sirrach

I was wondering if anyone has looked into a possible sequential twin turbo setup for the s2000? I was thinking that this might be a little easier to launch than a single turbo setup since t here isn't as much hp coming on at one point. You could utilize two smaller turbo's, such as the mitsubishi 9b's that are used on the 3000gt VR4. This won't yield as much horsepower as a single, but the 9b's give a nice extra bump in horsepower for the VR4.

I'm not saying that the 9b's should be utilized, but what are your thoughts on this type of setup? I think spool up time would be quicker.

Jason00S2000

THAGR81

This would be a bad setup. Basically 2 cylinders would be pushing 1 turbo. Which would have 2 possibilities to make it run-
1-such small turbos would have to be used for them to be efficent that the power output would be inferior to a single turbo, so much so that it would not be worth the money.
2-if using larger turbos, they would reach no where near the potential power output because of only being directly connected to 2 cylinders, causing both large amounts of lag, and very limited power.
For pure novilty to show to people in a parking lot you might get oohs and aahs from the Tiburon/Civic/Neon crowd, but to anyone interested in performance I think it might draw a laugh.
If somehow you increased engine displacement a huge amount where it was pushing tons more exhaust gas flow, it would then be worth looking into.
On my old 3000GT VR4 I used to race on the IDRC with, I went through many discussions with TEC and Garrett in reference to freaky custom turbo setups, but most were shot down because once again the bank of 3 cylinders it would be running off of would not be ideal.
I firmly believe an S2000 would go PLENTY fast if single turbo'd and of course proper supporting mods.
Just my .02
Del

beroznikmal

I think there is a issue with space....

AusS2000

THAGR81 - Twin turbo set up's generally use all 4 cylinders but have plumbing to allow the ECU to use one, both, then the other depending on the rev range. Also they generally use two different size turbos.

The problem as beroznikmal points out is space (and complexity and control). I doubt the results would justify the effort. And I think Subaru agree as their replacement for the Liberty (Legacy) B4 twin turbo is the GT (single turbo).

sirrach

Thanks for the replies. AusS2000 would an engine management system be able to handle something like this or would it be too complicated?

THAGR81

AusS2000-same size turbos, each running off of 3 cylinders on the 3000GT/Stealth and Supra. The Rx-7 is a rotary motor, so not sure which cars you refer to. Maybe some type of "hybrid" set-up for a 4 cylinder, but this would relate to custom work which I refer to.
Del

AusS2000

Sirrach - a custom system like the Motec shouldn't have a problem.

THAGR81 - Yes, there are systems that use two same size turbos, but they suit a larger displacement and fequency than a 4 cylinder.

I guess I assumed the problem you were trying to address was lag and bottom end. You won't achieve this with two similar size turbos as the smaller they are the less efficient they are. Two turbos small enough to run off two cylinders and give low end boost would run out of puff before getting anywhere near the top end. Two turbos big enough to give yo the same top end as one T03/04 (for example) would have terrrible lag and boost properties down low.

The cars I am familiar with that use sequential twin turbos are the Saabs and Subarus. Not sure if the RX7 TT's worked this way or not, but the typical performance upgrade for these is to convert to one big turbo anyway.

dre107

What 4 banger car has twin turbos?

Johnny

AusS2000

For the third time, the Subaru Legacy/Liberty B4.