140 Exhaust questions

[junkyardkustoms]

I looked around, but didn't find what I was looking for, so I bring my inquiry before the collective heads of the forum. I have a few thoughts on the exhaust system. I hate to say it, but I kind of hate the sound of the corvair engine. I believe it's the fault of the stock exhaust system. Most try to make it sound like a v8 muscle car, but it ISN'T! It drives me nuts because I love the flat six sound from the early 911's. After comparing them a bit, the main thing I see is the use of a crossover pipe or an X pipe (depending on design) and it looks like a little bit larger diameter exhaust tubing. Has anyone used a larger diameter tubing? Or ran a crossover pipe on a dual exhaust? Or am I alone in this thinking?

[bbodie52]

The camshaft grind also has a big impact on the Corvair exhaust sound. That being said, here is some material on a vairiety of Corvair exhaust configurations...

The 140hp cylinder heads utilize larger valves and ports than the 110hp cylinder heads, as well as intake manifolds that accommodate four carburetors and the dual exhaust configuration. The 140hp exhaust manifolds do have better-breathing capability with larger ports and a larger cross-section, but because of this they are not a direct fit that will properly mount on the 110hp heads. All Corvair cylinder heads, except for the 140hp heads, utilize exhaust port tubes that are 1-1/8" ID. The 140hp heads have exhaust port tubes that are 1-5/16" ID. So the 140hp heads are designed for better breathing from intake to exhaust, and simply fitting the exhaust manifolds and dual mufflers will not duplicate the rest of the system. As previously mentioned, fitting a dual exhaust system alone to the 110hp engine will provide some benefit, but without bigger valves and more intake capacity there are limits to the benefit you will realize from increasing the exhaust capacity alone.

The trombone-style dual exhaust offered by Clark's has been around since the 1960's. I had a set on my 1962 Monza back in the early 1970's, and I will likely fit a set on my 1966 Corsa.

http://www.corvair.com/user-cgi/catalog ... ow_page=35


http://www.corvair.com/user-cgi/catalog ... _page=MK-3


http://www.corvair.com/user-cgi/catalog ... ow_page=37


NOTE: For pricing and ordering information, click on the link to go to the actual webpage, and then click on any part number to display pricing and availability information.

Here is a review from a "voice of experience" who has a great deal of Corvair knowledge and who has worked with stock muffler configurations, the "exhaust extractor" (trombone-style) exhaust system, and the "ultimate" exhaust tubular header system. http://www.corvair.com/user-cgi/catalog ... ow_page=38

I have personally used the Ultimate exhaust, both type of exhaust extractors, and stock dual, and single systems.

The Ultimate exhaust header system is loud to me even with the baffles installed. The drone at certain speeds can be annoying and can be unpleasant for extended operation. Cutting or removing the lower shrouds can cause the windshield defroster to fog the windshield due to the extra moisture let in to the manifold area (not a problem until you need the windshield defogged on a warm rainy day). For best longevity I recommend ceramic coating the system prior to installation. I would not use these again myself except on a race car. (very slight performance difference noted from stock dual exhaust with a basically stock motor).

The Exhaust Extractor systems and pretty nice all in all. The large tip one is loud. I got tired of this after a while and ultimately replaced it with the straight small tip version. I really like the note of these and they are not so loud as to be annoying. This system is not without its issues however. The pipes must be bracketed to the engine or engine sheet metal near the front ahead of the first muffler as well as at the rear on both sides or drooping will likely occur. The connection at the manifold even though it seems very strong will allow the system to rotate and droop without help. Another issue is that the welded bracket that holds the extractor pipes parallel to each other in roughly the center bottom of each extractor is prone to coming loose after a period of time. I have re-welded a number of both small tip and large tip systems for this issue. The final issue is a small one. On the small systems I have installed the pipes do not stick out from under the rear grille the same amount on both sides, one side is shorter. (it is somewhat normal that they may not be spaced right to left evenly when viewed from the rear). These also should be ceramic coated for durability. No noted performance gain compared to stock duals but sounds and looks cooler.

The replacement stock type systems from Clark's are excellent. When installed with new brackets and hardware these are the most durable exhausts I have used on a Vair. No trouble or maintenance for 30,000 miles or more over 4+ years, something I can not say about the above systems based on my use of them. The complete dual system they sell with the larger tips is my choice in these. Ceramic coating not really needed for good durability but it will keep them looking good and stave off rust longer. I think there is a slight performance gain going to a dual exhaust system from a single.

http://corvaircenter.com/phorum/read.ph ... 249,513497

I remembered this from a December 2012 thread...

viewtopic.php?f=80&t=4848&p=33169&hilit=exhaust#p33169

Thank you for the update. Looks like beautiful work! Please keep us posted on your progress!

I had never seen a crossover balance tube exhaust setup like that before. Is that a commercial product or your own design?

The exhaust is a "Big Dual" from Matt Nall that's no longer in production. It's 2-1/2" and the mufflers are Hedman turbos.

[SyntheticBlnkerFluid]

If you want it to sound like a Porsche, then headers are the way to go with a set of chambered mufflers. I've installed the same setup twice with Magnaflows and both were Corsas with 140s. When you were on the throttle it definitely sounded like an early Porsche.

[martyscarr]

Rob
Do you recall which Magnaflow muffler you used?

thanks
Marty Scarr

[SyntheticBlnkerFluid]

I have it written down somewhere, so give me a couple days to find it. The first set was given by the customer to be installed and then another customer asked basically what you did, so we already knew what to look for.

[triumphcorvair]

Dave Keillor,
Do you have your mufflers connected directly to the heads? If so, would you mind sharing on how you did this? Is that a steel band around the muffler?

I've also got the Big Dual crossover tube from Matt. Too bad it's out of production as it is very well made.

[Allan Lacki]

Porsche 911s typically had single exhaust from the factory. And a low-restriction single-exhaust system sounds very nice on a Corvair. Here is my system, which I installed in 2011. Five years later, it's still on the car.

Click here: http://www.corvair.org/chapters/njace/n ... anbelt.pdf" onclick="window.open(this.href);return false;

My Corvair is equipped with a modified 110, with bigger valves, 140 exhaust tubes, Isky 280 cam, so it's probably putting out as much power as a stock 140.

[flat6_musik]

On one of my 140s from back in the 80's, I think I used headers turned around (flipped from one side of the car to the other) and aimed rearward, then had a muffler shop fabricate a 2-into-1 factory style looking single exhaust that exited with a chrome tip out the normal turbo car body cutout. I used larger diameter pipe like 2-inch I believe and a glasspack. It sounded great and different.

[wbabst]

I have a set of the exhaust extractors (C5037) in Clarks catalog, for my 61. When I tested my engine from my 63 I used them for the test. I think they sound great. Very smooth, silky and NOT trying to imitate a V8, to me more like a nice Jaguar. I like the way they look too, with long chrome tip showing under and out the back.

You can see it here, not too good because of noisy lifter but gives you an idea. https://www.facebook.com/Chevrolet-Corv ... 72/?ref=hl