high compression

[b16b bomber]

for a compression of 12.5, is it extremely neccessary for me to get air/fuel controller?

[fritz_269]

Just how exactly do you plan to run 12.5 CR without total engine meltdown?

[drift]

nah, u dont need a gauge. you just need a Spiralmax supercharger to swirl the air for more efficeint combustion. it will make you invulnerable to detonation at any compression ratio.

[praxis]

Yeah...and the SpiralMax is only $69.95 ($10 off ALL online orders).

WOOHOOOOO!

[VTEC_boi]

Forget SpiralMax - my Tornado will murder that thing on a dyno chart! so HA!

j/k

12.5 will require race-fuel.


Mark - you really should get a disclaimer LOL!
"WARNING: Extremely sarcastic - do not take seriously"


o yeah..unblock me please - i need to ask ya somethin'

[b16b bomber]

i didnt get 12.5 yet...but i went to a shop and they were telling me some of my options and one of them was to make a na car...and with the b18c crank and ctr pistons i would get 12.5

but i truely dont know if that will really work

[MAYHEM]

You will not be able to run any timing at it is better to run 10.5-11.1 comperssion and take back a lot of timing on your motor, and it will last for more than a month. It will also be more reliable.

[fritz_269]

Originally posted by b16b bomber
i didnt get 12.5 yet...but i went to a shop and they were telling me some of my options and one of them was to make a na car...and with the b18c crank and ctr pistons i would get 12.5

but i truely dont know if that will really work

If you want to run 12.5 CR and not melt the engine, you'll need to do one of two things:
1) Always run 110 octane race fuel (no good for the street...)
2) Run a very long duration cam, which would kill any low-end torque and the idle would have to be set to something like 2000rpm. (no good for the street...)

See if you can find a combo that puts you in the 10 to 10.5 range. You can proably make a good go of that on 92 octane fuel. If you can't find off-the-shelf pistons to do that, you can always have the pistons custom dished or the head chamber ported and cc'ed. And if that shop was really telling you to buy those parts for a street engine - you should stop going there.

Good luck.

[b16b bomber]

thanks guys...after hearing your advice i am not gonna do that...

I have just purchased the spoon 1.8l stroker kit...and i will be happy with that for now

[exospeedAMcrx]

We have ran a B20/VtecGSR head with 12:1 compression pistons on 91 octane. Its a daily driven car and we didnt encounter any problems. I believe you can run 12:1 if the setup is right. If the motor was pushing in more air with uprgraded cams, I think it would require a higher octane of gas. But 12.5:1 won't necesarrily require a octane of more than 110. 94-103 would be good enough but still, those cost more than your average gas price.

I'd stick with 12:1 the most for a street car.

And on the CTR pistons, we have one on an LSblock/GSR head. Runs on pump gas also. 91 octane. daily driven and estimated to be at 11:5 compression.

Wil www.exospeed.com

[fritz_269]

Originally posted by exospeedAMcrx
We have ran a B20/VtecGSR head with 12:1 compression pistons on 91 octane.

Stock cams? Wow. Where's the timing? And where's the intake valve close (IVC) set?

[VTEC_boi]

12:1 on street car?

I wish we had that kind of gas for street cars around here...