Oh ok... I'll definitely be doing that then after I get the AFR stoich dialed in. 14.25 still gave me a lean code so I dropped it down to 13.50. Will see how that works today.
thanks again
Oh ok... I'll definitely be doing that then after I get the AFR stoich dialed in. 14.25 still gave me a lean code so I dropped it down to 13.50. Will see how that works today.
thanks again
Last edited by jcmartel75; 05-09-2010 at 07:52 AM.
I can't see 13.5 being valid unless you are running E85.Originally Posted by jcmartel75
how about 12.75? The 14.25 didn't work so I figured to keep lowering it until I found something that did. What do you suggest?
I agree. I've got mine set at 14.20 for 10% ethanol and have no problems. Something doesn't seem right. Did you adjust the MAF curve?
2002 EB C5Z06. ECS Novi, Alky control meth & headers, 633 rwhp
No I didn't adjust that. I'm a goof though and thought I read people were putting their AFR down to the 12.5 level... they are for WOT in the PE table. I set mine that low in the stoich AFR table but, I didn't run it yet. I'm going to change it back to 14.2 and just adjust the MAF curve. Glad I checked in here beforehand. Just out of curiosity though... what would happen if I set the 0% value to 12.5? I actually ran it on 13.50 and the only thing I really noticed was that I got a little bit more KR, 8* and I had been getting 6* previously.
Yes, definitely do not enter 12.5 in the stoich table. If you did this your PE would be really rich and your fuel trims would be way off
14.2 stoich will be the baseline for the PE calculation. So if you want to target 12.5 AFR you will need to enter 1.136 in the PE table (14.2/12.5=1.136). However your car will only hit this value once you properly tune the MAF table. I used a wideband for the high MAF table which is where you'll be under WOT. Using your scanner and one of the histograms for AFR error, you compare the commanded AFR to wideband AFR at a given MAF frequency and adjust the MAF table by the error % (or sometimes half the value depending how close it is) so that the wideband AFR eventually equals the commanded. Once the MAF table is set you can command whatever value you want by changing the PE table and have confidence that it will hit it.
Now for the low MAF table which is where you'll be in closed loop crusing around, you can use the wideband like above, or you can adjust the MAF table based on your fuel trims. I used the fuel trims to tune the low MAF table since the O2 sensors run the show in closed loop. Plus, if you don't have a wideband this is the easiest way to get them in line. For example, if trims are +3% (PCM adding fuel to correct lean condition) at a given MAF frequency then you would need increase the value by 3% so that the PCM adds fuel based on the airflow value, if negative, decrease the value by 3%.
Last edited by turboffr; 05-09-2010 at 07:29 PM.
2002 EB C5Z06. ECS Novi, Alky control meth & headers, 633 rwhp
Thanks very much turboffr. This is definitely a learning experience but, a very fun one. I appreciate you guys helping me understand this. There's a lot of reading involved but, I constantly come up with questions and it's great to be able to come here and get them answered. Thanks to all
anytime. I was new at this not that long ago (still learning) but I'd be happy to help you if needed as you start tuning.
2002 EB C5Z06. ECS Novi, Alky control meth & headers, 633 rwhp
I will need all the help I can get... thank you
Reading BBA's tuning process write-up he says to copy the high octane timing table to the low octane timing table for the process of tuning the MAF. Just to make sure I'm copying the right table, is it the one under Engine>Spark Control>Spark Advance>Main Spark Advance> High octane and then low octane??? Everything else seems fairly straightforward.
thanks
thats correct. save the low in excell. so any knock does not throw you into the lowoctane table.
2003 Chevrolet Silverado SS
L92 Heads/ L92 Truck Intake
OBX LT Headers
Custom Ridings 3200 Stall Converter/Built Trans
6 Piston ZO6 Brakes/ 2 pc 15" Front rotors
OK I got that taken care of. Now I'm trying to disable LTFT under Engine>OL&CL. There's is no disable option however there is a Min and Max ECT box which controls when LTFT is disabled. Should I just switch those temps out of range so LTFT is disabled? Once I do that my MAF calibration tune should be ready.
yes. you can set the Min ECT to the max value to disable the LTFT's. Then you just need to log your STFT's vs. MAF Freq. in a histogram and adjust the low MAF curve by the error %. Best to do this while driving steady on the highway and gradually hitting all of the frequency's.
You can also disable your fuel trims through the scanner, although it will shut off both your STFT's and LTFT's. Click on the red/green "ON/OFF 100%" button in the header row, then select Fuel & Spark and set fuel trim learn to "OFF". This is a quick way to do it when tuning the high MAF table in open loop. No need to reflash the tune.
So to tune your high MAF table in open loop, do everything I listed above and log the AFR error between commanded AFR and your wideband - (MAF High - AFR error histogram). Then adjust the MAF frequency by the error value.
2002 EB C5Z06. ECS Novi, Alky control meth & headers, 633 rwhp
I don't have a wideband so, I unfortunately, have to do this the long way. It's a good learning experience though.
That's why I wrote it like that. I had to tune too many cars with mods and no wideband.
I'd buy a wideband or tune WOT on a dyno. Otherwise you're just guessing
2002 EB C5Z06. ECS Novi, Alky control meth & headers, 633 rwhp
I don't think I'd call it guessing. Maybe there's a bit of educated guessing involved. Reading BBA's write-up, it just looks like a more complicated way of doing it with a bit more fine tuning involved. I don't mind putting in the time.
Knowing what I do now, I'd probably just have gotten the pro tuner and a wideband but, I just got the standard tuner. Hindsight is 20/20... oh well. Like I said, it's more work but, I don't mind.
thanks
Definitely not guessing. Using a wideband is more guessing since the widebands are not linear in response after a few hundred hours of usage.
Using narrowband is more accurate than using wideband, and using calculated torque to adjust PE for max power is just as effective as using a dyno. Plus, you know AFR is determind accurately by PE ratio if the STFT/LTFT is spot on after tuning in closed loop.
BBA, it is you who wrote "BBA Tuning Process" ?
It is working for V6 engine ? I guess so...
Thanks...
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