Whats considered a normal/good AFR?
10-15-2011, 04:47 AM
#21
12.7 is a tad lean for our motors most people will tune at 11.8 rich is safe lean is mean. 12.5 is the money its where the most power is made however it tends to get a little hot around there. then again most every tuner tunes rich because you will never make any money tuning if your blowing motors up.
BTW Rich is not safe!
10-15-2011, 06:53 AM
#22
There is a very popular "professional" tuner who often goes much leaner than 13:1 and yeah he breaks ring lands in doing so.
In the 11s is certainly excessively rich for an NA LT1. I have heard of tuners giving the engine a rich shot like that just before shift rpm for a moment of cooling after peak power but the poster a few posts up is the only person I have ever heard make such a claim in my over 10 years of tinkering with this platform.
12.7ish is where I always targeted things though I never have gotten a wideband setup with a good rpm feed so my setup tends to range from about 12.4-12.8 across the rpm range.
Another thing that should be mentioned is we are talking about AFR but sofar I think everyone in this thread is talking per bank. I have seen some of the big boys pick up BIG power with 8 channel setups, cost lots but once you are playing at a high enough level it becomes a reasonable expense to protect what you have and get the last little bit of HP from it.
The LT1 or even smallblock chevy in general is not known for spectacular cylinder balance, some cylinders get more or less air than others and with port injection they get the same fuel.
In the 11s is certainly excessively rich for an NA LT1. I have heard of tuners giving the engine a rich shot like that just before shift rpm for a moment of cooling after peak power but the poster a few posts up is the only person I have ever heard make such a claim in my over 10 years of tinkering with this platform.
12.7ish is where I always targeted things though I never have gotten a wideband setup with a good rpm feed so my setup tends to range from about 12.4-12.8 across the rpm range.
Another thing that should be mentioned is we are talking about AFR but sofar I think everyone in this thread is talking per bank. I have seen some of the big boys pick up BIG power with 8 channel setups, cost lots but once you are playing at a high enough level it becomes a reasonable expense to protect what you have and get the last little bit of HP from it.
The LT1 or even smallblock chevy in general is not known for spectacular cylinder balance, some cylinders get more or less air than others and with port injection they get the same fuel.
10-15-2011, 01:30 PM
#23
Anyway.......my point is I don't think ANYONE with any tuning experience has tried to make a case where there's a reason to target above 13:1 for best power in an LT1.
My bolt-on setup made best power right at 13:1. My current heads/cam motor made best power on race gas on the dyno at 12.9-13.0:1. Running it on pump gas, I bring it back to 12.7-12.8, and I notice no difference in performance at the track.
