PD 130 to decat or not to decat?

pauldazzle

Registered User
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.
 

deano1978

different gear
I only have the cat by the turbo,middle and back boxes removed.
I've never read or heard of a definite answer to this Q
 

SL11CKK

Registered User
Ive heard in numerous tdi forums not to decat as the turbo on ours need back pressure. Something about boost spike as we have smaller turbos.

Hence I still have my poxy cat.
 
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pauldazzle

Registered User
There seems to be a lot of conflicting views on the turbo back pressure issue.:think:
 

pink.teg

Registered User
Yer just ask Charlie , think my cat is gone just got 2 back bboxes left
its done the job !!!
Alan
say u know Chinese Alan he may knock abit off for sure !!
 

Gaz!

Registered User
I went to have mine remapped, the company refused to map it as they said the turbo wouldnt last long. I have now reoved it. They said without the cat the turbo spikesand will certainly fail.
 

beachbuggy

Registered User
I went to have mine remapped, the company refused to map it as they said the turbo wouldnt last long. I have now reoved it. They said without the cat the turbo spikesand will certainly fail.

I imagine they refused because they have generic maps designed for cat cars, by removing the car you make it freer flowing and possibly will cause issues, simply as they are not capable of adjusting the map to compensate for the cat removal. I'd suggest you go somewhere that actually maps rather than just flashes a generic map!

main issue with removing cats or larger DP is the back pressure which goes somewhere to helping sealing the rear oil seal, it only assist by having a higher pressure outside the turbo than oil pressure inside and thus pushes the oil/keeps it in. By making it freer flowing you reduce that and can cause oil blow by..
 

@udi A3

Well-Known Member
VCDS Map User
Decatting makes naff all difference to power, darkside kindly kept that info from me before taking mine off and chargeing me for the privalidge
 

pauldazzle

Registered User
As per my research there's no definitive answer, just disagreement.
My own experience with decatting a Mondeo ST220 TDCI :)asskicking:) was that it made a big difference. Spool up was a lot quicker, & throttle response improved. I didn't see it as power mod, but as a driveability mod.
Maybe wrongly I was hoping for the same from doing it to the Audi.
 

pauldazzle

Registered User
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 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.
 

Mollygoogle

Registered User
My 130k PD 130 has been decatted for about three months, the difference was instant! The car pulls much better without it. As said above smoother and more responsive.

Decat, K&N Panel, DTUK Tuning Box all adds up to 178bhp. Just got to decide what to do next
 

deano1978

different gear
Guys... What did you use? custom pipe or hammer?
 

666markyboy

Registered User
I imagine they refused because they have generic maps designed for cat cars, by removing the car you make it freer flowing and possibly will cause issues, simply as they are not capable of adjusting the map to compensate for the cat removal. I'd suggest you go somewhere that actually maps rather than just flashes a generic map!

main issue with removing cats or larger DP is the back pressure which goes somewhere to helping sealing the rear oil seal, it only assist by having a higher pressure outside the turbo than oil pressure inside and thus pushes the oil/keeps it in. By making it freer flowing you reduce that and can cause oil blow by..


Thanks BB...... finally an answer from someone who knows about turbo's.... your explanation makes total sense
 

deano1978

different gear
So you wouldnt advise this mod??
 

pauldazzle

Registered User
Really glad I had it done, the car feels absolutely great. Best £50 I've ever spent on a car.:yahoo:
 

Jacko1

Registered User
How did you turbo hold up in the end with the de cat .....any issues?
 

Gazwould

Registered User
Necro2.jpg
 

pauldazzle

Registered User
I eventually sold the car with 240k on it & it never had any turbo issues after the decat.
 

Gazwould

Registered User
I'm impressed..

Frees up back pressure , only issue is stinky exhaust and slight turbo whistle , which is kind of in keeping with a Euro 3 car , with a Euro 5+ it wouldn't fit .
 
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