Cat Delete (Page 2/2)
pmbrunelle NOV 24, 12:38 PM

quote
Originally posted by owenspike:


Would I have to drop the rest of the exhaust system to weld it?



Depends on the skill of the welder. Personally, I'm just an amateur in my garage, so I would tack in place, then drop the exhaust to weld everything comfortably on the side.

I've taken a car to a muffler shop where they put the car on a lift, and MIG-welded an exhaust pipe for me all around. This was in the floorpan tunnel of a car. So for a muffler shop that's used to doing this work, if you bring the car with the pipe already slipped in place (and temporarily secured with a U-clamp), they can probably have the welding job done in half an hour.
pmbrunelle NOV 24, 12:53 PM
In general, if your car smells strong enough to cause choking or a strong fuel smell, I don't think a catalyst will fix that.

When the catalyst promotes oxidation of fuel remains in the engine exhaust, there needs to be enough available oxygen (either free, or in NOx) to burn the remaining fuel.

If the engine isn't working at a stoichiometric mixture, the catalyst won't be able to make a silk purse from a pig's ear.

To prevent strong smells, firstly the engine-out exhaust must already be good (so engine in good shape mechanically, and well-tuned). The catalyst is for the final touch of clean.

[This message has been edited by pmbrunelle (edited 11-24-2020).]

Dennis LaGrua NOV 28, 03:58 PM

quote
Originally posted by cam-a-lot:
Your car won't run better without a CAT. It also won't be faster.. If it is a stock Fiero, it will be a slug compared to modern cars, with our without a CAT... My wife's minivan is faster than any stock Fiero ever was... and that's with 3 teenagers and a dog in the car, and full of groceries. Fieros are slow cars by today's standards... Choking the drivers behind you won't make it fast.
A clogged CAT hurts performance, and can be cheaply replaced. The person sitting behind you in traffic will appreciate not having to choke on fumes


I should have clarified my comment. As you have indicated, if you replace an old clogged cat the performance will improve and you will get better mileage. Running without one and getting better exhaust flow and performance would depend on the design itself. Some cats are highly restrictive while others flow freely. As for the performance of the 2.8L I would agree that it is quite anemic by today's standards. In the mid 1980's the Vette wasn't much faster.

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