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View Full Version : catylic converters???????



tim s
04-14-2004, 01:15 PM
where is a good place to get catylics fo 1995 540i/a? my mech. suspects one of them is clogging up. i heard aftermarket cats are problematic. does anyone have any used ones in good shape?
thanks
tim s.

G Feller
04-14-2004, 01:24 PM
Another board member (I believe it may have been Drew, sorry if not) once stated "a cat is a cat is a cat," in other words it should be unnecessary to spend $1000 for each of two BMW cats on an E34 530 or 540.

Any M60 guys out there who have replaced their cats:
1) What did you do
2) What were the results
3) How much did you end up spending?

Mine's gonna go one of these days, too. . .


where is a good place to get catylics fo 1995 540i/a? my mech. suspects one of them is clogging up. i heard aftermarket cats are problematic. does anyone have any used ones in good shape?
thanks
tim s.

sbcncsu
04-14-2004, 01:31 PM
where is a good place to get catylics fo 1995 540i/a? my mech. suspects one of them is clogging up. i heard aftermarket cats are problematic. does anyone have any used ones in good shape?
thanks
tim s.

I know nothing of this company but their pricing is great:

http://www.import-catalytic-converter-warehouse.com

Tiger
04-14-2004, 01:32 PM
My suggestion is you call up a cat converter specialist... those who only sell cat converter... and get a high performance cat unit... cut your old one out and weld the new one in. OBD II compliant, etc.

The reason is the high performance cat converter is far superior than OEM stuff, more free flowing, and efficient. All they have to do is match the cat to our engine displacement. The second reason is the pipes around the cat converter never rust because it is the hottest point so water never accumulate to rust it out unlike the muffler.

The only thing you have to watch out is the welding process... alignment... cut old cat out... place new one in place and spot weld it to hold position... then drop the entire unit and weld it all the way around.

In the end? Far cheaper than OEM ($1335 each) or even aftermarket ($381 each). That's nut! $1335 per side???!!!!

tim s
04-14-2004, 01:34 PM
tim s.






My suggestion is you call up a cat converter specialist... those who only sell cat converter... and get a high performance cat unit... cut your old one out and weld the new one in. OBD II compliant, etc.

The reason is the high performance cat converter is far superior than OEM stuff, more free flowing, and efficient. All they have to do is match the cat to our engine displacement. The second reason is the pipes around the cat converter never rust because it is the hottest point so water never accumulate to rust it out unlike the muffler.

The only thing you have to watch out is the welding process... alignment... cut old cat out... place new one in place and spot weld it to hold position... then drop the entire unit and weld it all the way around.

In the end? Far cheaper than OEM ($1335 each) or even aftermarket ($381 each). That's nut! $1335 per side???!!!!

Tiger
04-14-2004, 01:37 PM
That is great prices... standard cat... worth the price... considering a cat by itself is $70... and the pipe seems to be stainless although look like aluminized... but must call to verify... it is best to get stainless steel. Pipework worth $100... so they make 100% profit...

Tiger
04-14-2004, 01:38 PM
I'll help you look tonite... G Feller is right... a cat is a cat is a cat.

tim s
04-14-2004, 01:44 PM
thanks
tim s.

Unregistered
04-14-2004, 02:09 PM
I'll help you look tonite... G Feller is right... a cat is a cat is a cat.

sbcncsu
04-14-2004, 02:30 PM
thanks
tim s.

I put a "Carsound" performance cat on my 96 Jeep GC V8. It is a 3" and has very little restriction. I like it and a lot of the Jeep guys and girls at Jeepsunlimited.com have used them with good results. They are made by magnaflow. See their information here: http://www.magnaflow.com/02product/converter.htm

HTH

TimGinCentralNJ
04-14-2004, 02:39 PM
...and while I believe they're based on the left coast, they apparently have a warehouse in Edison, NJ in which they do some work. I had an app't to bring my little E12 down there back last May (since I was rejected by the fine State of NJ due to having holes in my downpipe), but never made it as a result of some other issues making the car non-roadworthy.

Anyway, might be worth looking into a Borla cat, as I recall their prices weren't bad either.

Hope that helps,
Tim G



thanks
tim s.

Rigmaster
04-14-2004, 02:46 PM
I've got a pair from a '94 530i, the pipe is bent on 1 but I could cut the cat out and ship it no prob. Let me know.

Thanks, Bret

winfred
04-14-2004, 08:57 PM
aftermarket cats are fine on non obdII cars, but i have herd nothing but bad news about them on cars with the post cat o2 sensors (obdII) we have a good friend that owns a high end euro car shop, he has tried all of the aftermarket cats on obdII bimmers and with in a year the check engine light is on again bitching about dimished cat performance, nothing but a factory cat keeps the light off

tim s
04-14-2004, 09:14 PM
aftermarket cats are fine on non obdII cars, but i have herd nothing but bad news about them on cars with the post cat o2 sensors (obdII) we have a good friend that owns a high end euro car shop, he has tried all of the aftermarket cats on obdII bimmers and with in a year the check engine light is on again bitching about dimished cat performance, nothing but a factory cat keeps the light off

Tiger
04-14-2004, 09:34 PM
Mmm... then that means the aftermarket cats chosen are undersized... The surface area must match original size...

winfred
04-14-2004, 09:41 PM
i don't know if it's over all surface area or just a inferior catylist, but he said even the nice 4-500 each highend aftermarket cats crap on e38s (and the v8s seem to eat cats) the only thing for them is $800 plus each oem cats, i totally trust his word, i've known him for over 10 years and worked for him for a couple of those

Tiger
04-15-2004, 10:23 AM
I always noticed that aftermarket cat are way smaller than OEM... The smaller one may be more efficient than the old OEM muffler when new... but because of smaller surface area... gets clogged faster and then they have reduced efficiency... dramatically compared to OEM.

Ask your friend about the size of the new cats he put in... were all of them much smaller than OEM? The other thing that we need to consider is why it failed... did the engine had problem shortly before it failed? Thereby causing the clogging (which would occur much faster)... I know you are in the business but you know... it is not like a magic bullet... not only the OEM has the magic bullet... there has to be a reason...

Bill R.
04-15-2004, 10:38 AM
federal clean air act which specifies on older cars that the cat is warranteed for 5 years or 50k miles and on newer cars after 95 the warranty period for the cat is 8 years or 80k miles...The original cats have to be built to last for that length of time or the manufacterer gets to eat them.. Aftermarket replacement cats are under no such restriction. That said an aftermarket cat should still last a fairly long time provided everything else is as it should be with the engine... Keep in mind that it doesn't take a misfiring plug very long to cook a cat...and the newer ones that Winfred is talking about have an o2 sensor before and after the cat the measure the cats performance, it there isn't sufficient difference in the emissions between the 2 sensors it will trigger a code on the obdII cars.









I always noticed that aftermarket cat are way smaller than OEM... The smaller one may be more efficient than the old OEM muffler when new... but because of smaller surface area... gets clogged faster and then they have reduced efficiency... dramatically compared to OEM.

Ask your friend about the size of the new cats he put in... were all of them much smaller than OEM? The other thing that we need to consider is why it failed... did the engine had problem shortly before it failed? Thereby causing the clogging (which would occur much faster)... I know you are in the business but you know... it is not like a magic bullet... not only the OEM has the magic bullet... there has to be a reason...

Tiger
04-15-2004, 12:58 PM
I C now... so when buying aftermarket Cat... the size matters tremendously and it is best to get one that is just as big is OEM. I understand about the OBD II now... if the O2 sensor differential is not enough, then we know for sure that the cat has died and offered substandard burning of smog.

Thanks Bill R for your insight. I always learn something from you.

sbcncsu
04-15-2004, 01:48 PM
...and the newer ones that Winfred is talking about have an o2 sensor before and after the cat they measure the cat's performance, if there isn't sufficient difference in the emissions between the 2 sensors it will trigger a code on the obdII cars.


Yep. My Jeep is a 96 with OBD II. It has two O2 sensors, one fore and one aft of the cat. It has been a year and a half since I had the Carsound cat installed with no problems.

Elekta
04-15-2004, 02:02 PM
I had a local muffler shop indy find the TX DOT spec replacement cat for my 530iT, and he cut two in in about 3 hours for $475 all in including tax. My cat's were completely hollow...all the baffle material had blown out. I was lucky none of it lodged in my muffler. They rattled for about 2 months, and after it all went quiet again, I got worried and changed them out.

No change in sound, performance, mileage....nothing. If I had my act together I would have had him screw in two new 02 sensors while he was at it...but he said they went back in fine.