XSeries-forum

Morning everyone,

On my previous 330ci clubsport, I removed the 2 pre cats (leaving the 2 main cats alone), larger air intakes etc amongst other things, and even tho it was a petrol, can the same be done on the X5 3.0d.
Been reading other BMW forums with regards to the 330d E46's and some have removed the 2 precats and downpipe etc for more power. As my 2002 M57N engine is the same as the early 330d e46, will I get the same benifits.

Anyone tuned their diesels in this way?

my mate has an E39 530d

Remapped, decat down pipe with pipercross filter (just replaced original in existing housing, no cone filter bollo%*s).

It ran 245 bhp (originally 193)

Beware that under the 2012 MoT regs, removing the cats if fitted OEM will fail the car now.  Some are getting away with it, but not all.  There may be a way around it, but I don't know the details - other than 'fake' cats in the pipes.

Richard

Cheers X5sport, has the 3.0d got 4 cats like the 3.0 petrol version????, as the 2 rear cats on the petrol were only for more lower emissions, mine passed with flying colours every MOT when I removed the rear 2.

I think it's only one at the front.  There's an option to replace it with a DPF/CAT Combo.  As I've sold mine now, I can't remember exactly what is underneath, but I don't think there are any at the rear.

Have a look at Realoem and put you last 7 characters of your VIN into 'Serial Number' and it will come up with the right model and all the exhaust parts will be in the relevant section with a diagram.

Richard

Looking at the realoem, your right, theres only one cat, which has 2 outlets for the 2 pipe exhaust system, however, whats interesting is the downpipe looks as if it has a precat in, which with some gentle coaxing will come out. Taking the precat out of my other cars has always been a good mod, hopefully will be the same on the X5.

Might have to price up a sports cat and see how much to have it welded in place of the standard cat.

Also be aware that the fitting of some sports cats can also lead to MOT failure.

Cheers Huck, i was under the understanding that its the 100cell cats that are emisson dodgy, I had a 200 cell cat on my astra coupe and it passed no problem.

100 cell will 'barely' pass. 200 cell will pass through.

Diesels go through a smoke test though dont they?

Yes, but emissions are also looked at.....newer versions have DPFs now which weren't fitted to UK E53s.  I have to say that's the only part of the test that makes me cringe every time, especially as you have to sign a piece of paper that says the tester can rev the nuts off it and if it breaks it's not his fault....I make sure mine is fully and completely warmed up before ever letting a tester anywhere near it!!

Richard

Makes more sence to get it remapped, would give better results than messing with the exhausts. A TD is completely different exhaust, and intake, flow wise.

[quote="huck"]
Also be aware that the fitting of some sports cats can also lead to MOT failure.
[/quote]

Depends who you use 

[quote="535dboy"]
[quote="huck"]
Also be aware that the fitting of some sports cats can also lead to MOT failure.
[/quote]

Depends who you use 
[/quote]

That is very true.

I would've thought most places fitting decats can suggest somewhere for an MOT. Been catless for 2yrs on my Exige and also the M3 before it.

Diesels are only subject to a smoke test (plus visual confirmation the cat/DPF is there if the garage is anal).