Funny business at WOT
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Funny business at WOT
Hey guys, I took it out for a WOT blast today and the AFR was high 12s, low 13s. I wanted everything to be mid to high 12s so I went back to see what RPM it was going into the 13s at. Well the second time around it was at low 12s!
Also when I was data logging I noticed that a few times at 20 grams/sec it was like 126 and other times it was at 136...
Something weird is going on here.
Any ideas?
Also when I was data logging I noticed that a few times at 20 grams/sec it was like 126 and other times it was at 136...
Something weird is going on here.
Any ideas?
Pro
Joined: Jul 2002
Posts: 703
Likes: 0
From: Milwaukee Wi
20 grams is not WOT. If the car is cammed it is sensitive to exhaust gas finding it way into the combustion chamber at lower RPMs. So that change in BLM/INT could be expected.
As far as WOT I would expect that to be more consistent than you witness. What is duty cycle for each episode? Possibly the FP is not keeping up or filter clogged partly.
As far as WOT I would expect that to be more consistent than you witness. What is duty cycle for each episode? Possibly the FP is not keeping up or filter clogged partly.
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
20 grams is not WOT. If the car is cammed it is sensitive to exhaust gas finding it way into the combustion chamber at lower RPMs. So that change in BLM/INT could be expected.
As far as WOT I would expect that to be more consistent than you witness. What is duty cycle for each episode? Possibly the FP is not keeping up or filter clogged partly.
As far as WOT I would expect that to be more consistent than you witness. What is duty cycle for each episode? Possibly the FP is not keeping up or filter clogged partly.
Melting Slicks
Joined: Aug 2003
Posts: 3,407
Likes: 400
From: Lakeville MI
Your MAF is pegged at WOT, so above this point your tune is blindly fueling based on the LV8/pulsewidth table and PE tuning.
It will not be able to adapt to conditions, so sometimes it will be a bit richer or leaner depending upon the actual mass air flow which changes with the air density.
The LV8 will always decrease linearly as a function of rpm above 4800 rpm in a predictable pattern since the maf is pegged. Since this is predictable, it can be compensated for in the tune, but there will be no automatic correction for conditions.
It will not be able to adapt to conditions, so sometimes it will be a bit richer or leaner depending upon the actual mass air flow which changes with the air density.
The LV8 will always decrease linearly as a function of rpm above 4800 rpm in a predictable pattern since the maf is pegged. Since this is predictable, it can be compensated for in the tune, but there will be no automatic correction for conditions.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
If you're talking about INT and BLMs, then they are both fixed by the ECM at 128 when it's in open loop mode. If you're talking about BLMs, then...
There are 16 BLM cells, so you might have been bouncing between some of them. Note that the BLM cell boundaries changed with different BCCs, but these are the ones in my car:
Code:
; Block Learn Multiplier cell matrix at L001C: ; ; 700 1200 2000 ; RPM RPM RPM ; | | | ; --------------------- ; | 0 | 1 | 2 | 3 | ; ---------------------- 12 gm/sec ; | 4 | 5 | 6 | 7 | ; ---------------------- 22 gm/sec ; | 8 | 9 | 10 | 11 | ; ---------------------- 34 gm/sec ; | 12 | 13 | 14 | 15 | ; ---------------------
Last edited by Cliff Harris; Nov 7, 2014 at 12:31 AM.
