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Old 08-01-2009, 09:32 PM   #1
wwotr
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Exhaust diameter question

When I went to my Exhaust Man yesterday, I was asking him about replacing the exhaust from my Headers back (to in Front of the Rear Wheel).
I told him I want it LOUD & OBNOXIOUS!
He asked if there were any Mods to the engine and I told him as far as I know, it was a stock Vortec engine out of a 1994 C1500 Silverado.

He said, "Then I'd go with 2 1/2" Diameter Pipe".

I was wondering (for some of the more knowledgeable members on the list), what Perimeters dictate the Exhaust Pipe Diameter?
I'd like to go 3" just because I think the :LARGER the pipe ....the BETTER the Flow. Would a larger pipe make it sound louder?
Would a smaller Pipe give it more back pressure?

This inquiring mind would like to know.

Rogere
"RATIKLE"
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Old 08-01-2009, 10:02 PM   #2
mclairmo
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Re: Exhaust diameter question

The 3 inch pipes will be louder but may hurt the low end torque of your stock motor. There will be less of a scavenging effect, the process whereby the exhaust flow itself actually sucks more exhaust from the cylinder allowing more fresh fuel and air to fill the cylinder. I would go with 2.5 inch and Flowmaster 2 chambers if you want loud. This will give you good power down low and still be loud. Will also be cheaper to build than 3 inch. Also, if you dump the exhaust under the body, the body acts like a drum and will amplify the exhaust sound, if that is what you want. If it dumps off to the sides or out the back, then it will be quieter. However, if it dumps under the body or off to the sides, there is a chance you will smell exhaust fumes while sitting at a stop light.
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Old 08-01-2009, 10:05 PM   #3
ed2552
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Re: Exhaust diameter question

Too large for your application will hurt performance. For a stock motor, 2.5" pipes should be more than enough. If you want loud and obnoxious, get some cutouts, or some cherry bombs. Or both.
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Old 08-01-2009, 10:29 PM   #4
QKENUF4U
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Re: Exhaust diameter question

from what ive read in HOT ROD a long time ago... use what the motor needs BEFORE THE MUFFLER and then whatever you want after ....i was gonna do a 4" tailpipe on my 91 but the 3" sounds fine...
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Old 08-02-2009, 12:18 AM   #5
jbristo67
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Re: Exhaust diameter question

Quote:
Originally Posted by wwotr View Post
When I went to my Exhaust Man yesterday, I was asking him about replacing the exhaust from my Headers back (to in Front of the Rear Wheel).
I told him I want it LOUD & OBNOXIOUS!
He asked if there were any Mods to the engine and I told him as far as I know, it was a stock Vortec engine out of a 1994 C1500 Silverado.

He said, "Then I'd go with 2 1/2" Diameter Pipe".

I was wondering (for some of the more knowledgeable members on the list), what Perimeters dictate the Exhaust Pipe Diameter?
I'd like to go 3" just because I think the :LARGER the pipe ....the BETTER the Flow. Would a larger pipe make it sound louder?
Would a smaller Pipe give it more back pressure?

This inquiring mind would like to know.

Rogere
"RATIKLE"
Vortecs werent in C1500's until 96
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Last edited by jbristo67; 08-02-2009 at 12:18 AM.
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Old 08-02-2009, 12:28 AM   #6
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Re: Exhaust diameter question

Quote:
Originally Posted by ed2552 View Post
Too large for your application will hurt performance. For a stock motor, 2.5" pipes should be more than enough. If you want loud and obnoxious, get some cutouts, or some cherry bombs. Or both.
Actually I was going to go with 2 1/2" Diameter and a set of
"Flowtech Race Readies Exhaust Cutouts Twin Pack #53026",
and have them installed at the same time. Their about $79.99 a pair but I found a guy, that has a set (never installed) but he says theres some "Light Rust" on them. He asking $34.95 for the set.
I figured with some light sanding and some High Heat Flat Black Paint,
I can have myself a nice set at HALF the price!

Roger
"RATIKLE"
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Hello members...
I'd like you to know that I sold,
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I don't visit the site much anymore,
but please feel free,
to drop me a private message.
RIP...."RATIKLE"
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Old 08-02-2009, 12:32 AM   #7
wwotr
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Re: Exhaust diameter question

Quote:
Originally Posted by jbristo67 View Post
Vortecs werent in C1500's until 96
I'm sure your right.
The guy I got this Truck from was a Deaf Mute (**** you not), so all of our coorespondence up untill the Trade was e-mail & Texting.
He bordered on "Stalking" so I hesitate to contact him again.
I'll look through my original e-mails and see if I can nail the year down.
I DO know its not the original engine and it looks like an Aluminum block, similar to my Wifes 97 Pontiac TA.

Roger
"RATIKLE"
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Hello members...
I'd like you to know that I sold,
my 72 GMC (Ratikle),
back in November of 2011.
I don't visit the site much anymore,
but please feel free,
to drop me a private message.
RIP...."RATIKLE"
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Old 08-02-2009, 12:36 AM   #8
ed2552
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Re: Exhaust diameter question

Vortec heads were from 92-99, IIRC. I could be wrong.
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72' GMC C2500, 350, TH400(?), Dana 60
'67 K10 4-spd., 305, SM465, Dana 44, 12 Bolt, RUST!
'65 C60 292, 4 spd, 2 spd Rearend, 15' Grain Box, MINT!
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Old 08-02-2009, 12:41 AM   #9
prostreetC-10
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Re: Exhaust diameter question

2.5 is all you need. 3" exhaust can also cause routing issues. It can get tricky around the trailing arms.
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Old 08-02-2009, 12:53 AM   #10
wwotr
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Re: Exhaust diameter question

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Originally Posted by prostreetC-10 View Post
2.5 is all you need. 3" exhaust can also cause routing issues. It can get tricky around the trailing arms.
Actually the exhaust route right now is exactley where I want it.
I'm just having new 2 1/2" pipe put in, with Chrome Tips that will be exiting right in Front of the Rear Tires!

Roger
"RATIKLE"
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Hello members...
I'd like you to know that I sold,
my 72 GMC (Ratikle),
back in November of 2011.
I don't visit the site much anymore,
but please feel free,
to drop me a private message.
RIP...."RATIKLE"
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Old 08-03-2009, 07:12 PM   #11
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Re: Exhaust diameter question

Flow Tech 2 1/2" Race Ready Exhaust Cut-Outs ordered and on their way

Found a guy on E-bay who's selling them NEW, for $45.00 SHIPPED!!!

Saved myself about $40.00 from purchasing them from Summit and other Internet Dealers.

;+()!~~~~~

Roger
"RATIKLE"
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Hello members...
I'd like you to know that I sold,
my 72 GMC (Ratikle),
back in November of 2011.
I don't visit the site much anymore,
but please feel free,
to drop me a private message.
RIP...."RATIKLE"
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Old 08-03-2009, 07:50 PM   #12
Scott Webster
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Re: Exhaust diameter question

I hope that deal turns out great since I've been thinking about a set and see they're EXPENSIVE new.
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Old 08-03-2009, 08:33 PM   #13
wwotr
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Re: Exhaust diameter question

Quote:
Originally Posted by Scott Webster View Post
I hope that deal turns out great since I've been thinking about a set and see they're EXPENSIVE new.
Everything I've seen on the internet (depending on the Diameter) has them priced from $79.99 up to as much as $113.00!

Roger
"RATIKLE"
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Hello members...
I'd like you to know that I sold,
my 72 GMC (Ratikle),
back in November of 2011.
I don't visit the site much anymore,
but please feel free,
to drop me a private message.
RIP...."RATIKLE"
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Old 08-04-2009, 01:12 AM   #14
BCOWANWHEELS
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Re: Exhaust diameter question

2 1/2"a and flowmasters is perfect imo
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Old 09-02-2009, 08:51 PM   #15
Scott Webster
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Re: Exhaust diameter question

so how'd it work out?
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1971 C-10 longbed 355/4spd
Future mods: 67 front clip

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Old 09-02-2009, 09:07 PM   #16
wwotr
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Re: Exhaust diameter question

Quote:
Originally Posted by Scott Webster View Post
so how'd it work out?
Looks/Sounds great.
Video & Pictures posted at my site.
Exhaust Install: http://home.pon.net/wwotr/towing.htm
Short Video Driving: http://home.pon.net/wwotr/audio-video%20page

Roger
"RATIKLE"
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Hello members...
I'd like you to know that I sold,
my 72 GMC (Ratikle),
back in November of 2011.
I don't visit the site much anymore,
but please feel free,
to drop me a private message.
RIP...."RATIKLE"
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Old 09-02-2009, 09:24 PM   #17
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Re: Exhaust diameter question

3" will kill the power. 2.1/4" is best for stock engine 2 1/2" max and make sure your mufflers have back pressure
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