Is a decat possible without dealer detection ?

AM Salie

New member
Iv heard guys speak about decating by removing cat inner?can anyone please explain please, and who in cape town can do it an what the average cost? Thank you.
 

Twinz

Forum - Support
Staff member
Let me deal with the question in your heading. Yes, the dealer will pick up if you have aftermarket DPs (Catted/catless). On a casual browse when you do a oil change they would be able to spot it. How they will react is up to your relationship with them. But waranty work will and can be denied & your M/P will be scratched.

Some "guys" use the stock DPs and simply remove the inner (catalytic) core using a screwdriver and strong hand. But on your x35 turbo car, decatting it that way has no real value. I have more comments but will chip in again.

AM Salie said:
Iv heard guys speak about decating by removing cat inner?can anyone please explain please, and who in cape town can do it an what the average cost? Thank you.

 

AM Salie

New member
Thanks Twins, I ask the question cos there is a rotten egg smell when I drive the car hard- I was told about the inner when I had my 330i, so didn't realize the turbo setup would react differently.
 

AM Salie

New member
Twins, I bought it as a used car, but nothing that I'm aware of, as a assumed the Claremont dealership would have killed the motorplan if it was not stock.

So all I fitted thus far is the jb and cone intakes and the sprint thing.
 

Twinz

Forum - Support
Staff member
okay...

The filter below the windshield could be dirty causing the rotten smell...its the filter just above the cowl, on top of the ECU...check it

 

i8am3

Member
Rob Green hollows the cats out...he says the dealers won't be able to pick this up and will give you 20whp:biglol:

He mentioned that it costs R4300 for them to do it:roflol:
 

P1000

///Member
Wow, that is a stupid price; noiseboys quoted me R500 for the same, though they cut windows into the cats, so it will be visible from outside. You wont gain any power by removing the cat, since the charge pressure is electronically controlled. The turbos will spool up a bit faster and run a bit cooler and you will increase possible mapping gains.
 

moranor@axis

///Member
Official Advertiser
if you can get at the cat inners without cutting i would just get a long screwdriver and take them out myself... they would have to take the exhaust off to see the cats were not in place so thats as good as it will get...
 

Rapido WP

///Member
My decats are both undetectable as they re-welded the housings very carefully, both at the headers and mid-ships. Each car cost R3k and took 2 to 3 days. It made very little diff on my 330 but a huge one on my wife's 320i auto - it was like a different car. Before, it would just sit on the driveway when you shifted into reverse, but now it immediately rolls back without touching the pedal. Much faster & responsive too. On BMW's before I think 2006 you don't need to put in mini cats to fool the ecu. Old cats smell more like resin than rotten eggs.
 

Speirie

///Member
@Rapido
where did you get the cats done? in cape town?

im out of motorplan in 500km and would like to have this done.

Thanks
 

Hellas

///Member
Here's my cat gutted. I made the cuts on the existing weld since that gives you a bit more material for the re-welding afterwards.

A steady hand and you're done!

EDIT: On hindsight, it should only be necessary to cut open ONE end of the box and you would still be able to remove all the bits. :thumbsup:

Decat.jpg
 

DikJoe

New member
M3_FTW said:
The rotten egg smell is the cats. Guaranteed to do it after a spirited drive.

If that's the case, am salie knows exactly why cos his car had the spirit driven out of it at last track day.lol
 
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