ok currently i have the Hahn 3 inch catback and i posted a thread a while ago about how i lost all my low end touque and some mid range. and would need a lot of modds to make up for it. its not that bad but pretty bad. . . will the Injen Air Intake i justt bought from turbo tech racing make up for some of it. it says it adds 17 hp and 16 tq. Gains

 

oh noes.....proof that 3 inch isnt ubah godly?


your gonna need to push some pretty major power to get that low/mid power back with a 3 inch exhaust
like the twinscrew swap....or turbo.

 

A smaller pulley will compensate for the low end torque loss of a 3" exhaust.

 

gonna need to be a mighty small pully.

 

maybe it was due to lack of back pressure

2.5 is where its at

 

so intake wont do anything

 

intake helps free up hp, and make that sc scream

 

No it's not. A 3" or less should compensate fine for the loss. Get TM removed and you won't even feel a loss.

 

can i put a 2.9 inch pulley on it without injectors or a tune

 

At least need a gm stage 2 tune and 42 lb injectors

 

You lost most if not all your backpressure. So now the exhaust cant help itself by scavanging it out. It works like a siphon. But anywho, get a smaller pulley that about all you can do unless you restrict your exhauast a little somehow. You can get a away with some 3" but all depends on how the muffler and bends restrict it, and the supporting mods.

 

No. 3.2" should be the smallest you should do with stock injectors.

 

but w/ tune and 42.5's it's alright

hell, id even say bump up to 60lbers

 

interesting.
I know someone with a 2.6 60lbs intake and meth injection with custom tune...
who got a 3 inch custom, and who felt that loss in mid/low end.

but whatever

 

Was it proven through dyno graph's or was it the butt dyno? TM is the key

 

no. nothing was proven on paper.

but after seeing it time and time again, its pretty obvious what is happening

 

thats why i went with 2.5" all the way back. i didnt lose alot, if any mid range...
and low end torque loss was very minimal.

 

Stock car, stock pully, stock tune and a 3" catback. Not quite a good mix. However, you could install a 3,1" pulley boosting 14 PSI and you shouldn't have any problems. Yeah the injectors will reach 100% duty cycle, but only at the very latest RPM's. But take care with the Injen CAI it will flow even more at high rpms. Definitly need a wideband to see if it's safe.