I have search this and cannot find the information . I have a 2002 WS6 A4 Trans Am that must stay emissions legal because I'm in the smog psycho state of CA. I have an SLP lid, Magnaflow exhaust, P&P Throttle Body and TB bypass, drivetrain is stock. I know about stalls for the A4 but want to focus on the heads right now.

I want to put on ported 243 heads leaving the rest of the motor stock. I know that it is best for a tune but for right now I can't. My question is can I bolt on ported 243 heads and not do a tune and drive the car? My mechanic says that the computer will do the work regarding air/fuel and lean conditions. The computer will compensate but will keep the motor safe. He stated it should not impact drivability other than more power. I talked to someone else and they said I must get a tune otherwise the car will go too lean. Who is correct? The cam and motor is stock so I believe the mechanic as he has done many LS motors.. I just need a sanity check regarding tuning a heads only motor. Tune will come later but for now is it safe to drive it with the factory tune? Thanks for your time.

 

If it stays in closed loop, where the ECU adjusts the AFR based off of O2 readings, and that the injectors are still stock, I would think you would be okay.

 

That is exactly what my mechanic was telling be that the AFR is off of the stock O2 sensors. I'm feeling more comfortable and now realize the other guy was just trying to sell me tuning. Thanks.