Meth and AFR question

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May 11, 2009 | 07:17 PM

mike13

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From: Lake Tapps, WA

Meth and AFR question

I made some changes to my turbo car which increased airflow causing the car to run lean. We didn't make any fuel changes just turned on meth injection and it richened the motor right up. Mixture of 50/50 single nozzle cooling mist vari-cool II system.

Does methanol really add that much fuel? At 8lbs boost we aborted the run because the afr was 13.8 turning on the meth/water injection we we're right back in the 11.5 afr range.

May 11, 2009 | 07:22 PM

BigRich954RR

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From: NJ

yup meth is fuel my car with out meth would run in the 16. A/F i run 100 % meth

May 11, 2009 | 07:32 PM

mike13

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From: Lake Tapps, WA

what size nozzle? I'm running 500cc/m. I was really surprised how much richer the a/f got by adding the 50/50 mix.

May 11, 2009 | 07:33 PM

DeltaT

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I like to get the no-meth AFR's under boost (~8#) at about 12-12.2:1. Then tune the meth to get you to a minimum of 11.2 at WOT and your 8#. That's a pretty safe tune. Best case would pull some timing if the meth ran dry, and turn on an idiot light.

You numbers seem plausible, but maybe the nozzle is a bit big for that level boost.

Jim

May 11, 2009 | 07:43 PM

mike13

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From: Lake Tapps, WA

The way I have it set up now is if I run 6lbs boost my afr's are right in there without meth, if I run 8lbs and have the meth on at 500cc/m my numbers are 11.2-11.5. My controller doesn't spray until it see's 6lb's. It's also progressive.