how long does my exhaust have to be - JeepForum.com

 
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post #1 of 4 Old 07-17-2013, 07:06 PM Thread Starter
sphippler
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how long does my exhaust have to be

How long does my exhaust have to be. Im not talking about legal or safety reasons. Im talking about performance and not damaging the engine. I have a 304 with 2.25" dia pipe and no muffler or catalytic converter. I've heard that if the pipe is too short that it can damage the engine.

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post #2 of 4 Old 07-17-2013, 08:08 PM
LMontycj2a
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On a Chevy 350 I used to have, I had headers, mufflers, and 6 inch turn down pipe. I drove it like that for 5 years. I never had a problem with it.

1997 TJ Sport, 4.0 I6, 32RH A/T, 31x10.50 General Grabber AT2, totally stock as of now. (need to install the Ballistic diff covers I bought)
1946 Bantum trailer
1946 CJ2A
1968 C-101 (Jeepster)
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post #3 of 4 Old 07-17-2013, 10:08 PM
5-90
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Quote:
Originally Posted by sphippler View Post
How long does my exhaust have to be. Im not talking about legal or safety reasons. Im talking about performance and not damaging the engine. I have a 304 with 2.25" dia pipe and no muffler or catalytic converter. I've heard that if the pipe is too short that it can damage the engine.
Theoretically, the exhaust manifold should be long enough to prevent damage (the "damage" you've heard about would be cool ambient air getting sucked back in between exhaust gas pulses, which would warp exhaust valves rather rapidly.)

Since you've got a V8, I'd go so far as to run back to a cross-over pipe (helps with scavenging, since each bank can assist the other,) and then install a spark arrestor on the ends of the pipes (I'm assuming you're off-road only, from what you've said?)

There would be no harm in installing a cat on each pipe - something from Random Technologies, perhaps - as it would show "environmental consciousness" and (hopefully) make a couple of greenies' heads explode! However, even with the cat, you'd still need to install a spark arrestor on the after end - but that may simply be moved from cat to cat, if/when they plug up.

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post #4 of 4 Old 07-18-2013, 06:15 AM
wellmax
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be sure it's long enough to keep the exhaust fumes out of the vehicle.

if you have kids, dogs, buddies, riding in the back, you do not want fumes coming back into the back seat area.

maybe if you turned the ends out

all I know in my old jeep that sits in the barn with no top, each time I take off down the road, dust, dirt, paper, what ever all flies out then comes back and hits me or the wind shield then makes the circle once more before flying out.

fumes would do the same I guess

my old jeep the exhaust come out the back on the drivers side, pipe sticks out about 2" past the body,
have never smelled any exhaust fumes.
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