Chambered exhaust hanger

[fireZ]

Anyone have a good picture of the exhaust hanger that supports the chambered pipe just before it goes up and over the rear axle. Not sure were this hanger bolts to the car. Thanks

[BlackoutSteve]

I would think it's the same mount location as the N10 dual exhaust hangers.



I don't think there are any other locations in that area.

[IZRSSS]

You can find the information in AIM NC8-A1 thru NC8-A3.

[Stingr69]

The GM hangar looks like this. It uses basically a large sheet metal screw attached to the bottom of the car and is clamped to the pipe on the other end.:



-Mark.

[IZRSSS]

Can anyone tell me if the chambered exhaust was an option for the L48 or was it strictly for the big block cars? Also, when was this option available during the '69 run. Its my understanding it was latter in the year...is this correct?

[mark x22]

It uses the two holes shown in BlackoutStves picture.

[Gramps69Z]

Can anyone tell me if the chambered exhaust was an option for the L48 or was it strictly for the big block cars? Also, when was this option available during the '69 run. Its my understanding it was latter in the year...is this correct?

Chambered dual exhaust was initially standard on Z28, L34, and L78, but was made optional in November 68 due to noise restrictions (also available on COPO cars), and was finally discontinued in May 69.

CRG 1969 Model ID

[IZRSSS]

I read an article in MCN Muscle Car News of a L48 owned by John Miller from Indiana (this was a few years back), a hugger orange car that has the chambered exhaust. This is why I asked. Seems this exhaust can add another 25hp.

Thanks for the info John

[fireZ]

As always help as soon as I asked. Thanks guys

[tom]

I thought I read it was actually more restrictive.

[IZRSSS]

I thought I read it was actually more restrictive.

Not sure but here's the quote from the article;

"It's one that Chevy fans have forgotten about because it doesn't have one of the 396 mill", (referring to the L48) the Hoosier State owner explained. The point must be made that this particular 350 engine makes more than the factory figure, and it's done with a factory available option. "The car carries an optional chambered exhaust system which provides for a more free-flowing exhaust and a slight increase in horsepower, probably pushing it very close to the 325-horse 396 engine."

Sure hope we can get it confirmed one way or the other here...

Thanks Tom

[fireZ]

Ok now the big problem does anyone sell just that hanger and reinforcment piece? I bought a complete set and misplaced the 2 hangers at the border when customs checked my parts.

[Stingr69]

The chambered exhaust was not a power adder - it was/is a power robber.  I run one now but only because the car came with it originally.  Are you 100% sure you want to run it? It is LOUD and slows you down. Not a great system really.

You can buy chambered hangar kits from the usual suspects. About half of the original set was still attached to the back of my car when I got it.  D&R sold me some loose pieces to complete my system. My car did not demand NOS so "functional" pieces were used as opposed to exact reproductions. I have not seen perfect repros of those.

-Mark.

[JohnZ]

The chambered exhaust was not a power adder - it was/is a power robber.

That's correct - the same convoluted "muffler" section (patented by Walker Manufacturing) of the chambered system had a 1-7/8" diameter core pipe, and was also used on the Corvette factory sidepipes, where it cost upwards of 50hp on big-blocks compared to the stock 2-1/2" under-car exhaust system. The Camaro stock system used 2-1/4" pipes, so the chambered system on the Camaro was also more restrictive than the stock system.

[IZRSSS]

The MCN article about the chambered system was written back in '06.  I held on to it all this time thinking that one day I would consider using it.
 
Thanks for the clarification John & Mark

[william]

Chambered is not a performance exhaust system. Many years ago Bill Porterfield dyno'd a ZL-1 engine in varous states of tune but through the stock chambered system. For the last run they pulled it off; picked up 80 hp.

http://www.camaros.org/copo.shtml

[IZRSSS]

Why was the chambered exhaust originally developed? Was it being passed off as a HP booster or has this misnomer developed on its own based on preception rather than facts?

Thanks for the link William

[JohnZ]

Why was the chambered exhaust originally developed? Was it being passed off as a HP booster or has this misnomer developed on its own based on preception rather than facts?

The chambered exhaust system was a Sales & Marketing idea, not an Engineering idea, just like the sidepipes on Corvettes.

[paceme]

Why was the chambered exhaust originally developed? Was it being passed off as a HP booster or has this misnomer developed on its own based on preception rather than facts?

The chambered exhaust system was a Sales & Marketing idea, not an Engineering idea, just like the sidepipes on Corvettes.

I actually have a Gardner chambered system I had on my Black Z for a month. I replaced it with a Gardner transverse system because I am not particularly fond of the sound. Its been stored away for 5 years...I guess I should sell it. I think chambered sound a bit better on a big block, but certainly not a performer.

[IZRSSS]

Well that pretty much blows that system out of the water.  What are your thoughts on a Gardner Exhaust System?

Thanks John and Steve.

[paceme]

Why was the chambered exhaust originally developed? Was it being passed off as a HP booster or has this misnomer developed on its own based on preception rather than facts?

The chambered exhaust system was a Sales & Marketing idea, not an Engineering idea, just like the sidepipes on Corvettes.

This baffles me regarding power loss using the chambered system. You would have thought some testing would have been done to validate the efficiency of the system prior making it standard on all their HP model. In actuality Chevrolet choked the life/performance out of these cars with this system. A ZL1 does have a lot  more flow due to its displacement and compression, so it would be effected the most by the system. 

[JohnZ]

This baffles me regarding power loss using the chambered system. You would have thought some testing would have been done to validate the efficiency of the system prior making it standard on all their HP model.

It wasn't about efficiency - it was all about the sound, as it was on Chevelles and Corvettes. Spoilers and stripes didn't make cars go any faster either, but they sold cars and the options made money; don't confuse Marketing with Engineering.

[x77-69z28]

IZRSSS, gradner is the best exhaust system if you are looking for originality. if you go to their website, they tell you flat out if you are looking for more performance, go elsewhere. if you want originality, they are it!

[IZRSSS]

  !!! Any idea on the cost for an L48?

[paceme]

I paid $1180 plus tax in 2004.

[tmodel66]

I have a couple options to choose from when I finally order. The guy said between $1700 to 2 grand.

[IZRSSS]

Thanks Steve & Dan! Not bad for a factory look-a-like and performance to boot!

[BULLITT65]

John,
 I figured since Mark Donahue used them on his 69 Camaro in the trans am series, that the spoilers were engineering at work to make the car more efficient on the track, right?

[lynnbilodeau]

Back on exhaust systems, particularly hangers.
I have all my original hangers.
The screws removed from the side hangers are 1/4 sheet metal screws.  Is this correct?
AIM shows 1/4 self tapping, but doesn't id whether it is a machine thread or a sheet metal thread.

Thanks again to all you guys who know.

[lynnbilodeau]

Gary pulled his originals and they are self tapping machine thread 1/4 inch.