how much fuel?

[sharkcohen]

I'm running the 91 octane tune on my 2012 Challenger SRT8. As expected, I'm getting a small amount of knock, although it doesn't look like an alarming amount. So far, there is no LT knock. I'll be adding fuel and doing more data logging to see how it goes. Posting for info for others, and looking for advice on how much fuel should be added.

[mikel]

maybe 5%

[sharkcohen]

Thanks Mike, that might be about right. Here's a look at what 2% across the board did for me.

[mikel]

your on the right path.

[mopar-srt8]

We have winter blend gas here with less heat energy than summer gas. The actual stoicometric mixture for winter gas is 14.2 when summer gas is 14.7 a/f meters are calibrated to 14.7. So if you are shooting for a AFR of 11.5 at WOT your meter will read 11.0. My car is a GWE 392 and I have fattened up the 91 octane tune +10 +10 +5 and at times I see the desired AFR at 10.8 and it feels like more torque. It is a good thing that I am running drag radials.

[sharkcohen]

Winter gas here, too (CA), thanks for the tip. I really need a wideband for the car.

[sharkcohen]

I finally ran a log of the stock tune to see how much if any knock I get on it. I think I need to reconsider where I fuel up.