Question about afr
Thread Starter
10 Second Club
Joined: Jan 2010
Posts: 2,317
Likes: 20
From: Hurley, VA
Question about afr Ok I had my car professionally tuned and I have Hptuners so I decided to go in and take a look. Well stoich in the car is 14.62 and they have my PE table set at 1.31 from 5k on up. Wouldn't that mean the car is running at 11.1 at WOT? Unless I'm missing something. Its speed density tuned could it be an error in the VE table and the extremely rich PE is just making up for that? I just don't understand why the car would be set that rich. It made 523rwhp so I haven't really ran the car out on the street to actually see if the AFR is 11.1 on the wideband. Car is a N/A 408 11.5 comp motor.
Go run the car at WOT snd see.
Set up your scanner to show Commanded AFR and the WB AFR in the same chart. Set the scaling the same for each.
It will be real obvious if commanded matches actual.
If you trust your WB, and the two dont match, i'd say the VE table is not calibrated properly.
Set up your scanner to show Commanded AFR and the WB AFR in the same chart. Set the scaling the same for each.
It will be real obvious if commanded matches actual.
If you trust your WB, and the two dont match, i'd say the VE table is not calibrated properly.
TECH Resident
Joined: Aug 2003
Posts: 970
Likes: 4
From: England UK
11.5 does sounds very rich indeed. I aim for 12.5afr at max tq, and 13.1 every where else until above 5500rpm then back towards 12.5afr.
Not for Forced injunction 11.5 may sound more correct or to be on the safer side for NOS.
Looking at your power output it seems you are running a power adder, so the rich AFR may be set for that.
523 at the rear wheels must mean you are near 620hp at the crank. Thats a lot for H/C on a 408. Not saying its not possible, but sounds like you have some power adder like NOS to do that.
As Ron said run the car and see what happens at WOT and check the readings.
Not for Forced injunction 11.5 may sound more correct or to be on the safer side for NOS.
Looking at your power output it seems you are running a power adder, so the rich AFR may be set for that.
523 at the rear wheels must mean you are near 620hp at the crank. Thats a lot for H/C on a 408. Not saying its not possible, but sounds like you have some power adder like NOS to do that.
As Ron said run the car and see what happens at WOT and check the readings.
Thread Starter
10 Second Club
Joined: Jan 2010
Posts: 2,317
Likes: 20
From: Hurley, VA
The car is a n/a 408 251/259 cam, PRC 247s, and a FAST 102. The car actually shows 12.6-12.7 at wot but the stupid thing spins to much to really watch what your doing. I didn't set the log up I have a wideband married into the car its just an aem one but it will show in the upper 12 range while the commanded manually looking and doing the math is 11.1. The car also has a terrible hanging idle thats intermittent. Sometimes it drops back to normal perfectly and sometimes it'll hang at 1600 and its annoying as ****. I'm gonna call the tuner tomorrow. If in 6th gear I give it say half throttle it'll peg my wideband 10.00. I'm assuming the VE table is off on the upper end. Monday I'll call rather.
