Cat. Converter ?'s

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Dec 26, 2015 | 12:05 PM

BlackBetty06

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From: Manheim PA

Cat. Converter ?'s

I'm sure this has been covered but I could not find it. I'm looking at taking my stone stock 01 M6 coupe and putting a borla atak and x pipe on it. My question is, should I hook straight to the manifolds or leave the 4 cats in place. The main concerns are
1) is there going to be a much better sound without the cats?

2) is there any kind of real HP and mpg to be gained?

3) how bad is it going to stink? Will I smell like I mowed the lawn if I'm driving with the top off? I run a Dmax with a straight pipe that stinks pretty good but I like the smell of diesel fumes lol.

Any insight or real testimony feed back that you guys could give me would be greatly appreciated! Thanks as I'm new to corvettes and modifying gasoline engines! I've messed with diesel all my life.

Dec 26, 2015 | 12:15 PM

vice726

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From: Raleigh NC

1) In my opinion no

2) nothing that you will notice.

3) If you like your straight pipe diesel, I doubt the gas smell will bother you

Dec 26, 2015 | 01:14 PM

grantv

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From: Kelowna BC

1 - If you like louder, yes; it will be louder.
2 - Agreed with other poster, barely noticeable on a dyno; not by the seat of the pants.
3 - No idea what a Dmax is, but nothing sounds and smells worse to me than a diesel. If you like diesel smell, maybe you like gas also. But will your friends, GF, family...?

Dec 26, 2015 | 02:14 PM

BlackBetty06

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From: Manheim PA

DMAX is short for Duramax diesel. It's my daily driver and work horse. It's also pretty punchy at 491 rwhp and 1018 rwtq with just an intake, exhaust, lift pump, and engine tune via EFI LIVE. I did have to build the Allison trans however lol! Anyway, I like loud but don't know if a little louder is worth the hassle of removing the cats and all that. I have to try and find some to listen to. Just coming into a bad time of year for that though. For those that say louder are you talking a good bit as if there were two side by side you could definitely tell? I know these aren't the easiest questions to answer as sound can be perceived differently by everyone.

Dec 26, 2015 | 02:26 PM

Nyt_Muves

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From: Surprise AZ

Once the car is warm you won't notice much smell. Most modern OBD II cars would pass emissions without the cats once the car is warm. It will smell a bit after a start. Especially a cold start. You will probably notice about a 1-2 mpg gain without cats. Cats are an outdated technology for most modern cars imho. I keep mine on the vette out of convenience at inspection time. I have had other cars where the convenience meant less.

Dec 26, 2015 | 02:29 PM

grantv

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From: Kelowna BC

Yes definitely noticeable side by side, but different mufflers will accentuate that more. You should listen like you said if possible.
Duramax, OK, heard of that. A friend has an F250 (I think, 350 maybe?), and (I think again) it says Duramax somewhere on it.

Dec 26, 2015 | 02:30 PM

BlackBetty06

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Interesting. I am not worried about the inspection police because I am putting the car on a classic tag which is emissions exempt in my state.

Dec 26, 2015 | 02:32 PM

BlackBetty06

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GrantV if your buddy has a ford truck they call their diesels powerstrokes unless he swapped in a Duramax. The Duramax is used by GMC and Chevy for their diesel pickup trucks. Thanks for the input so far everyone