Exhuast Issues

[71MoneyPit]

This is the first time I have ever posted anything to a forum so bare with me. I have a 71 Bronco that I have been working on for several years now. I have always had an issue with the exhaust getting into the cab area. I now pretty much run topless the entire time but the fumes still circle into the cab and gets really rough at times. I put all new exhaust from the manifold back and still have the issue. I have re-routed my pipes several times and the only way that helped was running them all of the way to the bumper and then turning them out to the side but I don't like the way it looks. Does anyone else have any suggestions. Thanks

 

[73azbronco]

route them out behind the tire, with the pipe exiting about 4 inches low from the body and even with the edge of the vertical line of the body and on a line drawn from the bottom of the tire to the rear of the truck/bumper.

It is what it is, anyplace else gets you backdraft.

I had them straight out as well and almsot got carbon monoxide poisoning.

 

[Heus33]

Welcome to the site!

You're not alone in your quest for a fume-less experience.

Routing the pipes behind the rear tires with an exit out the sides seems to work the best.

Here are a few other ideas:

You can route the tailpips at a 90 degree angle so they exit out the side or a 45 degree angle so they exit toward the back and out the side (I've had good luck wiht both of these).

The best one I've personally run was a 2 into 1 exhaust with one single exit behind the passenger rear tire at about a 45 degree angle.

You could always run a catayltic converter too to help cut down on the fumes.

Hope that helps.

 

[71MoneyPit]

Thanks for the info guys. I figured running the pipe out the side was going to be the most effective way.

 

[Dude seriously]

I had the same issue, the PO had dual exhaust straight out the back which I think looks and sounds better, but the fumes were too much. Routing the exhaust out the sides behind the rear wheels solved the problem.

 

[71MoneyPit]

Right now I have them coming out right in front of the tire thinking it would go out the side and not have any issues but that is not the case so behind the tire it is.

 

[Heus33]

Right now I have them coming out right in front of the tire thinking it would go out the side and not have any issues but that is not the case so behind the tire it is.

Good move - take a look at this thread too - while you're in there doing exhaust work you might want to read up a bit on sound/tone so you'll end up with exactly what you want.

http://classicbroncos.com/forums/showthread.php?t=196828

 

[71MoneyPit]

When I take them out behind the tire do I have to take the pipe all of the way past the sheet metal or can I cut it about six inches short that way it is less noticeable. This will be the fourth or fifth time I have done this so I am ready to get it right. I am afraid if I leave it short I will still have a lot of fumes. Thanks

 

[patterdale]

When I take them out behind the tire do I have to take the pipe all of the way past the sheet metal or can I cut it about six inches short that way it is less noticeable. This will be the fourth or fifth time I have done this so I am ready to get it right. I am afraid if I leave it short I will still have a lot of fumes. Thanks

I have a bone stock 1970 the pipe exits behind the passenger rear tire 90 degrees to the body and is about even with the "drip line". That would be the farthest line that the rear fender sticks out. There is no exhaust problem in the cab at all.

 

[Heus33]

I have a bone stock 1970 the pipe exits behind the passenger rear tire 90 degrees to the body and is about even with the "drip line". That would be the farthest line that the rear fender sticks out. There is no exhaust problem in the cab at all.

Do this and paint the tailpipes with a high temp black spray paint - like the kind used for bbq grills. That will help it blend in.

 

[DirtDonk]

When I take them out behind the tire do I have to take the pipe all of the way past the sheet metal or can I cut it about six inches short that way it is less noticeable.

I'd have to say yes, you hav to leave it all the way out. If you cut it short you are still in the wrong air stream for one, but the main thing is that you're concentrating enough of a roiling cloud of crud under there that it's going to get sucked right up the stake-pocket holes in the rear corners, come up through any gaps in the tailgat, any bolt holesl left un-seen in the body, and any seams in the fenders and wheel wells that are not quite perfect.
In other words, lousy with fumes.

That's my thought on it anyway.

Paul