Exhaust?

[Hedgehog]

After some drive time in the CJ5 I'm having a problem that is not entirely unexpected. The Jeep has a 360, headers, 2 cats, 2 magna flow mufflers and tail pipes that exit directly out the back approximately where the frame rails are. Well, no surprise the exhaust is sucked up into the passanger compartment. The pipes will be cut and turned out at a point near the back of the rear wheel. Others have experienced this problem, so rather than reinventing the wheel I thought it would be good to find out exactly where the best place to exit the exhaust would be. Also, would it be better to use turn down tips or straight out tips?

 

[Dolamite]

Hedge,
I ran into the exact same problem on a '78 CJ5 I used to own. Dual exhaust straight out the back. I always smelled like exhaust.

On my current CJ5 , I angled the exhaust out behind the rear driver side tires. I am happy with the results.

 

[Hedgehog]

In the picture it looks like you brought them out at the corner? Or is this a picture the Jeep you had trouble with?

I wonder if there would be a problem with bringing them out close behind the tire with the pipe running through between the spring and the frame. The pipe would be high next to the frame.

 

[IOPort51]

any possibility you are smelling unburned fuel? Maybe a little rich? Do you smell this at idle, setting still, or just when you are driving at speed?

 

[007]

Hedge,
I ran into the exact same problem on a '78 CJ5 I used to own. Dual exhaust straight out the back. I always smelled like exhaust.

On my current CJ5 , I angled the exhaust out behind the rear driver side tires. I am happy with the results.

To add to what Dolamite said, I have read multiple times that the best way to handle this is if the pipe is running parallel to the ground, then it needs a 45 degree bend out coupled with a 45 degree bend down behind the tire as shown.

My "guess" is that the exhaust drafts into the air current surrounding the rotating tire and in doing so it diffuses the fumes thus lessening the likelihood of them being able to travel back up in the seating area.

 

[cj7inthetwigs]

For what its worth, my dad always had K5's. Duals straight out and fumes always made us tear up due to the seals at the tailgate being old. My CJ7 has single exhaust turned out behind the wheel as factory believe, either way no fumes come in . I think turn downs will only help.

Sent from my DROID RAZR HD using Tapatalk

 

[Hedgehog]

IO - I believe the answer is a deffinate yes to both of your questions. Even though it made it through emissions with no problems I do believe it's running a little rich. However the exhaust is deffinately in the drivers compartment, which is easy since I'm running a bikini top and half doors.

This sort of exhaust problem is not new, when heading out on a camping trip, we were 15 at the time, one of my buddies darned near passed out from exhaust smoke while riding in the back of a pick-up. He looked green for hours.

This will be easy enough, exhaust pipe ends are easily available from various automotive supply stores, but I only want to do this once. Now I'm ruminating on whether to use clamps or weld the ends on. Welding seems the obvious choice, but the gas tank is right there only inches away. It would be easy enough to put up some sort of a welding shield though. Speaking of sparks, I'm going to need to cut off the fancy square pipe ends, those I'll miss. The Saws-all will probably get that job done, but the cut off wheel on the angle grinder would get-er done quicker.

 

[Old Dog]

FWIW mine come straight out the back with a 90* turn down at the end.
I have very little smell with the bikini top. You might try this before you cut yours all up.

 

[Dolamite]

In the picture it looks like you brought them out at the corner? Or is this a picture the Jeep you had trouble with?

I wonder if there would be a problem with bringing them out close behind the tire with the pipe running through between the spring and the frame. The pipe would be high next to the frame.

It was a pretty poor picture, I know. This is my current set-up (please ignore the rust). It is angled slightly down and slightly out and in my case it seems to be working well. It is kind of close to the rear spring shackle, but doesn't rattle at all.

My original intention was to run out behind the tire and through the spring and frame as you describe, but the existing pipe hanger was too far back to allow for that type of set up. I suppose I could have taken the time to move it, but I was too darn excited to get the Jeep on the road!

My previous Jeep had dual pipes run straight out the back and it caused some eye burning.

 

[Hedgehog]

That is what I'll try first, a pipe going down and to the left/right. The square pipe ends that came on the Jeep look so nice, but I also want to LIVE! A head ach after a day in the Jeep would be so very unfun.

 

[mstar]

Hedge, sounds like good advice you have received.Just for a little background info on the station wagons they always had the pipes exit to the side.I had my pipes put out the back once on the '69.that lasted 1 day.bad idea. Prior to that experiment I always had side exit.Like you said between the frame and spring closer to frame with a tailpipe hanger attached near frame.I think angled down a bit is ok just don't do 90* or youll have dust blowin everywhere first time offroad. I always like the guys with the muscle cars that pull in to a cruise-in with turn down exhaust dust'in out every car in sight. mike

 

[Hedgehog]

To finish the story:

I ended up cutting the square exhaust tips off and had some tips made with a decent turn to them. The exhaust now dumps behind the rear wheels.

It is amazing to hear the difference. Originally the exhaust exited straight out the back and sounded a bit hot rodish. I was always trying to grab another gear. Now the Jeep sounds a little boring, but that is exactly what I like.