Thnx Aong these lines I think it would be extremely beneficial to wrap, shield, thermal coat the primaries. Again this will allow then to retain heat more efficiently (thus exhaust velocity will be greater than primaries w/o wrapping, shielding, thermal coating, etc.) and this greater velocity will reach the snail faster thus producing superb/instantaneous "low end torque."

 

Here is a Dyno Chart of my friends evo with the 2.75 inch HKS Downpipe, 3 inch Test Pipe, and 3inch HKS Cat Back Exhaust.

Car has hks 264 and 272 Cams, 660cc Injectors, 255lph Fuel pump, Upgraded Intercooler, Upper and Lower IC pipes and HKS Filter.

Can anybody here post their dyno chart with a 3inch DP and TB with similar mods.

I want to compare the torque, not the horsepower.

Car was tuned via UTEC using 91 CA pump gas

 

Unfortunately, the dyno curve can differ somewhat between two different cars just due to tuning (or a lack thereof) alone. Even two bone stock cars can differ by some 15whp. You'd need to try both on the same car, and dyno tune each one to make a real comparison.

 

BTW I dont believe HKS makes a 2.75in downpipe. I thought they only made a 65mm (~2.6in) downpipe. The Tanabe and Works Downpipes are 70mm (~2.75in)