Decat my diesel

[Ibiza 130 tdi]

Hey guys, thanks for advice about the headlights. worked a treat! got another one to test your knowledge! lol. decatting my diesel, how will it affect it power wise? improve? make it worse?

 

[EdButler]

On TDIClub (complete boffins some of em!) its the general consensus that theyre not worth removing. They may halp the turbo spool up a nanosecond quicker but power will either be not affected or only 1% increase.

There was a test on there that proved the mufflers/silencers to be more restrictive than a CAT so people have them removed instead. Provides slightly quicker spool up and again perhaps a tiny power increase (but also releases ~20 KG's of weight from the car!!) - Do a search for "Mufflerectomy"

If your hardcore and dont care about legality - have a straight pipe, but that will start getting into 'loudish' territory!

 

[depresion]

Milltek are hopefully going to be doing a Decat pipe soon (possibly with my car as a development mule) so it will have all there usual noise and emissions tests done to make sure it's still 100% road legal.

 

[Triple D]

Milltek already did a development decat on mikeobd's car (jbs mike) and they decided against it, so maybe they are thinking about it again now then. Id just say if you want a decat, get one done, wont cost any more than £50 or, get a Milltek sport cat £280 iirc and then just be happy with that.

 

[sssstew]

yep ed is spot on, the search for mufflerectomy will return good results for more info.

 

[EdButler]

Oh just to add, it makes it smell like a Bus... Yuk

 

[Ibiza 130 tdi]

Ok...

Cheers for the advise guys. I had my backbox changed last week. I have had a Powerflow back box put on. The back silencer is as the size of motorbike can now! But still, its not loud. There is a rumble around 2000rpm and if you flat it, but nothing special. I just wanted it decatting to get more noise...but obv if it was going to decrease performance I wouldn't have bothered...

 

[EdButler]

Just remove the back box all together mate, you wont regret it.

T.Spark on here and i had them done at the same time. His is a twin and mine is a 6x4 Oval. Mine is quite a lot raspier and a little louder than his, whereas his you can hear the turbo a little more.

 

[Ibiza 130 tdi]

I orginally wanted a 6x4 for mine. Does it look any good? I didnt know if it would too big with me having a standard Ibiza bumper and not the Cupra bumper.

 

[Sisson]

Mine had a 5x3" exhaust and was fine on the standard bumper.

Just get the FR rear valance, [only £20] so it has the exhaust cut out...

 

[davels]

here's a link to my thread with vids clips of the muflerectomy, not the best quality but sould give you an idea of what no rear silencer sounds like

 

[Ibiza 130 tdi]

thanks for the help guys! Getting my car decatted on Feb 10th. Its gonna seem so long til then! time will drag so much!!!! i obv have to put the cat back on when going for MOT and service?

 

[muddyboots]

No you won't need the cat for the MOT on a TDI

 

[Ibiza 130 tdi]

So why do you not need a cat for a diesel? on MOT i mean. thats good anyway! saves hassle!

 

[davels]

i it help back pressure for steady turbo spool i believe, plus as someone said in an earlier post it stops it smelling like a bus, plus ofcourse the sound issue

 

[Sisson]

So why do you not need a cat for a diesel? on MOT i mean. thats good anyway! saves hassle!

diesels dont get tested for emissions... only smoke i believe..

 

[davels]

correct i got my muflerectomy checked a week or 2 ago and thats what the testers said

 

[D-Power]

I have today had my exhaust replaced with a fully custom job (cat back) from powerflow, i had their smallest backbox fitted as i didnt want any MOT issues. So far i've noticed the turbo spools up quicker and the turbo whistle is much louder! Expecting it to take a while to loosen up and the real sound to show.

I would'nt be too put off by low statistical power gains, its things like throttle response and smoothened power delivery that really make a difference to how a car drives.