Adjustment to get LTFT down
Thread Starter
On The Tree
Joined: Dec 2002
Posts: 176
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From: Orlando, FL
Re: Adjustment to get LTFT down It is my opinion that the MAF tables should not be touched if the MAF unit is 100% stock. The MAF is calibrated to its phsyical characteristics. Now if you de-screen or port the sensor then it would obviously be out of calibration but it is likely not to fall as some exact percentage or shift across the board. The only way to correctly recalibrate is on a flow bench and compare it against a stock unit. There is no reason to port or descreen the MAF if you are tuning with LS1 Edit. One thing not realized very often is that the error in MAF readings increases as the flow rate increases. If you change the tables incorrectly you could be introducing more error.
The transfer function for a stock MAF is (King's Law)
frequency = a + b * flow rate^c
Using non-linear regression analysis on our MAF table (I used a 98 table here)
a = -1552.817
b = 2381.265
c = 0.2779244
I've tried shifting and scaling the curve to come up with a ported MAF curve but the data logged doesn't matched a strict shift or scale. Scaling really introduces alot of error in the upper end. I need to flow a ported unit to get an accurate curve.
The method I would suggest is to bump the injector flow rate tables. They will have the least impact elsewhere in the system.
Tim
<small>[ December 18, 2002, 02:57 PM: Message edited by: Tim Sloper ]</small>
The transfer function for a stock MAF is (King's Law)
frequency = a + b * flow rate^c
Using non-linear regression analysis on our MAF table (I used a 98 table here)
a = -1552.817
b = 2381.265
c = 0.2779244
I've tried shifting and scaling the curve to come up with a ported MAF curve but the data logged doesn't matched a strict shift or scale. Scaling really introduces alot of error in the upper end. I need to flow a ported unit to get an accurate curve.
The method I would suggest is to bump the injector flow rate tables. They will have the least impact elsewhere in the system.
Tim
<small>[ December 18, 2002, 02:57 PM: Message edited by: Tim Sloper ]</small>
Adjustment to get LTFT down is the best way to do it by bumping up the MAF table which effects timing table location
or is there a way to bump up the base fuel or something like that.
or is there a way to bump up the base fuel or something like that.
