EXHAUST BACKPRESSURE...GOOD OR BAD???

[EPIK]

I HAVE A 96 GT WITH WELD IN 40 SERIES FLOWS.I HAVE THE STOCK PIPING AND TAILS WHICH IM SURE EVERYONE KNOWS ARE 2 1/4. I HAD A LOCAL MUFFLER SHOP INSTALL THE MUFFLERS AND THOUGHT EVERYTHING WAS COOL 4 A WHILE. THEN I BOUGHT A BASSANI CATTED X THAT IS 2 1/2 AND WANTED TO EITHER GET A 2 1/2 INCH CATBACK OR GET CUSTOM TUBING WELDED IN. WELL TO MAKE A LONG STORY SHORT, WHEN I CALLED BACK THE SAME SHOP,THE GUY SAID THAT I SHOULDNT GET 2 1/2 TUBING BECAUSE I NEED SOME BACKPRESSURE OR I WILL LOSE SOME TORQUE AND HORSEPOWER. HE SAID UNLESS I HAD AT LEAST 300 OR 400 HP I SHOULD KEEP THE 2 1/4 PIPNG. IS THIS TRUE OR IS HE FULL OF S**T.

 

[BigHairyMonkey]

You might lose a little bit of torque down low if any, (mabey 1 or 2 tq), but you will gain hp up in the higher rpm. Id say he isnt full of it, just a little mis informed. Id say get 2 1/2 in piping

 

[jrc_03_gt]

you will notice a loss in lower rpms. It will not snap out of 1st & 2nd gears like they did when they were stock.

Just put 4.10's in the rear end that will make up for any loss and then some!

 

[bdcardinal]

also remember, that when you get the car smogged take that bassani pipe off and put the stock one back on. i hate being the guy that alwasy brings this up, but the bassani midpipes are NOT LEGAL for use in CA. ignore anything anyone else told you, they are illegal. the only CARB approved ones are Magnaflow and there are a certain list of cirsumstances that must be met before they can be used.

anyway, backpressure to an extent is good. when at lower RPMs you do want some backpressure as that will help create some torque, however at higher RPM you want a freeflowing exhaust with little to no backpressure. there was an episode of PHRTV that explained this really well.

 

[kboy262]

You might notice it a little down low, but it will run much better up top. It will help unchoke some of the lost power of the NPI motor. To me I would also do the whole catback because it gives it a cleaner look in the undercarriage.

 

[nickthegenius]

backpressure = teh lose

 

[KaPPaBaLL]

let me get my reading glasses real quick. haha jk..

there's always a good amount and a bad amount. too much is bad and too little is bad. but 2 1/2 is certain not too much much flow