I was wondering if going to a small AR exhaust housing would cause the need for a retune. I was thinking maybe not but then since compressor maps would be different it might.

 

thats going to affect spool time. Therefore you'll be boosting in areas you normally didn't see boost before. Its going to need some adjustment.... If you had an experienced tuner - he could just quickly modify the map for the areas where the new setup will see boost. Otherwise you might run lean when the turbo comes on. But a fresh tune is always recommended.

 

It changes the flow of the system, so it will change your A/F ratios while running. Whether it changes them enough to require a retune or not is a judgement call.

-Max

 

changing the housing is like changing to a different size tires for your car. do you need to recalibrate the speedometer for accurate speed?

 

Pluto I might face the same problem if I switch mine out and either dont have a chance to meet up with you in STL or all the spots fill up. Would fuel just need to be change or timing also?

 

timing for the most part should be okay but you really want the lowest timing at peak torque. your a/f ratio will be off for sure