RotorRon

So my motor has pretty low compression now, and a local is selling a new motor with s5 na rotors and e-shaft. s4 t2 block. Rebuilt with rotary aviation kit. has a minor street port.

Could someone explain why the s5 rotors would be better? I understand they're higher compression but ive been told you don't neccesarily want really high compression? If someone could list some pros/cons about it. Maybe tell me about your setup? I'm just curious if this motor would suit me. Any info would be greatly appriciated.

dillrx7

iTrader: (3)

List your mods you had for your prev 13b please

Will help understand what your getting into haha

RotorRon

stock motor, rtek 1.7, 3in exhaust, unrestricted intake. no emissions, no idle air. pretty simple motor.

I plan on going with the adaptronics ecu, tubular headers, t04 w/ 12psi and a front mount. Nothing crazy. I have everything besides the ecu, and injectors.

I'm just unsure why he would put different rotors in it? Any experience with doing so? pros/cons?

dillrx7

iTrader: (3)

S5 internals have a 9k redline lighter, but also n/a s5 rotors are higher compression, great for low boost situations, bad for high boost cars

Just stay with low compression rotors, that's where the power lies, I'm doing a 6 port highcompression turbo atm, only due to budgets m not getting a low comp motor

RotorRon

Try to get as technical as possible. Why is high compression bad for high boost?

Craze8

Theres a higher chance of detonation. It requires a finer hand at tuning. There are two schools of thought to compression and boost. Low compression, low low end torque and lots of boost make for top end power. Higher compression, less boost, better low end grunt, less boost needed for same power. A high compression turbo motor is a good thing, however, its less forgiving in mistakes in the tune or bad gas.

RotorRon

Now, i've heard lots of great stuff about e85 and how it doesn't detonate as easily as pump gas. Was thinking it would be a good idea for this motor? As for tuning wise i think i'll be ok.

Correct me if i'm wrong but the only problem with having high compression is mostly just a higher risk of blowing it up.

Anyone ever work with e85? i'd have to assume my fuel system will have to be upgraded a bunch then.

Craze8

E85 is really easy to get a bad batch out of a pump, and unless youve got pumps local its not really worth it. You are correct that e85 would be the better fuel, however it takes ALOT more e85 then regular fuel. You would have to upgrade fuel pump and injectors.

Turblown

iTrader: (12)

E85 makes a world of difference in these engines. Not only will it make more power, but it will be DEAD reliable. I would highly advise you do the necessary modifications for it, add the flex fuel sensor to the ECU and it will self adjust for the alcohol content.

RotorRon

I'm just curious, i have my omp removed. Can i still premix gas with e85? would i have to go get a new omp system?

Turblown

iTrader: (12)

You have to run an E85 specific premix like Klotz Benol

TougeMonster

iTrader: (1)

The guy at the triumph dealer here where we have Klotz says you shouldn't mix at 100 to 1? Not sure tho any idea?

Turblown

iTrader: (12)

1 oz per gallon