new catalytic converter

nynor · 10-09-2005, 01:23 PM

i am thinking i need a new catalytic converter.

has anyone used a universal one? i am thinking that a high flow cat put in where the original one is, just cut the old one out, weld the new one in its place and be done with it. before you flame me for wanting a high flow cat, keep in mind that they want $2000 or so for a new one for my car. i am not able to spend that much.

McFly944 · McFly944's Garage

$2000 for a new cat? I have seen some for much cheaper around the net. I can't recall which site, but it was more like $400-600(for the turbo) I think 944online list one for $2000 and one for 500. Granted the $500 one is aftermarket, but with a low budget it still gets the job done.

mlue · 10-09-2005, 04:06 PM

Quote:

Originally posted by nynor
i am thinking i need a new catalytic converter.

has anyone used a universal one? i am thinking that a high flow cat put in where the original one is, just cut the old one out, weld the new one in its place and be done with it. before you flame me for wanting a high flow cat, keep in mind that they want $2000 or so for a new one for my car. i am not able to spend that much.

Nynor, you can use a hight flow CAT from any of the manufacturers.

The car will sound louder, the Porsche CAT is longer than other CATs because it is has the catalitic area plus a resonator section.

Before you buy a CAT make sure you trouble shoot the boost problem that is causing you to fail the smog test. Changing the CAT may not fix your original problem.

nynor · 10-10-2005, 10:33 AM

i am thinking that the cat is plugged, which is causing the boost problem AND the failed emissions.

legion · 10-10-2005, 10:43 AM

Have you pulled your BOV and looked at it? That was my problem.

IanS · 10-10-2005, 12:00 PM

Agreed, make sure the BOV/bypass valve holds vacuum. That will easily kill most of your boost.

-Ian

nynor · 10-10-2005, 01:07 PM

yeah, BOV seems good. its brand new, diaphragm is good. the car builds boost from about 3200 RPMs and will hold it until about 4800 RPM's, then starts to cut out.

stevenhuey · 10-10-2005, 01:13 PM

I bought my Hi-Flow Cat from Jegs.com. Cost me $40.00 at a local muffler shop to install.

Steve

ae1969 · 10-10-2005, 01:17 PM

PUll the cat............ and go for a rip.

It will be loud....

but at least it will be easy to rule out a bad cat.

legion · 10-10-2005, 01:20 PM

Quote:

Originally posted by nynor
yeah, BOV seems good. its brand new, diaphragm is good. the car builds boost from about 3200 RPMs and will hold it until about 4800 RPM's, then starts to cut out.

Hmmm...that makes me think "wastegate"...

I could be wrong.

You can pull your muffler and take a look at the cat without removing it from the car with a flashlight. It should look kinda white.

nynor · 10-10-2005, 01:26 PM

as it is, i have two problems: it cutting out and failed emissions. i am thinking a plugged cat might cause both problems. i am not ruling out the wastegate, however. how do i test the wastegate?

legion · 01:50 PM

I can't think of an easy way. (Hoping someone more knowledgeable chimes in.) You could get one of the relatively inexpensive TiAl wastegates.

Edit:

My method involves an air compressor, some ATF, and a duck. Unfortunately, the duck is consumed by the test...

nynor · 10-10-2005, 09:26 PM

so, i pulled the cat tonight. the shop that sold me the car was very nice and let me used their equipment, gave me a used cat to try out, etc. turns out the cat on the car was utterly empty. this may explain why it failed emissions. i'll have to try that again tomorrow.

the boost, on the other hand, is still problematic. it builds boost sooner than before, holds it for a bit, then cuts out. i am thinking i may have an overboost problem, or a wastegate problem. while i was under the car, i did check the hose coming from the wastegate, it looked solid, new actually. any thoughts?

i did check the A/F ratio, all seems well there.

legion · 10-11-2005, 05:43 AM

The problem with the stock wastegate, from what I understand, is that the springs wear out over time. So it might look fine from the outside, but it is opening early and causing the turbo to slow down when spooled.

nynor · 08:35 AM

the boost problem is more like a sudden loss of power, as if the engine has completely stopped. i am leaning towards an overboost problem, like the wastegate isn't opening when it is supposed to and the KLR is shutting everything down.

nynor · 10-12-2005, 11:31 AM

car passed emissions with the 'new' cat. now, if i can just get the boost problem sorted...

legion · 10-12-2005, 12:12 PM

Any easy way to check for exhaust leaks?

nynor · 10-12-2005, 12:19 PM

get underneath it looke for soot at any of the pipe junctions and at the head where it meets the headers. i've also heard that you can pressurize the system at the end of the tailpipe and see if it holds pressure, or if you can hear leaks.

do you think you have an exhaust leak?