Im looking at getting the invidia header for my AP1, however i was wondering what if any problems i will run into with the computer. I have the test pipe however i have the CEL on for it. Will the ECU change too much of the MAP to run ok or will i need to have it tuned when i install this. Any advice would be great. thanks.

 

I would take it to a dyno and check the Air Fuel ratios, should be ok for a 2003 though.

The invidia is a tough install, good luck

 

Test pipe will lean out the mixture, the header will do it even more.

The car runs rich to begin with so you're balancing it out to more "optimal" air to fuel rations (12's), if you get into the mid to high 13's+ you will damage the motor over time

 

if the stoichiometric ratio is 14.7, then isn't 12s going to be "rich" in pretty much any application?

 

That ratio is only an ideal, you also have to leave overhead for heat, fuel quality, air density (Humidity, Elevation, Temperature, etc)

Run 14.7 all you want, just make sure the gas, temperature, air are always the same all the time

 

wish i had a good dyno/tune shop in the area.

 

Still on stock exhaust? Should be ok...

Like I said, I would get an Air Fuel reading if possible to make sure everything is in the green

 

nope got invidia duals and test pipe, hehe its loud wanted to make it louder hehe

 

so TP+header will lean you out? does MY matter?

would going back to stock cat make it any better?

 

yes. after my header install, the car ran lean through a lot of the powerband and very lean in a couple spots. i knew this was going to happen though so i never drove it hard until post tune.