SleeperZ

My fuel pressure was dropping off at boost with RPMs climbing, so because I had no time to buy and take delivery of a single pump that will deliver the fuel, I plumbed two pumps together (high pressure Bosch units, flow 145 l/h at 60 psi each). At idle and cruising, I get a good constant fuel pressure, but as soon as I start putting load on it, my fuel pressure makes wild swings between 30 and 45 PSI, and naturally it starts hesitating and backfiring into the intake. Does this sound like the two pumps are fighting each other? I also took out the pressure dampener (damper ) as I needed the room. The pumps are both fed from the tank through a "Y", and both outlets are plumbed together into the stock hard fuel line. I'm sure the easiest way to fix it is to get one good pump, as I obviously can't run it at the strip today , my whole reason to do a rushed, ghetto job. Anyone looking to sell a fuel pump, like a T-Rex or a in-line Walbro 255hp?

That's funny about the "set it and forget" thing. With my old school vehicles with carbs and mechanical timing advance, it's never "set and forget". I was always have to adjust timing to compensate for point wear, and the carbs were constantly needing idle mixture adjustments and leak fixes (to pass emissions anyway). I've never had to time my EFI vehicles - that truly IS set it and forget it. And set the idle mixture - IT STAYS!

Ditto on the NGK 7 temperature range. The BMW application sounds interesting too, no monkeying with gap it sounds like.

Yeah, the small amount of condensation will get blown "dry" into the engine. Sort of like a miniature water injection - it's good for you!

The engine will never develop vacuum, so what's the use of vacuum assist?

I enjoy this arguement. I am going to prove to myself which is the correct one, at least for my car. I am running the T5 with 3.90 gears, and my first run at the track is tomorrow. I will be swapping a 3.54 back into the car soon - it is prepped and lubed, ready to install. Hopefully there will not be too many variables, and I will get a definitive answer. Personally I don't like how the 3.90 with the T5 works on the street anymore. I jump on it and I'm out of gear immediately. It's just too low.

You should check out your fuel system for faulty injectors or pressure regulator. It sounds like you could be running way too rich. Verify fuel pressure first, then start looking for leaking injectors.

Yeah, nice job with the explanations. I'm lucky I was first in answering that one, or I obviously would not have posted at all

The Nissan owners manual recommends 80-90 weight gear oil for manual trannies, although there is no mention of a manual different than the Nissan for a turbo model (T5 is not mentioned anywhere). Personally I've used gear oil in mine, and it works fine. I just switched to Redline 75W90NS, and it is good too. IMHO, ATF really SUCKS for lubrication ability, is just way too thin for a gear lubricant. I've also heard the ATF for a T5 is really just for the World Class T5 that has a unique sychronizer that gear lube cannot squeeze in to lubricate.

Well, there was a reason for the ZX injector fan - to keep the rail a bit cooler and prevent heat soaking of the injectors. If your fuel pressure is maintained when the car is shut down, it certainly is more difficult to vapor lock, however the fuel return ensures you will purge all vapors as soon as you fire up the pump. A deadheaded system is prone to vapor lock; I've never had any problems with the Z EFI fuel system. As far as racing goes, I race with a mostly full tank. God forbid my pump sucks air on a good launch - boom, instant lean condition under boost.

The fuel is circulated and cooled by the fuel in the tank. That's what keeps fuel injected vehicles from vapor locking - a return line. If you use coolant from the engine, my guess is your fuel will be warmer. The finned rail stock looks cool, but there is not a lot of extra surface area to make any difference in cooling. Just MHO.

It sounds like you have the primary reference already. For supplemental stuff, although it's dated, try "Turbochargers" by Hugh McInnes. After absorbing that, ask questions - this forum is an excellent resource. Just don't go over to clubsi.com or some rice place like that

I cut off 2/3 of the metal housing, and shaped the 3-1/2" mandrel bent 45* piece to fit it. The hot wire was still a little close to the side of the pipe for my taste, so I spaced it out further into the center, and extended the leads of the thing so it would solder up to the circuit card. It's not perfectly centered, but not bad. I thought about screening it, but I got too lazy. My first drive with the thing, my air filter was too low to the ground and fell off after hitting something. I guess I got lucky nothing came into the MAF (or my turbo!), but the intercooler should give marginal protection for the engine against debris. Hence, the new higher flowing K&N

I like the Eibach progressive set, with the tokiko struts (I don't have the Illumina, those would be ideal I think). But I do all what you intend to do - street driving (in Denver, no less, the streets are crap), road racing a couple times a summer, and drag racing too. Last year I managed a 1.9 60' with drag radials, and with some practice I think I can get it a bit lower.

Doood, that's insane! Looks wicked, nice job. BTW, what's the retail on one one of those? Oops, wrong thread I meant to ask, what's the weight savings with the VG motor over the L28?

$$$ -- I've not seen a Z32 in the scrapyard to date' date=' and Z31 MAFs are $20. The ECUs are different, and I don't know if the wiring is compatible. And my implementation also addresses intake restriction. My intake is a full 3-1/2" up to my new K&N, which is an oval 7" long, 4"x7" diameter. Comparing it to my old one, I've easily got double the surface area. [img']http://zdriver.com/gallery/data/500/7291intake_640x480-med.jpg[/img]

TBS - one thing you might want to consider is the stock MAF. I believe the reason JWT went with a bigger Ford MAF is the stock Z31 unit may max out on airflow rather quickly. Unless you want to mess with reprogramming airflow values as well, I'm not sure how useful changing the injector map will be. That's another reason (besides cost of ROM programming equipment) I went with a larger MAF housing.

It would be RICH if it was venting under boost. And the O2 meter registers lean because it's cold and wet with fuel. Trust me on this if you don't believe me. It could also be your fuel pump crapping out as well - the stockers really do suck for flow at higher pressure.

Because you have to compress down the rear struts on the control arms, and try to yank the tops from out of the fender. This usually means you disconnect the brake lines, the half shafts and the stabilizer bar. It was just a PITA, and with a good tool now available, you don't have to do it.

If your BOV is venting all your boost, you will get too much fuel - this has the effect of cooling the O2 sensor enough to shut it down, and it looks lean, but it's really wet!

I am, of course interested in reprogramming, but I have to say my bigger injectors are working out real well, and I haven't had to do any electronic tricks (yet!). As a matter of fact, to avoid running so much fuel pressure (45 psi base), I was thinking about putting in my 420cc units (N/A RX7 gen 2). Then my fuel pump would have more overhead. I do intend to reprogram to eliminate the rev limiter (fuel cut), I have the information to do that, but I'm uncertain how the ECU fuels above the old limit? Bernard?

That is a good point that upgrades to the triples are minor to accomodate motor mods. But for a stock engine, triples are overkill, and certainly more expensive than a factory EFI. But the original post said nothing about motors except it's a 280 FI conversion. I will never dis the triple setup - it is so cool looking and sounding - it's part of my Z inspiration! Too bad I jumped into turbos, bypassing the whole carb thing. I truly suck at carbs - I can't even repair a lawn mower carb - bought a new lawnmower instead.