I am getting ready to install a set of vance & hines big shots and se air filter. The question I have is I have a exhaust gas analyzer that I use for automotive repairs could I use this by taking readings stock at different rpm's and retune after changing. If so how much richer should I go at idle, mid, and upper ranges. Thanks

 

I would first reprogram with a canned SERT(my vote), or PCIII file calibration. Then adjust to: Air/Fuel ratio 13.8:1 under load which is middle of the road for 14.5:1 for best mileage(lean), and best power 13.3:1(rich). If you can find a dyno tuner that uses a SERT or PCIII that would be the best. You can also use the SERT road test program, set up the analyzer, go through the runs while watching the analyzer, change the SERT A/F mapping, save the program with new name, reprogram the ECM. Test it again. It might take a while but, it will work. Good luck, and let us know how you did.

Thorns