auto_editor

I am sure my great-grandchildren will curse my name for ruining the environment just by driving a gasoline-fueled car anyway, so I have no moral (or, thanks to Michigan, legal) reason NOT to straight-pipe my CC's exhaust now that I have to go to a muffler shop anyway to fix the "gap" that now exists between the exhaust manifold and the crossover pipe's upper flange. If it turns out not to be a simple "replace gasket and re-bolt" operation, and welding is required, can't I remove a "potential point of failure"/present restriction by having them remove the cat at the same time?

That thing is old enough to buy alcohol, and knowing what I do about her service history (or lack thereof) tells me that she's been coughing out crud for ages now. Working backwards in time we have a likey leaky head gasket, TONS of oil and unburnt fuel, etc. And even with much of that fixed, her exhaust smells like a five-pack-a-day smoker that drinks gasoline.

Not promising news on the cat's behalf.

SO, in a fit of while-you're-in-there-itis, if it comes up, is there a reason NOT to "bypass" the cat, as it were? I already get the "SERVICE THE G**DAMN ENGINE" light on a semi-regular basis, so I don't care about that. And seeing as how she's already running a "half-open" exhaust thanks to that gap, I don't think the drop in exhaust backpressure would do any harm.

It's "deckchair-rearranging on the Titanic" time here folks, I know, but as my grandfather would say, "Askin's free, though the answer can cost you." Now I need to know more about those possible costs, and which ones will at least not be total wastes of my limited resources...

redoldsman

I doubt you will find a muffler shop that will do this. The possible fines they face are stiff and they would have to be nuts to take the chance. You might try talking them into making you a pipe you could go home and put on yourself but I doubt it. I remember buying a straight pipe for my Delta 88 that was sold by an auto parts store as a test tube to test for a defective converter. Then they yanked them off the shelves and acted like they never had them. That was in the 80's.

jaunty75

I agree with the above. I believe it is illegal to remove a catalytic converter from a car that originally came with one no matter how old, and I doubt you'll find a muffler shop that wants to stay in business that would remove it for you. If you think yours is crudded up, I'm sure they'd be glad to put in a new one for you.

Oldskeeper

You could straight pipe through the converter and it would have the right look when checked visually. Me I would replace it with an aftermarket one and allow it to do it's job and then the exhaust would pass through the muffler and not leave any deposits or buildup in the chambers.

jensenracing77

Around here, You have to take the plates off, trailer it to the muffler shop, tell them it will be for off road use only, Sign a paper saying so, then Trailer it home.

oldcutlass

It also depends on the laws in your individual state on whether it can be done or not. As mentioned above, they use to have test pipes so to speak that bolt in to replace one. Although I have not seen one in years.

The other problem would be how will the computer react. There is cause and effect programming based on sensor input.

Mikes442

Around here we would take off the pipe in the back of the cat then take a long concrete drill and make a few holes inside. Use a 1/2" or bigger drill bit. Did that to one car that couldn't get out of it's own way, after that it could burn rubber. No more back pressure. LOL

auto_editor

I was born and raised in California so I was reveling in the lack of emissions testing. I forgot that the cat was a Federal requirement regardless. Guess I'll have to call on some of our (surprisingly) numerous "speed shops" and see what's what there.

Regardless, I just cracked my factory service manual to find that what's ACTUALLY not connected properly is NOT in fact an actual "pipe" per se, but the entire, inexplicably HUGE one-piece "crossover pipe" that looks like it was built for a steam locomotive, not a car. And why does it have springs in it?!? And not only bolts but studs? And not just a gasket but a seal, too?

Did GM decide to make this so overcomplicated for a reason? I know flexible chassis mounting points can fail, but to give the crossover its own internal suspension system seems a bit much.

[I bet that thing weighs a ton, too. I could increase her performance just by replacing the half-ton of iron in her exhaust system with aluminum...]

Still, I guess it's better than the thing dragging along the ground, though that never EVER has happened in any car I know of that uses just bolts and a gasket to keep its manifolds and downstream bits together.

Are these remnants of engines that had horsepower and torque and therefore could twist around in their mounts? Because if you muted the sound of a video of someone alternately idling then wringing the neck of my 307, nine times out of ten a viewer wouldn't be able to spot the difference.

Except for the smoke. Oh, how she loves to smoke...

tru-blue 442

A couple of years ago I had to have the cats
replaced on my 02 Cheb because they had plugged up.
Replaced with a set of Magnaflows and wow what a diff.
If you decide to replace I highly suggest them if they are
made for your application. Good luck with it. Back in the day,
if we couldn't fine the "test pipe" we would take 'em off
and just reem 'em out. But as Eric said, that damn C/E light
will come on and you can't turn it off unless you pull the bulb.

m371961

Depends on the state and if you wanna be an outlaw. Me, I would dual exhaust it, no cats, but I don't know how it would affect carb, if it is computer controlled. I know you can bypass sensors with the proper value resistor and fool the engine light on some vehicles. What age does a vehicle in your state have to be for historic tags? Here it is 25 and no inspection, no emission tests and 10 year tags.

drrocket

I took the cat off of my 87-442 three years ago, replaced it with a straight pipe I had a friend with a shop make. 5,000 miles and no computer or carburetor issues to date. It increased the tone of the exhaust noticeably but I don't believe there was any performance increase.

joe_padavano

Modern honeycomb style cats don't provide any more restriction than a comparable piece of straight pipe. A good 2.5" high performance cat can be had for under $100. Your VIN Y motor won't notice the difference between having a cat and not.

Redog

You could pick up one of these puppies, or should I say kitties

http://www.ebay.com/itm/2-0-High-Flo...ht_1953wt_1121

tru-blue 442

^^^New School test pipe, excellent!
Get one before the EPA pulls 'em?

BlackGold

I agree. The aftermarket "high-performance" cat I bought from NAPA several years ago for my '85 442 didn't even have a honeycomb in it. It looked more like window screen, it was that thin. Right around $100.

pizza442

Interestingly, diesel models had a pipe in place of the cat. (found that out when researching exhaust catalogs to find the correct dual outlet, crossflow muffler for my 79 Hurst/Olds) Take a look at the Walker catalog for the different systems for your Cruiser's year. But that might entail replacing some of the pipe after where the cat was, too. Perhaps someone would make a pipe for you if you bring them the cat off the car for measuring purposes (and not have the car there so they don't get into trouble)

joe_padavano

There were no emissions requirements for diesel vehicles of that vintage.