no s5 has a better turbo than s4 due to the design of the hotside and manifold.

 

What kind of torque and hp should S4 and S5 T2's get? I was told the '88 T2 (S4) I'm looking into was dynoed (not sure how recently) at 214hp. Is that low? average? (I wasn't given a torque figure)

 

the power numbers are dependant on the engine not turbo. the turbo is the same power wise.

The S5 manages the hotisde better. That's all.

As for the T4 footprint statement. I think that is incorrect and the footprint is proprietary. If it were true then lots of people would have already gone with better flwing manifolds.

Can anyone comment on that statment?

 

I can. I agree. IMO the S4 vs S5 argument is sort of pointless. Yes the S5 hotside might be better designed but after a port job on the S4 its pretty much as effective as an S5. If you are going to upgrade from an S4 to S5 turbo, so ahead and go aftermarket or BNR or something. Its not a big enough of a difference to warrent paying to change them.

 

well aside from th s5 turbo being much better what are the other major differences?? If i were to upgrade my s4 turbo to a bnr stage 1 how would that compare to a s5????

 

I wasn't asking about the turbo, I was asking about the cars as a whole. Nobody's answered my question about the standard hp and torque of these cars yet.

 

Ever look in the FAQ or do a proper search?

It should be 183 lb-ft and 200 lb-ft.


-Ted

 

The S4 and S5 Turbos are the same on the cold side, the hot side is different. S4 had twin scroll, the S5 had that 'independant twin scroll' which was really a simplified system without an extra actuator. The wastegates are also different, the s4 is smaller and the s5 as 2 'holes' for the wastegate. upon inital porting (no re welding or anything) the s5 can be ported larger, however if you want to reweld the wastegate flapper on the s4 you can go up to 34mm (as per BNR's turbos). Also if you plan on doing a hybrid later on, you might wanna focus on the hotside (since the cold side is gonna get upgraded) and pickup a s4, right now i recommend BNR for a hybrid and he can port the wastegate and weld the flapper to the 34mm.

The reason for the HP difference between the s4 and s5 (specifcally for the turbos IIRC) is that the s5 ran a higher boost, think it was something about being electronically controlled compared the the s4. The further difference could be the fact of different rotors used in the s5 (but thats just an assumption).

If your looking stock for stock, s5 is the better way to go, if your looking to mod the turbo after (hybrid or whatever) really either can go just depends on what you find. Keep inmind you will probably find s5's in better condition but more pricey since they were made up till 91, but again if you decide to get it rebuilt or hybrid then its a moot point. Personally i would get a s4 and get a hybrid setup done to it and your pretty good.

Also if your looking @ a BNR turbo and comparing it to a S5 stocker the BNR is better, its rebuilt, possibly ported wastegate and if youve gone high enough in the stages you get a upgraded compressor its like comparing apples to oranges.

I would recommend that you get more knowledge before going to do all this turbo stuff. I was like that too once and lots of ppl told me to take it 1 step at a time and learn the car first with the current power and then go from there (not sure if your in the same boat, but if you are... take your time and learn it all, guarantee it will pay off in the long run).

Reted's site gives a WORLD of information and the SEARCH button is a godsend. Use them both. And once your done.... use them again then post!