Is there a noticable difference between the S4 and s5 rotors, or should I not go through the trouble of tracking them down. Aslo, will the lighter rotors allow for me to rev the engine higher?

-Dan

 

They will allow you to rev higher, and will give you a bump in HP due to higher comp.

 

How much of a bump in hp would he gain if he did this?

 

how high could you be able to rev to?

 

I have an S5 engine...and its better than my cousin's 89 GTU. Its stronger..so yeah.

 

Wow, a true testimonial.. Too bad both cars have the SAME bloody ENGINE!

Sheesh.

ANYway... S5 engines are rated to 9K RPM, but you gotta have the ECU to do it (or get the RPM limiter removed from the S4 ECU, and even then not sure how it's going to handle fuel at 9K rpm)..

To use the ECU, that means the engine side wiring harness, new injectors, AFM, CAS, etc.

Besides, the extra RPM isn't necessarily useful, if you're not making power there.

PaulC

 

well looks like I'll try and chase down a pair of S5 rotors, can someone give me a ballpark estimate of as far as HP increase? and anyone know a good place to get a used pair? Thanks.

-Dan

 

True, I don't think my buddy rev the engine past 7700 rpms on his 88 engine with 89 internals.

My apologies for the confusion

 

Remeber to get the counter weights also

 

my estamate is around 10hp

 

bah counterweights are for wimps

 

They're not the same engine...The S5 has high compression and lighter rotors, among other things.

If you are rebuilding the engine, I say go for it. Good for around 10-12HP. Otherwise, don't worry too much about it.

You will also need the counterweight.

 

yeah Im in the middle of a rebuild, I was just going to to leave out all the counterweights and save some weight. j/k