i have the stock 3' catless... is that good enough or recomend me to get an aftermarket down pipe? why?

 

if the dp is catless how can it be stock?

 

thats what i was asking my self when i read that... there is no way its stock with out a cat. dealer emissions wont allow that to happen

 

Yes, If you removed both cats and the crimped part between the cats. The Stock DP is indeed 3" and it does not neck down at all from what I can see.

 

so if the stock dp has cats and a fabricated/aftermarket catless dp doesnt have cats, what makes a catless dp stock?

 

i cut off the dp cats... i mean its stock piping but i cut off the cat.... is that good enought or its better to get a aftermarket one

 

its not stock piping if you took of the cats. and to answer you question it should be good enough vs. an aftermarket catless dp

 

Just the stock flanges and flex coupler I guess

 

so its not stock

 

Correct, but what would you call it? A stock custom DP?

 

Aftermarket would be better imo. When your done with the car, sell the aftermarket dp and put the stock on eback on

 

no, just a custom downpipe

 

well i guess i have a custome dp....

 

lol!

 

Custom with stock flanges.

 

correct

 

which are the flanges??

 

one end from another

 

oooo....

 

The two cats are the real restriction in the stock downpipe. The next restriction is the crimp which I assume is probably still there. What you have now flows a lot better than stock, but maybe slightly worse than aftermarket.

 

u dont make any sense. you just said that the restriction is the 2 cats so how is it worse than an aftermarket

 

Epic.

 

It should flow the same as an aftermarket one unless you have crush bent tubing instead of smooth mandrel bent tubing.
What he said makes perfact sense the stock cats do not flow as well as the 3" high flow catted or catless aftermarket DPs. GM also crushes the stock DP down right where the O2 sensor is.

 

There are three restrictions in the stock downpipe. The major restrictions are the two cats. The remaining restriction is the crimp near the O2 sensor (which I suspect was not replaced). Unless this crimp was replaced with a mandrel bend piece, this DP will still not flow as well as the aftermarket. Maybe I could of worded it better, but the original post basically says the same thing.

 

The stock DP isn't three inches!


Look at the flanges!


Besides with that fail crimp in the middle you haven't really done anything but made it emissions illegal