Mufflerectomy - should I decat or not ?

[muddyboots]

OK I think I'm going to get a mufflerectomy done on the barge, but I'm not sure whether to decat it as well...

Any downsides to removing the cat as well ? I've heard some comments about whether the lack of backpressure after the turbo could cause it to over-spool / spin too fast.
What are peoples thoughts on this - any hard evidence of this actually causing problems ?

 

[mrcoyote]

You want your barge to sound even more like a tractor?

 

[muddyboots]

 

[Sisson]

i kept my cat just to be on the safe side...

i had no middle box and the smallest rear box they did.

Sounds deeper but not that louder on idle.

 

[EdButler]

Id keep the CAT and straight pipe everything after it. It saves the hassle of putting it on at every MOT and the CAT deadens a lot of the noise too. I think 'Devonutopia' on TDICLUB and Briskoda (and here i think!) has a straight through pipe and it sounds rather loud of his furby!

The guys at TDiClub have basically summarised its just not worth it, and it makes the exhaust fumes smell like a bus! VNT17's are quite noisy too so id leave it in mate, do your bit for the environment

 

[Sisson]

^^^^^ although it should still pass the MOT without a cat as diesels don't need them.

 

[muddyboots]

That was my thinking Sisson...

TBH I'm not too bothered about noise or smell, the only thing that would put me off a decat is the chance of turbo damage.

 

[EdButler]

You might be best asking on TDIClub then matey, there all TDi guru's on there, im sure they can give you a reliable answer.

 

[muddyboots]

Had a nosey round TDIClub yesterday Ed, guess which SCN member popped up in my first search results

 

[EdButler]

Just been investigating applying Silicone Dielectric grease to the MAF connector plug. Looks like a gem of a mod, performed it to a contractors Passatt yesterday and then plugged/unplugged the connector about 20 times to clean it. My god does it run smoother, less lumpy and no hessitation like it had before! It stops arcing/bouncing between connectors and insualtes condensation etc. as im sure you know (useful as the things will get hot/cold!).

I hope it improves mine, but if not, it'll protect it for the future £6 for 50g though, eek!

 

[muddyboots]

Ed

That's quite scary, I think you've been reading my mind.

Over the last few days, on the same tank of fuel and similar temp/weather conditions, it's been horribly smoky on some journeys and completely smoke-free on others (not even the slightest bit visible in following headlights, either on spool-up or high rpm full-bore).
Anyway my mind had been working overtime theorising what it could be down to, and I decided today I was going to find out more about applying contact grease to the MAF connection, as I remember reading about it on here before. I wondered whether the connector suffers from damp.

Where can I get hold of some ? There used to be a Maplins close to me at work in Stockport but I think it's closed or moved further away...

 

[devonutopia]

Id keep the CAT and straight pipe everything after it. It saves the hassle of putting it on at every MOT and the CAT deadens a lot of the noise too. I think 'Devonutopia' on TDICLUB and Briskoda (and here i think!) has a straight through pipe and it sounds rather loud of his furby!

Hello.

And for the record, a cat is not needed for MOT. A TDI will pass an emissions test without any exhaust fittings at all. Mine's been through two decatted, and the latter one with the "pipe" of an exhaust fitted. Next MOT will be the "pipe" + Allard race downpipe. I expect it to fly through yet again.