Question on exhaust system
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From: Niles ohio
Question on exhaust system
Is there any difference in a 2 1/2 exhaust system compared to a 3? The headers are 1-3/4. The engine is a 350 with 11.25 compression. A solid racing cam with 106 lobe separation. Trick Flow heads with a vic jr intake.
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From: San Pedro CA
yes. and much more then the obvious .5"!
I would go with 3". With those headers and that compression, you need to suck those gases out!
If you are still running the stock style exhaust with the center cat/pipe, you may want to go with 3.5". If its true duals, stick with the 2.5".
I would go with 3". With those headers and that compression, you need to suck those gases out!
If you are still running the stock style exhaust with the center cat/pipe, you may want to go with 3.5". If its true duals, stick with the 2.5".
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From: Niles ohio
It's carb. No computer. I saw a good deal on 2-1/2 inch tubes with crossover pipe exhaust system for my new headers. I was just wondering if there was a difference between power and sound? So with the true duals I could get away with the 2-1/2. Thanks for replying.
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From: San Pedro CA
oh, yea. That will work good.
With a cross over, that will rock. The 2.5 should be good... you might want to do 2.75, if it's available.
3" is just too much... there will be little backpressure and little scavaging.
With a cross over, that will rock. The 2.5 should be good... you might want to do 2.75, if it's available.
3" is just too much... there will be little backpressure and little scavaging.
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From: Niles ohio
I called around today. I called the tech's from Summit Racing, Trickflow, and Crane Cam. They said the same thing 2-1/2 is fine with 50 series flowmasters. When I called Flowmasters tech they said when you start pushing around 500hp you need 3 inch. I know the number is 3 to 1. Should I trust the Flowmaster tech because he might have more experience in exhaust systems? Is there anyone around here running that size pipe with that kind of hp?
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A 2 1/2" pipe will flow about 560cfm and about 2.25cfm/chp is required for no noticible back pressure power losses. This of course assumes gentle mandrel bends in the pipe.
So, with true 2 1/2" duals you should be good to around 500chp; looks like Summit gave you the correct poop.
Remember that you may be limited by cat or muffler if they do not meet or exceed 560cfm.
Also, do not worry about going with 3" exhaust as the LT headers do the tuning so you need no further back pressure.
So, with true 2 1/2" duals you should be good to around 500chp; looks like Summit gave you the correct poop.
Remember that you may be limited by cat or muffler if they do not meet or exceed 560cfm.
Also, do not worry about going with 3" exhaust as the LT headers do the tuning so you need no further back pressure.
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
I didn't know there was such a thing as 2-3/4" tubing.
65zo1, where'd you get your data from? I'm curious to see the basis for it, and where 2.25" exhaust fits in. It exhausts me to read these exhaust posts where they keep saying bigger is better, which I know is false.
65zo1, where'd you get your data from? I'm curious to see the basis for it, and where 2.25" exhaust fits in. It exhausts me to read these exhaust posts where they keep saying bigger is better, which I know is false.
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From: Niles ohio
Originally Posted by mikey whipreck
YOu could always pick up a true dual 2 3/4" system... for next to nothing on the FS/T section
When you're saying the FS/T, do you mean the parts for sale section for C4 parts? Thanks
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Originally Posted by 84 C4
When you're saying the FS/T, do you mean the parts for sale section for C4 parts? Thanks