What is an acceptable air fuel ration at wide open throttle on a A4 with a GTRS turbo kit? I keep hearing tuners mention AFRs in the 12's, butI've always heard that turbochargedcars should be in the 11 to 11.5 range.

 

Running in the 12s is still decently rich, and most likely the recommendation to run mid-11 ranges is just to err on the side of caution. A lot of it will depend on how much boost you're running. The higher the boost, the higher the heating in the engine, and the more potential you have for hot spots which can create detonation. The extra richening of the A/F ratio will safeguard in that it a) ensures that you have more than enough fuel for the boost you're supplying, and b) the extra atomized fuel in the airflow can give somewhat of a cooling effect, which can help fight against the development of hot spots in the combustion chambers.

 

12-12.5:1 for the most power. 11-12:1 for added safty. Just keep it around 12:1