I need some diagnostic help. I recently installed a 35R kit. At 15 psi boost, my injector duty cycles are approximately 70% when AFRs are near 11. These numbers are nearly identical to what was recorded with my stock twins at 15 psi. Since the fuel and the AFRS are the same for both the single and the twins, I assume the mass of air is nearly the same (ignoring air temps).



Without any knowledge of the compressor mapping for the stock twins, I had assumed the 35R flows more as evidenced by some dyno data. Does anyone have any insight as to why the single is not providing more air or are my assumptions incorrect?



Aside from checking the intercooler couplers, what would be some possible diagnostic checks?



fwiw I am running 1300s and datalog AFRs

 

The only sure way would be to look at the compressor maps on your turbo, but without getting scientific, your twins at 15psi are at their limits, almost out of thier efficiancy range. Where your single is at its optimum flow characteristic range. I have seen your turbo on another FD. It is a small turbo, but the numbers do seem a bit low, never the less.
And like you stated, you could very well have a boost leak, but the dyno graph should show a slightly irratic/jaged curve showing this.

 

thanks for the response,

initially with the single I was having oscillating boost, however this has been corrected
yet the injector duty cycles still mirror the twins at 15 psi