This is just a pet project of mine, and hardly even comes close to the projects you are guys are running with Coyotes and EcoBoost like my SHO.

My 07 GT has CMCV delete, FR500S/GT500KR mufflers in terms of "power" mods. I installed the Pypes off-road X-pipe about 2 years and went to the track last year with the Steeda CAI (Shelby GT intake). I saw 35 lb/min MAF flow at 6200-6500 RPM.

I got tired of the smell of uncatalyzed exhaust, and went back to the stock cat H-pipe (it only had about 15k original miles) this year. I datalogged it and found a max of 30-31 lb/min of airflow at 6500 RPM, a relatively big difference. I swapped between the Steeda CAI, the Saleen 98mm airbox/tube and found that they both offered comparable flow with the Steeda flowing a hair more at really high RPMs but with the IAT at 10-20F over ambient even at speed (whereas the Saleen was more controlled like the OEM airbox). I figured the higher IAT can't be good for power, with most dyno's operated in a controlled environment not really subject to heat soak.

The ECU PID for torque also maxes around 290-300 ft-lb, with calculated horsepower peaking at 260-272 hp - I understand this is mostly inferred from various sensors, but I know from tuning my EcoBoost SHO that when heatsoaked, these values can be 30-40 ft-lb lower than when there's adequate airflow or if the air conditions are bad/good.

I've been playing with a full E85 tune (after datalogging the MAF flow differences between the various intakes I had) and I believe the stock pump and 24lb injectors could handle up to 35 lb/min and that's about it. I don't think the injectors are the restriction but they are pushing like 85% duty cycle with 30-31 lb/min airflow. If I get it back to 35 lb/min, then I will probably need bigger ones or try pushing 70 psi.

I looked back at my notes, tune files, etc... and can't figure out why there's a delta of about 4-5 lb/min other than the stock cats and/or H-pipe crossover being the restriction. Does that sound right?

Should I try a cut-in/splice-in X-Pipe crossover? Or is the restriction from the cats? If it is the cats, I'll just leave it as-is and call it a day.