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'modifying' magnaflow dual system on an 81

Forum: C3 HVAC, Fuel, Emissions, and Exhaust

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'modifying' magnaflow dual system on an 81

Posted: 7/17/23 8:00pmMessage 1 of 8
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NJ, NJ - USA
Joined: 2/13/2023
Posts: 58
Vette(s): 1996 c4 coupe black / black
2000 c5 coupe pewter / black

i just had the stock system replaced with the dual system and magnaflows with the shorty headers. i was a bit surprised to find out it was marginally noticeable over stock. sounds decent when you really get on it , but i dont thrash the car too much. i remember a friend in high school had a 71 or so lemanns , and he poked a couple of holes in the back of the muffler with a screw driver and it actually didnt sound bad at all without being obnoxious which i dont want it to be.  other than poking a hole in new mufflers , has anybody tried this? i figure if it doesnt work i can slap some sealant goop in the hole. ive driven maybe 80 miles on the new system so i thought it would "settle in " and maybe sound a little better






|UPDATED|7/17/2023 8:00:13 PM (AZT)|/UPDATED|
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Re: 'modifying' magnaflow dual system on an 81

Posted: 7/17/23 8:51pmMessage 2 of 8
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Burke, VT - USA
Joined: 1/23/2002
Posts: 7601
Vette(s):
SOLD - "The Toy" - '70 Convertible
SOLD - "The Beast" - '90 ZR-1 (#682)
SOLD - "Betty" - '28 Ford Model A Tudor
SOLD - "BLKBRRD" - '78 Pontiac Trans Am
"BLUBYU" - '04 Coupe

Personally I wouldn't be poking holes in brand new parts.  That's just inviting bad things to happen.  When we were looking to put a new exhaust system on "BLKBRRD" my wife spent some time going to the websites of different places that sold mufflers and listened to the sound bites that were associated with them.  Granted, you can't get a really good feel for what they will actually sound like but she found a sound that she liked and that's what we went with.  Over the years we have gotten a lot of positive comments on the sound of the car.  So a little pre-purchase homework was worth it.

When I put a new exhaust system on "The Toy" I went with larger diameter pipes than stock and basically stock mufflers.  The result was a more throaty sound that was not obnoxiously loud.

The exhaust system on "The Beast" was left alone.  It was sweet as it was even tho' only 2 of the 4 exhaust tips were functional.  I had considered opening up the other two to see if doing that would have upped the performance a bit but it was never high enough on the project list to do.

My 2 pennies worth.

Jim Olson 

"The Toys"...!!!  Save the Wave!

Where I've been in a Corvette...!!!

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Re: 'modifying' magnaflow dual system on an 81

Posted: 7/19/23 6:51amMessage 3 of 8
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Eagleville, PA - USA
Joined: 11/1/2001
Posts: 27294
Vette(s): Used to own a 1979 Corvette now owned by JB79

I can't see spending all that money and then poking holes to ruin it.

Do you have state inspection where you are? If so, those holes would probably fail your inspection.

 

-Adam Wartell
NCM Lifetime Member #1222
Founder: Vette Registry 

My first Vette, now owned by JB79:

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Re: 'modifying' magnaflow dual system on an 81

Posted: 7/19/23 9:48amMessage 4 of 8
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NJ, NJ - USA
Joined: 2/13/2023
Posts: 58
Vette(s): 1996 c4 coupe black / black
2000 c5 coupe pewter / black

yeah thats my basic line of thinking. will just hope maybe they get a little louder as miles go on.  nj doesnt have inspection for anything older than 25 years so thats not an issue

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Re: 'modifying' magnaflow dual system on an 81

Posted: 8/14/23 6:07pmMessage 5 of 8
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NJ, NJ - USA
Joined: 2/13/2023
Posts: 58
Vette(s): 1996 c4 coupe black / black
2000 c5 coupe pewter / black

so ive been combing the net for exhaust sound options on these cars. im thinking my magnaflows are way too quiet. i thought id have a nice burble , but its almost like stock. any recommendations for something that will sound good with headers and true duals?

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Re: 'modifying' magnaflow dual system on an 81

Posted: 8/14/23 10:25pmMessage 6 of 8
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Rock Springs, WY - USA
Joined: 12/14/2018
Posts: 25
Vette(s): 1979 Corvette, Black w/Doeskin Interior. L48, 4-speed. Cooper Cobra tires on rally wheels. T-tops.

I agree that punching holes in your mufflers is a bad idea.  I purchased a dual exhaust x-pipe system from "PYPES" for my '79 4-spd manual.   Going to connect it to the stock exhaust manifolds, and eliminate the big old original cat.  I am not running any catalytic converters.  I had a choice of mufflers to run with it.  I chose the "Street Pro"based on description, reviews, and some sound bytes.   My thoughts are to run the Street Pros, and I can decide if I like them; or I can swap them out with with something else.

 

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Re: 'modifying' magnaflow dual system on an 81

Posted: 8/15/23 1:48pmMessage 7 of 8
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Grapevine, TX - USA
Joined: 8/26/2006
Posts: 1537
Vette(s): 1972 LT-1 convertible with factory air. 2017 Black Rose Grand Sport M7 convertible.

You could put a couple of flowmasters on it.

   

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Re: 'modifying' magnaflow dual system on an 81

Posted: 8/15/23 1:50pmMessage 8 of 8
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NJ, NJ - USA
Joined: 2/13/2023
Posts: 58
Vette(s): 1996 c4 coupe black / black
2000 c5 coupe pewter / black

yeah ive been researching to death... i think i settled on series 44 deltas

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