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Old 08-24-2013, 08:51 AM   #1
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correct AFR for a supercharged enigine

I have completed the installation of a TPC supercharger kit with a SMT6 used to drive the 7th injector. Im now at the stage where Im tuning it and Im looking for some help to keep me on the road and not blow my engine. This is not going to be a track car and I want to keep my AFR on the conservative side.

I have read some threads that have posted their AFRs for NA engines. It looks like normally the engines run lean at idle; maybe 18-20. It also looks anything below 18 is considered safe based on the chart posted here.....

Dyno results!!

Im going to try and stay richer than that, more like 12-13 because Ive read that forced injection engines typically run richer. In my case the 7th injector has the one benefit of cooling the air charge. After lots of reading I came to conclusion that this was my only fueling solution because I run a 2.5 and the ECU was never cracked for (correct me if Im in error - I came to this conclusion because APR had no flash for that ECU).

If anyone has some words of wisdom I'd appreciate the input. Note that I am fully aware of the dangers I face due to the design faults of this engine but I went down this path because I could simply not resist and I know cars that have safely run these kits for years with no incidents. One forum member in particular has been extremely helpful as he has owned one of these cars. I say owned in the past sense because sadly the car was lost in a tragic house fire.

Last edited by tranceatlantic; 08-25-2013 at 12:44 PM.
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Old 08-24-2013, 02:07 PM   #2
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PK2 is your best source for FI tuning because he had the longest running SC 2.5L. Send him a pm.
2009 Cayman 2.9L PDK (with a few tweaks)
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