11.8AF Question

[whiterocket54]

I recently attempted to lean out my A/F to 11.8 from 11.4. My truck is a CA truck and 91 octane gas is only available. I was running 14* with no problems at 11.4A/F...had to take the timing down to roughly 10* so it wouldn't ping with 11.8A/F. I am currently getting 11.5 lbs on the boost gauge this winter. What gives? SCT recommends heavy blown vehicles to a 11.0-11.5 A/F in their ProRacer booklet, but most of you guys are around 11.8A/F. Any advice would be appreciative. I tend to think the shitty gas in CA is forcing me to run rich A/F ratios to starve off pinging.

 

[Fade 2 Black]

Glad to see you still around. That's a hefty signature you have there.

For the octane gas, especially winter mix you are running too much timing and that's causing it to ping (detonate). The a/f of 11.8 is well proven and safe. You should tune for this a/f and lower timing to 12 or maybe even 10* IMO to prevent detonation.

You may also occationally get some bad gas that will cause part throttle pinging as well as well worn sparkplugs may cause it. Leave the a/f where it was and back out 2* timing to start and see if that helps.

 

[typhoon43]

I think timing has more to do with it than AF as well. My block let go 2 weeks ago in 47 degree weather. Wideband showed 11.5 across the board, but my tune was set for 17 degrees max on 93 octane.

Better safe than shopping for a new block IMO..

 

[Fade 2 Black]

Damn! 17*, that's high. I'm running 12* on my street tune for pump gas and 11.6-11.8 target a/f.

 

[bransharksfan]

That's a hefty signature you have there.

HAHA Finally one bigger than MINE!!:rockon: :beer: