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Re: Catalytic Converters
Posted by: American Mel ()
Date: July 03, 2022 05:57PM

I have read something along those lines.
It seems the "Ideal" outlet length was around 9 or 9.5 inches ? ? ?
But that was on a smaller diameter pipe.
NOT 2"+

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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.

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Re: Catalytic Converters
Posted by: KenHenry ()
Date: July 03, 2022 07:16PM

In general a single exhaust tends to be quieter than a dual w the same muffler(s). I think a bigger single muffler will do the trick. Mine is a take off late model Mustang GT muffler… not “quiet “ but no drone whatsoever. Ken

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

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Re: Catalytic Converters
Posted by: cschneider53 ()
Date: July 04, 2022 01:38PM

Got it. So I'm going to try a different muffler and then look into having the exit be smaller diameter to act as a sort of silencer. Any recommendations on the quietest muffler I can get? Seems like the Dynomax Super Turbo claims to be pretty quiet.

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Re: Catalytic Converters
Posted by: jjohnsonjo ()
Date: July 04, 2022 05:27PM

cschneider53 Wrote:
-------------------------------------------------------
> Got it. So I'm going to try a different muffler and then look into having the exit be smaller diameter to act as a sort of silencer. Any recommendations on the quietest muffler I can get? Seems like the Dynomax Super Turbo claims to be pretty quiet.


They are at first but will get a little louder with time. I am running a 2 1/2" in my turbo. try getting a turbo tip and play with the length and the angle the tip is pointing.

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


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Re: Catalytic Converters
Posted by: cschneider53 ()
Date: July 28, 2022 02:08PM

UPDATE: Just got it back from the muffler shop and much better. He used every last bit of room to weld back on the Clarks stock muffler. It has a nice deep tone with a bit of rumble but almost no annoying drone. That coupled with the clean smell makes me a happy camper.







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Re: Catalytic Converters
Posted by: KenHenry ()
Date: July 29, 2022 07:49AM

Wow, you have a talented muffler guy!! I'm happy to hear that the drone is under control with the bigger muffler. A few guys mentioned experimenting with the tip length, which I have considered to reduce exhaust noise further, but it would require cutting an opening in the body. Unless someone is satisfied with droopy mufflers spinning smiley sticking its tongue out Ken

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

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Re: Catalytic Converters
Posted by: cschneider53 ()
Date: August 08, 2022 02:07PM

I've now driven over a hundred miles with the new setup and love it! It's got a nice throaty tone but really none of the drone. The best part is that it really does smell like a 80/90s era vehicle rather that burning your eyes if you have the top down at a stop light. I really can only smell it when I get out of the car and go behind it. My wife even commented that it doesn't make the garage smell bad anymore. MISSION ACCOMPLISHED!

So the setup is simply the Clarks welded muffler, a Miller 74004 catalytic converter, some pipe and some really skilled/frustrating welding.

I bought the 140 mufflers because mine is a 140 so I don't know if the non-140 mufflers will produce the same result. The muffler guy used the left one but I don't think it would make any real difference which side you used. If someone wants to try the right, I have mine that's basically brand new.








Edited 2 time(s). Last edit at 08/08/2022 02:12PM by cschneider53.

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Re: Catalytic Converters
Posted by: joelsplace ()
Date: August 08, 2022 02:16PM

It is hard to tell from the pictures but it looks really close to the shock. You may need a heat shield. Those cats get really hot.

Joel
Northlake, TX
5 Ultravans, 138 Corvairs and counting...

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Re: Catalytic Converters
Posted by: Phil Dally ()
Date: August 14, 2022 08:35AM

Just for info.

[www.yahoo.com]

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Re: Catalytic Converters
Posted by: cnicol ()
Date: August 15, 2022 07:26AM

The objectionable smell is caused by unburned aromatic hydrocarbons in the exhaust stream flowing out into your garage and passenger cabin.

'66-9 A.I.R. carburetors were designed to leave fewer unburned hydrocarbons in the exhaust with the final remaining HC incinerated/combusted in the exhaust manifolds.

Your catalytic converter takes it one step further and converts the leftover HC and CO into CO2, N2, O2, and H20. In the process, the converter gets very hot but that heat is proportional to the amount of HC being processed. If you find your converter is getting excessively hot or its producing a "rotten egg" smell, both of those issues should be improved through use of '66-9 A.I.R. carburetors.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
65 Canadian Monza 4dr 110/PG 40k
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

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Re: Catalytic Converters
Posted by: cschneider53 ()
Date: August 17, 2022 07:27AM

Since mine was a '68 it was originally equipped with a smog pump. However, it was removed sometime before I got the car. Regardless, I have EFI. There's no reason you can't run cats with carbs and it seems to make sense that the AIR carbs would fare a bit better but with the high price of cats I wouldn't want to be burning one out every year or two.

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