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TRUE Dual Exhaust (Gacknar look here!)

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21K views 60 replies 28 participants last post by  Kpate  
#1 ·
Okay so before anyone even says anything i HAVE REASEARCHED!

So there is this guy that works for my dad that says that he could put me a TRUE dual exhaust (not cat-back) on my 96 BKO for $250 :)shocked) with flowmaster mufflers. now from what i have read on here and seen under my truck, there is no way to do a true dual exhaust system since the transfer case is in the way? :banghead

will a true dual system sound good? will it be insanely loud?

i just need some clarification and advice on this subject.
 
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#2 ·
It can be done by running 2 pipes uder the passenger side and once the are behind the gas tank they can exit on both sides. i have shorty headers with no cat running into a 3in inlet and two 2.5 in oulet stainless strait through muffler. the pipes exit at a 45deg angle behind the wheels with 4 inch tips. the whole system is stainless. my rig has a 302 and it i give it an 7 or 8 for loudness. really true duals can be done but what i have flows and sounds just as good with less hassle. 250 sounds cheap so i would see what u are gettin
 
#3 ·
I have a true dual exhaust with flow 40s on it with long tube headers and yea its pritty loud espeshaly if u romp on it but its not insanly loud but some of my buddys say they can here me across town (its a small town) but i have a 3 inch body lift and it runs over the t case and its fine but there is other ways of doing it.
 
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#4 ·
Again its pointless to run a dual exhaust on a bronco. Single 3" pipe is more than you'll ever need, and will give you the power where you need it.
 
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#22 ·
This is absolutely true, in fact, a single 3 inch pipe would likely produce more low end power and be easier to run if you can get someone to bend 3 inch pipe without crimps in the bends.

True duals won't produce better fuel mileage than a single system, if my BKO didn't already have the dual system on it, it wouldn't have one. A cat does not reduce system efficiency if sized correctly, it has no effect at all except as a pre-muffler.
 
#13 ·
where are you going to put 2 pipes out the back of a bronco so it doesnt look like half assed shit? dont forget exhaust straight out the back goes straight in the rear window
 
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#19 ·
broncodude26 said:
also id have the exhaust coming out the back at angles so it wont go back in the window.
Click to expand...
It'll still get in the back window. Everyone here that's ever experimented with exhaust set-ups on our Broncos will tell you that. Pretty much the way to keep the most amount of exhaust out of the window is to have it exit the side of the body.
 
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#20 ·
I have true duals on my '96, the PO put them on. It has dual cats and dual Flowmasters on it, with the exits going to each side at the rear. I don't have photos of it all, here's what I have.

Dual Flowmasters.
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The exhaust pipes turning right and left.
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The right side tail pipe.
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One of the two cats is in this photo, the other one is above and behind this one. One of the pipes has the third O2 sensor in it, but the PO couldn't get that one to function with the computer. It's my opinion that the cats don't light off in the time allocated by the engine computer, so the check engine light was always on. I eliminated that issue with a device that works with the computer much better, and all is well.
Image


I don't know what the PO paid for this system, and since there are headers too, they may or may not have been part of the overall price. I'd expect the system without headers to run more than $250.00, but as I say, I don't really know. The PO didn't include a crossover pipe in the system, which reduces efficiency and low end torque somewhat. The sound would be much better with a crossover, aka X- or H-pipe, and no, I don't like the sound. Too "blattey" for my tastes, but it's not overly loud because the cats act as pre-mufflers.

My BKO has a six inch suspension lift, so that provides some additional clearance.
 
#21 ·
I have a 357 with 33s and a stock 3.5 gear with a 435 gearbox. Sure, first it a low gear, but the other day I did a rolling burnout in second gear. I got it rolling and then just rolled into the throttle and it started smoking both of the tires. Lest you have some hoss engine that is over 400HP, 3" will be MORE than enough for you. Mine is a long tube with a 3"Y pipe, to a single inlet/outlet flowmaster, to a single mandural bent 3" tail pipe. Looks okay, sounds better, and performs flawlessly.

Chris
 
#23 ·
One question I have is would a 2.5" single w/ a free flowing muffler be just as adequate as a 3" system on a bone stock engine (no modifications/ manifolds/ single cat/ smog gear in place). It's just something I'm pondering for my F-150 since I lost part of my exhaust coming home from work last night (and I have a new 2.5" in/out Flowmaster 50 series in a box that was a freebie:chili: )
 
#35 ·
Absoutely. Since the engine is just stock, 2.5 will work just fine. I would not hesitate to do that for mine if it was just stock with a 302.

Also, it depends on the company and the type of exhaust that the cat back system is. I do not agree that there will not be a difference with one.

You also need to understand that exhaust is not just a "throw a size at it and go" type system. If you have two pipes, you have to understand that the surface area is taken into account. One 3" pipe flows better than two 2.5 pipes because of the surface area.

Chris
 
#24 ·
a cat back setup will do nothing for performance or mpg. it will change the sound is all. you need to upgrade the system from the manifolds back and like everyone is saying stick to a 3" single setup. your making this way to hard on yourself.
 
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#26 ·
As stated, a single 3" Exhaust will perform just as good as a properly designed dual system. It will flow better than a poorly designed dual system.

For a 2.5" dual system to flow as good as a single 3" the system must have a crossover pipe and it must be mandrel bent. No crossover pipe and one bank wont scavenge the other and it will make a popping sound at higher RPM's. Non mandrel bends will lower the cross section of the pipe producing back pressure.

I ran duals on mine for one reason and one reason only, I wanted it to sound different. (not like a truck)

Click for sound clip


I have still not ran tail pipes yet, but plan to in the future.

It cost twice as much to run a properly designed dual exhaust than it does to run a good 3" system. So unless you just want to do it to be different, stick with a single 3"

My system cost me about $600.00 and doesn't even have tailpipes yet, just turn downs. That said, I am very pleased with it's sound, performance, and design. Wile I would not recommend it to most people due to cost, it works very, very well on my 357w.

Here is the main article on my exhaust system.
http://www.fullsizebronco.com/forum/showthread.php?t=77217

And a few pics.
Image


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Image


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Also take a look at the "Exhaust sound clip" thread.
http://www.fullsizebronco.com/forum/showthread.php?t=97374
 
#30 ·
Gacknar said:
No crossover pipe and one bank wont scavenge the other and it will make a popping sound at higher RPM's.
Click to expand...
Mine doesnt pop with out a crossover :shrug Although I do agree that I need one. I was amazed with the amount of low end my brother gained with adding an h-pipe on his 79.

Anyways, sounds great Gacknar. I was torn between using the spintechs and aerochambers on mine. I was also going to add, dont some of you guys think some people that want true duals do it for the sound? I know it sounds stupid, but Ill be honest thats why I did it. I couldnt really tell any difference from going from a 3" single to true duals. Mine was poorly done also. I wish I would have payed more attention to what the shop was doing, some of the bends are just ridiculous.
 
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B
#28 ·
Nice exhaust Gacknar sounds good! I have true 2 1/4 duals without a H-pipe, But i have a body lift and it runs over the T-case . I'm not that happy with it because of the popping sound. I'm going to put an H-pipe on it then I'll be happy. My duals cost $480 with flowmasters.
 
#29 ·
I have a dual exaust on my 96 too. w/o cats, and headman headers. Check my stupermotors for pictures. It looks similar to Fastpats' but mine went stright out the back.

That was my fault because i just did it with out searching on here to find out thats a bad idea. But I don't need to worry about it till spring when it gets warm out and i want the window down.

Are you getting headers? If your getting an exaust, no point in hooking it up to the stock manifolds, go get some headers and see if the guy will put them on for you when he's under there.
 
#34 ·
It would only do it under load at higher RPM's. Not just reving in park.

Maybe "pop" is not the right word, perhaps "cackle" would be a better definition. I have never heard a true dual system without a crosover that didn't do it atleast a little (depending on the type of muffler used).
 
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