exhaust dumped in front of rearend - Ford Bronco Forum
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post #1 of 30 (permalink) Old 01-29-2017, 07:41 PM Thread Starter
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exhaust dumped in front of rearend

I have headers with true duels, flowmaster 40s and the pipes exit behind the rear tires on my 79 bronco. I was thinking about dumping them right in front of the rear end. What are the pros and cons of doing this. Just want something different and if they are dumped you cannot see the pipes. What do you guys think
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post #2 of 30 (permalink) Old 01-29-2017, 08:11 PM
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I have seen at least one bronco that frenched in the pipes inside the lower body. it looked pretty damn cool too. In front of the tires is fine if you have the room. It will shorten the pipe and be louder by a smidgen. Other than that, not much of a difference.
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post #3 of 30 (permalink) Old 01-29-2017, 08:14 PM
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I think the pros outweigh the cons, if you wheel.

Not going to get smashed. EVER.
Sleek hidden look
Not in the way anywhere in the back if you need to service gas tank, add an air tank, do custom mod work, or whatever
Oh and yeah NEVER GETS SMASHED! :)

Will coat your rear axle with sooty residue that needs to be cleaned off by hand with a brush and soap if your anal about how your undercarriage looks like me
Can't see the pipes...if you like chromed exhaust or something
I think the sound resonance may be worse with it exiting under the cab, but mine have never exited out the rear since I've owned it so I don't know (ran Flowmaster 40 series then went to 70 series delta flows)
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post #4 of 30 (permalink) Old 01-29-2017, 08:28 PM Thread Starter
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One thing right now I dont like now is when it is idling and someone walks buy they smell like exhaust.I was hoping to turn them down right in front of the rearend and at least blow it to the ground.
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post #5 of 30 (permalink) Old 01-29-2017, 09:21 PM
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I've done this several times on different vehicles. Only downside is the soot on the underside and it does resonate between the ground and body and makes the exhaust really loud right outside the doors. With any kind of loud muffler expect not to be able to hear conversations 5ft away at idle. If you turn the exhaust out to the sides it doesn't make much difference other than the exhaust smell.

A con might be if you get stuck in muck the exhaust could clog underneath and fill the cab with fumes, or make it hard for the engine to run. Only had that happen one time in a quicksand hole.
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post #6 of 30 (permalink) Old 01-29-2017, 09:59 PM
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My exhaust currently dumps out under the Bronco and at an angle beside the gas tank. It is loud so expect to hear it at a louder rate and it will come in the Bronco when the rear window is down.
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post #7 of 30 (permalink) Old 01-30-2017, 04:24 PM
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No experience with a Bronco, but I don't like dumps in general. The fumes alone are enough to steer me away.
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post #8 of 30 (permalink) Old 01-30-2017, 05:24 PM
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I had mine ran with a dump after the muffler and didn't like the decal crackle that is made, It was also kind of loud as noted above. I found that adding the bends to go up and over the axle then to ground to be much better. I ran it like that for a good length of time with really no negatives. I feel that some tubing and bends after the muffler helps make it sound deeper, which is what I like. However I agree with the above that coming out the quarter right in front of the tire is cool looking. BonsaiDave has his like this.

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post #9 of 30 (permalink) Old 01-30-2017, 06:52 PM Thread Starter
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I was talking to a guy at work and he said the exhaust fumes would be worse while in traffic idling if they were dumped in front of the rearend. So I will probably just leave them where they are for now. Thanks for all the commits.
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post #10 of 30 (permalink) Old 01-30-2017, 06:56 PM
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I currently have mine dumped in front of the axle. Setup is a 3" single Magnaflow that was on the truck when I bought it, stock cat and headers. I chopped the over the axle pipe, which was a stock style side exit, with plans to re-do the exhuast from the headers back, with a side exit in front of the tire, but haven't got 'round to it... so the current state.

Mine sounds good and isn't overly loud, but you will get more resonance with it dumping under the body. I ran Flowmasters with dumps on a Mustang years ago and they were quite loud.... they would consistently set off car alarms in concrete parking garages.

The thing I really don't like is it pulls fumes in the back with the rear window down. It also did this with the stock location side exit.... I'm hoping moving it in front of the tire will minimize the issue, though reported results here vary widely.
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post #11 of 30 (permalink) Old 01-30-2017, 07:37 PM
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Dumped in front of the rear tires. Flowmaster 40s. Sound great.

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post #12 of 30 (permalink) Old 01-31-2017, 05:25 AM
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Fender well exit headers makes it pretty easy to dump the exhaust in front of the back tires.

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post #13 of 30 (permalink) Old 01-31-2017, 07:56 AM
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Mine is dumped at the rear axle and the only time i have had issue with fumes is if i have the top on and drive with the rear window down.

Haven't had the top on in a few years, so haven't had any fume issues since.

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post #14 of 30 (permalink) Old 01-31-2017, 10:58 AM
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Had my 95 f250 460 set up with no cat, a super 44 muffler and an immediate turn-down. It ended at the back of the single cab. Never had an issue with fumes or with it being too loud. Don't get me wrong though, it was loud. I have similar plans for my 85 and 96

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post #15 of 30 (permalink) Old 01-31-2017, 11:08 AM
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Used to run the M30001 tailpipe and loooooved the sound, but swapped to a turndown in front of the axle because I kept smashing it. The turndown is great, no smashing/etc., but my exhaust note isn't perfect like it used to be. One of these days I'm gonna swap the tailpipe back in and try to tuck it up a bit higher. I really miss that sound.

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post #16 of 30 (permalink) Old 01-31-2017, 12:04 PM
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If you DD or drive it on the highway like tow as you do you will get exhaust fumes in the vehicle, I only know this because I have don it with side pipes. If noise is an issue it will be sudsyatially louder, you also will loose torque dumping exhaust shorter will increase top end like for drag race but loose bottom end and response. The noise level will increase due to the sound is not bouncing off the ground if you use down facing turn downs, think of when you drive pass a retaining wall or under a bridge with side exit exhaust. The sound bounces back at you and increases cab noise. I would do header dumps before the muffler but after the crossover for best power when you need it then when you want that extra 20% and that nasty open header BB sound flip a switch and surprise open flames shooting out just behind the fron tires. It funny to watch the mini pickup guys shit when you burn the paint off the side or their truck when you stomp on it.
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post #17 of 30 (permalink) Old 02-01-2017, 07:48 PM Thread Starter
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The fumes is what I done not want. The sound being louder would be ok. I guess I will just replace the pipes from the mufflers back and go out behind the tires like it is. Thanks.
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post #18 of 30 (permalink) Old 02-02-2017, 01:13 AM
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Why is everyone driving with the rear window down???

79broncoowner, do what you want with your exhaust. No matter how you route it, if someone drives with their rear window down (and the top on), that's just dumb. The low pressure zone created at the back of the vehicle deposits all the fumes and dirt/dust back in to the vehicle no matter what.

I have no cats and my exhaust dumped behind the rear axle, angled slightly toward the pass rear quarter. Unless I just sit there and idle with the top down and windows open, I never notice my exhaust. But I would never just drive with the back window open, mainly because I don't want the dirt sucked back in to my Bronco.
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post #19 of 30 (permalink) Old 02-02-2017, 06:57 PM Thread Starter
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I dont run with my window down either. It will like you said suck the fumes. I was wanting to know if I turned the exhaust down infront of the rear end would I be choking on fumes in traffic at a slow pace because the exhaust is under the bronco. I had my top off once and had not had it off since because of all the dust on my interior.
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post #20 of 30 (permalink) Old 02-03-2017, 04:14 AM
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Originally Posted by sk1nw4lk3r View Post
Dumped in front of the rear tires. Flowmaster 40s. Sound great.

Sorry to break the line of discussion but wow. The paint looks great. is spray on bedliner or rolled on or what.

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