Chambered Exhaust vs. Standard Exhaust

[David D.]

Re: Chambered Exhaust vs. Standard Exhaust

I have been reading all the comments on side mount exhaust being restrictive, that may be. All I can offer is my REAL WORLD ACTUAL EXPERIENCE with FACTORY STOCK exhaust systems on TWO 1966 convertibles, circa July of 1966, when both of these cars were less than 6 months old. The cars were the most part IDENTICAL, except for the exhaust systems. Both were conpletely stock, with L72, 4speed, 4:11 posi & stock bias-ply tires. The ONLY difference was the car with side mount exhaust had F-41 suspension. From a 25 mph rolling start, in 4th gear (to prevent the tires going up in smoke), side by side, and slowly increasing to 35 mph, then pedal to floor. The car with stock under car exhaust, pulled ahead immediately about a half a car length, and held it to approximately 110-120 mph. From there on, the car with the side-mounted exhaust slowly pulled ahead, to about half a fender ahead of the car with the stock undercar system, and stayed there to top end (140-142 mph/6800-7000 rpm). The difference could possibly be the factory engine tolerances, who knows for sure. But, in my opinion, the under car system seemed to produce more low end torque, than the side mounted system at low engine rpm, and the side-mount system was a slightly less restrictive at top end. So, in average street driving conditions, I believe the undercar system would have a slight edge. But, that it just my opinion, others have their's. FWIW Dave

[Craig S.]

Re: Chambered Exhaust vs. Standard Exhaust

Dave - now that sounds like a fun test!!

[Mike McKown]

Re: Chambered Exhaust vs. Standard Exhaust

Mike:

Sorry for the confusion. I knew about the under car exhausts. I guess I took it for granted that when I said I know nothing about the aftermarket stuff, everyone would have assumed I wasn't talking undercar. I was mainly trying to address your concern of a stifling of performance with the chambered design.

For what it might be worth, Walker made some chambered systems a few years ago. Might check with them.

Mike

[Clem Z.]

Re: Chambered Exhaust vs. Standard Exhaust

go to http://www.sweet-thunder.com/ses_65-67_vette.htm

[Clem Z.]

PS

for all the systems go to http://www.sweet-thunder.com

[Patrick H.]

Re: Chambered Exhaust vs. Standard Exhaust

Mike,

My parents got married in 1965. I'm an early 1968 model year myself (Nov 67). Didn't hear much in '65 at all...

And, as a corrollary, I've only heard the "chambered" (without the terms side exhaust attached) used to describe the Camaro or current aftermarket undercar Corvette systems.

And no, the car isn't running yet. But I think I'm closer.

Patrick

[Everett Ogilvie]

Off-road vs Sidepipe

One of my L72 cars has factory under-car off-road exhaust. My other L72 has factory sidpipes. Which is faster... ? According to seat-of-the-pants driving, the under-car off-road L72 feels stronger, BUT, the car with the off-road system has 4.11 gears and the sidepipe car has 3.36 gears - I submit that is the difference.

As far as one system making better top-end power - it makes sense to me that the sidepipes would make better top-end power with their open design. Any time you add aftermarket exhaust (to cars, motorcycles, etc.), if it is an open, low-restriction design, top end power is usually gained, with some reduction of low end power (once the carburetion is correctly set up for the open design).

[Steve Hess]

Chambered Exhaust vs. Standard Exhaust & noise

Lots of good discussion on one vs. the other, but performance issues were not a concern with me. The undercar chambered units installed by the previous owner were so loud that the radio was not an option. Before I removed them I took a few readings with my Radio Shack Db meter.
1965, 327/365hp 2 1/2" exhausts. 4:11 gearing.
At cruise 4th gear, 3000 rpm, 60 mph - 85 Db. in the cockpit. If I jumped into it I got readings of 90+ Db.

Now I have a set of ( Mid-America) chambered exhausts with about 1000 miles on them in the rafters of my garage and they're really quiet.

[Mike McKown]

Off road mufflers

While we're talking about it. Anyone know where you can purchase a reasonable facsimile of the factory off road mufflers? Love to have a quality set of these.

Mike

[John H.]

Re: PS

M.C. Productions is Mike Cederstrom, one of our Michigan Chapter members; specializes in "60's sounds"

[Dan White]

Popping through exhaust with chambered pipes?

With a chambered sytem on my 66, from Mid-America, it popped loudly through the exhaust under decceleration and decending long grades. The motor is now apart, and I found bad intake and exhaust seats in the heads. The motor was also sucking back through the exhaust on the passenger side. Was this poping due to bad valves, or is it the nature of the system? I read on another board that with glass packs, popping like this is common during decceleration. I put the chambered pipes on it before I started it for the first time after taking it out of a 20 year storage, so I dont know if it would have popped with the origional style exhaust, that it had before. Thanks, Dan

[Mike McKown]

Re: Popping through exhaust with chambered pipes?

Popping through the exhausts has nothing to do with your exhaust system. I think you found your problem in the valves. Only other thing I could think of would be slow timing or maybe your carburetion is off.

Mike

[Tom Freeman]

Re: Popping through exhaust with chambered pipes?

Dan,
I have heard of the glasspack like rappping and poping from the chambered exhausts. Most remedy this with tuning or with a crossover "H" pipe. The H pipe will help mellow the exhaust. But most of the rapping/poping is from the engine tune. The new exhaust is like adding headers, you need to rejet. Most don't and have the rapping problem.

tom...

[Dan White]

Re: Popping through exhaust with chambered pipes?

So, could it be from a lean condition?

[Mike McKown]

Probably a dumb question

What steps would you take to re-jet to eliminate the popping?

Mike