peterek

Hello,

I just did some reading about true Dual exhaust ,
And needs some opinions

I have '81, mostly stock setup, No computer,

I'm thinking about getting a dual exhaust system with headers and magnaflow mufflers from Corvette central for $629. do you guys think that is it worth it price? how much Hp i can gain, and how better the exhaust sound will be? ( currently it sounds plain boring)
or is it better to just remove Cat Converter and put a " test pipe" m which would cost me a fraction of the cost of new full exhaust ( im in Illinois - no emission test for car older than 94).

Also i would like to remove Smog/Air system (would be nice to have new headers, would i need to adjust a carb?

Thanks

birdsmith

If you get rid of your existing exhaust you'll probably be looking at doing some jetting changes unless your mixture is on the rich side right now. As for $629 for that particular system it's a little on the steep side but not outrageous; it depends on how much money you've got to spend. You could cheap out and buy some eBay stuff that would net nearly the same power gains but it wouldn't be as well made as Magnaflow stuff. A dual system with tube headers would definitely not sound "boring" anymore...unless you really want a much louder car you might tire of the noise after awhile. Ultimately it's up to you, but in reality the biggest gains will be made simply by going from a single to a dual exhaust so you could actually leave the cast iron manifolds on there which would be a lot quieter.

mauiwilly

I just removed my original exhaust in my 81' Replaced it with the true dual system from CC....trust me I'm so happy with the sound and the car appears to be a little more "peppy"....definitely not offensive sounding but nice n throaty...One thing...there is an air tube running from the smog pump to the exhaust just before the cat.....you will have to cut this and plug it or leave it open. It was to provide fresh air to the cat for emissions....I still have my CCC and was looking at removing my pump as well. Still undecided but plenty of threads on the forum about it....

pippo350

I have an '81 4 speed with headers,this year I put a true dual system with X from pypes it sound and run great,I also have an EDL 600 carb with phenolic spacer.

No cats or smog stuff.

damoroso

The exhaust will help the engine breath, but the computer system uses the O2 sensor in the factory set up. If you keep the O2 sensor in the new set up, you should be fine. If the computer system is otherwise in place and working, and you don't keep the sensor, you'll see a "Check Engine" light that won't go out unless you disable or otherwise by pass the system.

As for re-jetting the carb....nope. These carburetors are NOT set up to change jets. They have a mixture control solenoid that varies the air fuel mixture based on engine temp, O2 in the exhuast, throttle position and manifold pressure.

Keep in mind those engines are 190hp, and have a compression ratio of 8.2:1. They aren't a power house to begin with, but still are a nice running engine when everything works correctly. To get good horsepower gains, you're likely looking at a cam, intake, headers, carb work, a distributor (the factory one is computer controlled and has a very limited advance curve) on and on. A true dual exhaust system and perhaps headers (the factory exhaust manifolds aren't bad though) is about as far as you can go without a much larger investment IMHO.

peterek

Thanks guys for all of your opinions,

My car doesn't have Computer, one of previous owners removed it, and I'm sure he changed the distributor,

I'm removing the Cat So I don't think I need O2 sensor,

Yup, i dont want my car to be too loud I just would like to have that nice deep throttle rumble,

I think im going to go with full exhaust from CC

qwank

if the computer is already gone, I wouldn't worry about keeping the smog crap on there. I took my AIR pump and converter off when I did headers and true duals. the engine is a lot cleaner and easier to work on without the smog stuff there.

damoroso

Umm, the computer runs the carb. Is it the original carb??

mauiwilly

Right...O2 sensor....I left mine in. The CC exhaust system has a bung to hold the O2 sensor. If you don't have a CCC I don't think it matters much ?

rdroe

I too have stripped down my 82. I have the CC dual system. It is great! I sealed up the exhaust manifold air injector ports. THe original exhaust manifolds are pretty good header-like substitutes. The sound is throaty, but not annoying. Mine has the computer still controlling things. It has a perceivable better response and more HP. It could be the same thought as *red cars go faster*.

jb78L-82

I have owned my 78 L-82 4 speed since 1983 when I bought it with 25,000 miles on it and it now has 65,000 miles-It was bone stock when I bought it with all the OEM exhaust and emissions. Keep in mind that the L-81 is not an L-82 primarily due to the cam, heads, and compression ratio. The original y pipe exhaust in the rear was crushed to half its original diameter, running a pancake cat (I believe the L-81 cat is slightly better-slightly) and very restrictive original mufflers. The First thing I did was remove the cat and bought a new 2.5 inch y pipe. The idle sound of the exhaust improved immediately but the OEM mufflers were so restrictive that at higher revs the engine was still very chocked. In 1989, I added Monza Turbo mufflers which are still on the car and essentially straight through although not as much as Magnaflows. The power and sound improved greatly even running the original manifolds and 2.5 inch Y pipe. A Big increase in power and sound occurred with the installation of the stainless steel 2.5 true duals running the same Monza Turbo Mufflers-not obnoxious sound but definitely noticeable. in 2007, I removed the stock mainfolds and installed McJacks shorty headers with the same 2.5 true duals and Monza Turbo Mufflers-Big increase in power above 4,000 RPM up to 6,000 RPM and it is much louder on the highway now cruising-much more airflow with the shorties.

The 80-82 tubular exhaust manifolds are better than the cast iron manifolds but make no mistake that they are NOT equivalent to headers of any type primarily due to the header primaries being very small, probably 50% less diameter than true headers which helps low end power but kills power at higher revs. I just last year replaced the tubular exhaust manifolds on my 1994 Mustang GT with BBK Shorty headers (primaries are much larger now) after I had previously installed at separate times a Magnaflow cat back exhaust and then a Maganflow X pipe with high flow cats. The headers made a HUGH difference in sound and power, again at high RPM's

One last thing-save anything and everything that you take off the car-someone may want it in the future!

Hope that helps!

81$$pit

I was thinking of doing the same thing as well. this thread is ery helpfull. I was concerned about if I could just remove all the computer/emission crap and still have the tranny work ok, I heard it controls the lockup. Any mods to tranny?

79vettecrazy

I have a '79 L82. l have removed converter (plugged) and added long tube headers and duals with Flowmasters......on deceleration it has a very annoying exhaust pop.....does the fuel mixture need to be leaned out to compensate for the unburned fuel to make pop go away?

7t9l82

its just free breathing, it doesn't annoy me

LannyL81

The problem of putting dual exhaust onto an 80 - 82 model is the routing of the pipes. I think the CC system has the pipes routed in the stock location which means that the left side is longer than the right. I have no idea how this will affect a street car, probably no difference.

I have read postings that getting this system to fit requires some effort as usually is required with aftermarket stuff. So be prepared to take to a shop if you do not have the tools.

I put Hooker Side Exhaust system onto my '81 with the MaxFlow inserts. Sound is quite nice, but would not want to drive it everyday.

Something else for you to think about; if the engine has the original heads on it....get rid of them, as they are cracked. A better flowing head will use the headers and dual exhaust whereas the original smog cracked heads will not near as much.

And since the CCC has been removed, the smog pump is not doing anything. Remove it and the line going to the cat. With no CCC there are no commands to the gulp valve to do anything with the air supply that the air pump is providing. And this really cleans-up the engine compartment!

Good luck with it.

Mike Ward

Popping the exhaust means that it's already too lean either by fuel mixture or an exhaust leak at the manifold.

81pilot

Most likely you have an exhast leak, check for an exhast leak at the heads with smoke. Even a rich motor won't pop if it has no good oxygen to ignite it, a leak provides that.

Street Rat

Gut it!