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What compression ratio and AFR are turbo nutters running?
james h - 20/4/17 at 04:58 PM

As above! Car and bike engines.

My engine simulation project is coming along nicely - results seem to correlate with the real world!

Now it's turbo time....

1. So what did you lower your compression ratio to?

2. And your air/fuel ratio

If you've original figures, even better!

Cheers guys


chillis - 20/4/17 at 06:31 PM

Depends a lot on what engine (combustion chamber design) and who built it. And what boost you want to run?
Anywhere between 7:1 and 11:1 CR, again dependant on boost which could be 1/2 bar to 3 bar maybe more. Afr anywhere between 8.5:1 and 13:1 dependant on CR and boost and what your pre turbine temperatures are.

Benzine - 20/4/17 at 06:40 PM

21.8:1. Didn't lower it, just put more fuel and boost in.

mark chandler - 20/4/17 at 06:52 PM

Straight out the cbr900 bike, 11.1:1, boosted at 7psi, AFR was around 12 from memory

[Edited on 20/4/17 by mark chandler]

coozer - 21/4/17 at 01:57 PM

I'm planning 8.0 with forged pistons, looking for 350bhp out of my blacktop.

madteg - 21/4/17 at 07:02 PM

7:8:1 @ 2.3 bar 10.5 AFR with large intercooler equ 320BHP. But turned down to 1.5 bar to make it more drivable and save the tyres

jeffw - 22/4/17 at 06:29 AM

Not turboed but 10.5:1 on 1.4bar of boost. 400BHP/300 ft lb out a blacktop Zetec.