SleeperZ

I think you can do better than the Starion IC. The plumbing will be about half the cost, and for $200-250 you can get a used intercooler like an NPR or a MKIV Supra, both of which are far superior. I agree, an intercooler will get you the biggest bang for the buck at this point.

That's good stuff, Scottie. I am assuming the stock turbo ECU has some bit of timing retard based on load (don't know if that's a good assumption or not). Obviously since there is no MAP sensor, the ECU has to assume stock boost, and there may not be enough retard at higher boost -- especially since I've slid down the load scale by scaling the MAF in a larger intake and adding larger injectors. In that case, I might be able to get a more tailorable ignition curve by using a N/A ECU and a MSD BTM, or by simply getting a fully programmable ignition, and not using the ECU to control timing at all.

James, those manifolds are nice. I notice on the stocker manifold the runners come out of the plenum at different angles and varying lengths as well. Is that supposed to balance the flow for even mixtures in the cylinder? Will equal lengths and straight angles on the custom result in a more uneven mixture as a result of the flow from the throttle body coming in at a right angle? I remember an early manifold you made (I think Shane bought it from you) with the throttle body offset to the plenum to address that issue. I'm just wondering what your thoughts are now - it all seemed and still seems speculative, and I have no idea of the merit of any of it.....

I've asked the question in various threads, and no one seems to know the answer...I just thought I'd make it a thread and see if I can get any feedback. I'm running mine at the stock initial timing, 20* BTDC. It has always worked well, but I just don't know where I'm going to be with total advance at (what?) RPM. As I increase the boost, I'm unsure whether to retard the timing, or advance it or leave it alone...I'd like to keep running my local pump gas - 91 is the best commonly available. So far 15 psi boost, stock timing, intercooled and fueled is running great. I was running very cold EGTs, about 1400F peak at the top of fourth gear, so I dropped the fuel pressure 1 psi - 1-1/2 psi, and it seems more lively, but my EGT quit working (again). I'm getting a new gauge, and I will get to a dyno with a wideband just to see where my mixture is across the band. Any comments or suggestions? I'd like to find out what the ignition curve of the ECU is so I can optimize the ignition advance either using stock initial timing, or if I can't get it where I need, I can invest in an MSD that can add some retard with high boost. Thanks in advance.

The data you could log will not tell you the information your gauges will. You cannot measure fuel pressure, mixture or exhaust temperature from your ECU - you need the gauges. However, you can get a portable multichannel oscilloscope, like a Fluke graphical multimeter, and measure injector duty cycle (from the injector signal), timing advance (from the tach and the CAS), and airflow, at least the AFM signal - you could tell if it was maxxed out.

Ugh, forget carbon film - that is 1940s technology. Fit metal film resistors in there instead - you can get better tolerance and reliability.

No problem. I cannot personally testify to RRFPRs being hard to tune - maybe someone with real-world experience can chime in. Increasing fuel pressure with boost may seem like a good idea, but it really only works well with a speed-density EFI system, like on Hondas. The Honda systems cannot recognize when the manifold pressure rises over atmospheric (they have a 1 bar MAP sensor) - they fire the injectors like the motor is at open throttle, according to the rpm of the motor, regardless of how much boost there is - so rising rate is good here. For a Nissan system where the air is directly measured and fueled instead of inferred by a MAP sensor, a RRFPR will raise the fuel pressure the same amount whether at 3000 rpm or 6000 rpm. If you are smart, you will optimize the fuel pressure for maximum boost at 6000 rpm and that leaves the engine running PIG RICH at 3000 rpm. At any rate, what I am saying is a RRFPR is an effective band-aid for a turbo'd Honda, where it is an inferior tuning device for an EFI that is designed to run boost.

I hate to pee in your wheaties, but why do you want to install a RRFPR? What fuel pump are you using? These RRFPRs are hard enough to tune -- even when you know what it's specifications are, they cannot be tuned very well (you run rich at lower RPMs). I'm just curious - I've run 250rwhp with stock injectors and FPR, with just a pump upgrade. Why do you want to sacrifice driveability to get a tiny bit more on the top end?

I think gas pipe is thick because it is cast iron - not the easiest to work with, or the strongest. You might use mild steel like electrical conduit tubing, I hear some folks have made strut tower braces with that...

You might be thinking about the Nissan PU with the VG30ET. He was asking what it would take to get into the 12s, and it's basically the same thing. http://www.hybridz.org/phpBB2/viewtopic.php?t=21595

Stock motor: Upgraded exhaust, fuel system, turbo, intercooler and a reliable engine management system. Here are some posted pictures of intercooler piping. http://www.hybridz.org/phpBB2/viewtopic.php?t=21413 That's for solid twelves. You can run 13s on stock everything, just up the boost with an intercooler (or NOT, check out Jersey...)

I used the stock flange as a spacer between the stainless downpipe and the turbo - there is 0.5" more thickness (and an extra gasket). The studs were not long enough (and I double-nutted them too, as a lock washer WILL NOT work here). You should have no problem with 2 45* mandrel bends 2-1/2" OD. You just need to be very precise about the length you cut them, and the angle you weld the sections together. The room is there, but it is tight, and there is not much margin for error. I looked at my setup last night, and I get about 1/8" clearance between the bellhousing and the pipe, and 1/8" between the firewall and the pipe in the same location. There is no contact to the firewall under accelleration because the movement is along the firewall, not to it.

Sounds to me like you are describing a stock suspension That's pretty much how I drive my car; I have Eibach progressive springs (anything stiffer is going to hurt on the street), hd strut inserts, urethane bushings and a solid TC bushing. The stock setup works great for me, even for my occasional track day. Best of all, I have all of about $500 in the suspension.

I don't think Corky originally derived the formulas, they predate him (or us) by several hundred years... And I don't recommend running much boost on PVC - I'd be surprised if it sustained 10 psi more than a minute or two, but maybe I'm being too conservative.

Yes, gasket on each side of the spacer. I like my T5 - strong, shifts really nice with a B&M short shifter.

Put it this way. PVC is rated for pressure up to 80C. A turbo compressor, depending on how much boost you run, has exit temperatures around 150C under pressure. All it takes is a little melting, and BOOM, the pipe splits. It might last 8 days on the cool side, where it only has to deal with underhood heat, but I wouldn't even try to put it on the compressor outlet. I used a piece of it for my air intake, and I had to constantly tighten it, as it was flowing out from under the clamp (just from under hood heat - no pressure inside). It did last all summer, but it is gone now (and believe me it's not round anymore).

It sounds to me like you have a failing pump. If it were a simple line restriction, your base pressure would be off as well. I wouldn't run 12 psi boost often with that drop in pressure. At the very least, replace the pump with a high pressure Bosch pump, the stock one will not flow well over 12-14 psi boost anyway. I just installed a new CIS Bosch pump for a 77-79 Porsche 911, and it's working well with 15 psi boost. Opinion: RRFPR is not right for AFM or MAF systems. It works better for Hondas and other EFI systems that use 1 bar MAP sensors. HTH

My solution involved cutting off the flange from the stock ZXT downpipe, milling it flat, and installing it between the downpipe and the turbo outlet. I had to install longer studs in the turbine housing as well. I then ground a small area away from the bellhousing and from the fins on the gear case. It's tight everywhere (close to the firewall, close to the bellhousing and gear case), but I've been running it for two years now without a problem.

Yeah, Scottie isn't making them anymore. He may have drawings, but as-is the pipe will not fit around a T5. I made mine fit around my T5 by adding a spacer between the pipe and the turbo, and by extensive grinding of the bellhousing and fins on the case of the tranny. When I made the switch to the downpipe I was running stock boost with no intercooler, and I am not sure of the differences. It sure flows nice now, but I have no comparison to the old one.

A 2-1/2" downpipe is more than enough. Lots of us are running one ScottieGNZ designed. I run one and attached a 3" exhaust off the end of it.

I ran last season with stock injectors and a high pressure pump into the low 13's like you (but I bet I do have a couple hundred more pounds ) I was starting to run lean at the top end with 1600F EGTs. I was running 14 psi with the intercooler, but that is about equivalent to 12 psi down low (I'm in Denver, 5800' elevation). The intercooler will allow you to make the same power with your stock fuel, with less boost.

You know, that's pretty damn funny! Sure, why not? Whatever flips your wig, eh? There's a fellow drag racer I know, brings his shorty bug to the events just to show off - it's about 6' long with a massive supercharger on top of the air cooled engine. He'd never launch it because it would literally flip over backwards (even with the wheelie bars on it). It's just a show vehicle, but very creative...

Wow, that is really excellent, especially your launching. I've not been able to get a 1.8 60' on drag radials yet. Maybe I'll do better when I switch back to the 3.54 (I've got a T5 with 3.90). Your car just gets up and goes.