two in one exhaust question

[BroncoKid]

My dad is almost done with his bronco rebuild and is ready for the exhaust. Me and mom are going to buy his mufflers and pipe so we can get-r-done.

Dads sort of old school and likes the sound of duals so for those that have a 2 in 1 exhaust, or have heard one run. How does the sound compare to the dual setup? does it still have the low rumble like the flowmaster duals?

 

[Broncobowsher]

Mine has a 2 in 1 out flowmaster under the passenger seat. I has a rumble.

 

[coupe66]

2 into 1

How abought that magnaflow exhaust kit from BC broncos has anyone used it and how does it sound ? Thanks

 

[TOFIC]

I like the spintech muffler has a real nice sound to it.
Us older types really like the sound but it comes at a price.
Check out the spintech site
TOFIC

 

[musetech]

Optimum setup is to incorporate an "H" pipe. Hard to do with all that 4X stuff under there. The pulses from each bank will help a great deal with the scavenging and give you that tuned sound. Otherwise it will be like two four cylinder engines running next to each other. Lots of crackle and pop.

 

[00gyrhed]

I run altered 1-1/2" shorty headers with 3" collectors. 2-2.25" promaries connecting in a wye to a single 2.5" tailpipe. I used a 3" core Dynaflow super turbo muffler. It has a nise deep rumble at idle and as you crack the throttle. As you give it the gas it actually seems to get quiter. THe big benifit to this system is that you can cross the driverside pipe to the right between the bellhousing and transmission and wye the passenger side into it from the top. The whole thing can be kept above the frame. You can also drop the transfer case without pulling the exhaust.

 

[coupe66]

oogyrhed Do you have any pictures of your set up . Trying to figure where to run the pipe .

 

[Kaw-Liga]

I have original exhaust manifolds w/ dual Magnaflows, this was done my the PO, I have dual flomasters on my '73 mach 1 with headers, and it does sound mean. The bronco is fairly quiet at low rpm, but still rumbles nicely. However, once you stomp on it, the beast rears its head and people tend to take notice quickly. I personally love the combo of quiet idle/loud and mean at high rpm. Maybe I'm not as die-hard flowmaster as I thought I was.

 

[BroncoKid]

more info

I have been pumping my dad for more information and his main concern on the 2 and 1 setup was the flow.
He likes the fact that with the 2 in 1 exhaust it leaves the driver side path open for gas and elect, air lines and such. The bronco has a well buitl 351W pushing arond 400hp, it has the JBA shorty headers that start out with 2 1/2" collectors. His worrie is once the exhaust dumps into the muffler then exits out the the 3" pipe, the flow will not be eqivulant to the two 2 1/2 duals = 5".
But then again dad tends to over analize things waaayyyy to much, what do you guys think?

I am not sure if mom and I will be able to suprise him with this as he seems to be uncertian on which option to take. "sheee! he'll probable bust me anyway once he does a search on this great site and see's this post"
Thanks guys for all you help!

 

[Broncobowsher]

Flow from a pair of 2½ pipes is equeal to the flow of a single 3½" pipe. That is how I set up my ranger.

My Bronco is running a built 351. 11:1 compression, alloy heads, injected, etc. Took the highest HP at the local Bronco Dyno day a couple years back. It runs a pair of 2¼ into a 70 series muffler with a 3" turndown. At a cold idle parked against a block wall the reverberation really pounds you. It has no trouble setting off car alarms. But it is quiet enough to listen to the wind noise inside the truck or carry on a conversation with the passenger.

Rumble is about the only thing left, the snap and pop are gone. And yes, it still sounds like a flowmaster, just a little more muted being that I am running the 70 series.

 

[00gyrhed]

I do not kinow if I will get this right but this website has a nice chart, for selection of exhaust size related to engine horsepower. It is more than large enough. Use the street tables unlessyou intend to run at peak horsepower all the time or you will loose torque. Anything larger than listed in this table is a waste of money and space under the truck.

If the image doesn't come through the link is

http://performanceunlimited.com/documents/exhaustguide.html

 

[DirtDonk]

I'm not sure that dual 2.5's wouldn't actually flow more air than a single 3" would, in theory. But a single 3 should still be plenty for what you're talking about. Unless he's going to mud-bog or sand race it. As long as it's hooked to a high-flow muffler as well, he should be happy with the performanc, and the sound.

I think that all the mufflers recommended above are good choices, but if your Dad is a die-hard Flowmaster fan, then stick with that and keep him happy. And yes, a two into one Flow can still sound damn fine.

I'm more a fan of the straight-through designs like the Spintech and the Ultra Flow and the Magnaflows myself, but there's no denying that good old classic V8 sound coming from the correctly matched Flowmaster.
Don't go too small or too few chambers and you should be golden. Stay away from the 2-chamber versions if he's even remotely past his teenage leangings. Go with a 40 or 50 (or even a 70?) series and if you intend to take it on long trips with the hard top on, go with the Delta-Flow version of whichever model you choose.

Oh, and good luck. Like you said, don't over think it or you'll get grey hair before he does. But then again... Overthinking is the fun part of building up a Bronco. Then, after all that, you get to second-guess your decisions for years to come. Until you try something different only to decide that you really liked the way it was before.
It's a Bronco thing...

Paul

 

[scottmcwms]

The cross sectional area of two 2.5" pipes is 9.81 square inches combined.
The cross sectional area of one 3" pipe is 7.07 square inches.
The cross sectional area of one 3.5" pipe is 9.62 square inches.

The drag coefficient of two 2.5" pipes is 60% higher than one 3" pipe. Therefore a 2 into 1 setup with a good set of headers is you best option. Dump that into a 2.5" or 3" tube out the rear and you will be good to go.

The headers will help increase the mass flow at the exhaust ports and will help increase your torque and vacuum. The 2.5" or 3" tube will provide enough backpressure to really get that flow velocity up and provide great exhaust scavenging performance.

If you need a chart to go by then check out this link. Chuck is showing off the dyno results of dual exhaust vs. 2 into 1. I think the chart shows everything you need. You can show this to your dad and he will think you are very cool for putting this much thought into it.

All that being said, I will be running dual exhaust just because that is what was on my Bronco when I bought it. The exhaust is still good so I will reuse it, until I get the funds together to purchase the BC Broncos 2 into 1 exhaust.

Scott

 

[AustinBronco]

new pipes

I have a 72 302 standard and i ran new headers with 2.25 exhaust thru dual flow master 2 stages and it runs and sounds great. I had the pipes exit right in front of the rear wheels and it looks great good luck with whatever you decide.

 

[brian72]

see my thread
http://classicbroncos.com/forums/showthread.php?t=88778

 

[adunham]

I just sold this truck, but here are some videos I made for the buyer. At the end of "Cold Start", the camera moves to the tailpipe for a listen and "Street Pass" is the sound from a distance.

http://video.google.com/videoplay?docid=55748951363776611&q=1969+bronco&hl=en

http://video.google.com/videoplay?docid=167336633602720771&q=1969+bronco&hl=en


It is the 2 into 1 setup decribed in this thread:

http://classicbroncos.com/forums/showthread.php?t=72146

 

[BroncoKid]

thanks guys for the replies.

Brian I seen your thread, how do you like the sound of the 2 in 1 compared to the dual set-up.

 

[brian72]

thanks guys for the replies.

Brian I seen your thread, how do you like the sound of the 2 in 1 compared to the dual set-up.

Don't have anything to compare to...except open heaers. the sound though is really good. but you can still talk in the cab.