I have not tuned the car yet, running on my uncle's mail order tune, he has the same build that I do. Took it to the track last night and ran a 13.003 @ 111 mph, the car has a cc306 cam in a stock short block and lt's, has le2 heads and a ported intake manifold. I logged the car with freescan during the run, was getting 7 degree's of knock retard from 4000 rpm's to 6000 rpm's in every gear, I think it is false knock. I did give the tune more fuel the day I installed it, I increased all the MAF table's by about 5 afgs which I know is too much. The BLM's are running in the 108 to 114 range, I know the PCM is trying to remove fuel. If I can get the BLM's @ 128 and lean it out what do u all think the car will run?

 

11.70's-12.20's @ 114-117mph. Your 60ft times will be a big factor. What was it on your 13.0 pass?

 

1.97 on some worn DR's, launched @ 2000 and the car bogged real bad.

 

Increasing the MAF tables will not help you at WOT. The MAF tables are not looked at while at WOT. For that, you need to add to the WOT tables. If you were lean in that range before, then your probably still lean there now. The MAF table change you made will affect part throttle driving out of WOT at those air flows. You can pull a few deg of timing in that rpm range as well and see if that helps.

Ken R.

 

I guess I need to add fuel in the "% change to AFR vs RPM @ WOT", that table in tuner cat is @ -5.0 % from 4000 rpm's to 6800 rpm's.....Now my question is do I increase from -5.0 to richen it up or do I decrease from -5.0 to say -10.0% to add fuel. I am sort of confused, any help would be great.

 

Yes, that is the correct table. You would increase the values to richen it up. I would guess if your logging on a wideband, you would probably see a good change just going from -5 to 0. While your in there, look in the AFR vs Temp table right above or below it and make sure that the values in the area of the engine temp you run are the same, so that way your AFR wont change say going from 150deg engine temp to 180deg. You know what i mean? If thats good, then the AFR vs RPM table should be the only values you need to mess with for AFR's.

Ken R.

 

All my % change to fuel/air ratio vs. cool. temp.at wot are set at 16.0 from 80 degree's to 104 degree's C. The engine operates at 185* F

 

You indicated you thought it was "false" knock. Why not put some 100-octane unleaded in it, and see if it really is false, before you start changing the A/F ratio or the ignition timing?

I'm a bit puzzled by the comment "The MAF tables are not looked at while at WOT". Could you explain how the PCM determines the mass air flow at WOT?

 

It uses the tables . Changes in the higher maf tables WILL show up at wot, he is mistaken.

 

Injuneer that is a great idea, The next time I go to the track I will do that. The tune on the car now is a mail order tune, I have not adjusted any of the timing tables, I did increase the MAF tables a bit and the BLM's are indicating rich. Last night I adjusted the fuel trims at idle and now the cars idle BLM's are at 128 and the intergrators are at 128. The knock module is a stock lt1, I think it might be false knock due to the fact my uncle is running the exact same build and I am running his mail order tune and his logs show no knock and his PCM has a lt4 KM.

 

I was hoping he would have come to that realization......

 

I guess i was incorrect in that statement due to the fact that i was always maxing out the MAF to the point of where it was no longer used after i went FI. The point i should try and make though it that is it really necessary? I never once touched the MAF tables for WOT tuning weather it be NA or when i went boost. I only ever corrected the RPM WOT table and always got my AFR's spot on and had my BLM's right around 128 utilizing the factory MAF tables in the higher air flows. I got my added fuel by using the WOT table. The only MAF tables i ever adjusted were in the lower air flow range while out of WOT to get my BLM's in check.

Ken R.

 

I'm not suggesting how you should or shouldn't tune the A/F ratio. It simply concerned me that you would suggest the MAF tables (and hence the MAF) were not used at WOT.

 

Point taken. I've just been spending too much time in "Forced Induction" i guess.

Ken R.

 

I don't want to get things too far off topic. However, there is a need to tune the maf tables and they must be as accurate as possible. If they are not and you tune with the pe rpm tables you will end up with a tune that moves around with barometric and temperature changes. Now with your forced induction stuff, the severity is going to depend on how wide the variations you see in iat's and boost in cold weather vs warm. When you just max the maf and compensate with pe you can still get the tune wandering around with changes in density. I much prefer speed density vs maf tunes for boosted cars for this very reason, but its time consuming and annoying with a stock pcm car.

The maf calibration effects can be most readily seen under steady heavy throttle (1/2-3/4). In most cases if something is not done when you have these conditions the car that may run 12.8 a/f at wot will often times be rich. Basically if you work on that part of the tune passing gear is much more effective and requires less fuel and throttle to get the same result.

I guess theres 'tuned' and then theres tuned.