Driving with bad converters...

[Silver Bullet]

I was told by a mechanic two months ago that I had two bad catalytic converters. He told me the drivers side had 10 pounds of back pressure, and the passenger side had 8 1/2. They are VERY expensive, and to be honest I just haven't been able to get the extra money to fix them. My main concern is that I "Hope" I am not damaging my engine by driving with the bad cats. Does anyone know what happens to the engine when the cats go bad, or what driving with bad cats could do to the engine?? I have 111,000 on my engine, and I'm hoping to get a lot more out of it!! Thanks, and take care...

<small>[ February 28, 2003, 07:41 PM: Message edited by: Silver Bullet ]</small>

 

[Mike Kopstain]

Unfortunetly you are. You are putting a lot of stress on the bearings, specifically the rod bearings. What your bad cats are doing is the equivilent to lugging (high load, low RPM) your engine.

As far as I can remember, all the documented cases we have had, with people realizing their cats were clogged, were followed by stories of them replacing rod bearings weeks or months down the road.

<small>[ February 28, 2003, 08:38 PM: Message edited by: Mikeys_Taurus ]</small>

 

[NotSoSlowSHO]

you should visit www.shotimes.com and read up on nasty cat. issues. Very scary stuff...

right now im looking into SHOshop's catless Y-pipe for my SHO... you might want to do the same.

 

[89 Gary]

If those pressure figures are considered bad then for about $80 apeice from Summit you can have new ones. But------if your cats are stock then it'll be almost impossible to replace because of the ridiculous 90 degree configuration design (someone should be shot) of our sho exhaust. Your going to have to bite the bullitt and get a Y pipe . If cats are bad you will have NO chance of passing the inspection in this state. As far as being bad for the engine-yes it "could" cause an overheating--but you would get very sluggish performance and that would be your tip off as to just how bad the cats are getting. You do have a 6 cyl? 8 cyl could be a different exhaust set up. Good luck eek!

 

[IAS92SHO]

I just bought a 92 SHO with 60K on it and had a nasty rattle, it turned out to be one of the cats, it broke up and actully clogged the exhaust pipe so very little or no exhaust could pass by. I thought before i inspected the cats that the rod bearings were bad, so i inspected them, and they were bad, and from the post above, the cat might have been the reason. I pulled the y pipe off and cut open the cats removed the catalyst and welded them back together. problem solved, and it was a cheap fix, if you have welding resources. As far as the SHOtimes info, i don't know how true that all is.....

 

[MOSHO92]

Where and how can you get that accurate of a backpressure reading? "8 1/2 lbs" ??

 

[DavidT]

Midas inserts a probe by drilling a small hole in your exhaust to measure the backpressure. Less than $20.

 

[Dave Ladely]

I had similar problem, live in Wash where they dont do a visual, so I got the catless Y pipe from ShoShop, very good quality, easy to install, passed emissions with room to spare.
Also, suddenly could use regular for 1st time, since catless cooled down combustion chamber. Also got about 3 mpg better mileage at 65 mph, also more power all through rpm band. Noisier, though, so I replaced the resonator with a bullet type straight through muffler. No more cats to worry about, saved money, still runs very clean.

 

[PROPHET]

dkautumna:
Midas inserts a probe by drilling a small hole in your exhaust to measure the backpressure. Less than $20.

Where exactly do they drill,David?

 

[DavidT]

just past the cats (on the exhaust side). Actually, they can drill anywhere on this side of the cats to determine a backpressure problem. The closer they do it to a cat, the more they can determine if the problem is actually in the cat.