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Help! Exhaust Replacement - 84 Coupe 4+3

AussieCorvetteNut

Well-known member
Joined
Dec 19, 2010
Messages
189
Location
Gold Coast Australia
Corvette
1984 Two-tone Blue Coupe
Hi Guys,

I have a slightly damaged rear Y-pipe section (near the spare tyre holder) and am thinking about replacing the original exhaust when I drop the gearbox and diff.

I have been looking at the Walker products, but I need something to eliminate the catalytic converter.
I Australia, catalytic converters are only required from 1985 onwards, so the cat in the 84 is coming out.

For a couple of grand, I could get someone here in Australia to build a new system, but I am looking at either a dual chambered system or the Walker products less the cat.

Is there a cat eliminator for the Walker system?

Front Y Pipe - 40449
Cat - 15618
Rear Y Pip - 40305
Mufflers x 2 - 22324

I must admit that the 22324 mufflers look lame though.

I have also ben looking at the following on eBay:

Item 151131856733

Item 381077698797

Any thoughts?

:beer

Tony
 
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BRUTE86

Member
Joined
Jul 19, 2013
Messages
13
Location
NEW ZEALAND
Corvette
1986 COUPE, SILVER ON RED, 6SPD, 390 LO98
Exhaust replacement - 84 Coupe 4+3

Gidday Ocker,
If you are thinking of replacing your exhaust system, I would recommend a custom made system. Removing the catalytic converter will also make it a bit cooler inside cabin around the floor area.

Presuming your Corvette is like mine, [that is converted to right hand drive,] if you purchase a package, the right hand side headers will require some serious alteration. Keeping in mind that the factory shifts the engine 10mm to the right, which does not leave much room with the steering shaft and brake booster assembly there. Custom made headers will cost you.

If your engine is standard I would keep the standard factory headers, they work well and would fit well, with a dual exhaust system. With the new dual system [less catalytic converter] from headers back, I would have an 'X' pipe [to balance the back pressure] just below the rear of the transmission, and the dual system continues around each side of the wheel well. The pipes from the 'X' pipe to the rear mufflers, I would have them in stainless steel, as the bends around the wheel well tends to rust through.
If you are changing mufflers as well, be careful and choose well, as without the catalytic converter, some mufflers could resonate right on cruising speed. With a custom made system there is plenty of muffler selections in OZ. I selected Cherry Bomb stainless steel mufflers, with single inlet pipe and single centred outlet pipe, using LT1 tail pieces. It looks good.

If your car is not converted, then any full package would fit straight on, with a pipe fitted where the catalytic converter was.
Hope this helps.

Cheers,
A Kiwi
 

AussieCorvetteNut

Well-known member
Joined
Dec 19, 2010
Messages
189
Location
Gold Coast Australia
Corvette
1984 Two-tone Blue Coupe
Gidday Ocker,
If you are thinking of replacing your exhaust system, I would recommend a custom made system. Removing the catalytic converter will also make it a bit cooler inside cabin around the floor area.

Presuming your Corvette is like mine, [that is converted to right hand drive,] if you purchase a package, the right hand side headers will require some serious alteration. Keeping in mind that the factory shifts the engine 10mm to the right, which does not leave much room with the steering shaft and brake booster assembly there. Custom made headers will cost you.

If your engine is standard I would keep the standard factory headers, they work well and would fit well, with a dual exhaust system. With the new dual system [less catalytic converter] from headers back, I would have an 'X' pipe [to balance the back pressure] just below the rear of the transmission, and the dual system continues around each side of the wheel well. The pipes from the 'X' pipe to the rear mufflers, I would have them in stainless steel, as the bends around the wheel well tends to rust through.
If you are changing mufflers as well, be careful and choose well, as without the catalytic converter, some mufflers could resonate right on cruising speed. With a custom made system there is plenty of muffler selections in OZ. I selected Cherry Bomb stainless steel mufflers, with single inlet pipe and single centred outlet pipe, using LT1 tail pieces. It looks good.

If your car is not converted, then any full package would fit straight on, with a pipe fitted where the catalytic converter was.
Hope this helps.

Cheers,
A Kiwi


Hi Cuz

Yeah I had an 81 coupe a few years back that was RHD and I had a set of headers custom made and then HPC coated, they were $1250 at the time.
I am married to a KIWI girl, so didn't want to spend too much on the exhaust for a while if you know what I mean.

I checked the exhaust out again after your post, and the RH side has had modifications, but the block hugger seams to be stock. I also notice no mufflers at the ends,neither only the cat still in place.

I might just do the rear y pipe section for now, have the gearbox, diff and clutch to do.

Cheers Tony
 

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1cooldaddyo

Active member
Joined
Oct 26, 2014
Messages
25
Location
Minnesota
Corvette
1985 Silver/Gray two-tone
It's very easy to gut that cat.
Only 4 bolts on either end, they may look rusty, but actually an impact wrench will usually back them right out.
After that, a little quality time with a hammer and really big screwdriver and you have an open pipe.
 

AussieCorvetteNut

Well-known member
Joined
Dec 19, 2010
Messages
189
Location
Gold Coast Australia
Corvette
1984 Two-tone Blue Coupe
It's very easy to gut that cat.
Only 4 bolts on either end, they may look rusty, but actually an impact wrench will usually back them right out.
After that, a little quality time with a hammer and really big screwdriver and you have an open pipe.

I have been looking at the CAT and looking at the rest of the system which has no mufflers, it is the only thing keeping things quiet at the moment.

I may have to bite the bullet and see if there is a mobile exhaust guy in the area, who will come out and make me up something.

I took the spare tyre holder and spare tyre off the car and found that my fuel tank has surface rust on the outside of the tank.
As the exhaust has to come out for the tank removal, I might wait until I have the rest of the parts before I pull it out.
I have a parts 84 Coupe which has a tidy fuel tank, it also has another DANA 36 diff. I picked up another DNE 4+3 on eBay in Sydney, so I will get these parts ready for a swap and look around for the exhaust guy to come out.

:beer
 

forrest

Well-known member
Joined
Aug 9, 2014
Messages
86
Location
new port richey FL
Corvette
93 polo green
I have been looking at the CAT and looking at the rest of the system which has no mufflers, it is the only thing keeping things quiet at the moment.

I may have to bite the bullet and see if there is a mobile exhaust guy in the area, who will come out and make me up something.

I took the spare tyre holder and spare tyre off the car and found that my fuel tank has surface rust on the outside of the tank.
As the exhaust has to come out for the tank removal, I might wait until I have the rest of the parts before I pull it out.
I have a parts 84 Coupe which has a tidy fuel tank, it also has another DANA 36 diff. I picked up another DNE 4+3 on eBay in Sydney, so I will get these parts ready for a swap and look around for the exhaust guy to come out.

:beer


Tony
the Cat covnerter pops out real easy with a good impact and some rust buster sprays, but I have to warn you that if you choose to hollow out the cat do it in clothes you wont wear again, wear a good partical mask not the cheep paper ones do it in a well vented area out side with wind blowng dust away from you, and your home contain it all on a sheet or tarp. the stuff inside contains heavy metals and other nasty stuff.

when your done safely despose of all of it in a plastic trash bag. so you need to ask yourself does the benifit outway the Aggravation that stuff dosent ALWAYS come out easy.
 
Last edited:

AussieCorvetteNut

Well-known member
Joined
Dec 19, 2010
Messages
189
Location
Gold Coast Australia
Corvette
1984 Two-tone Blue Coupe
Hi Forest,

Thanks, yeah I probably won't be doing too much with that CAT except throwing it in the waste bin...it serves a purpose at the moment, it keeps "Blue" quiet enough not to attract attention.

At the moment though, I have to leave the exhaust system alone and try not to disturb or destroy any of it until I pick up work again.

I also only want to do the job once, removal and installation of the exhaust, as I have fuel tank, diff and suspension, gearbox and OD and clutch to do.
All of these require removal of the exhaust system, so I think I may have to progress some of the other work in preparation for all this work.

I have a spare DANA 36 and DNE 4+3, so will have these rebuilt and ready to swap once the exhaust is goneski...

:beer

Tony
 

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