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Old 04-25-2007, 05:37 PM   #1
Rtony103
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Default Highflow cat insides melting? need opinions

so just wanted to get some opinions so i dont get screwed... i got a 2.5 rs with borla headers stromung axel back and a highflow cat section that i had made at a local custom shop....once i put the stromung on the cat went to **** and all the insides were rattling around within about less than 2 months.... bare with me here
so went back to the shop said hey cat went bad so im dropping the car off friday to have him throw in a new one... magnoflow i beleive.. but then we got into talking and he said that maybe theres too much heat and its melting the insides of the cat... now in my mind i say thats bull cuz ive worked with alot of exhuast and never had that problem or seen a cat melt.. and besides with the borla headers highflow cat and stromung muffler it should be fairly free flowing..
so let me know what you guys think...
thanks

also he suggested that maybe the muffler was clogged and that could be the reason for heating up enough to melt the cat
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Old 04-25-2007, 08:09 PM   #2
legacy1907
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it may have just been a poorly built cat if you had it made at a local muffler shop
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Old 04-25-2007, 08:53 PM   #3
EBWRC#1
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Quote:
Originally Posted by legacy1907 View Post
it may have just been a poorly built cat if you had it made at a local muffler shop
Dito...
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Old 04-25-2007, 11:00 PM   #4
t3hWIT
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Your cat can also melt if you're getting unburned fuel into the exhaust system... A melted catalytic converter is more common than you might think.
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Old 04-26-2007, 01:28 AM   #5
Rtony103
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alright well then if im running too rich then what do i do... i mean right now im having the new cat welded in but i dont want to put it back in and ruin another one cuz then most likely ill have to pay for the one after that... is there any way to know if theres extra fuel in the exhuast or if the temp is getting hot enough to melt the cat...? wouldnt the O2 sensors pull a check engine light if something was going wrong?
i mean maybe it was just a bad one and then new one will be fine... but id rather trouble shoot it before putting it back in

Last edited by Rtony103; 04-26-2007 at 01:34 AM.
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Old 04-26-2007, 10:12 AM   #6
crampfan
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Is the converter melted, or just rattling? if its rattling, or broken then it would be a defective converter. If its melted, you might want to make sure you don't have a misfire or other condition that might cause the converter to overheat, if has melted the new one will meld also.(faith healing does not work with converters) also the location of the converter. As far as a check engine light, sometimes its better to look at data, long and short term fuel trims ect. I have seen a leaking injector not turn on a MIL.
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Old 04-26-2007, 11:25 AM   #7
Aaron'z 2.5RS
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I own a 99' RS and it has NEVER liked ANY of the exhaust mods I've done(never done any intake stuff besides a K&N either, as they are REALLY sensitive on the intake side with the MAF sensor)... I had a 2.5" cat back made up for me once, and the car hated it... When it was time for me to have a new pipe made i had them do it in 2" and things have been much better.... IIRC the stock pipe is 1.75"

Seems they are VERY sensitive to lack of back pressure... the headers, high flow and the cat back, you have, ALL could be contributing to the problem...

I can't imagine the cat getting TO hot, they maintain 1800-2000* anyway don't they??
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Old 04-26-2007, 06:24 PM   #8
Rtony103
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im not sure i took the cat section out and its at the shop now and im dropping my car off tomorow so maybe while im there ill have him cut it open and look that way if its just loose and rattleing then ill put the new one in and if its melted ill hold off and try and figure out what my problem could be
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Old 04-27-2007, 07:57 AM   #9
Aaron'z 2.5RS
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Well, it's your car, but i can tell you from YEARS of reaserch that the 99' SOHC doesn't like the intake/exhaust mods....

If you could somehow get rid of the MAF i bet you would be much better off...
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Old 04-27-2007, 05:11 PM   #10
Rtony103
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yup.. so got the car back and checked out the old cat.... the insides just rattled loose so either it was a bad cat or I bottomed out on something and broke them loose... got the new one back in and its good to go.. sounds good and and after driving with the stock cats on you can deffinetly feel a nice little powerband with the highflow
thanks though guys
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Old 04-27-2007, 05:15 PM   #11
Rtony103
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and now that you mentioned it have you ever heard of anyone getting rid of the MAF? like converting it with the newer style
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Old 04-27-2007, 06:15 PM   #12
Honkey3k
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who uses cats anyway.....
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Old 04-27-2007, 11:15 PM   #13
ballitch
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not me.......but im going to put one in when i go turbo.


~Josh~
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Old 04-28-2007, 05:42 PM   #14
Charlie-III
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Quote:
Originally Posted by Rtony103 View Post
and now that you mentioned it have you ever heard of anyone getting rid of the MAF? like converting it with the newer style
It's been done.....some (lots?) of rewiring and then hook up a later model (2000?) ECU that uses a MAP instead of a MAF.

The MAF's have a good side though, they learn engine mods better than the MAP does. The MAP really likes engine management when you change things that allow more air into/out of the engine.
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