Concerning the LoPresti cowl mod: What actual difference – if any – could you detect in aircraft performance after installation?
Honestly, I can’t say. I don’t have engine instrumentation to give me the straight scoop on if it made any difference on the engine temps. Further, I did not do a direct back-to-back speed comparisons. One thing I can say with confidence, though: after the install I had a consistent 100 RPM gain across the board in speed at the same throttle. I can fly the airplane over redline below 8000 feet, and at full throttle I can maintain redline up to 10-11000 feet burning less than 9 gph. I true out at 140 KTAS up to 8-9000 feet burning 10 gph, and if I let if run over redline (2800-2850) I’ll true out at 145-147 KTAS. I tend to not like doing that though…
