I have a constant issue I cannot tune out of this setup.
I'm tuning on a 72 chevy truck with a LSx blocked 427" motor 6-bolt /w Trickflow 235cc heads, 238/252 blower cam, Carb intake /w elbow & 90mm throttle body. F1 procharger, air/air intercooler. Currently running the lowest boost setup (only seeing 12 psi) with current pullies. Truck has ran 9.16 @ 147 and has no issues at full throttle leaving on the transbrake.
At the track, you hit the transbrake, stomp the throttle, the truck falls on its fast popping dead lean (20:1 a/f) for about 1 second then cleans up and comes on the brake hard and then you are full throttle and never lift through the pass. Airfuel is great through the whole pass and has no issues once its full throttle.
It has a 98 fbody wiring harness still running the MAF /w 98 pcm. Ive got dual widebands that read exactly whats going on. It idles about 14.0:1 a/f and runs about 11.5:1 with C16 race fuel
Ive got 60lb injectors and some 79lb'ers that i just put in but the transition problem got alot worse...
Basically it fires up and runs great..idles and cruises down the road fine with light throttle changes. If you roll the throttle too fast or even worst stomp on the throttle, it goes dead lean (like 20:1 or worse) and basically cuts out completely and then comes back to life hard. But basically it makes street driving horrible if you want to do more than touch the throttle lightly.
If you bring it up in the rpm's slower, you can bring it up to redline cleanly with no problem, but roll the throttle too fast and it stumbles horrible. It has a red procharger vented to atmosphere. The maf is after the BOV right before throttle body.
Truck is running open loop all the time. never closed loop. No front or rear o2's due to running C16. MAF maxes out pretty much at 4000 rpm instantly at full throttle and the PE table does all the full throttle fueling with no problems.
What ive tried
1)Everything possible with the PE table, thats not the problem. It stumbles before it gets into PE.
2) MAF table, I have tried adding a ton to the areas where the stumble happens and it doesnt have any affect. After the stumble, then it will go pig rich when I try this.
3) VE Table: Ive tried adding tons of fuel, it just makes it run rich as soon as the lean stumble clears up.
4) Open loop table: couldnt get any improvement.
What table will fit this transition lean stumble problem with the blower? Ive done a ton of setups without the blower similar and never had this problem, so i definitely think its because the amount of air that floods in so quickly with the blower when you crack the throttle quickly. Like PCM doesnt react fast enough to add fuel.
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