As some of you know, I recently supercharged my 2.4. I'm still getting crazy readings on my wideband only in open loop (and boost) and someone mentioned that I may have too much backpressure in the exhaust system which is giving me those crazy readings. The 3.34" pulley is boosting 9lbs.

I have a stock exhaust system. I am going to try a backpressure test and see where that gets me, but I don't have anything to compare it to. Does anyone know what the stock backpressure reading should be on the 2.4? Maybe one of the GM techs on here can help?

 

back pressure should not be more then like 2psi at about 2k rpm.....

 

sorry man no idea, but I can't see it being that restrictive, get the gmpp setup then, sounds good, and flows better than the ss/sc exhaust, or find someone with a stock ss/sc exhaust and swap it

 

Under a load or just sitting in neutral revving to 2000rpm and holding it there

 

hook up the backpressure tester to the pre-cat o2 bung....start the vehicle and leave it in neutral, bring the rpm's up to 2k rpm and monitor the backpressure gauge.....it should not go more then 2psi

 

gotcha. If it does go over 2psi then:

a. clogged cat
b. too restrictive exhaust
c. ?

 

eh cat's suck... only thing they're good for is chinese food lol

 

Just upgrade to a more free flow exhaust and down pipe and eliminate the cat. Also do you have any vids of it yet, I would love to see how a supercharged 2.4 sounds.

 

well, if you do the back pressure test in the pre-cat o2 bung and you have excessive back pressure, that would lead to a clogged cat......

if you then do the back pressure test in the bung after the cat and still have excessive back pressure, then that would lead to a plugged muffler/exhaust

 

http://smg.photobucket.com/albums/v3...t=100_1706.flv

I need a cat for emissions I think. In this vid, you can't hear the supercharger, intake or exhaust. lol.