Mel, notice I said "possibly". I haven't tried it, so I offer it only as a consideration. I think something like what I mention would be a good way of going about it.

I've tried a dual pipe conversion back in '68 that involved cutting the standard crossover off under the bell housing and joining it with a kind of mirror image section, for a dual muffler setup with integral balance tube. With a pair of glass packs, It was way too loud, but may have been fine with standard mufflers.

I also tried just a single turbo muffler on a standard crossover, but again too loud.

The "Extractor" / trombone exhaust that Clark's sells might be the ticket. Don't know it's DB rating, but heard one such system once that simply had a nice low volume "Porsche" like sound to it. Very pleasant.

-Mark

Mark,

The extractors are going to be significantly louder than the Clarks turbos. Hearing a system at idle outside the car doesn't do anything. You need to drive it around to actually assess how well it works and how loud it is. I went through this last spring on my '68 140. I don't like loud exhaust at all. We first tried the cat with the quietest Walker Turbo muffler that would fit. Way too loud and droned horribly. Went back to the stock Turbo from Clarks as seen in the picture and it was perfect. Drone gone but a nice soft throaty sound.



Edited 1 time(s). Last edit at 11/25/2022 08:56AM by cschneider53.

I searched for "exhaust cat expansion" and didn't find anything that looked like the picture above. Can someone tell me more or direct me somewhere to learn.

Jim Brandberg
Isanti, MN
CorvairRepair.com

[corvaircenter.com]

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa

Mark, notice I said POSSIBLE.

-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
WA. state, 1 mile south of the Canadian border, I am not at the end of the world, but you can see it from here.

MattNall Wrote:
-------------------------------------------------------
> Mike!!we need some pics!


Matt,

Check out the exhaust page below on Clark's website.
Confirms that 67-69 w/smog used the larger 140 type exhaust and mufflers, just single muffler if a 110 engine.

[ssl.corvair.com]


64-69 We offer original oval style mufflers with "regular" size tail pipe (1 1/2") or larger (1 3/4") (less back pressure). Larger was original for 67-69 with factory smog

I learn something every day.

Mike

1966 Monza Convertible, 140HP-4 speed, Ermine White
1969 Monza Convertible, 110HP-PG, Frost Green

Black Mountain,NC

Others in the menagerie...
72 Corvette Stingray, 58K miles, owned since 87
72 MGB, 112K miles, bought from original owner in 09
78 Chevy pickup, 124K miles, bought new in 78
93 Corvette, LT1/6spd, 210K miles, daily driver since 96
02, Chevy Z71, 4x4, 93K miles, my Dad's truck, inherited 2021



Edited 2 time(s). Last edit at 11/28/2022 12:33PM by MtnVairMike.

Okay, please correct me if I am wrong, but I was always under the impression that "Tail-Pipe" refers to JUST the section of exhaust tubing that extends FROM the muffler, to the very end of the system.
The Clark's statement therefore TO ME seems to indicate that just the pipe section after the muffler is bigger, not the entire exhaust system including the Cross-over.
NO???

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WA. state, 1 mile south of the Canadian border, I am not at the end of the world, but you can see it from here.

I was thinking off the top of my head that all LM single oval mufflers have a 1 3/4" inlet and outlet.
I was thinking some EM round mufflers might be a smaller outlet.
A 1 1/2" tailpipe looks small and I just can't remember thinking that when looking at a LM.
I'll have to have a look tomorrow, I've got a lot of used stuff.

Jim Brandberg
Isanti, MN
CorvairRepair.com

I still have my “super-single”exhaust system on my Corvair. Although it's a 110, it has 140 exhaust logs (and several other performance modifications)

If I were to build another one, I'd do it a bit differently. My design hangs a bit low under the differential. Also, I designed it for a dual-offset single-side inlet/outlet muffler, which is somewhat rare to find. (Attached is a photo of one). And finally, the body of the muffler can't be longer than 13 inches, otherwise it won't fit with a proper tail pipe.

The dual-offset single-side inlet/outlet muffler is not an absolute requirement, but it makes for a nicer-looking tailpipe from the rear of the car. My original muffler was too loud, so I adapted a Hush Thrush muffler to it, with the inlet and outlet on opposing sides, like a more conventional muffler.

The design also called for 1/625 inch tubing, but the pipe bender didn't have that in stock, so we went with 1/75.

It was also difficult to find flanges for the pipes. The late Danny Monasterio had some left over from the "Big Singles" partnership between him and Matt Nall. So, I bought mine from him.

Looking back, I think the better way would be to use an old stock 110 exhaust crossover pipe as a pattern, with bigger tubing and a more aggressive muffler. I think the stock configuration would allow a longer muffler to be used for better noise reduction.

Attached are three items for you: (1) layout drawing of my system, (2) exhaust flange drawing with dimensions, and (3) the kind of muffler I originally used. They're hard to read, but I attached them just to let you know that I can provide full-size images to you if you want them. I didn't want to post the full-size images because the file sizes would be much too large for this forum.


Al

Here are three photos of the "super single" exhaust system I designed for my Corvair back in 2011. It was fabricated for me by Mervine Exhaust, which is currently based in Wernersville, PA.

In addition to the drawings, I also provided Mervine with a wooden jig. I don't think they do custom exhaust projects anymore. Allan Lacki

I love this! Going to see if I can get one made for the Rampy I'm building.

Thanks for posting the photos and info Al!

Enjoy the Corvair!

Paul Sergeant
CORSA Central Division Director / CORSA Treasurer
Lee's Summit, MO
CORSA since 1975
Member – HACOA, Corvair Minnesota, CORSA, Little Indians, POCI

---

Hi Paul, FYI - My exhaust system doesn't fit under a Forward Control Corvair. Tim Schwartz tried it.

American Mel Wrote:
-------------------------------------------------------
> Okay, please correct me if I am wrong, but I was always under the impression that "Tail-Pipe" refers to JUST the section of exhaust tubing that extends FROM the muffler, to the very end of the system.
> The Clark's statement therefore TO ME seems to indicate that just the pipe section after the muffler is bigger, not the entire exhaust system including the Cross-over.
> NO???


Yep, looks like only the muffler outlet is bigger. Crossover pipes are the same for 65-69

1966 Monza Convertible, 140HP-4 speed, Ermine White
1969 Monza Convertible, 110HP-PG, Frost Green

Black Mountain,NC

Others in the menagerie...
72 Corvette Stingray, 58K miles, owned since 87
72 MGB, 112K miles, bought from original owner in 09
78 Chevy pickup, 124K miles, bought new in 78
93 Corvette, LT1/6spd, 210K miles, daily driver since 96
02, Chevy Z71, 4x4, 93K miles, my Dad's truck, inherited 2021

I copied my system after Allan's diagram posted above, but moved the merge collector "up" in the system to before the 90 degree bend at the muffler inlet. This allowed me to fit a longer (quieter) muffler. I used the same tubing diameter as the stock 140hp U-pipes which I believe is 1 5/8", and 2 1/2" after the merge. Ken

Ken Henry, Rochester, NY USA
1965 Corvair Corsa
140 hp, 4 speed

Thanks for attaching the document. I copied it to Microsoft Word and printed it off but it's pretty small to see. It looks like if I can figure out how to rotate it I can try making it bigger. That function doesn't seem to be working for me on Page Layout at the moment.

Yes I bet the muffler with the inlet and outlet offset on the same side would be hard to come by, I don't think I've seen one before.

Jim Brandberg
Isanti, MN
CorvairRepair.com

Thanks for the detailed post, Alan!

Here's where maybe that 90 degree collector I mentioned earlier may help. I note that the distance between the muffler and the crossover pipe (longitudinally to the car) is excessively long, making a short (dare I say stubby) muffler a necessity. Having the collector in the radius instead of past the radius and in the straight part would allow for a longer (quieter) muffler.

What I'd be after is a free-breathing but quiet system. Something that, unless you crawled underneath, would look and sound like a stock system to most people.

-Mark

The single exhaust I took out of this 63 has a round EM muffler, looks to be 1 3/4 Inlet and 1 1/2 Outlet.
Having the Outlet smaller than the Inlet feels restrictive to me as far as flow goes but scientific analysis of exhaust flow can sometimes be surprising.

In a EM round muffler do you suppose the flow goes back and then forward and then back again?
How do you suppose the flow goes in the oval muffler pictured above where the Inlet and Outlet are both offset in the same direction? Maybe it simply steps left and then steps back right again.

I need to learn more about what goes on inside different style mufflers. There must be a Primer somewhere.

Jim Brandberg
Isanti, MN
CorvairRepair.com

this might help.

[auto.howstuffworks.com]

Good stuff is around page 4

Dan Central MN
1968 Convert