Negative Fuel Trims After Long Tube Headers

[n8dogg]

I installed some long tubes on a customers 99 LS1 Vette. Logged his car and I am getting about a -3% LTFT average. To correct this should I apply that to his MAF curve? He also has an intake and LS6 intake manifold.

[WeathermanShawn]

Personally that is within my range. Anywhere from +/- 2-3% (some like slightly positive for WOT).

If you were really trying to hit perfection, you could apply each MAF Freq vs LTFT1+LTFT2/100.

IMO, I would leave them alone. New gas, different IAT's..you would be chasing them. It might be wise to log it against the MAF Calibration Curve. Sometimes headers will shift the MAF curve. Your average might be -3, but it could range from a -9 to a +3..

Make sense?

[joecar]

For -3% it is best to leave the MAF alone...

Do you have any logs before-after showing DYNCYLAIR...?