I was wondering about using a Renesis E-Shaft in my T2 engine when I rebuild it. Its something like 1.5 pounds lighter and says can be swapped over. Will the shaft work with stock S4 counterweight and stuff, or will I need to mix and match parts at all?

Also, curious as to if anyone has used renesis rotors in a t2. they too are lighter, but have a higher comp ratio of 9.7:1. If someone was going to run low boost wouldnt this be ok? Im just toying with some ideas, that and im bored

 

Renesis rotors are 10:1 comp ratio. They are lighter and can be used because they are still 13b rotors. The e-shaft should be swappable also but I'm not 100% sure on that. If you just swap the e-shaft over and keep the same rotors then your counterweights will be fine. The counterweights have to match the rotors. So if you went with renesis rotors you'll need the corresponding conterweights.

 

yeah, i should have thought that one out a bit more. eshaft is balanced to itself, rotors to the counterweights. now ive just got to decide if its worth the extra few hundred bucks for the renesis shaft. wonder how it would perform with the renesis rotors, shaft and about 12psi. might be a bit high on comp ratio but no worse than someone with an s4 running 15-20psi

Correct me if Im wrong, but wouldnt having 10:1 compression ratio mean more hp per psi (10psi on 8.5 would be less hp than 10psi on 10:1)? Also wouldnt off the boost/ low throttle/ low rpm make more power since youll be making the power off boost? so faster out of the hole?

 

I'm going to run the rx-8 e-shaft. the bearing clearances are a hair different but everything else should work.
its only .6lbs lighter, and not in the best spot for weight loss, so its more of an affordable brand new e-shaft. don't look at it as weight reduction.

the rx-8 rotors suck, stick w/ old style 13b rotors even if you're gonna go n/a, im doing 9.4:1 for my turbo

i chose to do the racing beat hardeend stat gears instead of the rx-8 stat gears because I didnt feel like having RTV where an o-ring should be.

I also looked at using the rx-8 corner seals and springs and have since gone w/ FD corner seals and springs instead.

-Ben Martin

 

who said i was going n/a? i was just looking at this as an option for less rotational weight in the engine, not so much the increase in comp ratio and whatnot

 

even IF you're gonna go n/a

meaning even in a situation where you want high compression rotors, the 13b rotors are a better choice for a performance motor.

the s5 rotors can be lightened more than the rx-8 rotor even though it starts out lighter.
rx-8 rotors are thoroughly crap in a couple ways compared to the 13b rotors.

mazda cheaped out in the manufacturing of them. the 13b rotors are of higher quality

 

ah, ok i see now. anyway, i wasnt going to use the rx8 rotors, was just bringing it up for the learning aspect of it. if i WAS going to I would probably do like you said and stick with old 13b stuff. So back to the early question. Would it be worth it for me to throw in a renisis e shaft when i rebuild or not? it does weigh less, though not much, but it seems like even that half of a pound would make up for something wouldnt it?

 

If your going Turbo I recommend 9.0 T2 rotors or at most 9.4 NA rotors. The higher compression ratio would give you better off boost response or course but you will be able to make more power with a lower compression ratio because you can throw more air into the combustion chamber without worrying about detonation.

 

the only benefit in my eyes of a rx-8 e-shaft is that its about $150 for a brand new e-shaft.

its only .6lbs and at the very center of the motor. it wont really do **** for weight loss, you're 1000x better with just a light weight flywheel for lost weight.

its supposedly as strong as the previous shaft (FD) but i can't confirm this, just hearsay from some people who know some people who robbed some people

 

E-shafts are dime a dozen. I have two perfect condition e-shafts I don't even know where they came from. Go clear out your closet you probably have one too.