Bob_H

Uhh, minor point. The diesel rods are NOT a performance option. They are designed to take the massive compression of the diesel,(upwards of 20:1), and are much heavier than "normal" rods. (discussing in general terms). I have not personally seen the nissan diesel rods,(DAW has) and cannot say how much heavier/larger they are specifically. The crank works, but I wouldn't use the pistons or rods from the diesel. -Bob

Ok Devil: At very low engine speeds,(say cranking engine speed of 2-300 rpm), there is not much velocity in the intake charge. Therefore, the overlap and the intake valve closure point have a larger effect. Once the engine is running, there is some momentum to the intake charge, which allows some of that "pressure" to stay in the combustion chamber when the intake valve is still open after the piston starts rising from BDC. At cranking speed, as soon as the piston begins rising from BDC, some of the charge is pushed back out the intake valve until it closes,(which by some areas I have read, is effective at about .050 lift). Late (radical) intake valve closure causes some mixture to escape even at lower speeds. So to answer the Devils questions, the intake valve event timing,(i.e. when it closes), has a large impact on pressures read during cranking. A cam that was designed for really high rpm will have an intake event timing that might not close the valve until the piston is almost halfway to TDC,(that is exagerating a bit for example). So at cranking speeds, you are only compressing about half the volume... But on cams that are similar, the difference shouldn't be too much. And Yo2001, your cam specs are smaller in regard to exhaust timing, but not intake timing or overall lift. And what is not known is when your intake valve actually closes,(can be derived from your cam spec card). I dont think your readings are low or abnormal. I think Norms are high. -Bob

Don't forget what cam you have impacts that rather significantly. A stock cam with high compression will have high psi. A large aftermarket cam,(read long duration), will have a low psi reading for a given CR. My ~9.7:1 with a 270/280 .460 lift cam is about 175-180 psi. You must have a fairly small cam would be my guess. -Bob

Easy folks. Lets not all jump on the bashing bandwagon. That's my designated job, and I feel a little job insecurity right now! John was indirectly saying that high power FI setups on the stock FI are, as I said, neigh to impossible. I don't know if it is intentional or not that Nismo280zEd has not responded yet. -Bob

Diving further...to steal Lockjaw's thoughts about eagle rods with no rod bearings.... Nissmo280zed posted earlier: Post about "wimpy" headers So if this was posted last week,(well, just over a week ago), I find it hard to correlate the two. If you have what is called a "wimpy" header,(totally subjective) from a Z guy and if you have 230 at the wheels, why are you changing your header? I'm going out on my limb, I say BS. I say this claim is BS and cannot be backed up. 230 hp with "stock" FI is neigh to impossible and you exagerated your claims to make the arguement sound better. If you can prove me wrong, by all means, please do. Let others laugh at my follies. -Bob on further edit: I would not be surprised at all if this were a G-tech hp reading. With an accurate input of weights, etc.. into my G-tech, I got nearly 300hp to the wheels with my setup. Which, oh by the way, put 178 to the wheels on a dynojet and runs mid 13's in the 1/4.

Ok, I'm game. First some questions. To get "about" 230 at the wheels in ANY NA L6 setup is approaching a race type setup,so your post is somewhat misleading unless I am missing something. I am well aware of what a full bore race motor will put to the wheels when starting at 320 at the flywheel. I also know what a triple throttle body FI system will put out vs a triple carb system,(near equal hp, but vastly improved torque spread). So the first questions is what mods have you done to your engine? I would bet good money that to keep the "stock" ecu you have played with a lot of things. I would also bet you have a fairly large cam, over .500 lift and over 300 duration. I would also bet that the power is not spread as well as Dan's. Now those are all "bets" meaning I am guessing to an extent. Let me go on record as saying I personally prefer Fuel injection, as it has more potential. However, carbs are simpleton easy. Joe back-yard mechanic can work on SU's. Where the Datsun FI system requires a little more "knowledge" and "brains". So since it requires more knowledge, would you please share with us what you have done to get approx 270+ at the flywheel. You are approaching 100 hp/L if it is a 2.8L., which again you did not specify. If this seems somewhat confrontational,(besides that being my style to an extent), it is. You offered up no details of how you got "around" 230 to the wheels. Is this via chassis dyno? Is this via 1/4 mi times/mph? Is this Vericom/ G-tech or G-tech pro? And the most important facts left out is the actual setup of your motor including changes to what the ECU "sees",(way to many ""'s in this post...). To come in and say FI is better, and you got lots of hp w/o details is tanamount to me saying the stroker is superior to the non-stroker, but not saying why. There are just too many variables. And yes, I had a 260 SCCA race car,(honestly have no idea what class would let a 260 have a 280 FI motor) with FI and a big cam and I did try tuning it to an extent. Ran like dog crap. Mainly b/c I didn't buy it for the motor, I bought it for the Gleason rear end. Swapped that out and sold the car. -Bob Waiting for details...

So based on Pete and Zr8ed's measurements...... Pete you got some great width under the fenders! So the "theoretical" I am exploring would fit maybe with fenders, maybe.... I was looking at 58-59 inches track front and rear. Assuming a high positive offset,(lots of rim inside of car), it might make that 3-4 some odd inches on each end wider. So that means tire to tire edge is something like 64-68 inches. With pete at 64 inches under stock fenders, I should be able to get another 2-3 some odd inches on each side, so 66-68 inches, fitting my "fantasy" arrangement. And I feel certain the rears can fit with flares. Thanks guys. You know, this whole project might go by the wayside if I can find my dad's original car. I am searching for the '68 convertible corvette he bought new in 68. BRG, tan leather interior, 400/427, 4 speed, air, power windows/locks, etc.. If I can find it, I would gladly put my Z project on hold to buy it back for him. But secretly, I kinda hope I don't find it so I can try this stuff with my Z! -Bob

I think you should post this in the correct forum.....that would be "Alternate 6 cylinder, Non L6 board..." I also think you have never driven a well built 3.0 TT motor. You wouldn't be worried about stroking, destroking, RPM's, etc.. Drive it, mod it, THEN worry about the things you are asking. And my personal opinion is your idea is not good at all. WAY too much money, not the results you want. Just boost it, and forget about the RPM. Sorry, sick of folks who b/c of all the honda's and such feel they HAVE to rev to 9-10k to make great power. GIVE IT UP! Not directed at you, just ranting. -Bob

Man, Finally some pics. Scottie, is this a 300zx rear end? nissan irs from scotties page BTW, which rear I am considering is wide open from completely stock,(Dan B's idea), to Supra TT, 300zx or "others". Trying to find subframes to look at. -Bob can't leave good enough alone

On the following page I found the 84 specs for rear track width: 84 'vette specs But you measured hub to hub as 63 inches. The "stock" 240z track width is 53 inches. The "spec" rear width of the vette is 60.4 inches. And you narrowed that 3 inches to fit your setup. And I am really looking at the front, not the rear, but trying to get an idea of what exactly the track widths are measuring. I have a feeling it is tire center to tire center. With the big positive,(negative, whatever) offset of the corvette rims that seems to make sense. Hmmm... And John, I haven't lost it yet! Working on it though. I may very well end up with 100% stock setup. But what I am looking at may be fairly easy to do all things considered. And John, you should be getting the new input flange in the mail sometime next week. -Bob

Scottie, I forgot you had measurements on that page. 66" end to end? Wow, the largest I have looked at is 61. However, that is published track widths. Does anyone know how that compares to actual wheel end to wheel end? Is that measured wheel center to wheel center or otherwise? Hey, I just thought, I can look up the C4 vette specs. -Bob

What, its not like your the ONLY guy out there... Well, just you and Cuong. And a few of us in process. BTW I now understand what you had to do to the tranny mount. When I was test fitting the T5, it made sense how it would not fit through. With some of the things I am considering now, that really doesn't matter anymore. Still looking for a engine management I like. Mainly one that can deal with the MAF's. Most of the systems on the market are speed density, like your SDS. 6 on one hand, half a dozen on the other. Don't know what this whole 6 finger thing is.... -Bob

Looking to find what the widest track widths people have. The "stock" front track width is 53.5 inchs,(1359mm), and the "stock" rear is 53 inchs,(1346mm). By track width, I mean from the outside of one wheel/tire to the outside of the opposite wheel/tire. Scottie, what is the wheel to wheel distance for your C4 setup? Pete, what is yours in the front and rear? Just looking for a tape measure distance, accurate to about a half an inch. Trying to find out how wide you can go with some small flares and under the stock fenders. To give you an idea, I am looking at something that has a track width in the 58.25 range, front and rear. So roughly 5 some odd inches over stock. I think 3 of those inches will fit under stock fenders. Trying to see if that extra 2 or so inches will fit under small flares. That is why I was asking you Scottie and you Pete,(since yours is about as wide as you can go under stock fenders and scottie has the small flares). Yes, I am looking at some crazy things, but not telling for a month or so. It is pretty exciting. And no Dan, not what we talked about. If you know, no telling! -Bob

Don't touch it. The bigger that hole, the more pressure you are taking away from things like your turbo, the main bearings, etc.. I am running a bigger cam in my P-90A than you ever will in a turbo motor and I have no problems at all with the stock size openings. Trust me, you need that oil in other places, not the lifters. -Bob

92awdgsx has info on his site about the cleaing of the mitsu. hyd lifters. The same really applies to our lifters. Kinda what you are talking about, or you can use a bottle of techron. Then you need to compress the lifters repeatedly until they operate smoothly. Realize they are not easy to compress, that ain't no small spring in there! After a day of soaking, see if you can compress them. Then do it several times a day throughout the next day or two. -Bob

Mike, Good lord, GT-2 spring pressures on a hydrualic turbo head?! I would bet good money that is a large problem, not to mention what John said about it robbing you of power. Take a look at my webpage,(link in my signature). Look at the P-90 page and read what Nissan Motorsports said about the hydraulic lifters... I am running about 30-35% more pressure than stock and that is what I consider to be the upper limit that the lifters can take. You have shown they will survive with much more up through about 6500. Save your lifters, swap them out for stock springs,(if you have close to a stock cam), or very mild springs at best. You'll be amazed at several things, first, no more problems above 6500, and two, more power for the reasons John cited. -Bob

Jeff, I am interested in where you got that production run info? Was that second hand, or documented? Before Quaife started offering up units for the R200 and R180,(more the 180 now for ITS and such), a Gleason R-200 would pull upwards of $2000. I don't know what it is worth right now, but I'd bet I could still sell it for close to $1500. Ironicly I bought a race car, pulled this rear, and sold the race car. Yes, bought the car just for the rear. -Bob

well, sort of... Mike is right, but the explanation is unclear. The lifter is pressurized by oil pressure. As the cam rolls around and starts to push on the follower and valve, an internal check ball/valve in the lifter "engages" and locks the lifter in its current position. when that ball/valve fails to seal, the lifter slowly "bleeds down" meaning the valve sees less and less of the amount of lift it is supposed to. Symptoms would include a drop off in power, or just plain refusual to go above a certain rpm. The motor still runs, it just has less power, in some cases, much less. First, are you talking about taking your turbo over 7k? If that is what you are doing, lifter bleed down is not really a problem, but airflow capabilities of the head/intake/exhaust. On my P-90A 3.1L, with good lifters, I have taken it to 7300+ with no lifter problem. I wasn't making much power up there due to other issues,(cam was too small for that rpm powerband). To better identify your issues, you need to provide more info on what is happening. -Bob

That's about what I figured, but not your last comment about the MAP system being better. As I understand it, you can change what fuel the EMS puts in based on the signal from the MAF. I.E., xx fuel/lb air for a stock setup, modified to xxx fuel/lb air. I know the speed density system can be programed to deal with more, but MAF is much more "accurate" if you will for a given load/airflow intake. To me, x amount of air means x amount of fuel, with a factor for boost pressure and throttle position,(I realize that is all the speed density system is doing, just you have to manually input the points, vice it doing it for you). But the real question is which systems can deal with a MAF and still be programable? AEM is clearly not an option unless they get off their butt and get the Race system out in a month or two,(which by their posts earlier this month, that is clearly not the case). So which other systems would offer the ability to support the MAF, data logging, and still have decent selection of options to play with,(tune). Really, most of the systems on the market are the same, just a different name and different interface. Some might have a few more inputs, etc.. But all the ones I looked at aren't designed for a MAF sensor, but a MAP/speed density setup. Any thoughts? -Bob

Ok, still in the "research mode" for the RB26dett EMS. A large majority of the units on the market today are a Speed Density system. With the 6 individual throttle bodies of the RB26dett, it is harder to put a map sensor in an appropriate location to sense load. You can stick one in the main manifold log, but then it won't see vacuum behind the throttle plates. You could tap into each runner behind the throttle plates and run a log to the map sensor, but with its close proximity to the valve, you start to get funny reversion and pressure changes. I really don't want to switch to a single throttle body,(personal preference). The way I see it, using a MAF should be more precise than a speed density setup since you know the exact amount of air coming into the motor at a given time. To me that would make part throttle tuning that much eaiser. I am interested in hearing opinions either way, and not "I run speed density and it works great". That is not what I am looking for. I want to know why I should choose one or the other, besides simplicity or cost,(and that it works great for you). What makes one better than the other? Also, if someone can point me to links with more info that would help as well. Also, any info on EMS's that support MAF's vice speed density only is appreciated. -Bob

David, Thanks for the number! I'll be calling them later this week to see if the lash is correct or not! -Bob

Well, I have to disagree here. Having bought "remanufactured rocker arms" I am not happy with them. My take is thus: The stock rockers have a hardened surface on the point of friction,(cam touches rocker arm). When you "refinish" them, you grind it down past this point. On nearly half of my rocker arms, I have a nice divot where the cam rotates.... I think Bryan Little addresses this on his page, the Datsun Garage. Somewhere I also read recently about using chevy luv rocker arms. Apparently a much better option. Anyone know where that link is? I can't find it. -Bob

SK was obviously a japanese company that combined the "best" of the weber and mukini's. They are no longer in business, and OER is sort of the replacement. When Dan came to see me, we had each carb apart next to each other. They are very similar, still being a combination of weber and mukini. I don't know if they are still in business. Dan bought it from a guy in Japan who had it on a 3.0 or 3.1 motor. The beauty of sunbelts grinds is they allow that kind of lift with stock or less spring pressures. Quite an accomplishment. So no worrying about running 200lb seat pressures and 400+ lb open pressures. As long as you can fit the cam in,(i.e. not touch the pistons), you are fine. Dan is really close right now to hitting his pistons. He had to retard the cam one hole to ensure they didn't hit. I'll bet he posts sunday night like a little kit with a new bike. You'll be able to see the glee on his face. -Bob -Bob

something about "near race cam" specs. like .550 or .590 lift and 310+ duration. That and $1000 worth of sunbelt head work. Yea, that will help. My poor cam is tiny in comparison, practically stock. Remember folks, his is a near race setup, that he occasionally drives on the street,(dan would disagree ). He wants to win his class in the time trials with COMSSC. Great numbers Dan. Quite a jump from the 175-180 with the SU's and the still quite big .500 lift 300 duration cam. I guess that goes to show Sunbelt must have a rough idea of what they are doing with that new grind! -Bob edit-btw, his motor and mine are very similar. 3.1L, 89mm pistons ground to flat tops,(both had dishes). 0 deck height. He runs the N-42 reworked by sunbelt with their new proprietary grind, and near race specs. Just a tick below John C's cam in size. I think,(not sure), that he has the Nissmo header. Electronic ignition, and that's about it. Other than our heads and cams, we have the same motors, he has 45's carbs I have 40's, he has OER, I have SK. And no, I won't go into the "N-42 is a better head, see!", cause I'd love to see my head with similar work! ). But I put the priority on the RB swap, so that won't happen.

Well, turned up zilch on my google search. Did find out the detriot true-trac is very similar to my gleason torsen, if not the same. But no mention of any freeplay in the gears. Yes mention that the worm gears work by sliding outward, and the accompaning friction is what causes the torque biasing. It is late and I need to go to bed. -Bob