What is to much back pressure in the exhaust while crusine around town, or when you are really on it. Has anyone ever checked this.
Ricky

 

According to Corky Bell in his book "Supercharged", 3 to 4 psi before the converter is typical. But working to achieve less than 2 psi under boost is desirable. And you can expect "1 1/4%-1 1/2% increase in HP per psi decrease in backpressure" (p249). I've checked mine prior to charging and found about 2 psi before the cats on my TTS LT headers w/ cats. I haven't tested yet under boost.

 

I think TTI has logged backpressure at boost on their kits but I dont remember what they were seeing, George is good about returning emails though if you were curious.