Whilst attempting to rectify a big on takeoff and and gear changes, got me thinking if there is a target or ballpark AFR during AE mode

my wb touches 10s during a throttle jab and this after me reducing the AE MAP and TPS values (ebl) by about 40%. Car idles open loop in the mid 13s (AFR) and I believe the bog off idle is much improved

but just wandering if I should be targeting a ballpark AFR alongside seat of the pants want feels best

 

I dont really, its too fast of an event really to accurately capture it i guess. I mean You see the gauge or datastream jump but its such a small amount of data. if i see it that rich and car feels ok, I usually just try reducing it until it stumbles then add it back til its crisp again.

on gas i try to idle leaner than that but only if engine tolerates it.

 

Thanks. Yeah it’s a mild vortec hotcam setup but I find anything leaner than low 14, the idle starts to suffer. Havnt got my iat tables down yet and see about a 1 point swing between a low iat idle and a high one

Good suggestion on reducing the AE until it stumbles. I thought taking 40% out was aggressive. But fair given my rich idle AFR, I can possibly go even further

 

Too much AE can cause a bog and too little can cause hesitation. As you're finding out, there's a sweet spot.

A lot of the bog on the too-much-AE-side can be due to how long the AE lingers around.

For example, on my Miniram, in 8D there are two parameters that dictate how long the AE lingers around.... one for delta-MAP and one for delta-TPS.

On the delta-MAP side, there's the table for AE Delta MAP decay vs coolant. Factory is about 40% at full operating temp. I increased that to 62%.

On the delta-TPS side, there's the scalar for "AE-TPS, Done if DRP Counter =" at location 0x530. Factory is 12 DRP's (Distributor Reference Pulses). I put that to 8. This parameter is available in the S_AUJP xdf, but I'm not sure about the other standard 8D xdf's.

The Miniram seems to like a very big shot of AE, but tapering off very quickly. On my car now, during normal throttle transitions, my AFR's will dip down to low 13's and then recover back up to low-mid-14's pretty quickly.

On a quick throttle stab (>50% change in throttle), it'll quickly dip to low 11's for like a fraction of a second, but then recover to commanded AFR very quickly.

Seat of the pants-wise, it feels very crisp and seamless.

BTW, I too idle in open loop. The Miniram seems to like about 14:1. But I also run about 25° of spark advance at 650 rpm in gear (similar to the 4th gen LT1 Vettes), which goes a long way toward smoothing and stabilizing the idle.

 

On your IAT tables...

What's your IAT configuration? Is the sensor still in the TPI upper plenum?

 

Thanks ultm8

I have a pro flo xt intake which I suppose isn’t too dissimilar to a Miniram wrt runner length. Will keep those other tables in mind though will need to figure out the mapping to ebl tables

yep iat is in the air intake piping down by filter (sitting in front of the coolant jug). You might recall me asking about the iat tables and you helpfully guiding. As a result the AFR swing from cold iat to heat soaked iat is a lot better; from about 3 points to 1. So I’ll keep at fine tuning as, for me, about 0.5 points I can live with

 

Did you disable the INV MAT vs Airflow table? If not, I would recommend that.