My A4 is booked in to Prospeed next week to have the cat insides removed, & a pipe welded in to keep it looking OEM. Just wondering if anyone on here has decat'd there PD, & their opinion on the results.

I just wonder how the MOT exhaust emissions would read ??

not much benefit to be had unless you suspect high back pressure   but if cleaned out I don't see it needs a pipe welding in just a further expense--- emissions should be unchanged 

d  

Edited 3 August, 201312 yr by cheshire cat

MOT tester can now fail a diesel if it's obviously got the cat missing. Hence me wanting it to remain OEM look. Decat shouldn't make any difference to the smoke test so MOT shouldn't be an issue.

not much benefit to be had unless you suspect high back pressure   but if cleaned out I don't see it needs a pipe welding in just a further expense--- emissions should be unchanged 

d  

 

I've heard it'll flow better with a pipe welded in, but I'll go with whatever Prospeed advise.

My A4 is booked in to Prospeed next week to have the cat insides removed, & a pipe welded in to keep it looking OEM. Just wondering if anyone on here has decat'd there PD, & their opinion on the results.

 

Hey Paul, funnily enough i followed a derv bora recently to a local car meet. When we arrived we parked up next to each other and as he was really flipping quick i asked him when he got out the car what he was running. He said basically stock car (130) IIRC give or take but mapped with decat and this thing shifted He seemed to rate the increase over with cat fitted.

 

I want a mildly modded derv, i know i shouldn't but i do!

keep thinking about putting a derv lump in mine...

Well the cat is gone, & it's made a very noticeable difference. Much smoother & feels more responsive. The cat was seriously sooted up, & partly blocked! Gave it a good blast & the black smoke was unreal for a bit, but cleared after a few redlines, & if anything there's less smoke than before. Charlie at Pro-Speed reckoned the cat was just about shot so as I suspected 188K had taken it's toll.

Pleased so far & will update in a few days.

I've done a couple of hundred miles now, & it's the best £50 I've ever spent on a car   Spool up is way quicker & throttle response has totally changed. I don't know whether its all down to the decat or whether the old cat was so sooted up & blocked that the engine couldn't breath properly. I guess its probably a bit of both, but whatever the car feels absolutely great.

I know so little about engines but I know Derv's love to be de-catted! On the Mondeo TDCI they can release an extra 8-11 horses from a de-cat.

Don't think I'm gaining bhp as such, but the driveabilty is much improved & very little turbo lag is making it much more fun. MPG seems unchanged, but I think it'll probably improve once I get over the novelty of being pinned back in my seat & no black cloud in my wake.

Do it .

Mine with a map was great, and without is just as good .

It will smell of diesel smog lol. But nothing a MOT guy will pick up on unless your suffering with injector issues ? (Air Leak)

Gives a nice feel to the car and boos noise is better too .

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