspension design from the M3, equal tires do not benefit me the same. I cannot run the same size tires all the way around for a different reason though. The car has speed sensors front and rear, and when you upset the change in diameter difference f to r, the traction control comes in much earlier, and in a much more unpredictable way. It also changes the ABS operation,(that was most noticable) I have heard other people say the same, and more importantly, I have experienced it to a small extent when I had to run the 235 fronts with a set of 245 hoosiers on the rear. It cuts in at bad times, and too early. Yes, you can disable the traction control, but remember, I drive this on the street and to and from the track. I do not yet have a set of track rims, and if I do, they will likely be 8,(maybe 8.5 if I am lucky) in in the front and 9.5 in the rear. So bottom line, I have to keep that ratio F to R fairly close to stock. Second, to an extent don't see why I can't affect the F to R distribution. Take the extreme, and jack both rear perches all the way up. I now the fronts should be carrying more of the static load. My thought is to set both fronts a little high and transfer more to the rear. My thought is it would affect static distribution, but more importantly, it should make a bigger difference under transistions,(to acceleration) Next issue, the bars: As I said at CC.com, I am shying away from increasing the rear bar setting. It is very well balanced at higher speeds, and when I did run a stiffer setting in the rear than currently, it got very nervous. The car is hard enough to drive fast right now for it darts all around, that did not help. That is why I was talking about changing the shock settings. I did run the current setup with a softer front spring. The car didn't like it, rolled too much in the front, and was overworking the tires. And for the front bar, here is what I worked changed/worked through: I originally had an eibach adjustable up front. I ran it on the softest setting,(also tried the middle setting). No good, so I swapped the stock bar back on, which has no adjustments. The comment by someone about actually increasing the front stiffness to change the understeer characteristics was intriguing. I have tried a 350 lb front spring with the eibach bar and stock bar. I have tried a 425 lb spring with the eibach and the stock bar. I don't have quanatative data, but the fastest I went around TWS was with the 425's and the eibach, ironically the stiffest setup. I still felt I was dealing with understeer though. This car has a fine line between understeer and swinging the rear around rather quickly. I think I am going to put the eibach bar back on the front, increase the rebound setting on the front shocks, and see where that takes me. And as for the inside to outside wear issue, I mentioned it to help shed light on the fronts being hotter than the rear. However, there is not much I can do about the camber gain curve of the suspension. That is a fixed issue for this car. Bottom line for the BMW, I think the fronts are doing about 60% of the total work, and it is showing in their heat retained. That heat is wearing them faster. I need to find a way to use more of the rears, not necessarly use the fronts better. And I am not set in my ideas either, even though I seemed to dismiss most of your ideas. I just wanted to give some more background and see the responses. Here's another thought: I was reading about a Le Mans effort, and that they couldn't get the tires to come up to temp during practice. So they kept backing down the springs until they started warming them up. This was in reference to competion with the Audi's,(that class). So my softer setup in the front may be TOO soft, and overworking the fronts. Maybe that is why the stiffest setup worked. For now, that seems to be a reasonable assumption and may be my next change. -Bob

DAW, Pulled this up while doing some research. I never responded to the last post. First, there are round port headers out there,(how good they are? who knows). And I think NISSMO has a round port header in their 3-2 racing header design. The main drawback of course being the $300 retail price tag. And my experience adapting a square manifold to a round port head? Minimal. But, I discussed with two people who had done that, (one ran a square port header on a round port head and the other person ran the square stock manifold on the round port head). They never considered removing the liners, so the square port was larger in all areas, and the match was fine. And your last question, adapting a round to a square? Absolutely no experience. I would think that with the round port being smaller in size than the square port, you would be blocking/impeding flow out of the exhaust port. Where putting the square on the round port has the lip away from the chamber, vice in the way,(that doesn't sound real clear, but I think you understand). Sorry for the long dealy in a reply! By now you have likely figured it out. Shoot, I just thought about that diesel oil pump question we talked about a few days ago. I meant to look into the actual part number for the diesel oil pump. You know, it wouldn't surprise me if it turned out to be the same as the "competition" pump for the L6.... So have you adapted the Maxima N47 to a motor yet?

cam, I defer to the turbo guys to answer that specific question. However, you were posting about swapping a VG30 into a 240 just last month? Do you already have a turbo motor in the car,(what kind of car - you were also looking for a zx turbo)? It may be a stupid question on my part, but it makes a big difference in the answer. -Bob

First, Z content: I own one. Ok, this question concerns my '00 BMW M coupe with coilover suspension, i.e. my track car. I am looking for a solution for the track. And yes, the alignment is within spec, with 1/16 tow in,(don't want toe out on the front, it is a dialy driver) I posted the original problem here: Post on uneven wear front to rear And below is the first post. My second and third posts in that thread explain my thougths on the suspension tuning to fix it. And yes, it will be corner weighted as soon as I can find someone who has the proper setup to perform it. And I am leaning towards biasing it towards the rear,(say 45/55). I'd appreciate your thoughts on that as well. John, I put your name in the subject b/c I know your tuning experience with suspensions and your recent admission of the love of the challenge. So here is my challenge: Alright, general question on tire wear. My car is a '00 BMW M coupe, 7.5 inch front rim, 9 inch rear, running 235/40's up front and 255/40s in the rear. stock size was 225/45 and 245/40, (all 17's). ~3200 lb car with me and gas with about 220 rwhp. The life of the front tires are usually about 2:1 front to rear,(i.e. I can almost get through two full sets of fronts for one set of rears, about 1.7 to 1). It was that way with the stock suspension, and with the GC coilover setup it is almost the same, but a bit more equalized. My question is this: what can I do to equalize the wear? I already have a pretty serious understeer issue,(well, pretty serious in my opinion, it is a fairly well balanced car). I am still tuning/working that out, and consequently, part of the extra wear in the front is my working harder to get the car to rotate, etc... trying different options to rotate the car around. Looking for ideas as to "in general" what causes fronts to wear faster besides -"you are turning with them.", and what can be done to minmize this. I would love to run 245's up front, but with the restriction of stock rims,(and the issue of traction control on the street with non-standard relationships front to rear for wheels speed), I don't want to go there. That would require 275's in the rear, which kills my rear end ratio to my already,(relatively speaking), low power. That and some have rubbing issues on larger rims anyways, (rubbing the car, not the rims). I would love to kill the rears first, but that is not the case. You high hp Mustang owners would love to swap places with me! Another interesting wear item is the inside of the tires. I have several on track pics of some extreme cornering situations. In all cases, the outside tire is planted nearly vertical, while the inside is draggin the inside of the tire, (camber curve of the suspension). I have run 1 degree, 2, 3, and even 4.5 degrees of negative camber, all produce the same excessive inside wear,(well, not 1 degree). BTW, the 4.5 was a bent strut, some idiot woman ran me off the road. Ironically I turned my fastest time at TWS with 4.5 on one side and 3.5 on the other. But it was hell on the tires, insides were gone about 25% faster than the outsides. I have played with tire pressure,(helped a bit, but the fronts heat up so much, again, street tire, that they can go fron 40 to nearly 50. I then drop it a bit to keep it around 45. Much more and I see a drop in traction up front. So what about shifting more weight to the rear? The car has NOT been corner weighted since the coil over install,(noone had a good setup, will next month). So for all I know, I am running 60/40 F/R, vice the near 50-50 stock. Open to suggestions, Bob (edit for here, I discuss the actual inner wear difference in a later post in that thread. It is not major, just not even).

Can I hear an AMEN! Reminds me of the older ferrari sounds... -Bob (I always post in twos, don't I?

Ok, I gotta have more info on this one,(I know I'm not alone here). Tell us what you can about this titanium sleeve. And is 100 over the overall size of the sleeve or the bore? I have never heard of a titanium sleeve are you sure it isn't something else titanium? And why was it sleeved in the first place? Again, it is the first time I have heard of someone having to sleeve a L6 block. Sounds like a lot of prep on the block and such, more than many all out race cars. More detail would be appreciated. -Bob

Ok, the topic came up in another post,(where I entertained others with my buffonery). I already have some other peoples head airflow data, plus my own. I have been compling them together for a while trying to post on my site for others to compare. (and for those asking right now, I currently only have access to my own P-90A numbers. I just moved and stuff is everywhere, packed and unpacked). If you have your flow sheets from your head, past or present, could you send it to me? Scan it in, write the figures, anything will do. The caviot to this project, and it will be clearly posted, is no two airflow machines are alike. You can pull data from one superflow bench and do the exact same on another and get two different readings. When you send or post the info, could you please include the inches of water it was done at? (25, 27, 29, etc..). Important info to include,(as much as you can): Head: i.e. N-42, E-88, etc.. Valve size: Stock, 1mm oversize, etc.. Porting done: pocket only, port matching only, full blown shiny surface job, etc.. Chamber mods: unshrouded, none, etc.. The inches of water the test was performed at: 27 inches, 29 inches, etc.. And the lift/flow figures and anything else you feel is important. If your lazy and just want to scan it and send it, that's fine too. Again, these are not to be used to compare your specifc head, but rather to give you an idea of different heads and how different mods affected them. And just b/c I have certain figures for a P-90A, doesn't mean someone else will, or that if you can't get that much yours isn't as good. It is merely a reference. -Bob PS- I've got my engine builder searching through his files to see if he can find his race E-88 head data. Ought to be interesting if he can find it. Side note on that GT-2 motor. He didn't know about the P-90 head when he built it. Tried very hard to remove the liners in the P-79 and make it better than the E-88. He had no luck at all. He chose the E-88 b/c of the small chamber to start with allowed him big leeway in chamber design. Plus he had cut several heads up to see where he could take metal and not.

The only one I have immediately available is my own P-90A. I just moved and many things are still in boxes, or somewhere waiting to be discovered. It will take some searching. Actually, I'm gonna post asking for some more. There are a few of us out there that have our flow sheets from our heads, and that can add to what I have. -Bob

Man, I suck, I always forget something and then have to go back and post again! Yo2001, I would love if you could scan the flow sheets. I have flow data from several people, and am trying to complie a list. If you don't want to post it somewhere or here, you are more than welcome to e-mail it to me. And I should clarify the 10 hp increase a little better. I said it was a compression game. Yes, but it is also switching to a flattop which changes the quench characteristics of the chamber. Pushing that burning mixture towads the center,(causing turbulence), as the piston approaches TDC is also helping gain some more power. And there is a caviot to my example,(which I so conveniently left out ). Bolting an N-42 to a flat top motor produces a CR near 10:1. That is the big reason why it will produce more power than a 8.6:1 motor, head nonwithstanding. Now, bump that P-79 up to the same CR, and it will produce more power. I was getting carried away when I responded. Guilty. -Bob

and Touche. First though, I wasn't calling you out. As I said before, if you took it that way, I'm sorry,(actually, it was some smart ass wheaties comment ). What I was doing was disputing/looking for more info on the facts. My method however, was most certainly unconventional. I have done the polite post part for a long time. And after several posts, it usually comes out that they know what they are talking about or are blowing smoke. Often, it ends up with confusing or conflicting info. Sometimes it takes something big,(oh, like me being a jackass) for people to change their ways,(talking the board in general). I knew before hand,(from watching you post), that you were not blowing smoke. Second, for me it was like playing devils advocate since I personally prefer the P series heads,(and that fact is fairly well known). And I have no problem disagreeing about the best head for minimal work. And AGAIN, I, nor anyone else, was trying or wants to convice you different. And noone here, me esp. considers you crazy for your P series ideas,(now that whole living in Alabama thing... ). I will take the above comments under consideration. But it is likely I will keep my approach. I still take issue with vauge and indefinite examples. People like John, Dan, Norm, TimZ, JeffP, yourself, and many others,(those were mainly L6 type folks), bring so much to the table with actual experience. And most of the time that is what I see. But as we stay on mailing lists and message boards for long times, our answers get shorter and shorter as the same questions are asked again and again. I can think of one person on the IZCC list who fits this bill very well. An amazing amount of knowledge, but usually responds in a sentance or two. It robs the reader of a good answer. I chose to be the one to bring it to everyones attention. You and I spared (sp?) over it, but in the end, all is ok. We need an icon for a dead horse. I rest, as I think we have beat it well. Datto, I'm sure we muddied the waters for you in the process. But between the P and N series, you can't really go wrong with your carbs. Big thing, pay someone to tune it properly, or as Lockjaw says, "it won't fall out of a tree" (BTW, hadn't heard that one before! )

No attack assuemed either, hope you feel the same way. I was never looking to change anyones mind nor convince you that you were wrong, (because I happen to agree with you on most all your points). My "higher level" is quite simple, (well, from my point of view anyways ). It is not new and is borne from having a webpage on the net that far too many people took as gospel. When I first wrote it, I didn't understand how people on the internet interpreted webpages/info on the net. My credentials were solid enough that people assumed what I wrote was 100% correct, and for mulitple applications at that! Over time, I saw that since I chose to put that information out for people to research with, I had a responsibility to ensure it was correct and was backed up by facts. I am still working to improve those things. You can read my page now and still find hearsays, ambiguities and such. Over time I hope to eliminate all of them. I guess I have been spoiled with sites like corner-carvers.com. When someone comes asking about a cylinder head, suspension parts, etc.. for xx platform, you must back up your claims in your suggestions. Otherwise you had to qualify your answer. You were doing just that, but in a way which left much to be questioned,(ambiguity, vauge). The reason I chose your post was I knew you would have the real data to back it up. I would not have picked on someone with 10 posts who was a relative unknown. Sorry to call you out in that way. I did get carried away when I did it to yo2001 as well. Sorry. And thank you for the details on that motor. That adds so much more to the discussion, and lends more credibility to your assertions. I realize most people don't care if people think their posts are "credible" but I do. Too many people bench race and napkin draw on the internet boards for the uneducated to sift through. For those who have actually built, driven and seen the numbers, (1/4 mi, flow charts, dyno figures), they have much more to share. I know by now you understand where I am coming from,(whether you agree or not). A few small notes. Yes, you said in your first post a car with a P-79 ran 8.40's,(an incredible time for any NA car - even if it did have 4.08's). But we had no way of knowing that was the same car refered to in the second post. It might be infered that with the shaving amount, but we had no way to know, hence my comments. And when you said I muddy's the waters to talk about realative skill at the track I think I was misinterpreted. I wasn't saying posting actual times are bad, but rather saying you beat XX on the street is bad. There are so many unknowns in that situation, and I see that as muddying the waters. If they suck at the track, it will show in their time. I gave the moron in Norm's car as an example relative to the street. I see how that is interpreted to mean talking about cars on the track. I mean talking about cars on the street. Something like saying, "Hey, I lined up against Norms' car,(a known sub 13 sec car), and beat it! What is not mentioned is someone else was driving it, and they didn't know what they were doing, and it wasn't at the track. Not clear, my fault. Not arguing, discussing. And the head setup thing, your right, its their problem. However, if they decide to shave a P series head 80 thou or 110 thou, they now need to know how to set their valvetrain up. It is only fair to warn them they will have to seek someone like you out to walk them through checking the setup of the wipe pattern, lash pads, etc.. Most people don't have that knowledge, that is why I tell people to shy away from it unless you know what you are doing. You know, so it is not a big deal. Most can learn very easy, but someone has to show them,(and warn them). Lastly, I agree 100% about building your own motor. However, Sunbelt has developed their new cam grinds, allowing huge cams with less than stock spring pressures. For that, I am willing to pay them to setup the head properly to work with their cam. I'm actually pretty excited, because I will switch to FI at the same time. But that is a next year project. -Bob

It never was about believing you or not. Yes, I have seen a P-79 and a P-90 on a NA car outperform a similar N series. I have seen it the other way as well,(N beat P). I have driven them and built others. It is already established I have one and am a big fan of the P series heads. The whole point of that diatribe was to raise the bar on posting. I realize you and others may not take it that way, and I can't help there. Things like the cars are the same, vs the description you just gave make a difference. The little tidbit of it ran 8.40's vs some other cars 1/4 mi time is huge. That starts to give concrete proof and strengthen your case. The only real opinion we have put in any of our posts is what head is best for NA motors. And it is just that, an opinion that we all expressed as such. As soon as you start talking about specific performance, it is no longer an opinion but fact, and should be backed up as such. And it should be noted that when I send my head into sunbelt for the new cam setup, it will be a P-90A, not an N-42. That was from your first post. To qualify it with "no matter what people say" is stating quite clearly that you are the only correct source,(or more correctly, your view is the only correct one). It highly depends on what the end user wants. John C showed the N-42 can be an incredible head for serious performance, so it is my opinion that either can be the best. It is important to note that John was/is running very high compression, like 13.6:1. To take a P series and run it to that compression requires incredible work on the head and money for pistons. Again, I would personally run the P-90 for a similar application. (By similar, I mean almost everything but lower compression for street gas). The reason I believe the N-42 is better is the minimum amount of mods required to make good power. Minimal if any shaving,(which means no monkeying with the valvetrain), minimal if any porting, and just bolt it on. That is why I endorse it vice the P series head. For 75%+ of the people here, they are getting a professional to setup up their head, or are doing it themselves and don't have the experience. Often, the "professional setup" is by a local builder who has little if any experience with L6 motors. An unported, unshaved N-42 can provide 200+ hp on a L28 with an aggressive cam and good carburetion setup. To get the same performance from a P series requires some significant shaving on the head and re-setup of the valvetrain. Bottom line for everyone: Provide proof, back up your claims, and no absolutes. And oh yea, the N-42 is the best! (sorry, had to ) -Bob Remember, its all in good fun.

yo2001 wrote: I don't think its is. They swapped to flat tops, and the compression ratio went from 8.3 to 8.6:1. Put the flat top pistons with an N-42 and you have better performance than the same motor with a P series head. It is a compression game. No, it is not identical. It has a different design on the combustion chamber, different size valves,(you said old E-88) among other things. They are not the same head, that is why they went to the N designation. And not all N-42 heads have fuel injection notches either. Looks better? Come on. You again told us the reader nothing. It does have slightly less curve in the intake, but that is more a function of the sideways D shape of the port. It allows the air on the bottom eaiser movement into the chamber. But the N-47 has the same design.... And less pocket area is NOT a good thing. That is why "pocket porting" is endorsed for your first time porting. The idea is to enlarge that bowl area making that transtion into the chamber eaiser for the airflow. I do assume that by pocket area, you are refering to the bowl behind the valve in the intake runner. If not, please correct me. And: Data? on the N-42 or P-79 head? vs. the P-90 or the N-42? Or an E series? And where did you get this data? the Net/someone else? Just raising the bar for "posting" info on the net. If you are going to educate, back it up. And second, where you shift has no bearing on the previous statement. For all non-race cars,(just that, not raced at or on a track), you are only going to shift at a max of 7000 anyways. The only reason you go over that is you put some serious mods into the head, camshaft, and rotating assembly to witstand higher than 7k. There are few if any street setups that require or produce good power with the "stock" L6 cylinder head over 7k. I say "stock" to mean unmodified or pocket type porting, i.e. minor and cams of less than .500 lift and 300 duration. A .490 lift and 290 duration cam would push the limits of my defintion. SEATS! -bob

Ok, time for a corner-carvers type reply. I don't like heresay or claims that are hard to prove/back up. I will first start by saying this is not a personal attack,(if you take it that way, eat more wheaties), it is challenging your ideas and asking for more concrete proof. And for those unfamiliar with corner-carvers.com, here is a post that should give you and idea: Corner Carvers suspension tech forum post about KB Be forewarned, it is not for the faint of heart. If you like to sing songs while lightly strumming the guitar, stay away from that link. BTW, it follows a previous post from one of Kenny Brown's employees,(they make Mustang stuff). The first half is somewhat pointed, the second deals with the products. Good site for track knowledge though. Ok, on with the show. And my response is SO? First, there are no two identical cars. Tuning, compression, tires, brakes, rear end ratios, tranny ratios, relative condtion of all of the above, etc.. All those play into something like that, and ESPECIALLY the skill of the driver. If a moron took Norm's 240 to the track, I bet the best we would see is very high 13's, low 14's. He smokes the 1/4 because he can launch that car and turn sub 2 second 60 foot times. In addition, he changed the gear ratios of his transmission for drag racing. Also, saying they were shifting at 5500 and somehow implying that if they went all the way to 7k they would be faster is absurd. In some cars, yes, in others no. It may have produced no power up there and was actually faster shifting at 5500. We have no dyno sheet or acceleration runs to look at. In my stroker, I get the best acceleration short shifting second and third gears, by almost 500 rpm,(discussin 1/4 times). Second, the E-31 is a terrible head for serious performance, likely your worst choice. It used to be the one to use, because of the small combustion chamber. But without proper unshrouding of the valves,(not to mention bigger valves to at least match the later heads size), and some good port work, it is no good in a performance application,(talking serious performance). John Coffey has built what I consider to be the ultimate NA L6. He is putting out a fair amount over 300 hp, (he asked not to give out the final numbers) with a very wide power band,(3-4000 rpm), and (drum roll please), an N42! If he and Sunbelt Motors,(arguably the best in the business for L6 motors right now), thought the P series heads were better, I am quite sure they would have chosen such. However, with unlimted choice, they chose the N42. Why? Because it is a great head and very easy to modify. While I am a big fan of the P-series, and use it on my car, I don't reccommend it to anyone not building a stroker motor, and a full stroker at that. It is not always that simple. What if you are dealing with a regrind and a reduced base circle? How about going from a stock cam to a Crane cam? And how about not all lash pads are the same size even on one given motor? How does the avereage joe deal with that? Yes, it can be worked through, but like tuning webers, it requires knowledge. I am not about to reccommend to people that they start messing with their valvetrain geometry. Sometimes it works out perfectly with no shimming/etc required. But sometimes it is a nightmare. It is like craps, you roll and you might win or lose. I did it and know what is involved. Unless you really know what you are doing, I cannot suggest you do it. First, NEVER use a Vericom to discuss hp in a rebuttal or to prove your case. Only chassis dyno's #. Engine dynos are even suspect. You can talk ACTUAL times for that car on a track or power to the wheels. Otherwise, the data is only as good as the user input.I can take my G-tech, (yes, not as good as the Vericom), and it shows I have 300+ hp in my 3.1L. I have run it at the track and on the chassis dyno and an engine dyno. I know it produces nowhere near that much. There are far too many variables for what you stated. If you plug in Norm's times into generally accepted power equations it shows a bit more hp than he actually has. Again, a function of how hard he is able to launch that car, coupled with the gear ratios. When I plugged in my times into the same equations, the power was nearly the same as the chassis dyno. But I now have a 3.9 gleason,(had a 3.54 open), much wider stickier tires and a better ratio set in my tranny. Haven't been back to the track, but power to the wheels is the same, and I know it will go faster. My point? They are guesstimates, nothing more and not a good way to prove a point. What head, what motor, what tranny, what rear end, what tires, how was it tuned???? All those and more are a significant factor in how well they work together and how well they run and importantly, how it compares to another car. And, they make a difference in how the car is jetted/setup. As I said above, for power, unless you are talking actual 1/4 mi times or chassid dyno numbers, you are talking guesswork. And my friend beat this 13 second car, and I beat him, so I must run 11's! Be careful, that is starting to sound borderline rice. Comparisons to other cars, unless on the track itself are totally pointless. See my link on street racing after this paragraph to show how something as small as .5 sec difference can make in a equally match race. And you said the turbo car ended up running low 13's. Do we take that to mean it was not running low 13's when they raced? And I would expect the MPH to be higher for a turbo than Norms. And what was the setup of the turbo car? 240/280/280zx? tranny rear end? how well was its state of tune the day it raced. Was it cooler or hotter when it ran the low 13's at the track vs the day your friends car raced it? See where I am going? The comparison does nothing for us the reader except produce smoke and mirrors. Your friends car in question may indeed be a well setup mid 13 second car. Or it may be a mid to high 14 second car that sounds fast. The actual difference btw those two types are hard to quantify. Here is the street racing link: Street Racing is a crock And they didn't put that development into the N and E series? The E series was an evolution of the 4 cylinder heads. The N series was an improvement on that,(look at the N47 with its D shaped ports and such). The P-series was designed for the ZX. The application was different as was the requirements. That alone does not imply it is better. They flow well? Well tells the reader absolutely nothing. They flow well in comparison to what? A blow dryer? The N series flows well too. And the heads with liners flow well. I just told the reader nothing. The reality is the ACTUAL flow btw a P-90 head and an N-42 head for the exhaust is almost identical. No difference. The P-79 and the N-47 with their liners have great,(not just good) exhaust flow with very minor work. The radius coming out of the combustion chamber is larger, making it eaiser for air to make that 180 degree turn out to the header,(we are talking performance here). Just b/c the square ports are bigger doesn't mean they are better. They have more potential in a race application, but until you are talking serious turbo or race levels of power in a NA motor, that extra flow is not requried. (I know you would not use an exhaust liner'd head in a turbo). I have seen flow charts for both types of heads. Until you get some serious port work, you cannot tell the difference btw an N-42 exhaust and the P-90 exhaust flow. And for that matter the N-47 and P-79. Those four head are within a few % of each other. Closed combustion chamber? And how many people on this board do you think know what that means? Can you adequately explain the difference between an open an a closed combustion chamber? I can, but I don't think it really applies to our heads. You have a smaller area,(talking flat), that is the combustion chamber, but the volume is bigger, so the effect is not as significant. And high swirl? Squish maybe, but certainly not swirl. And I quoth: For those who want to know the difference btw a closed and open combustion chamber, here is a picture of a closed one, the second is the same type head, but open:Closed combustion chamber, Toyota 5 valve Open combustion chamber Toyota 5 valve Notice the flat area of the cylinder head on the closed chamber is more in the shape of a star, where the open chamber is more circular. It is not just the flat area, but the whole chamber in relation to the valves. But I digress. Next: We weren't discussing what makes a race car or not. But you were fine until the last sentance. I sure have put it on a bunch of people as well. And? It is irrelevant to proving your point and only weakens the defense. Along the lines of "I beat this Supra rolling down I-85" I close with this. Lockjaw, I realize I broke down most of your post, but this is not about you, nor is it an attack on you. My P-90 page and Bryan Little's pages are a big reason why many of those myths are out there. I have finally corrected my pages. Bryan has made his setup work. He could have gotten very close if not better results with an N-42. Its personal, and he wanted to be different. Everyone runs the N-42. Your backgrond is a turbo motor. And for a turbo, there absolutely is no better head. But for a high power NA 2.8, the P series are mismatched and require too much work for them to make decent power. The N-42 yields the same result for a much lower entry price/knoweldge level. I just got sick of smoke and mirrors as defense to ideas/performance. It was not you, this has been building up for a while. I expect the same from everyone. If you are going to give an opinion, say it is that. When you start talking about performance being better than something else, it is no longer opinion. You are now "educating" someone else on the net. And we all know the high quality we often find on the net. I am posting this to set a higher standard for proof. Talk about your setup, times and dyno numbers. Saying you walked on a Z28 means nothing. A granny could have been driving an automatic and had a 2 second reaction time. The defense rests your honor: -Bob

Well, "Bobby" with his 40mm SK carbs and 3.1L put down 180 hp through 7k with a much smaller cam than Dan. Actually, in all fairness, I paid someone to jet the carbs on the engine dyno. It took a lot of work b/c they were sooooo far off to begin with That and Chuck really knew the triple carb setup. That formula Dan provided is biased more towards race carburetion. By comparison, the same shop that built my motor, ran a 2.8L in a GT-2 car,(300zx, they got a weight break not running the VG30). That motor make ~330 hp to my ~220,(I give mine as a reference only b/c it was the same engine dyno). They ran 50mm carbs with the venturis removed. Yes, it wouldn't idle below ~2000 rpm, but the venturi's were restricting the motor at high rpm. It was funny to look at, for it reminded me of the TWM throttle bodies. Nothing then a throttle. That was their approach, everyone elses is a bit different. That being said, for the cam sizes Dan is running, I believe 40mm would be to small. I think my carb setup would be good through about 210-215 hp at the wheels. After that, I would be choking the motor. My current cam is only good for about another 5 hp and 20 lb-ft of torque. I still need to build a heat shield,(BTW Dan, consider a heat shield MANDATORY). The important distinction I made when building my motor was the daily driver status. I wanted a car that my Mom could hop in and drive to the store if she needed. So mine pulls cleanly,(and strong) from idle in fourth. I think if I did nothing other than switch to 45's, I would lose a little bit of the low speed driveability and might gain 10hp on the top end. The key is tuning. So if you already have 40's, go for it. I would suggest limiting your cam size to something smaller than Dan's, maybe bigger than mine,(which is the Motorsport Auto 2003 grind, .460 lift, 270/280 split duration Schneider cam). Search out and find someone who really knows sidedrafts and can tune them. If you can marry them with a chassis dyno session, expect to pay 2-400 and have a great running car. Dan said: There's probably nobody better than Sunbelt for building a high-performance Nissan L6. I agree 100%. Their new cam profile seals the case. Expect to pay a bit more, and have to wait a bit longer, but it is worth it. And Lockjaw said: No N series, no matter what people say, the P series is the best. Sorry, I have to disagree with this. I helped perpetuate this myth on the Datsun Workshop when I first built my 3.1. For a stroker motor, it is not bad, for a 2.8, it sucks. Shaving .80 thou is A LOT and requires a bunch of work to set the cam back up correctly. Sure, Bryan Little did it and told everyone on the Datsun Garage how to do it. However, think about this for 1/8 mi times: Norm is in the low 8's, like 8.1 with an N-42 and SU's. Sure, his experience is vast for drag racing, but I'll be so is Lockjaw's friend. The N-42 is a plug and play head and is hard to beat. Now for a Turbo, you can't beat the P-90 series. -Bob Hanvey