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favorite off the shelf exhaust package?

Monster Mike

Sponsor/Vendor
Bronco Guru
Joined
Dec 29, 2010
Messages
1,768
Any update on the Duff kit?

I need some new plumbing under mine but would like a shorty header/ 2 into 1 combo I believe.

Yes, we are currently doing market testing.

What drivetrain are you running in your EB?
 

bronkenn

Contributor
Bronco Guy
Joined
Apr 27, 2017
Messages
2,662
Loc.
Southeast Ohio
I have the M5OD with Duff's long tube ceramics. Will be doing exhaust in a few weeks(6 to 8). Was wondering about 2 into 1 as well. Ken
 

Monster Mike

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Bronco Guru
Joined
Dec 29, 2010
Messages
1,768
I have the M5OD with Duff's long tube ceramics. Will be doing exhaust in a few weeks(6 to 8). Was wondering about 2 into 1 as well. Ken

Wish we could help but our 2-1 does not work with long tube headers. We supply shorties instead.
 

sykanr0ng

Bronco Guru
Joined
Aug 11, 2014
Messages
5,363
Looks like a custom exhaust is a must for me.
I want long tube headers and a 2 into 1 exhaust and have a Dana 20 t/c, a 351W and a ZF5.
 

.94 OR

Contributor
Bronco Guru
Joined
Jul 5, 2009
Messages
1,654
302-NP435-D20 w/ 3.5" lift.

I currently have long tube headers and duals. I was hoping to change out to some shorty headers, 2-into-1 with a nice sound. Need to get the heat away from the fuel line.
 

Monster Mike

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Bronco Guru
Joined
Dec 29, 2010
Messages
1,768
Looks like a custom exhaust is a must for me.
I want long tube headers and a 2 into 1 exhaust and have a Dana 20 t/c, a 351W and a ZF5.

Yeah, I wish we could help. I have seen long tube 2-1 exhaust done really well. Wish you the best!

302-NP435-D20 w/ 3.5" lift.

I currently have long tube headers and duals. I was hoping to change out to some shorty headers, 2-into-1 with a nice sound. Need to get the heat away from the fuel line.

Sounds like you would be a good candidate for our kit. email me at monstermikeduff@gmail.com

Do you have a 2-1 that will work with an AX15, D20, stock manifolds, 1" BL and 2.5" SL?

It depends on the trans/t case crossmember. the crossmembers that are made by or copied from Advance Adapters will not work with our exhaust kits w/o modification.

If your crossmember mimics the stock one there is a good chance the kit will fit.
 

centex77

Full Member
Joined
Oct 31, 2017
Messages
183
I bought a universal piping kit from Summit Racing along with Dynomax bullet mufflers and plan on building my own. I've got Tom's Broncos long tubes and there's not a kit made to meet up with these.
 

Monster Mike

Sponsor/Vendor
Bronco Guru
Joined
Dec 29, 2010
Messages
1,768
I bought a universal piping kit from Summit Racing along with Dynomax bullet mufflers and plan on building my own. I've got Tom's Broncos long tubes and there's not a kit made to meet up with these.

We have adapters so you can use our dual exhaust kit with Tom's longtube headers.
 

mjschneidy

Full Member
Joined
Nov 21, 2016
Messages
224
About to do a 2-1 and it appears all the mufflers are 1 in 2 out that people are mounting backwards. Is this the case or are there true 2 in 1 out performance mufflers available ? I see kits using Magnaflow for this but I don't see any 2 in 1 out Borla mufflers on their site.

I'm using L&L long tube headers, I believe I'll need to go custom vs buying a kit.
 
Last edited:

sykanr0ng

Bronco Guru
Joined
Aug 11, 2014
Messages
5,363
About to do a 2-1 and it appears all the mufflers are 1 in 2 out that people are mounting backwards. Is this the case or are there true 2 in 1 out performance mufflers available ? I see kits using Borla for this but I don't see any 2 in 1 out Borla mufflers on their site.

I'm using L&L long tube headers, I believe I'll need to go custom vs buying a kit.

Flowmaster Super Delta 50

If you want louder:

Flowmaster Super 44 Series Delta Flow
 

Monster Mike

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Bronco Guru
Joined
Dec 29, 2010
Messages
1,768
Since it's been discussed here I want to give a quick update.

I decided to make a change to our 2-1 kit before we put it in production.

My goal is to make it work with the Advance Adapters NV3550 and AX15 crossmember.

I will make an update here once I have it complete.
 

Joe473

Sr. Member
Joined
Jul 16, 2012
Messages
950
Since it's been discussed here I want to give a quick update.

I decided to make a change to our 2-1 kit before we put it in production.

My goal is to make it work with the Advance Adapters NV3550 and AX15 crossmember.

I will make an update here once I have it complete.
And the ZF/M5 crossmember with torque tamer installed too,right?? :)

Sent from my SM-G960U using Tapatalk
 

Monster Mike

Sponsor/Vendor
Bronco Guru
Joined
Dec 29, 2010
Messages
1,768
And the ZF/M5 crossmember with torque tamer installed too,right?? :)

Sent from my SM-G960U using Tapatalk

It will clear the Torque Tamer. Not sure what the ZF/M5 crossmember looks like. Is that the one BC offers?
 

centex77

Full Member
Joined
Oct 31, 2017
Messages
183
I bought a universal piping kit from Summit Racing along with Dynomax bullet mufflers and plan on building my own. I've got Tom's Broncos long tubes and there's not a kit made to meet up with these.

I ended up going with the duff exhaust utilizing their tbp adapters. I modified mine to make it dump just behind the rear axle but the kit fit great and the instructions were spot on.
 

Joe473

Sr. Member
Joined
Jul 16, 2012
Messages
950
It will clear the Torque Tamer. Not sure what the ZF/M5 crossmember looks like. Is that the one BC offers?
Yes, the biggest thing there is the transfercase ends up a few inches further back which puts torque tamer crossmember occupying same area as muffler and shorter main bar on torque tamer

Sent from my SM-G960U using Tapatalk
 

PaveBronco

Sr. Member
Joined
Oct 30, 2012
Messages
912
Since it's been discussed here I want to give a quick update.

I decided to make a change to our 2-1 kit before we put it in production.


I will make an update here once I have it complete.


Eagerly awaiting the 2-1 Shorty header Kit...
 

greenmonster

New Member
Joined
Jul 24, 2018
Messages
15
Loc.
Southampton
Wow...great timing for a thread like this to appear!

I apologize in advance but this is a windy post. there is a lot to cover so please take a bathroom break or grab your favorite drink and sit down before you get started ;D



I have just spent the last month working on the Duff 2.25" aluminized steel exhaust kits. We have had a few different companies build these kits for us in the past 20+ years. Other than a few guys on here, I have had very little negative feedback on the fit and finish of the kit. Not that your opinion doesn't count though! I decided after we bought a Bend-Pak bender that we would start making the exhaust systems in-house for the first time. I made copies of our current kit. Then, just to be sure all the bends and lengths were exactly like what we have been offering, I installed it on Hobby Horse, one of our EB's. I wanted to see what our customers were experiencing. Hobby has a 351W, the HD motor mounts that lift the motor a bit taller (3/8-1/2") and our long tube ceramic headers. She also has our 5.5" lift, 1" body lift, 36" tires and our long arms. The rest of the drive train is an AOD and a Dana 20 with a EB 9".

When we first designed these kits (the 1990's) we had some simple goals in mind. It had to be bolt on and it had to work with an EB that had a 302/351W and no body lift. From there a little tweaking was all it took to make our kit work. A lot has changed since we first debuted this kit and I realized that just the motors alone can offer 4 different deck heights when you factor a 302 vs a Windsor and a stock motor mount vs a HD motor mount. Then you get into all the different transmissions, body lift, long arms, anti wrap device, different transfer cases and extended wheel base. How could we possibly offer an exhaust kit that worked with all of that!? Well, we can't cover every configuration but most of them, i think we can.

When I put our exhaust kit on Hobby Horse, I found a possible clearance issue with the long arm frame brackets. I also noticed the intermediate pipes could take a little more bend in them. This allowed them to fit up to our headers at a more direct angle. From there, I found that I could move the mufflers so that they would work better with our Torque Tamer (our axle anti-wrap device) and be better protected from rocks crunching them. At this point, I thought why not just go over the entire system and see if we can make it even better.

To make sure that we had a variety of EB’s covered, I brought in one of our local customer’s rides. This way, I could “stare and compare” at two very different Bronco configurations to make sure that I didn’t screw up an already good thing. After all, the goal was to make it even better. The customer’s ride has a 302 w/ stock motor mounts/C4/Dana20/9", 2.5" suspension lift, no body lift, uncut with 29" tires. The 302 has stock EB exhaust manifolds. First I removed his exhaust then bolted up our stock exhaust manifold down pipes. The passenger side worked fine but the driver side had a different trajectory than our long tube headers. Before making any mods to that I then bolted up our exhaust kit. It bolted together OK, but I felt that it hung a bit low. It could stand a little more bend where the down pipe and intermediate pipe fit together. It also benefited from the same mods to work with our long arms and/or axle anti-wrap device. I could see if I bought this kit before several options and modifications were added to the Bronco and before the upgrade bug hit that this kit woud be more than suitable for most.

I have told customers that our kit is so simple you can bolt it on in your driveway with nothing but a drill and simple hand tools. I tried to keep that point in mind as I continued tweaking the system. I wanted to be sure that you could “upgrade as you go” and not have to worry about any of our parts not playing well with each other. I feel confident that we have achieved that goal. But, I am really looking for your feedback. It helps us create and improve our products and lets us know what you would like to see next.
It was a challenge that we believe will pay off and I hope that we have met the needs of the majority. Our original kit was a 4 piece design (not including mufflers). Our new kit is 6 pieces. The tail pipes are now 2 pieces. This makes the install easier and gives you 3 different options for how you want the tail pipes to exit: straight back, 65° angle out the side, or 90° angle out the side (both behind the tire). Also, for our wheeling guys, this makes the last part of the tail pipe (The one that could get crushed…ask us how we know!) an easily removable/replaceable piece (we plan to offer this piece by itself, just in case you need it or want to change it to a different style). We hope to soon offer a selection of exhaust tips as well. An added bonus in the design change is the shipping costs. We are now able to ship the system in a considerably smaller box. This will allow us to deliver at a lower total cost. That’s what we call a “win-win-win”!

There are a few challenges we still hope to tackle. Currently, our exhaust kit will not work with an NP 205 or Atlas transfer case. Our long tube headers do not work with a C6 (and I don't know if our exhaust kit would work with a C6 if you did manifolds…but it might). Our exhaust kit could work with shorty headers, but we haven’t built a down pipe to connect it yet. I think it’s something we should do because a lot of you buy shorty headers. Any feedback? What do you guys think?

While we are on the subject of exhaust…I would like to talk about mufflers and the difference they can make in sound and performance. We offer Cherry Bomb, Flow Master, and AP (others by special order with enough lead time). The Cherry Bomb mufflers are offered in two levels: Vortex (mild sound, without resonance at highway speeds, had them several years on Silver) and Pro (a bit louder, but more “throaty”; awesome on Hobby). The Flow Master is a 40 series and is similar to the Vortex and has that well known Flow Master sound. I love the sound of the Pro's, but I like aggressive sounding exhaust. The customer we installed our new exhaust on went with the Turbo's (by AP, the quietest of our mufflers). Turbos are just a touch louder than stock V8 exhaust with stock manifolds. Vortex and Pros are really great sounding, especially with our long tube headers. I haven't got a chance to test the Pros on the freeway, but with the AOD I don't think there will be a drone issue. The Vortex are an awesome muffler if you run a C4 on the freeway. They have never bothered me at 2800-3000 RPM.

On a final, exhausting note (thanks for staying with me this far!), I want to let you guys know that we took measures to make our long tube headers seal better at the collector. The flange is now welded to the end of the collector and the reducer cone also has a flange welded to it. This makes the flange more rigid and that prevents any warping of the gasket (which can lead to a leak). We also replaced the gaskets for both the head flange and collector flange. We now include premium, multi layered steel (MLS) gaskets with no increase in the retail price. We also found changed the way that we build our reducer (the part that adapts the header to the exhaust pipes). Our collector is 2.5” and our exhaust is 2.25". The reducer is now a full 2.25”, as well.

What does the future hold for our exhaust? With the new Bend-Pak bender we can expand our product line and do custom orders. 2" or 2.5", stainless, 2 into 1, down pipes to connect shortie headers to our exhaust kit. if you can dream it we can more than likely build it. We would like the chance to quote it for you. Just remember we are a production facility and custom orders are something we have to work into the manufacturing schedule. I enjoy working together with you guys and would love to offer more new and innovative products in the future.

I know I know...this post is worthless w/o pics! %)

*The new exhaust kits are made but I still have to get the instruction sheet finished and lots and lots of key strokes to get it all in our computer system so the packaging guy can box them properly, the salesman can sell them properly and the shipper can ship them properly. I should have that all done by 11-15-17*

Thank you for putting in the time to make these exhaust systems for us. I want to have an all stainless system, I have headers and a 302, 3.5" lift, dual exhaust, mello deep sound, no drone, X pipe, rear exit to dual tips, I have two into one and back out to two. I think it is one large Magnaflow but it sounds like a race muffler and is obnoxious. I suppose I could just change the magnaflow but not a fan of this 2-1-2 setup
 

Redbark

Full Member
Joined
Sep 5, 2016
Messages
177
Since it's been discussed here I want to give a quick update.

I decided to make a change to our 2-1 kit before we put it in production.

My goal is to make it work with the Advance Adapters NV3550 and AX15 crossmember.

I will make an update here once I have it complete.

Hey Monster,
How's progress coming on this kit for use with the AA AX15 crossmember?
 
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