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Tuning L-trims with MAF vs Injector scaling

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Old 07-20-2003, 05:49 PM
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Default Tuning L-trims with MAF vs Injector scaling

After about 6 months of playing with Edit I have come to some conclusions.
I've tuned a few different combo's and have tried different ways to get the best drivabilty and performance.
For Blower cars (running 42lb FMS injectors)I find scaling the injector's close to -2 L-terms works good but they need fine tweeking with the MAF table under 8000htz to get optimul results.
On NA cars I have tried both,Injector scale and MAF table changes and have found that the injector scale takes longer to tune in and is harder to pinpoint area's of trouble.On the same car I changed to just MAF adjusting and found it easier to get a desired -1 - -5 L-term all the time and seems to have better drivability (throttle response)and less likely to change much in weather.
All my testing was checked many times on dyno's to see if HP was affected and 1/4 mile runs to back up.
So I keep reading that you don't want to touch the MAF table,but by my experiences I have seen no reason why not.Also would like to add that all my MAF changes are only done under 9000htz and rolled smoothly.
I do not recommend trying to scale the MAF for bigger injectors though.

Anyone else have anything to add on what experiences they have on this subject?
Old 07-20-2003, 08:57 PM
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Default Re: Tuning L-trims with MAF vs Injector scaling

That is the way I tune my 01 M6 SS, IFR to get me in the ball park and MAF transfer funtion for slight tweeking, I dont tweek the MAF more than 2%, I dont know if thats the right way or not but has worked for me, I used that methode with a cam and seems to work great for me. I need to get to a dyno again and confirm my results.
Old 07-20-2003, 09:16 PM
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Default Re: Tuning L-trims with MAF vs Injector scaling

I have gone as far as 25% around 4k htz without problems and excellent drivability.Also did it with IFR and got the same results but took ALOT longer to tune in.
I've just seen posts that MAF adjustments are no good,but from my experience it is just as good as IFR.(not including scaling bigger injectors)
Would it be because it affects the timing?I custom make my timing maps so I haven't tried it with a stock map.
Old 07-21-2003, 02:48 AM
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Default Re: Tuning L-trims with MAF vs Injector scaling

It really depends. In a theoretical sense you should change whichever is "out of calibration" - with a new intake, descreening, etc. this is most likely the MAF.

On the other hand people do have valid concerns (mainly with an A4) that scaling the MAF differently will effect line pressure. If you are increasing it then this should kick up pressure across the board - I would be especially carefull with decreasing it as this could pull out line pressure.

I have had good luck with an initial scaling of 104%, but again, it's results in the end that matter - try it both ways and see what works better (which seems to be what you did).






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