84ZZ4

I was underneath the 'vette yesterday trying to find an exhaust leak. Seems like it's leaking in front of the cat and up by the exhaust manifolds.

While I was underneath the car I noticed how restrictive the exhaust system is! The y-pipe looks like it necks down to about 1/2 the diameter when it makes the 90 degree turn to head back, and the cat is maybe about 4" wide! I can't believe that cat is the original--I remember the original cat I took off my '84 Camaro and it was HUGE.

Anyhow, I also noticed that the frame passage the exhaust pipe passes through actually exists on both sides, and I was wondering if that was because earlier C3's had dual exhaust and GM didn't change the frame at all?

So I got to thinking... Hmm, I wonder what a good exhaust setup for this car would be. I did some checking around the forum and came up with some ideas, and could use some feedback.

1) Hooker headers (part number 2134). Anyone have any pictures of these from underneath? Where does the collector end up sitting?
2) Exhaust pipe size... I plan on going with dual 2.5". No way am I going to modify this car enough to need dual 3".
3) I'll probably run dual cats, one on each side. Is there room to bolt them directly to the header collectors? Also, the collectors on the Hookers are 3"... would I be better off running 3" cats and putting the reducer after the cats, or should I reduce it down to 2.5" right at the collectors and use 2.5" cats?
4) For a balance pipe.. where would be the best place to put it, and should I use an X or an H pipe? This part is new to me since none of my Camaros really have room for dual exhaust...

Comments? Ideas?

Oh, and unfortunately I do have to have cats... I have to pass the tailpipe sniffer test at curb idle and 2500rpm idle.

Neo Fender

I'm not familiar with your state's emission requirements but if you're concerned about about still being legal, you may be flunked for having dual cats since they were not OEM equipment in 1979.

The irony is a that even if a car's exhaust blows out nothing but roses, it can still be flunked on a visual inspection.


[Modified by Neo Fender, 9:43 AM 1/21/2002]

84ZZ4

Last I checked, for cars older than a certain year (I think 82 or 83 is the cut-off) I only have to pass a sniffer test. Once the car is 25 years old I don't have to pass emissions at all...

I'm aware of the visual inspection issues, but I don't think I'll have any trouble finding an independent mechanic that is willing to pass the car as long as the tailpipe emissions pass. I know several that are very lenient on the visual inspection, but I don't know ANY that are willing to fudge the sniffer test.

Besides... I don't much give a rat's patootie what the laws say. As far as I'm concerned, if the car's exhaust is squeaky clean, I don't have any problem finding ways around the rest of the BS.

Neo Fender

I was under the impresssion that the visual inspection was peformed by the state as well.

One other thing to consider. I've seen this done on later F-bodies. I don't know if it will fit through the crossmember but one 3.5" pipe will flow as much as two 2.5" pipes. Don't know about finding a 3.5" converter though.

84ZZ4

The laws are state laws, but the inspections are not performed by the state... they are done by licensed garages. I got mine done at the Chevy dealer the last couple of times.

84ZZ4

Wow, this dropped off the radar screen fast. Not quite sure how it got sidetracked into an emissions discussion...

TTT

ylose

I went header,duals on mine...
Dynomax ceramic coated, no cats, crossover after trans, out through
manza dual tip mufflers...I am happy.
:D

terryrudy

I have Heddman smog headers 68301 and go out to dual 2.5" exhaust (thru crossmember) and back to Super Turbos. I plan to have dual 2.5" cats put in before inspection time. I don't have any crossover, but many people seem to agree they are superior. Many go with X-type. I've seen them welded in between cats and mufflers. good luck!
-terry

Alwyn678

I love my sound..but i do not have to run cats......Dynomax headers and Delta 40 Flowmasters(two chambers)...50's are quieter but I like it LOUD :reddevil

79MakoL82

Actually, the laws that require you to maintin the original exhaust configuration are Federal laws. However, what the state does to inforce those laws are the States decision. It all depends on whether the State wants the Federal funds that come along with doing the sniffer tests or not. If ALL you have is a sniffer test, go with 1974 or earlier true duals and weld some cats in. If you have a visual inspection as well, you may have to stay with the original 2-1-2 configuration. In that case, I would look for a 3" singal pipe with a new high flow cat, which has slightly less area than two 2-1/4" pipes.