Dan Baldwin

As has been mentioned, tires, suspension, and brakes first. Depending on what the car will be used for, this could just consist of new high-perf pads and new fluid. As far as the L6 goes, I think the best thing you could do is boost your compression with an N42 head from a 280z. That'd take you from ~8.5:1 to 9.8:1. More power, better fuel economy, and better exhaust note for when you open that up. To my mind, that'd be the place to start building L6 power, getting the compression ratio up. Well, that or swapping in a turbo. Surely someone out there has done a flat-top piston bottomend/turbo topend L6 motor, eh?

Check out the "3x2 carbs installed" post below, details on 235rwhp 3.1 liter are near the bottom. You're on the right track, but you'll want KA24E pistons, not z24, for a decent compression ratio. Spanking 5.0s should NOT be a problem. Hp with 280/480 cam and 1 3/4" SUs, maybe 200 rwhp?

Here they are, costs for the 235 rwhp motor: Bottom-end was built WAY back in '94-'95, for something like $1100, parts and labor. Used motor, rods, head and crank cost $700. Head rebuild $100. Fast forward to Winter 2002: $1500 in the headwork and cam. Carbs, manifold, linkage, air horns were $600 used. ITG air filter and backing plate $280 (yow!). Carter fuel pump and MSD 6-AL bought last year were ~$55 and $200 respectively. Comes to $4435 when you subtract out the head rebuild done back in '94. Anybody know of a cheaper L6 motor with the same or more rwhp?

Won my class at NHIS (south oval)! 1:15.2 to a 1:15.2 and a 1:15.3. CLOSE. Oh yeah, the best from the better-populated V8/turbo-6 class was 1:16.5. The car ran great, but a little soft in the midrange. Pulled like mad up to the rev limiter, though! Something WILL have to be done about the jetting. Note that on my last run the A/F was at 13.9 up top, and every run was pig rich below 3000 and from about 4200 to 4800. But it did WORK over the weekend! Getting jets for the carbs will be tricky, there's no US rep. I've emailed the company in Japan, and they basically said to wire transfer money to a given Japanese bank account number and they'd send the parts. I dunno... General engine specs: L28 block bored .120" over, Maxima diesel crank, KA24 pistons (not shaved at all), N42 head shaved ported and mild cc work done by Sunbelt (40.6cc chambers), Sunbelt 302 deg/.550" cam setup w/light springs, 2mm HKS gasket, 10.8:1 CR, 93-octane pump gas, 45 (44?) mm OER Racing (formerly SK) carbs, unknown manifold (not long-runner cannon or S-bend Mikuni), 2" air horns, ITG single big oval filter (BARELY fits), Nismo 6 X 1 3/4" into 2 X 2 1/2" header, Flowmaster collector into 3", 3" Walker race muffler alongside drive shaft, 3" Walker UltraFlow in back. The Sunbelt headwork and cam setup was $1500, well spent I believe! Thanks to katman for talking me into it. Speed sure do cost, the air filter and backing plate was $280! With the 2" SUs, it put 177 to the rear wheels at 5000, BUT was breaking up above that due to a busted spark plug (discover later, AFTER I'd bought a loud-ass fuel pump and an MSD 6-AL to fix the prob). It was on its way to 185-190hp at 5500 or so, I'd bet. So, the Sunbelt work plus 3x2 carbs bought me ~45-50hp! Don't know how much from each mod, but certainly the two complemented each other well. Sunbelt head/cam with the 2" SUs had me 8(!) mph faster at the end of the straights at Watkins Glen and at Mosport. Can't wait to get there again. BTW, ever since I cammed the 3.1 liter it's been accused of being a v8. Sounds like one at idle, but rev it and it's obvious. Lap times, however, contribute to the V8 impression The sound at full song is definitely inline-6 music, however. I like all kinds of music, BTW, I-6, turbo, rotary, v8, V12, I-4, V-twin, etc. (but there is NO worse sound than a GM 2.8 V6/automatic through a loud muffler).

Details in the 3x2 carb thread below. Needless to say, I'm thrilled! Going to NHIS tomorrow and Sunday, be back Monday AM. Til then eat your hearts out!

That shoulda been LESS than 11 A/F from 2500-2800.

Hey all, just got in to work after a morning at the dyno. The good news is: 235 at the rear wheels! I was hoping for like 215 max! Guess I should try to scan the runs in, but the jist (gist?) of it is: I'm PIG rich from 4000 to 5000, not too bad everywhere else. Here's a rundown of the runs: 1: aborted (mad shuddering from resonance of bogging engine and dyno drum at low rpm/full throttle). Upped ignition advance upon advice of dyno guy (1 tick from I *think* 18 deg). 2: 212hp@6500. 125 lb-ft at 2500, 170@3500, 165@4200, 180@5000, 175@6250, 155@6900 A/F >11 2500-2800, 12-12.5 3000-3500, below 10 @ 4400, ~12 5000-5500, 13 - 13.4 6200+ Retarded ignition timing 1 tick, back to where it was (I *think* the ticks on the distributor base are 2deg) 3: 229hp@6500. similar torque curve, similar A/F curve dyno guy leaned out the idle screws some 4: 226hp@6700, similar torque and idle curves Retarded ignition timing another tick 5: 235hp@6700 Retarded timing yet another tick 6: 235hp@6500, broader peak Retarded 1/2 tick 7: 235hp@6500, slightly broader peak, A/F same as before EXCEPT with a less pronounced rich zone, 4300-4900, AND climbing from 12.9@6500 to 13.9@6500+ Seems to me the midrange rich spot could be fixed by smaller main fuel and air corrector jets, from 165 and 220 to more like lockjaw's rule of thumb, which'd be 150 and 210 for me. Whaddaya think?

Oh yeah, I had set the fuel pressure at just under 3.5 psi, then found the liquid filled Summit gauge was leaking at the pipe threads. Took it out and applied some pipe dope, no more leak but the pressure went up to 5 or so. That's when the rear carb started pissing, I think. Removed air filter and fuel streams were coming out of 5 and 6. I fiddled with the valve on the carb and reset the fuel pressure. Anyway, it guess it's *possible* that the brief 5psi fuel pressure mighta unseated the valve. G'night now, gotta git home.

Just put 'em on last night, I think the pissing problem is sporadic. It's not the floats, I took 'em out and the don't have any fuel in them. Played w/ the needle VALVE and now it's sealed up fine. If it happened once, though... Oh yeah, went to start the car and "rurr rurr ruNH.....". Hydrolocked either #5 or #6 while I was running the pump w/ the engine off. No prob, removed the plugs and now all is fine. Did a half-assed job of synching the carbs with the Uni-Syn. As long as it idles and all 6 throttle butterflies are fully open at WOT, I'm happy with it. Actually, it idles better than it did with the SUs! Regarding the dyno trip, they'll be doing A/F, but won't have a Weber expert on hand. Have any handy rules of thumb what to fiddle with for different scenarios? Like: lean on bottom/rich on top, vice versa, in the middle, during acceleration, etc. Since I don't have any jets, if I'm way off I'll either have to drill out what I've got, fill in with solder and drill smaller, or forget it and put the SUs back on. Can't really tell if the car's slower or faster, but I know for sure it's LOUDER. Gotta be good for somethin. Talk to ya tomorrow.

Thanks, Bobby, for the slap upside the head. Scheduled to be at New England Dyno tomorrow at 8:30. But now I have to solve the rear carb pissing fuel out the air horns with the fuel pump on, motor off. Guess it's the needle jet. I'd cleaned them out as best as I could. Any ideas on how to rehabilitate one? Thanks as always!

Sorry for the cross-post. Just installed my new used 3x2 45mm OER Racing carbs. Car runs fine, but limited to ~70% throttle at the moment. Anyway, I need to know if I'm running OK (not lean) so I don't hole a piston or something. Don't have time to get to the dyno before track days this weekend, and don't have an A/F or exh. temp meter. All informed opinions/thoughts welcomed! Thanks,

Hi all. Just installed my new used 3x2 45mm OER Racing carbs. Car runs fine, but limited to ~70% throttle at the moment. Anyway, I need to know if I'm running OK (not lean) so I don't hole a piston or something. Don't have time to get to the dyno before track days this weekend, and don't have an A/F or exh. temp meter. All informed opinions/thoughts welcomed! Thanks,

You'd need the L28 brain if you'll be running the FI, not if you use the 240's carbs. The rear end should be up to a mild V8 if you're not drag racing it. An R200 rear end from a 280Z-'89 300ZX can handle more torque if you feel you need it.

There is power to be gained from ram-air, but you have to address the fuel-delivery side as well or you'll run lean the faster you go, especially if you're carbureted. Maximum ram-air pressure is equal to 1/2 rho V^2. Using standard SL density of 1.378E-6 slugs/in^3, I get .34 psi at 40 mph, 1.37 psi at 80 mph, and 3.07 psi at 120 mph. So that'd be about +2.3%, 9.3%, and 20.9%(!) more power, respectively. IF you could get full stagnation pressure, which would likely require a scoop protruding from the nose of the car. Damn, those numbers seem too large to be ignored! Somebody correct me if I'm wrong.

I can't decide if you're more "retarted" on aerodynamics or spelling But cirrusly, we're talking about HUGELY different volumes of air here. The air feeding the engine would be a small fraction of the air you'd like to divert from the underside of the car. As far as hp required to divert the air, you should be able to FREE UP some hp by reducing lift. Reducing lift reduces induced drag, so (big generalization here) minimizing lift should minimize drag. The BRE-style spook, painted satin black, is your best bet. But hey, why not find out if you NEED anything first? Just lowering the car should go a long way to reducing lift. FYI: aestetics => aesthetics retarted => retarded pheasable => feasible

I never had problems up to about 105 with the stock ('cept for T/C kit and steering rack bushings) suspension with good struts in my car. Never went faster with that setup. With 1" lower, twice-as-stiff springs and Illuminas, never had problems up to ~130. Still w/ no aero aids. I've since added a BRE front spook and rear spoiler. Should reduce lift to near nil, and decrease drag. At the faster race tracks (Watkins Glen, Mosport), I do seem to be faster, but the car doesn't feel any more or less stable at speed. It's just fine, like it's always been. BTW, I painted the front and rear spoilers satin black (car is Ferrari red) to minimize their visual impact. From some angles they're all but invisible. Lemme know if you'd like to see a pic.

What's a lazorlite head gasket? thickness? bore D? I'm getting tired of paying $130 for HKS gaskets.

I screwed up *slightly* in the above post. Increased rotor size will NOT increase pedal travel, while improving braking gs/ effort at the pedal. Bigger calipers WILL increase pedal travel, while increasing braking gs/effort at the pedal. Serves me right for being a smartass.

A few things (real quick): Ask yourself WHY you need to do this. If you're roadracing and have enough power that you're smoking the best pads you can get and/or are boiling the fluid in the calipers, this mod *might* make *some* sense. Do you have brake problems now? ALWAYS consider what you're doing to f/r braking bias. An adjustable rear prop valve can help, as well as different cf pads f/r, but the basic hydraulic ratios and working rotor radii should at least put you in the ballpark. Also, consider what you'll do to braking effort/pedal travel. Bigger calipers and/or rotors means your effort at the pedal will be reduced quite a bit, but pedal travel will increase. The ideal brake setup is the absolute lightest-weight setup that will never overheat. Oh yeah, that's 4 POT calipers. Single piston e-brake calipers are called spot calipers. (OK, that's REALLY nit-picking)

The more I think about it, same wheels/tires at all corners has too many benefits to be ignored. Spares can go anywhere, and rotation is possible. M Coupe undoubtedly a superior street/track car, but no way as good a serious track car as a 240Z. Nothing magical in BMW suspension design, it's just geometry (and shock valving, but either way you'd be using new-tech dampers), no computers in there, no tremendous advancements in the basics over the past several decades. So I'd rather have the Z's Chapman struts and with poly or solid bushings. No getting around the 240Z's ~700 lb weight advantage. And COSTwise, there's no contest. M Coupes are more plentiful than 240Zs up here! Still pretty rare. I REALLY like the Coupe, a lot more than the roadster (which looks awkward with its massive frontend/tiny rearend). But DAMN it's heavy. Why should new BMW sports cars be heavier than their 4-door E30 325i sports SEDAN of 11 years ago?! (please, no talk of safety regs, etc., if Chevy can hold the line on weight, BMW/Nissan/et al should be able to as well) Of course now we'll probably meet on track and you'll hand my Z it's head with your cool-as-hell (but weighty) M Coupe! One of these days we'll have to get together at the track.

Contact Larry at Carbotech in FL, http://www.carbotecheng.com/main.htm I'm using his Panther XP compound on my street/track Z. Good cold performance, great hot performance with a noticeably higher cf than the regular Panthers or the Porterfield R4s I used to use. I've got stock Z rotors and calipers up front, and 280ZX rotors and calipers in back, BTW. Front pads appear to be lasting two 2-day track events. Rears, who knows, maybe five events?

Try 245's all the way around, or 245s/255s. Tires you're running now are ~24.4"/25.0" F/R, while stock are 25.0"/24.7" F/R, so you're already messing with slightly different F/R tire diameters. I can't imagine that 245/40s all the way around would give you any detrimental effects to ABS or traction control functionality. Better yet, stick to doing trackwork with the Z. Lighter weight, similar or better potential power/weight, and superior Chapman strut rear suspension design. VERY easy to drift out sideways and gently pull back in. No snap-oversteer EVER. Plus the camshafts don't break very often;) BTW, assuming an 18" high c.g., and a 98" wheelbase, you'd have to jack up one end of the car on the order of FIVE INCHES to make a 1% change in F/R weight distribution. For all intents and purposes, F/R distribution is fixed, according to c.g. and wheelbase. Hey, wish me luck, I'm on the verge of bolting on the OER 3X2 carbs. Hope the jetting is close to right.

Here's a thought: Put the rear tires on the front of the car (tee hee). Sounds like you need more rear roll stiffness or less front roll stiffness. Try a stiffer rear bar or softer front. Or, since you have coilovers, try increasing rear spring stiffness and/or softening front spring stiffness. BTW, you CAN'T change your front/rear weight bias by adjusting corner weights. Only the location of the c.g. of the car and the wheelbase are factors in F/R distribution. You only change the cross-diagonal weight distribution, which you'd generally want to be 50/50 LF+RR/RF+LR. Experimenting with weight-jacking (or wedge for roundy round guys) can be done to tailor the car's behavior to particular tracks, but I've never played around with that (no coilovers). BTW, my car is neutral at tight tracks, and oversteers at fast tracks, and my rear tires get hotter than the fronts, and pick up a couple more psi than the fronts. But I can rotate my tires (225/50-14 Hoosiers and 225/50-15 B'stone S03s), so front/rear wear differential isn't an issue. I'm getting even wear across the tread with -2.0/-2.5 deg camber up front, -1.7/-1.9 deg rear, running maybe 1500 track miles and 3500 street miles/year. Seems to me with your bigger rear tires, you should be able to get about even front/rear wear with a very neutral setup by changing front and/or rear roll stiffness. Or you could try 245s all around, that would allow you to rotate the tires. Lots of M3 guys do 245s all the way around in place of the 225 front/245 rears.

I still say an N42 is the best stock head for an N/A application. I personally wouldn't feel comfortable shaving 110 thou off, though it is done. I just don't see the need when the N42 is readily available. Haven't seen enough evidence one way or another to prove which is best in equivalent setups. That would take a dedicated EFFORT. All I've ever seen or read is that the P79/P90 MUST be better because Nissan put so much effort into them. Maybe true, maybe not, but a P79 car with Webers that MAY be as quick as Norm doesn't quite prove anything.

The "How to Modify your Nissan OHC Engine" book has the following formula: throttle bore = square root(liters/cyl * max rpm)*.82 main venturi = square root(liters/cyl * max rpm)*.65 This would dictate 47mm throttles for a 7000 rpm 2.8 liter. Now that I think about it, that may be a bit much. Bob Hanvey made good power to 7300rpm with his 3.1 liter, breathing through (I think) 40mm carbs. I should know better than to offer advice where I have no experience, but most of the experts I've talked to seem to agree that the 40s are better for smaller displacements, and 44+ for over 2.8, for hot street/mild race engines. But if you've got 40s, throw 'em on there and see what happens! I sent my tired stock N42 cylinder head down to Sunbelt in January. Got it just before my second time trials event of the year (had to drive the 240SX for the 1st event , but set a class record with it, on street tires, and with little to no brakes:), May 19th. Event was at Summit Point, on a Monday/Tuesday. Spent Saturday and Sunday installing the head and all ancillaries, put a battery in it 1st thing Monday AM, started her up and drove 9 hours down to West Virginia! Won my class (of 3 cars), despite a brake problem. Anyway, with the newly ported and reworked cylinder head, and new cam (grind developed by Sunbelt) with lighter springs, my straightaway speeds at Mosport and Watkins Glen went from ~122mph to ~130mph! Lap times went from 1:43s and 2:22s respectively a couple of years ago to 1:40s and (gulp) low 2:17s! (note: I am not a race car driver, and my car is not a race car. I'm pretty happy if I can post times similar to the top ITS cars/pilots) One downside: though I told them my piston heights above deck (+.022" for the raised "ring", +.003 for the flat area), I wound up with an intake valve/piston clearance issue. Clearance is only .045", with the cam retarded ~6 deg. I calculated that would go to .030" clearance if I went to the #2 hole in the cam sprocket, so I left it. So now I've got very poor low-midrange grunt. The engine doesn't wake up until maybe 3500-4000. This is a factor coming out of some corners, and is very annoying. But that's sort of the risk I took having them work only on the head. As it is I'm really looking forward to getting the pistons cut for valve clearance, so I can advance the cam timing and hopefully get some more midrange torque. There's probably nobody better than Sunbelt for building a high-performance Nissan L6.