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2002 grand prix se 3.1 - performance or better cat

S

sicayan

New member
i have code p0420, replaced front o2 sensor, erased code, and back to p0420 after 70 miles. since i am going to have to buy a new one anyway, i would like to get a better one, a direct fit and possibly a new muffler, don't know about the resonator. is this just a waste with a 3.1 or can i get something descent for a little bit more than what i would end up paying for an oem ($184, not including muffler, just direct fit cat) from shucks or napa?:th_scratchhead:

thank you,
 
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Well, consider the fact a stock exhaust is all your engine needs. So if it isn’t broke, IMO don’t mess with it.

If I were you, I’d take my car to a local shop that does exhaust work, and have them weld in a universal cat. Assuming your down pipe is ok, you can save like $50+.
Also, beware most high flow cats will pop a code even brand new. So just get a new “normal” cat and be happy.:th_winking:
 
the ses shut off today after getting gas from a 76 station, "plus" grade. low fuel light was on, stopped at 76 and only put in $8, thinking i will go to some place cheaper later. turned car on and no ses light!!:confused::)

i usually try to fill up at safeway or costco because of the low price on gas, i get their "premium" grade. maybe 76 gas will solve all the cars problems!

if i buy a universal from a well known local shop, total will be 295, if i buy a direct-fit for 184 from shucks, the shop will install it for 65.

thank you sir
 
I put a GMPP exhaust for the W body cars on my 2001 SE with the 3.1 single exhaust and was shocked at the increase in performance with the U bend delete after the cat as well with a 2.5 inch straight pipe with the O2 bung. The GMPP exhaust is actually a magnaflow all stainless 2.5 inch duals with polished stainless magnaflow mufflers and resonator. $450 from gmpartsdirect.com. This exhaust advertised as a magnaflow at other retailers is $800. Sounds real good and BIG increase in performance-equivalent to a stock 3.8- I should know since I have had a 98 GT, 2004 Impala with the 3.8 and a 2001 Bucik with the 3.8l. U bend delete and GMPP exhaust-3.8 power with 30 MPG.
 
Enough with the 1,000hp increase with exhaust work on a 3.1.

The converters in these cars are just fine...taken out they have been dynoed to show no more than ONE horsepower or so...I say get a high flow off of Ebay for cheap or at your local exhaust shop and have it welded in. It'll pass inspection and you'll get better MPG's. You don't need a GMPP Catback and yada yada yada like ^^this guy said.
 
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