Decat a 1.9TDI should I?

RJ8V · Post by **RJ8V** » Wed Jun 01, 2016 11:41 pm

Hey guys,

Okay so as most of you know I'm driving a citi golf 1.4 carb.

But what none of you know is that my wife drives our safe/ long trip car.

A 2005 Polo 2door 1.9TDI 6speed (the one with the seperate headlight and spotlight)

Going to JHB for the weekend and was thinking of taking the car or rather her car for decat on Friday morning, seems pretty simple, just cut it off and fit a pipe.

But there's a reason why I'm driving the golfie and she the polo. Everything STOCK on her car and always fussy about mods.

So I want to know is it worth it to do the decat? what will the pros and cons be? I don't want to f#$K up something and have to stare into the eyes of a devil lol. Ony looking to do a decat as I heard of the pros but want to know the cons as well.

Just considering the decat as funds are a bit low for performance exhaust and blah blah.

Shivbeanz · Post by **Shivbeanz** » Thu Jun 02, 2016 12:18 am

Hey bud, I have the same car with a downpipe and no mufflers at all

No problems so far, but from your post I see that's not what you're looking for.
A friend of mine did a decat (removed cat and welded pipe) on a 5 speed polo tdi, he noticed no sound difference, although his butt dyno registered a slightly quicker gain in low revs
Pro- no cat would mean less restriction on exhaust gases and help turbo life
Can't really think of any cons
Hope this helped

RJ8V · Post by **RJ8V** » Thu Jun 02, 2016 12:51 am

Exactly the info I need, thanx Shivbeanz.

Post by **panic-mechanic** » Thu Jun 02, 2016 7:27 am

The only con is that it will fail an emissions test. Seeing we don't have that here.........

P1LAYA-ZN · Post by **P1LAYA-ZN** » Thu Jun 02, 2016 11:46 am

Your rear view mirror will also stop working also

Post by **THANAS** » Thu Jun 02, 2016 11:58 am

Likely won't make any difference unless the cat is very blocked up from a turbo failing in the past, etc. My 200k km+ cat was perfectly fine, of course I only found that out after removing it. Also I'm not sure if the cat would even be functioning at all after that amount of time, so just remove it.

stig · Post by **stig** » Thu Jun 02, 2016 1:10 pm

Remove it one time. Reduces EGT's especially if it is bloked from the soot over the years

RJ8V · Post by **RJ8V** » Thu Jun 02, 2016 1:23 pm

Stig, Panic and Thannas thanx! Seeing that the car has almost 230k on the clock, I think it must be blocked as hell so why not.

Was just affraid I might make a mistake but sure seems worth it.

Unobeat · Post by **Unobeat** » Thu Jun 02, 2016 1:25 pm

I have read many times here that removing it, has benefits for the turbo.

Jueshen · Post by **Jueshen** » Wed Jun 07, 2017 11:43 am

pls update with info once removed..
was it blocked?, mileage?
differences if any?

Post by **Neuk** » Wed Jun 07, 2017 11:45 am

Very strong Yoda feels due to thread subject.

HendrikCTI · Post by **HendrikCTI** » Wed Jun 07, 2017 3:36 pm

I'm also very curious what the inside condition is after that mileage. Please let us know.

Jueshen · Post by **Jueshen** » Thu Jul 20, 2017 2:27 pm

did u decat?
any feedback?
was the old cat blocked? mileage?

RJ8V · Post by **RJ8V** » Sat Jul 22, 2017 9:06 am

Sorry guys the last couple of days was hectic.

Regarding the above since most of you are keen on the results, the best way I can describe is...

Upon removal of the cat, to be honest was quite stuffy and blocked, almost the same as opening the egr valve for the first time and all the gunk blocking leaving only a small gap for circulation.

Fitted a straight pipe where the cat was and I did infact saw and felt a difference.

When on full throttle she smokes a bit more than before since there is no filter and only straight rush to the exhaust.

I felt boost kicking in earlier than usual, noticed around 1200rpm where it normally was at 1500.

Stock dump valve can actually be heard now. When idling and just tapping the throttle, if you stand behind her she purrrs, or in this case low whistle.

Anyway havent notice anything else or if fuel consumptipn made a difference but personally think it was worth it.

Post by **MeanTdi** » Sat Jul 22, 2017 5:19 pm

RJ8V wrote: I felt boost kicking in earlier than usual, noticed around 1200rpm where it normally was at 1500.

Stock dump valve can actually be heard now.

Yes the turbo will spool up sooner and feel like less lag. Most importantly you are getting the hot gasses away from the turbo more easily now to prolong its life.

P.s. no dump valve on a TDI. That sound is the turbo vanes slowing down.

Jueshen · Post by **Jueshen** » Mon Jul 24, 2017 7:59 am

thanks for the update, something i need to maybe do..

Post by **Tman21** » Mon Jul 24, 2017 9:39 am

Definitely only for emissions and not the health of your car.
On the Diesels, decat, straight pipe and EGR blank off is the way to go.

Tswerie · Post by **Tswerie** » Wed Dec 27, 2017 5:02 pm

Anyone knows the cost of a decat? Will sensors be removed? Wil air fuel mixture be negatively affected?

stig · Post by **stig** » Wed Dec 27, 2017 7:03 pm

Tswerie wrote:Anyone knows the cost of a decat? Will sensors be removed? Wil air fuel mixture be negatively affected?

1.9tdi has no sensors in the exhaust. Decat is R300 depending where

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Tswerie · Post by **Tswerie** » Wed Dec 27, 2017 9:26 pm

Thanks, can you recommend anyone in the Gauteng area?

stig · Post by **stig** » Wed Dec 27, 2017 10:29 pm

Tswerie wrote:Thanks, can you recommend anyone in the Gauteng area?

Im not from GP so unfortunately not, vut its not rocket science on the 1.9tdi polo. Any exhaust shop should be able to help

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Decat a 1.9TDI should I?

Decat a 1.9TDI should I?

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