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just havin a heart attack
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Discussion Starter · #1 ·
Was on the highway last night, and exited and took my favorite sweeper. Ended that and dropped to 3rd and punched it. Car bogged down, the Service Engine Soon light began flashing and then went solid and the exhaust sounded goofy. Same thing that happened to my friend's 740iL. Hooked up my Peake tool, it said Catalyst Efficiency cyuls 5-8. What aftermarket cats have you guys used? I've heard Carsound are a decent alternative to most, and they make Magnaflow.
 

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bimmerd00d said:
Was on the highway last night, and exited and took my favorite sweeper. Ended that and dropped to 3rd and punched it. Car bogged down, the Service Engine Soon light began flashing and then went solid and the exhaust sounded goofy. Same thing that happened to my friend's 740iL. Hooked up my Peake tool, it said Catalyst Efficiency cyuls 5-8. What aftermarket cats have you guys used? I've heard Carsound are a decent alternative to most, and they make Magnaflow.
hey d00d,

no, i haven't changed my cats.. no codes yet, however, I still have a suspision that they're failing. Independent backpressure tested them with BMP gauge and said backpressure was 8psi... bmw tested and said backpressure was 3psi... I've read the TSI testing procedure allows 2 PSI at 2500 RPM. In any case, the dealer would not replace them under warrenty.

The 43005 is supposed to be most reliable. I've also read of Random Technologies working well and I know they are high flow units.
 

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just havin a heart attack
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Discussion Starter · #3 ·
My cats were replaced at some point before i bought the car. They have stampings of '02 on the bottom of them, so theyr'e fairly new. Are the replacements covered by an 80k mile warranty from when they were replaced?
 

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prehistoric bony fish
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I had a cat go bad on my car. I replaced both of them with Magnaflow 43005 cats. The check engine light went off and the car doesn't momentarily lose power anymore. The best part was that it was a few hundered bucks to replace both vs. $1505 as quoted by the stealership for one!:thumbup:

I got the cats from an ebay seller called performancepeddler. Much cheaper than anything else I saw.
 

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43005

Hey, how are you? Exact same issue I had. Unfortunately, I had to go about a month before replacing them: finance crisis and garage schedule. Anyway, put on the 43005 Magnaflow, as informed by this board. Work great. Good luck.
 

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just havin a heart attack
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Discussion Starter · #6 ·
Well, it's to the point where the car can't hardly pull itself along anymore. it got real bad at lunch just now. I'll be taking it to the shop later, where we will be removing the cats, replacing with straight replacement pipes, and o2 simulators.........lucky im in a non-emissions county. I'm starting to think an e39 540 is a bad idea for someone making less than about $50k a year. :rofl:
 

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Alt. Routes

Hey, how are you? You know, I was thinking about some alternatives routes such as the one you mention, too. The biggest problem is (as referenced in other threads about almost-death on highway) power loss. When I throw a six speed, almost 300hp engine, into 3rd gear at 75, it's for a reason. Stepping on the gas and having a car go no where, now, that's dangerous. Anyway, keep us posted on your alt. rout/solution. Stay cool.
 

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just havin a heart attack
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Discussion Starter · #8 ·
pjfox23 said:
Hey, how are you? You know, I was thinking about some alternatives routes such as the one you mention, too. The biggest problem is (as referenced in other threads about almost-death on highway) power loss. When I throw a six speed, almost 300hp engine, into 3rd gear at 75, it's for a reason. Stepping on the gas and having a car go no where, now, that's dangerous. Anyway, keep us posted on your alt. rout/solution. Stay cool.
yeah these 115+ days are apparently what's killing the cats out here. The muffler shop a buddy of mine works at has already replaced 6 this morning on various vehicles. Something about sitting in traffic, on a blacktop that's radiating the already 115-120deg heat and just causing the cats to fry. We are trying to find the correct voltages and whatnot to simulate the post-cat o2 sensors, and throw a pipe in place of the cats. I dont feel like spending $1000 on new cats, or even $600 to be honest. I'll deal with that later IF i ever run into an issue with lack of cats.
 

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Just remember lack of cats will kill your low end torque and improve high end HP. Sure the HP increase is great but torque is what gets you to 5250 RPM where HP takes over. Anyway, my $0.02

I have the Magnaflow 43005 installed in my 540i. Any yes, they are made by Car Sound
 

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just havin a heart attack
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Discussion Starter · #11 ·
KTrostel said:
Just remember lack of cats will kill your low end torque and improve high end HP. Sure the HP increase is great but torque is what gets you to 5250 RPM where HP takes over. Anyway, my $0.02

I have the Magnaflow 43005 installed in my 540i. Any yes, they are made by Car Sound
I'm in one of those debates right now. I'll decide which i want to do in an hour or so when i am talking to the guy at the shop.
 

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Hmmm...

Hey, how are you? That sounds interesting. Thanks for the link (I usually only go there to read the Kills thread and the flamming, ha). I'm going to look into that. Stay cool.
 

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To cat or not to cat?

bimmerd00d said:
I'm in one of those debates right now. I'll decide which i want to do in an hour or so when i am talking to the guy at the shop.
So, what did you decide on and how did it turn out?

I just got my Magnaflow muffler (14862) yesterday and was considering removing the cats. I decided to do a little research and this thread was right at the top! Sweet! :)
Now I'm considering replacing them instead with the high flow cats to save torque.

BTW, thanks a ton for the videos of your exhaust! It was helpful in deciding to go with Magnaflow! A local shop that services BMW recommended Magnaflow but I was a little hesitant until I check out your vids.
 

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just havin a heart attack
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Discussion Starter · #14 ·
UPDATE: The car is in the shop right now, pipes are being cut and bent to fit. The o2 sensor simulators are on the way, and i am heading over after work today to see if he fitted the pipes to it and maybe give it a quick listen :). Videos will proceed as well to see how it performs/sounds.
 

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Not intending to induce flames here, and I'm certainly not insinuating that anyone doesn't know this, but cats do perform a function. While it may not be critical to the operation of the vehicle, they do reduce emissions.

I'm by no means an expert (nor a tree hugger, I drive a 540) and am not claiming to be one, but the 80/20 rule has some application here: a vast majority of the emissions from vehicles overall come from a small percentage of actual vehicles.

I would be interested if someone out there was an expert could inform me what the emissions difference is with / without cats in a modern engine?
 

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just havin a heart attack
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Discussion Starter · #16 ·
sroberts said:
Not intending to induce flames here, and I'm certainly not insinuating that anyone doesn't know this, but cats do perform a function. While it may not be critical to the operation of the vehicle, they do reduce emissions.

I'm by no means an expert (nor a tree hugger, I drive a 540) and am not claiming to be one, but the 80/20 rule has some application here: a vast majority of the emissions from vehicles overall come from a small percentage of actual vehicles.

I would be interested if someone out there was an expert could inform me what the emissions difference is with / without cats in a modern engine?
Do you have $600 for me to borrow? :bigpimp: i'm a broke-arse college student. We do not test for emissions in my county, so the emissions must not be THAT high here to require it :rofl:
 

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I hear you on the money crunch, I was in college once myself (although those carefree days were 7 years ago). Back then I was looking forward to a job and the resulting income...if I only knew...

As far as I know, I think the TCEQ (state agency) sets county emissions standards based on population density for Texas. I'm guessing if you live in the Dallas area, you don't live in Tarrant county? I would think they would test Tarrant, since Harris county around Houston and Travis county around Austin both test.

Not sure the requirements in other states.
 

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sdfrog177
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Being from california I have learned a small amount about emissions.
First off emission testing is based upon how many people live in a certain area multiplied by square inch. Here in CA people fail smog tests all the time even with cats due to stricker regulations being implimented every year.
In case anyone was wondering cats dont rob that much power, in fact most newer cars run better with them. Plugged/fowled cats and a poorly tuned vehicle rob power.
At 112k I replaced my Cats (magnaflows) 02 sensors, plugs, valve cover gaskets, mass air, air pump, air filter, thermostat, expansion tank and all suspention components. The car feels like new again and gets a couple more MPG. I highly recommend to do all this at once (after you break the 100k mark you will actually save time and money in the long run) if you can swing it otherwise just putting bandaids on here and there will drive you crazy and broke with a 540. Certain things dont last more than 100k or so. Just my .02.
 

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just havin a heart attack
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Discussion Starter · #19 · (Edited)
sroberts said:
I hear you on the money crunch, I was in college once myself (although those carefree days were 7 years ago). Back then I was looking forward to a job and the resulting income...if I only knew...

As far as I know, I think the TCEQ (state agency) sets county emissions standards based on population density for Texas. I'm guessing if you live in the Dallas area, you don't live in Tarrant county? I would think they would test Tarrant, since Harris county around Houston and Travis county around Austin both test.

Not sure the requirements in other states.
My car is registered in a city of about 1100 people, where my parents live. I go to school/work in Dallas.
 

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Good stuff!

This is all good info guys and makes me think I'll have to do a little more research. I'm definately interested in seeing/hearing the results of the d00d's mod and how the car performs. :thumbup:
 
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