catalytic converter removal and specs for new one

[94c4lt1]

Hey guys,

We are trying to remove the catalytic converter on a 91 syclone. We have the clamps off...but now we need some ideas on how to get it free from the exhaust pipes. We have tried using a steel pipe and pounding it with a hammer to push it off the pipe. Does anyone have any tricks or tips for this?

Also, we need dimensions for ordering a hi flow cat and what to get (ie, type, entrance and exit diameters, length and width of cat (going into a borla 2 3/4" catback exhaust).

Any help or insight would be great!

Thanks in advance

 

[syntax]

Use a torch and cut two slits in the cat on either side where it connects to the downpipe, this is the only way I could get mine off.

 

[InvisiBill]

Do you have an upgraded wastegate? If you remove the cat or replace it with a high-flow version, you're very likely to have overboost issues due to the reduction in backpressure.

 

[94c4lt1]

Do you have an upgraded wastegate? If you remove the cat or replace it with a high-flow version, you're very likely to have overboost issues due to the reduction in backpressure.

Okay we are going to upgrade to an aftermarket catalytic converter and an aftermarket upgraded wastegate. Now what should we look for in a catalytic converter and upgraded wastegate? What kind should we get? Any help?


Thanks

 

[Sy769]

Cut two slits in the cat with a cutoff wheel and then use an air hammer to drive it off.

Cat choice depends what your plans are with downpipe,exhaust etc.

Any of the universal types without the air tube will be fine. All depends on what pipe size you want.

 

[InvisiBill]

Okay we are going to upgrade to an aftermarket catalytic converter and an aftermarket upgraded wastegate. Now what should we look for in a catalytic converter and upgraded wastegate? What kind should we get? Any help?


Thanks

While you're in there... =)

You may want to consider the JS/Christian Dionne method. There is a service port on the back of the turbo. If you open that up, the stock wastegate has a straight shot out of the turbo, which I have been told cures all of its inadequacies. You just need to replace or modify your downpipe to cover that service port too.

So you can open up the service port on the turbo, get a new 3" downpipe which will work with your new "wastegate exit", a 3" cat, and whatever you want behind that. Full 3" exhaust from the turbo back, with good boost control, without having to do any major mods to anything else.

That's what I plan to do, sometime... I prefer sticking as close to stock as possible for some reason. *shrug*

 

[94c4lt1]

Okay we are going to upgrade to an aftermarket catalytic converter and an aftermarket upgraded wastegate. Now what should we look for in a catalytic converter and upgraded wastegate? What kind should we get? Any help?


Thanks

While you're in there... =)

You may want to consider the JS/Christian Dionne method. There is a service port on the back of the turbo. If you open that up, the stock wastegate has a straight shot out of the turbo, which I have been told cures all of its inadequacies. You just need to replace or modify your downpipe to cover that service port too.

So you can open up the service port on the turbo, get a new 3" downpipe which will work with your new "wastegate exit", a 3" cat, and whatever you want behind that. Full 3" exhaust from the turbo back, with good boost control, without having to do any major mods to anything else.

That's what I plan to do, sometime... I prefer sticking as close to stock as possible for some reason. *shrug*

Actually guys, we decided (since the old cat is shot (wire screens are broken)), to just go with a stock replacement. ATR makes one for about $200. That is tons cheaper than the $450 GM replacement.

And since my buddies and me know very little about wastegates we think this would be the best option. Hate to waste money on something we know very little about.

Thanks for all your help.

 

[92BlkTy]

Do you have an upgraded wastegate? If you remove the cat or replace it with a high-flow version, you're very likely to have overboost issues due to the reduction in backpressure.

That all depends on the altitude you are at. I have a cat delete, and exaust cutout and here in CO i can run arround boosting left and right with full boost up until the 125mph govener (sp?) kicks in with out throwing a code. i went down to the S-Series nats, and couldnt run with the cutout open because it would overboost in a mater of seconds (WOT of course) but if i capped it, it was fine. which KC, MO isnt exactly sea level, and im sure at seal level you would have overboost problems with a cat delete, or even a high flow cat.