What are our cat replacement options?

[jajou318]

I'm going to need to replace the cats soon in the roadster and was wondering what our options are.

If anyone has video clips of a cat delete on stock exhaust I'd love to hear that too.

[fmcfad01]

I've been told that the only cats worth a damn besides the OEM ones are made by HJS. Custom Performance makes a couple (pricey) options for BMWs that use those cats. I know some folks that have used Magnaflow cats and they don't last long and don't perform well enough to pass emissions year over year.

[Wertles]

I replaced my cats with ones from Vibrant. There were no appreciable differences in sound on the stock exhaust. Stock right, aftermarket left.

[MartyBtoo]

I am living in fear that one of these days I will have to worry about cats, as the S54's have the cats in the headers. I have no idea whether you can get new ones from BMW, or whether anyone is making a 50-state legal aftermarket version.

Marty

[ADAz3M]

Move to FL.

we don't need no stinking cats

[Jonathan@BimmerWorld]

If you end up deciding to keep them, the DEC cats are an option, and although not currently listed on our site, Magnaflow is another option with part number 24189, I believe - assuming that's an S52 roadster you're referring to - call us to confirm p/n.

[jajou318]

Move to FL.

we don't need no stinking cats

I don't need them either. Just want to make sure I don't make this car sound obnoxious if I decide to just remove them (which might be the route I'm going after seeing the factory replacement midpipe price).

[ADAz3M]

I don't need them either. Just want to make sure I don't make this car sound obnoxious if I decide to just remove them (which might be the route I'm going after seeing the factory replacement midpipe price).

if it's just sound....throw some resonators in place

[slickbeamer]

i'll buy your old cats for $75 if you don't need them pm me

[robb1887]

If I didn't need them mine would be gone already. Stupid Visual inspection...

[FINZ]

Tony - I have the SuperSprint cats in my S54 and they work great. High flow, yet pass emissions in GA. Would they fit the S52?

[jajou318]

Tony - I have the SuperSprint cats in my S54 and they work great. High flow, yet pass emissions in GA. Would they fit the S52?

Hey Bill The midpipe is different at the headers doesn't mean it can't be modified. But I rather you sell that to someone who could use it without modification.

[jajou318]

Thanks though

[fmcfad01]

If I didn't need them mine would be gone already. Stupid Visual inspection...

Sounds like you need a new inspection guy. I shit you not, the guy I go to has his ODB-I and ODB-II requirements backwards. He thinks newer cars are the ones that shouldn't be tested on the rollers. He literally scans for engine codes and slaps a sticker on the car...pretty sure he doesn't inspect anything. Ya! Virginia!

[mpire]

You can make your own S52 O2 simulators for about $20.

The S54, unfortunately, is too smart to be fooled and you have to reprogram the ECU to ignore them.

[328 Power 04]

You can make your own S52 O2 simulators for about $20.

Not a bad price at all for DIY.
Alternatively, it's fairly easy to disable them out of MS41 flash as well.

[mpire]

True, but you have to get all the stuff to do the programming yourself, or pay someone.

[328 Power 04]

True, but you have to get all the stuff to do the programming yourself, or pay someone.

No really, your method is slightly better (even though MS41 tuning now requires a VAGCOM cable, a $30 program someone wrote, and a visit to RomRaider MS41 section) because you will have readiness set correctly for post cat O2's, instead of just N/A.
For MS41.2 there is an available edit to the logic of the rear O2s to keep readiness correctly, but it's still experimental. Instead of just turning off the DTC counter.

[mpire]

You are making me feel dumb.

I just bought an 02 simulator thing and made my own.

I did the same with the air pump. I made my own simulator for around $15 of parts at radio shack.

Granted, I run cats anyway, but you don't have to bother with getting the ECU to like them, you can run any high flow cats and pick them based on how the exhaust smells.

I like my exhaust not to smell bad and leave residue on the back of my car.

[328 Power 04]

You are making me feel dumb.

You don't need to feel so, and I apologize if I said anything to cause that.
I actually like your method better for the rear O2s. I always found the O2 sim options from vendors a bit too expensive (at least the ones over $100). Didn't know about the DIY route.

[mpire]

You damn kids and your computers!

Bah Humbug!

[328 Power 04]

Elderly and their resistors!