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-   -   How much HP 2.5 exhaust? (https://www.camaro5.com/forums/showthread.php?t=313866)

Craig B 08-19-2013 06:06 PM

How much HP 2.5 exhaust?
 
How much HP will 2.5 exhaust support in a N/A car?? Was wondering if it was worth it to go with a full 3in. system. Thanks.

LS3 SS 08-19-2013 07:24 PM

Quote:

Originally Posted by Criag B (Post 6916589)
How much HP will 2.5 exhaust support in a N/A car?? Was wondering if it was worth it to go with a full 3in. system. Thanks.

Zero. The factory exhaust is 2.5'', and flows pretty well. There is almost no gain to be had in 2.5'' exhaust. 3'' is overkill on an N/A motor unless you have some bigger cubes, high flowing heads and a beastly cam.

thahemp 08-19-2013 07:25 PM

Quote:

Originally Posted by LS3 SS (Post 6916925)
Zero. The factory exhaust is 2.5'', and flows pretty well. There is almost no gain to be had in 2.5'' exhaust. 3'' is overkill on an N/A motor unless you have some bigger cubes, high flowing heads and a beastly cam.

IIRC the stock system is good to ~600RWHP. Then the 3" is not just for sound anymore.

caverman 08-19-2013 07:27 PM

You won't get a true 3" system unless you buy one. I think KOOKS and LG are about the only ones that make a full header to exhaust tip in 3".

Most headers and cat-backs have a 2.5" connection point.

Unless you're making really big HP I wouldn't worry about going to a full 3" system. However, a 3" will give you a little bit of deeper tone when idling.

LS3 SS 08-19-2013 07:27 PM

Quote:

Originally Posted by thahemp (Post 6916935)
IIRC the stock system is good to ~600RWHP. Then the 3" is not just for sound anymore.

I stand corrected OP! You're gonna need a whole LOT of cubes then lol.

jcmG8 08-19-2013 07:31 PM

the magic number is 2.2cfm /HP. Any more flow is a waste of money.

Here is a decent unbiased article with science behind exhaust system design

thahemp 08-19-2013 07:33 PM

Quote:

Originally Posted by caverman (Post 6916945)
You won't get a true 3" system unless you buy one. I think KOOKS and LG are about the only ones that make a full header to exhaust tip in 3".

Most headers and cat-backs have a 2.5" connection point.

Unless you're making really big HP I wouldn't worry about going to a full 3" system. However, a 3" will give you a little bit of deeper tone when idling.

Lots of companies make a full 3".

dekan513 08-19-2013 08:07 PM

n/a i dont think the gains will be but like 1-2 hp if that. the weight of the extra pipe. will counter balance that tho lol

Craig B 08-19-2013 08:25 PM

Thanks for the replies. Looks like it's not worth changing to 3in.

thahemp 08-19-2013 08:34 PM

Sure it is. A 3" sounds like heaven on these cars.

Supercharged SS 08-19-2013 08:52 PM

JRE has an 800 rwhp on the 2.5" exhaust. Blower car though


I run the Kooks 3". It does sound evil at the track!:happyanim:

Baltimorejohn1 08-19-2013 09:19 PM

Quote:

Originally Posted by jcmG8 (Post 6916966)
the magic number is 2.2cfm /HP. Any more flow is a waste of money.

Here is a decent unbiased article with science behind exhaust system design

Great read

caverman 08-20-2013 10:07 AM

Quote:

Originally Posted by thahemp (Post 6916974)
Lots of companies make a full 3".

Not a true 3". I'm talking about 3" from the collector back.

Most 3" cat-backs have a 2.5" inlet so they can connect up to the stock mid pipes. KOOKS makes a 3" inlet cat-back as well as LG. I think ARH might have one setup that way as well.

thahemp 08-20-2013 12:32 PM

Quote:

Originally Posted by caverman (Post 6918970)
Not a true 3". I'm talking about 3" from the collector back.

Most 3" cat-backs have a 2.5" inlet so they can connect up to the stock mid pipes. KOOKS makes a 3" inlet cat-back as well as LG. I think ARH might have one setup that way as well.

And so does JBA. And so does SW. I know what you're talking about. I just know there are plenty of full 3" choices ;).


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