The Stovebolt Site Forums The Shop Area Engine Shop 235 dual exhaust experiences

Hi guys. Covid and winter blues have me in need of some truck work.

I am a putting a 60's set of Fenton headers on my 51 3100 with 55 235. I am water heating my intake and installing dual exhaust.

I'm looking for input/experience with dual exhaust.

What size pipes?
What mufflers brand/model do you like ?
What about exhaust routing ? I currently have a trailer hitch welded where the spare used to be. I'm currently thinking exhaust flaring down under bed at differential or flaring out at tires but I'm not sure about fumes accumulating back into the cab.

A sound clip would be awesome as well.

With all due respect - please don't chime in on this thread with why I should run the single exhaust or why I shouldn't do this.
You can do whatever you want with your truck. Please start a different thread if you feel like doing that.
We are all here to have a good time and I'm just looking to get some input from guys who have experience with what I'm doing.

Thanks guys.

If your mind is made up already, why bother asking for input? A simple search of the forum archives will provide you with hours of reading on a subject that's been beaten to death for years.
Jerry

It's replies like this that make me use this forum less and less.

JD1, I don't have the exact experience you're looking for but it's very likely someone here has gone down the path you've described on exhaust systems. If so I trust they'll chime in. That said, there are decades of great information here that does get overlooked as we look for instant answers. I'm a believer is using the search button. However I do find myself asking questions when a few minutes searching would give the answers I'm looking for. When that happens I feel a little embarrassed since I often wonder why, why, why didn't I look first.

Good Luck,

RonR

JD1, you forget that the knowledge base here is of a median age well above 55. It is obvious from your post you were having a bad day Wednesday. To end your post that way and your follow up comment today is a direct insult to those trying to help you. Sometimes you have to be willing to accept the criticism along with the helpful suggestions. You entered this conversation with a chip on your shoulder so, if you feel you are not going to get help here there are plenty of other internet sites you could try. Hope your day gets better.

I run separate 2" pipes from the Fenton headers thru dual Xlerator mufflers (one on each side) with the exhaust tips exiting out in front of the rear wheels. It has a little rumble at idle and you can hear it when accelerating, but not obnoxiously load. When cruising the exhaust seems to blend in with the road noise. I like the setup.

I have a completely stainless steel exhaust system on the 1960 261 (USA) in my 1954 Suburban (for at least ten years). It was sold by Patrick's for all 1/2 ton trucks. It is a beautiful system and installed easily.

However, it is a little "throaty" for the Suburban, The pipes exit to the side behind the driver's side rear tire (standard location for exhaust pipes on on panel-bodies). On a pickup, this would not be noisy in the cab; however, in the Suburban the low "rumble" noise is annoying when the rear side windows are open.

I now have a single muffler SS end-to-end exhaust system that will replace the Patrick's-SS system (and will, some day, post the Patrick's system for sale in the Swap Meet). I've been lazy in my retirement

Buckle up- - - - -the ride could get bumpy. Here's a bit over 50 years' worth of input/experience. Take it or leave if- - - - -but it seems that you're looking for affirmation of some preconceived ideas, not actual facts and figures.

Water heat:
The maximum temperature a cooling system can put into an intake manifold is around 200 degrees F. It takes several minutes of engine run time for that temperature to be achieved. The primary purpose of manifold heat is to keep the fuel in the intake atomized DURING WARMUP when water heat will be at a minimum.

Exhaust heat:
The original heat riser system applies exhaust gas to the bottom of the intake manifold, either directly when the heat riser flap is in the "hot" position, or indirectly from conduction when the gas flow is directed away from the manifold by the flap valve. Exhaust gas can develop temperatures of up to TWO THOUSAND degrees under certain circumstances. The usual way to apply exhaust heat to an intake from Fenton headers is to run stainless steel tubes through a block of aluminum bolted to the intake. This is a terribly inefficient way to heat the intake, but it's marginally better than water heat.

If you choose to run dual exhausts, it's much more effective to split a stock manifold and leave the heat riser system intact. Pipe diameters of over 1 3/4 inches are counterproductive because the exhaust gas velocity from bigger pipes slows down so much that the desired scavenging effect of the cylinder pulses is lost and the overall result is that as much or more back pressure than a stock exhaust system is developed by the exhaust impulses stacking up in the pipes.

The above comments are the result of decades of hands-on dyno testing, not something from an internet search engine. Feel free to refuse to accept them- - - -I don't care.
Jerry

I have a 261 in a panel truck that I switched back to a factory manifold to eliminate the drone resonating from the back of the truck .
The present muffler is just ahead of the rear axle on the drivers side and although the it is much quieter now there is still a drone when operating the motor in its happy zone. Its fairly quiet until it gets to the 2,500 to 3,000 rpm range , which is where it usually operates then the drone gets louder .
My question is , would moving the muffler back behind the rear axle make a difference in either interior sound or performance ?? Its a one ton truck with lots of room for a muffler out back if need be .

John

John, the further your muffler is from your exhaust manifold, the quieter it will be. That irritating droning noise comes right up into the cab if your muffler is below or even partially below where you're sitting. Because of the spare tire holder, springs, crook to go over the axle, etc a lot of mufflers wind up below the cab, but if you can move it back as far as possible, you'll improve things.

When I say "it" above, I don't mean the muffler...I mean the cab. You want to move that noise (which is going to be there no matter what) as far from the cab as possible. One other thing I've found...the round muffler used on these will produce a completely different noise than one of the elongated oval mufflers where there are 3 tubes inside...the middle tube being an unconnected chamber.

Like TC, I have a stainless muffler from Patrick's. It's actually a Bazani. After I installed the headers, I drove it to the local exhaust shop and let them do what they do for $500. I think mine are 1 and 3/4 to the muffler, and 2" out. The sound is magic. They sing at 2200 rpm!

I also use water heat. I use a dual outlet waterpump and a bypass thermostat housing from a 261. I plumbed it with a heat plate and 5/16 brake line. It works. The difference in warm up time between this and exhaust heat is negligible. What I really like is keeping my new aluminum intake at a lower and more consistent temperature once the engine gets hot. I ran it for a few years with my original cast iron intake and it seemed to work just fine.

In panel fan’s case, he can’t get it (the muffler) from under the cab as it’s a panel van. Just throwing ideas there out but I wonder if an insulated heat shield would help to muffle the sound.

My current muffler is left over from the dual exhaust set up and is a Magna flow probably designed to make a bit of noise but I have a long round muffler I used when doing the brake in procedure out of the truck ,I will install that and replace my whining rear end in the spring and hope for the best .
I have until July to get it dialed in to go to The event in Tennessee , if this don't work ,maybe a radio and some head phones ?????

John

I like water heat. Tom Langdon at Stovebolt recommended it to me years ago when he was still working at gm. I still use water heat to this day.

Mufflers for the Fenton's, it depends on what you want sound wise. A lot of guys like the sort of loud rapping sound. And that is ok if that is what you want. I prefer something a lot mellower and frankly quieter. You might consider looking at the Walker Quietflow mufflers. They would remind you of the old corvair turbo mufflers from former days, lol. Mellow rumble, no drone, not particularly expensive.

The factory-style muffler available through Jim Carter sounds pretty good. There is a tech article on Carter's website about how truck mufflers were straight-through design, and therefore louder than cars.
While it's not whisper quiet like a car muffler, its also not raspy and overly loud like a glasspack. I have one on my 261 with single exhaust pipe, and it sounds pretty good. PM me if you want to hear it.

I have a magnaflux 20 series on my 216 and love the sound.

Chris

I have dual glasspacks and I really like the sound from them....they are not too loud.

I have dual hush thrush turbo mufflers on my 261.

i have dual glass pacs on my 261. They are 30 inches long. Really quiet at idle. But wake up some under throttle. Truth be told. I would rather it be alitta louder. Maybe go with a shorter pac, if you go that route??

Jon G. Noticed you have completed the T5 swap and have a 235 from a passenger car. Since I am new to the forum I can
not private message anyone at this early point of membership.

Would you mind sharing your setup with me as I am right in the midst of considering the same setup you presently have....

Joe

I have these manifolds on my 235 in my 51. 1-3/4 pipes mufflers under from edge of the bed. Both turned out behind rear tires. I used donut gaskets instead of the flat flange gaskets. On donut is a 2” double bevel and in is a 1-7/8 single bevel with a collar that inserts into the manifold. I couldn’t get the flat gaskets to seal.

Hopefully you can understand what I was trying to type as spellcheck didn’t do a very good job and I didn’t proofread.

I have 1 3/4" pipes from the fentons , a muffler from an old 300 mercedes , twin inlet and twin outlet , 1 3/4" twin tail pipes . It runs very quiet. I have tried water heat and exhaust heat . Pic attached of successful item .

I have a similar setup on my '40 pickup, fitted with a '54 Blue Flame motor. My twin pipes exit at the rear, one each side. I don't know what the mufflers are, but when I hit the loud pedal with my size 15's, it gives a nice bark! My 12 yo grandson loves it. My sons call me the oldest hoon in town.
I must admit that I had some difficulty fitting the headers, and I had to use a die grinder & burr to remove some metal to allow the studs to line up. Also, one header had a flat surface, the other chamfered at the flange. Again, the die grinder came in handy to create the chamfer.

What's a hoon?

Common Aussie slang word for bit of a wild child car type. Usually associated with young drivers who do burnouts, doughnuts, drift, loud exhausts, etc. At 75 I don't really fit the bill except for the exhaust. When I took the pickup in to the exhaust guy, he asked me what I wanted. I told him "somewhere between a Tesla & Harley, but closer to the Harley as long as it was legal". He did a perfect job!

JD1, I have a bit of a temper, when it comes to speaking badly of people and some 70+ years of experience by many of those on the forums, I personally would be cautious. They are here to answer questions that you will not find in a 2021 manual. As a physics major and a mathematician I would show more respect of these fine people. One cannot make a silk purse out of a sow's ear. Attitude and learning is paramount. Doc.

Doc, you can probably make a silk purse from a sow's ear with enough time, effort, and money- - - - -but it makes the pig look funny, and it doesn't hear very well afterwards!

Jerry

Dusty, what carby are you running? I am looking at ditching the Rochester for something a bit better.

Riggles , I'm still using the Carter w-1 from the original 216 .
I have adjusted the fuel pump shot a bit , it runs strong , but I tend to drive my truck a bit like a diesel ..... kinda 800 to 1800 rpm .
With the '56 diff (3.9:1) and the tall tyres , I find 2200 rpm at a bit over 50mph within my comfort level.

JonG Get some of those rice burner mufflers that look like a big growth on the rear of your truck !!

JD1, I've had good luck with average but experienced muffler shops that have been around a while, they fab this kind of stuff all day long. Running duals off an early Corvette factory dual exhaust manifold (quite a lucky find), snug against the motor saving some room and keeping factory exhaust damper, Under your truck lots of room to fit pipes, ran mine drivers side out the back with glass packs, shotgun look and not crazy loud, 2" pipe. Best of luck

I have Flowmaster 40s.