The motor has a problem with the intake/exhaust manifold gasket that causes exhaust to get into the intake, and less pressure to be delivered to the turbo (or for that matter the intake manifold). It's a mess. I've been saying I should just get the fucker out of there and rebuild or replace it.
The problem with doing that is the car would have to remain road legal. And most of the stuff I want to do to the car is not road legal. So I'm left with the conundrum of finding somebody who will break the law and smog/inspect my car for me, or just not driving it.
I had a realization, after we got closer to driving the STI (our other car is a Subaru STI), that what I should really do is just go full-race with the Z. Throw emissions and DOT equipment to the wind. I have come up with a list of things to do.
At the top of the list you will note a couple selections of engine. The engine is an interesting choice. Getting power out of an L series motor is hard because there are some fundamental flaws. I then thought, why not get a Honda S2000 engine in there? I'd have a ton of room for a huge turbo and other stuff. But then I started looking at JDM engine importers, and people want like $4000-6000 for the K series motors. For contrast, they want about $2200 for the 2JZGTTE (the twin turbo second generation Supra motor). I have heard this motor is huge, and it's tough to get into a Z, so I'm gonna have to do some work.
The first step is not to go and add all these goodies to the car. The first step is to rip everything out of the car. Everything. I want it a bare, rolling chassis. Then I'd like to paint it, get all the body work sorted out, and also look for stuff that doesn't need to be on the car (like noise deadening, strange baffles nissan included, etc). Around this time, I'd also like to start adding brackets for underbody diffusers. Yes, this will be a fast, fast car.
So! Without further ado, the list!
- Supra motor, S2000 motor, perhaps RX-7 motor (although the '7 is a little anemic)
- Full aftermarket ECU, with diagnostics for dyno and in-car tuning.
- Aluminum dash with defi gauges
- Arizona Z-car's coilover suspension and tubular control arms
- A pair of Recaro seats
- A harness bar mounted to the rear strut assembly, so we have good positioning (no seatbelts, just 5-pt's)
- Plexiglass rear and corner windows
- Exhaust from turbo to "dump" without cat or muffler to the side of the car (if possible) - 3.5"
- External wastegate, with separate, smaller, but also unmuffled or catted exhaust.
- Front mount intercooler. There's no other place to put it except the wheel wells. This will require body work.
- Headlight covers
- Nitrous Oxide purge valve situated directly pointing towards the intercooler
- Small shot of Nitrous (75hp) from 2750-4500 rpm to reduce the feeling of "lag" and to help spool up the turbo
- 50/50 water-methanol tank available for water injection
- Griffin aluminum radiator
- Rear differential from a subaru STI
- Strengthened halfshafts from the folks at Xcceleration (these shafts are rated up to 750hp. I don't know how much power this vehicle will make, but it's kind of frightening.
- diff cooler
- transmission cooler
- oil cooler
I've also been toying with the idea of a "veyron button" that would turn on a secondary nitrous injector, water injection, and increase boost by some nominal amount. It would be slick, but not easy to implement.