Let's talk Cats (Catalytic, not feline)
 

So with an intermittent CEL relating to O2 sensors (which are all working) and a distinct metal on metal slapping sound, I've come to the conclusion that one (or both) of the internals inside the cats have come loose and/or broken. Giving the cat a tap also confirms my diagnosis on one of the two....

Now for any of you who have had to replace them, you know they don't come cheap!! In fact it's a bit like bend over the counter....lol. Now my game plan is to yank the manifolds, cut out the cats and tig in some replacement high flow spun units....a quick search revealed that at least one other member had gone to aftermarket units, but it was either a 4.4 or 4.6.

If anyone has any input on the matter id appreciate it.....if I'm blazing my own trail here, I'll be sure to do a write up for anyone who finds themselves in this situation down the road!

Welp, I hear crickets for you S.....


I'd say get the stock piping dimensions and measure the dimensions of the cats that are on there now, and replace with some higher-flow Magnaflows, you could tig them in yourself if you are the man like that or it shouldn't be too much trouble for a muffler shop to cut out and weld a new one in.


Either way I'm sure it would be a quarter of the cost of stock lol!

Luckily I came across this:http://www.xoutpost.com/bmw-sav-foru...s-headers.html

So i Have a bit of a starting point!!

Came across these, which are suppose to bolt right up. I'm still waiting on additional info from the company who produces them regarding the claims of increased hp & tq, and verification of E53 fitment. The Full stainless construction is a nice touch as well. I have yet to run any any factual testimonials regarding these, which has me a bit concerned...

I should point out that the 3.0 isn't a high performace machine by any means....and I'm not looking for a bonkers loud, catless system --- just something that breathes a bit easier, and bolts right up.

http://i598.photobucket.com/albums/t...d.png~original

If these do check out however, with a tag of $1150 USD, they aren't going to be for everyone.

The aftermarket headers that wallyx5 and I had done so .. Suckers is LOUND and you will have to send your ECU out to active Autowerk for them to flash so don't have have that check engine light..

You are wrong Mr.. These 3.0 engine can be mod up to 600HP at the wheel.
Check out e46fanatics kids did to their E46 models...

Anything is possible if you want to pull out all the stops....but I was speaking in context of the X5 specifically. :)

E46 X5 (330/525i) - i do not understand these designations...

E46 could be 330
then we have X5
and then, in the same sentence we have 525

I'd think that people who make something so specific for BMW should know designations and not mix them in such manner

E46 E53 E39; or 330 X5 525i

does it mean that they do not know what they are talking about? no, all it means, that they did not pay attention to the details... details... details is what the BMW is supposed to be all about, even though we all know that even the factory engineers are not that perfect...

just a side thought on the subject of cats that I have zero knowledge about... but they tried to train me in detecting small clues, that might need resolution before committing...

never mind my rambling, carry on...

any pics of stock headers for comparo S? That would give a good visual of whether the bends match up. I would think maybe you'd need a Conforti Shark Injector tune as well to offset the higher flow cat (and not trip a CEL for catalyst efficiency) Most tuners in the VW scene would take that code out of programming, i.e. a "testpipe" file which would not throw a CEL even if you had no cat in place. Only caveat to that is that you wouldn't pass emissions inspection since the car would not pass readiness as the catalyst would always show not ready.


$1150? Sounds about right for quality headers. Look at those beautiful welds too, definitely quality pieces.

T, I was a couple steps ahead, but on the same page as you with regards to their inconsistencies....it's part of the "additional info" I'm currently waiting on!

Ricky, I don't have a pic offhand, but will try to grab one later off google....the flanges and post-collector bends all look like they'd be good to go, but It's hard to know for sure without some specifics length wise.

What is this "shark injector" and Is it along the lines as the ESS stage 1 software? ---I have to look into it yet. If I absolutely need it, no biggie, but would like to stick with the ESS stuff if possible.