Originally Posted by first350

So I ran a few #'s for pipe flow to come up with the pressure drop from a few different set-ups...I had to make some big assumptions, but think it gives a good general feel for real life:

assumptions:
-10ft straight pipe
-Max exhuast flow = (1/2)*(3.5L)*(7,000 RPM) of air at standard conditions (I know exhaust flow isn't at Ambient pressures and temp, but it gets fairly close once it's at the exhaust tips...this is the assumption with the largest amount of error)



so, for peak HP at 7,000 RPMs, you'd most likley want the dual 3" exhuast. But you have to remember that there's much more going on to this...in the best of all worlds, you want to have high velcoties and low pressure drop.

high velocities - this helps scavenging effects of the cylinder...as the exhuast air exits the cylinder, it has a certain amount of momentum (mass*velocity). the more momentum it has, the larger % of exhuast will actually exit the cylinder before the exhuast valve closes....this will increase burning effeiceny on the next combustion stroke since it will have less residual exhuast in the mix. (in general, this effects mid range power)

low pressure drop - pressure drop is bascially resistance...the more resistance in the exuast system the more the engine has to work at pushing the exhaust out. (in general, this effects top end power)


In the end, you want to find an exhuast system that has a good balance - I went with AMM's 2.5" single exhaust b/c it'll greatly increase peak HP over the OE exhaust, while not giving up the mid range power b/c the exhaust velocities are still high enough. Plus the single exhuast is much lighter

Originally Posted by first350

not sure if that's true...it's hard to compare HP/TQ gains from what different companies advertise. from just looking at the designs, I would think AAM's exhaust would make more power - it's more or less a straight shot out the back w/ a few small bends.

AAM

STILLEN

-Peter

Originally Posted by IIQuickSilverII

I gained 12 whp and 11 torque with the injen SES so to me thats proven gains... eventually i added a full 19whp with teh setup including 2.5" testpipes...
I didn't notice the lowend torque loss but i saw it on the dyno sheet so i got custom H pipe fabricated fro like 60 bucks and i am sure it took care of it...
later on i added cai and plenum spacer and and utec and i was at 267 whp

I have heard the stillen makes the most power...
abotu teh AAM exhaust i dunno N/A but the true dual version tehy have is excellent FI and looks hella nice...
their single version which First has is comparable to the JIC, APexi Ti, Agency Power...they will definatly get more power out of a stock system and weight savings are greater than the true duals... still the stock muffler and exhaust system is soo heavy that most true duals are same weight or lighter. Adn a lot of people are not fond of the single tip look...