Turbo target AFR

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Turbo target AFR

Postby Bloubul7 » Tue Sep 16, 2014 8:59 pm

Hi guys,

I have done a bit of online reading and can't get a clear answer. What would the perfect target AFRs be when going forced induction?
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Re: Turbo target AFR

Postby nanovapour » Tue Sep 16, 2014 9:25 pm

12.4 would be perfect.
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Re: Turbo target AFR

Postby Shanks » Tue Sep 16, 2014 10:04 pm

nanovapour wrote:12.4 would be perfect.

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Re: Turbo target AFR

Postby Oom Piet » Tue Sep 16, 2014 10:07 pm

I have an Innovate Motorsport AFR gauge in my car and I run 14.5 under cruising, 12.4 fair acceleration and 11.4 under full throttle and full boost.

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Re: Turbo target AFR

Postby Umlungu » Wed Sep 17, 2014 12:32 am

Its dependent on the characteristics on the applied engine.
This is because AFR is a very delicate ratio which will determine how fast the fuel burns within the combustion chambers(burn rate).
On a N/A motor like yours that is turbocharged, it will be different ball game as the fuel is heated from the n/a high compression.
That itself establishes a faster burn hence why you wont advance a lot on the ignition as the pressure point will be at peak at low degrees.
Power AFR lies anywhere between 11.5-13 AFR, you unfortunately cannot be lectured on what AFR's is best because 1 degree of timing advancement unfortunately changes the AFR.
The way I used to tune was that i would quickly get the AFR to 12 and then start advancing whilst watching the AFR go leaner and listening out for detonation with my Knockphones.
When you hit Detonation instead of pulling timing, change the AFR richer and leaner slightly and see if the detonation per throttle angle gets worse or less.
You will notice, the more fuel you add, the more power you loose, the leaner it is the more likely it will detonate the fuel.
Thats the perfect AFR(whatever it is), between power loss(rich) and detonation(lean)...
Unfortunately you need a dyno for this advice.
BTW - its better to run a ball hair rich for the cooling and safety aspect.
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