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Lowest AFR target for low boost track car

 
Old 04-03-2016, 09:26 AM
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Default Lowest AFR target for low boost track car

Folks,

I'm running the 90mm pulley on my Kraftwerks Rotrex-equipped '99 HPDE car. She's hitting just shy of 7 pounds boost at WOT and about 6800 rpm, and I'm seeing around 10.8 AFR. I'm making some changes that require a re-tune--removing the gutted MAF and adding a sealed cold air duct. Should/could I have it leaned out just a bit at WOT?

Thanks,

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Old 04-03-2016, 11:15 AM
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there's no reason to run that rich. Us turbo folks like to target 11.8:1. S/C setups can get away with slightly leaner. I'd be targeting ~12:1; no leaner.
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Old 05-20-2016, 05:06 PM
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I'm at a solid 11.5 AFR from 4k-7k. My car has seen over 20 track days at 8-12 lbs boost pressure(Rotrex c30-74 with 80mm pulley). I'd be more concerned with your timing map honestly..
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Old 05-22-2016, 02:00 PM
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Originally Posted by HomebrewYata View Post
I'm at a solid 11.5 AFR from 4k-7k. My car has seen over 20 track days at 8-12 lbs boost pressure(Rotrex c30-74 with 80mm pulley). I'd be more concerned with your timing map honestly..
Your post reads like you're talking about my particular timing map?
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Old 05-22-2016, 02:05 PM
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Originally Posted by poormxdad View Post
Your post reads like you're talking about my particular timing map?
Sorry for the confusion. I was only trying to stress the relative importance of a solid ignition map. There's no magic AFR target to follow, I run something that makes good power but below 12:1
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Old 05-22-2016, 07:43 PM
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No worries. I asked the question because there has to be a compromise between using richness to help cool the motor, and having too much fuel contaminating the oil.
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