Air Fuel Ratio

[jetmech]

Really, how so?? About how rich will encourage detonation? I've never heard of this, then again I guess you learn something new everyday....

[farmtruc]

IMO it's not a big deal if it's too rich. When the a/f ratio is too rich, the truck will bog and not feel strong.
Even a 10.5 or 10.2 a/f ratio (at least on my truck and avalanche) still feels pretty decent.
If the a/f ratio is in the 9.0 area, the truck just don't run, so it's obvious that there is an issue, so detonation isn't a concern for me when running rich.
I've never had detonation occur when a vehicle runs too rich, cause 10.5 still isn't too rich, just my opinion.

I've heard others say this, that a rich condition will cause KR, but I haven't experienced it, but I'd like to hear about it.

[jetmech]

IMO it's not a big deal if it's too rich. When the a/f ratio is too rich, the truck will bog and not feel strong.
Even a 10.5 or 10.2 a/f ratio (at least on my truck and avalanche) still feels pretty decent.
If the a/f ratio is in the 9.0 area, the truck just don't run, so it's obvious that there is an issue, so detonation isn't a concern for me when running rich.
I've never had detonation occur when a vehicle runs too rich, cause 10.5 still isn't too rich, just my opinion.

I've heard others say this, that a rich condition will cause KR, but I haven't experienced it, but I'd like to hear about it.

Same here, I've had mine in the 9ish area (not by choice) and the engine started to bog down a little but no detonation or KR on the data logs. I keep my AFR around 10.8 on meth running hi boost and it pulls HARD. According to chemistry, running too rich shouldn't cause detonation but I really don't have a way to "MythBust" this.

[jeffreycastgsx]

TOO rich can't cause detonation, many factory boosted run in the 9's for there tune just to be EXTREMELY safe, leaning them out usually wakens these cars up a lot. The extra fuel in a way cools everything, opposite of what a lean mixture causes, heat.

[DBRODS]

good luck with thin oil from running too rich. Your bearings will love you for that... Geez

[jetmech]

TOO rich can't cause detonation, many factory boosted run in the 9's for there tune just to be EXTREMELY safe, leaning them out usually wakens these cars up a lot. The extra fuel in a way cools everything, opposite of what a lean mixture causes, heat.

My thoughts exactly. Again, speaking from a chemistry/engineering standpoint, I really don't see how running rich will cause detonation

[farmtruc]

TOO rich can't cause detonation, many factory boosted run in the 9's for there tune just to be EXTREMELY safe, leaning them out usually wakens these cars up a lot. The extra fuel in a way cools everything, opposite of what a lean mixture causes, heat.

GM never runs them that rich. take the ssr and cobalt for example, every time i tune one of those vehicles, the a/f ratio stays at 12.2 to 12.5 all the way up to 100mph (not that mph has anything to do with it), and 1-4 gears.
So if anything, GM runs them on the edge, but they are forged and can take it.
After i'm done with them, they are set at 11.7 and run much smoother and stronger than before. Never understood why GM runs these little engines so lean at wot, maybe they don't make enough power vs the parts they are built with to cause any damage, not sure.

9:1 a/f ratio is way to rich for any of our gm setups. I've run the avalanche for a while at 12.4 just to test power and drivability, runs good there too, but feels better, stronger and smoother in the 11's.
I haven't tested it, but the truck feels the same at 11.9 to 11.0, so i guess it's reasonable to say that 11.0 is probably better, since it's safer and cooler.

just my experience.