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Shelby Series 1 catalytic converter...


GTH298

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I have a supercharged series one with only 1000 miles on her. I just bought it, and as lick would have it, it runs bad. One side of the engine exhaust bearly has any exhaust pressure and I loose power accelerating and climbing any type of incline. I pulled the plugs and the drivers side spark plugs are nice (tan) and the passenger side plugs are black with carbon, with #3 wet. I replaced the coil for #3 and put in new plugs. It starts great, idles OK with an occasional random miss and still, the exhaust is weak (almost non existent and hot) on the passenger side.

Does anyone know the brand of catalytic convertors Shelby used on these cars? Where I can get one?

Also, any suggestions on it being something other than the cat?

HELP....Randy

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The cats are welded in behind the headers, I assume they are stainless as the rest of the exhaust is. I am pretty sure Borla made the entire system.

 

I have a horrible sulphur smell from my exhaust, I've been thinking of gutting my cats but will probably have to run an O2 simulator to keep the computer happy. Since you are from California that's probably not an option for you.

 

If you have access to a lift the exhaust isn't that difficult to remove, the exhaust pipes are a slip fit over the pipes from the cats. We did have to slit the exhaust pipes to get them off, they were a bit tight. If you remove the cat-back part you should be able to feel the exhaust pressure right behind the cats to rule out everything back of the cats. The only other thing I can think to try is a compression test.

 

If you do end up having to replace the cat I wouldn't worry about getting the exact same one, I'd replace them both with a good high flow cat and be done with it.

 

I have a supercharged series one with only 1000 miles on her. I just bought it, and as lick would have it, it runs bad. One side of the engine exhaust bearly has any exhaust pressure and I loose power accelerating and climbing any type of incline. I pulled the plugs and the drivers side spark plugs are nice (tan) and the passenger side plugs are black with carbon, with #3 wet. I replaced the coil for #3 and put in new plugs. It starts great, idles OK with an occasional random miss and still, the exhaust is weak (almost non existent and hot) on the passenger side.

Does anyone know the brand of catalytic convertors Shelby used on these cars? Where I can get one?

Also, any suggestions on it being something other than the cat?

HELP....Randy

 

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Good idea...could be a bad muffler also. I did a compression check and it is fine. I guess it could be a stuck injector as well, causing the cat to melt down.

I was think of putting straight tubes after I get it smogged but, that may mess up the O2 sensor calibration, or will it be OK?

Randy

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That's what the O2 simulators do is fool the after-cat sensors into thinking the cat is still working as it should. The problem is figuring which sim to use, possibly the one for a Corvette or Camaro but I'd have to do some research.

 

Good idea...could be a bad muffler also. I did a compression check and it is fine. I guess it could be a stuck injector as well, causing the cat to melt down.

I was think of putting straight tubes after I get it smogged but, that may mess up the O2 sensor calibration, or will it be OK?

Randy

 

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I probably should replace the injectors as well.

I believe what started the mess was the fact that the car sat for nearly 9 years and the bad gas has ruined some of the fuel components.

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That's very possible, could be the reason mine has the rotten egg smell from the exhaust. I'm trying to find out if the supercharged cars came with standard injectors or upgraded ones. It also may be possible to have your injectors cleaned without having to replace them.

 

Also, understand two things that I've run into:

 

The "upgraded" clutch on the supercharged cars wasn't very good, it was OK being dumped but hated being slipped. They wear out QUICKLY in normal street driving. Mine was gone in 1400 miles. I got a custom made dual-disc unit from a new GT500, but properly splined with the correct pressure plate for our cars. The install was LOTS of fun!!! :rant2: However, that clutch should handle anything I can throw at it.

 

The original rear tires aren't made anymore, and nobody makes a tire in that size (315/40ZR18) at all. After a ton of searching and calculating I found 3 different sets of matched front & rear tires in sizes that, while off a bit from the originals (shorter but wider), work just fine. My speedo is about 7% too fast, but I've got almost 14" wide race rubber on the rear and can still smoke the tires accelerating in 3rd gear!

 

However, once the car is sorted out and running right it is more fun that sex!!! You will never drive anything that handles close to a Series 1, and the blown ones are incredibly fast!!!

 

I probably should replace the injectors as well.

I believe what started the mess was the fact that the car sat for nearly 9 years and the bad gas has ruined some of the fuel components.

 

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Randy

 

The Series 1 catalytic converters were produced by Borla. One end of the cats were welded to the headers while the other end of the cats were clamped to the exhaust system. Give Borla a call at 877-462-6752 They are located in SoCal.

 

Steve

 

 

Just a follow up on this. According to Borla they sourced the cats from the Olds Aurora parts bin.

 

Steve

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Well, I found out the that the one cat was completely plugged and the other cat was getting there! No wonder it bogged down. The Olds cats are no longer available through GM, they said to use after market cats. I am replacing the originals with MagnaFlow cats, and keeping the originals for the sake of "having all the original parts".

 

John, Mine in also supercharged from the factory. Good info on the tires and injectors...I will take the injectors to a shop to have cleaned. Man I am dying to drive this thing!!!!

 

I will get it back from the muffler shop tomorrow.

 

Randy

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  • 2 weeks later...

OK, here is an update...the passenger cat was completely plugged and the drivers side was partially plugged. Had to put on Magnaflow cats as the originals are no longer available from GM.

The car still does not run correctly. The drivers side is very hot at the cat and running very rich, and has a random miss. Meanwhile, the passenger side seems to run OK now.

What I don't understand is: why one half of the engine runs different than the other.

The o2 sensors appear to be good and reading properly.

Any ideas guys....I am dying to drive this thing. Could it be something with the supercharger?

Randy

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  • 2 weeks later...

Finally, I found someone that can work on these cars. This guy is amazing with cars....Steve fixed it when no one else knew what to do. Along with the cats being replaced, all the fluids, plugs, and O2 sensors were replaced. He also worked on the fuel trims and did few other stuff to it. She runs great now! WOW....what a car. If anyone needs Steve's number, let me know. He is in Mountain View, CA. and owns a mechanic shop there. Randy

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Finally, I found someone that can work on these cars. This guy is amazing with cars....Steve fixed it when no one else knew what to do. Along with the cats being replaced, all the fluids, plugs, and O2 sensors were replaced. He also worked on the fuel trims and did few other stuff to it. She runs great now! WOW....what a car. If anyone needs Steve's number, let me know. He is in Mountain View, CA. and owns a mechanic shop there. Randy

 

 

Steve is my neighbor, lives a couple houses down the street from me. I talked to him today and he mentioned fixing this sweet Series 1.

It's a small world sometimes. Glad he got it going.

Andy

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