Make a donation

Author Topic: Pre-cat. . . . . REMOVED!  (Read 91987 times)

Offline jon-tfsi

  • Always Involved
  • ****
  • Thank You
  • -Given: 25
  • -Receive: 27
  • Posts: 404
    • Email
Re: Pre-cat. . . . . REMOVED!
« Reply #15 on: January 19, 2012, 08:32:41 pm »
A couple more pics :





GOLF R Mk7

Offline sideshowfred

  • Always Involved
  • ****
  • Thank You
  • -Given: 7
  • -Receive: 2
  • Posts: 115
    • Email
Re: Pre-cat. . . . . REMOVED!
« Reply #16 on: January 21, 2012, 10:15:40 am »
I'm really keen to do this when the weather warms up. One question though, are there any sensors i have to worry about that might not make it run smoothly??

Offline GrayMK5GTI

  • Global Moderator
  • Just look at my post count
  • *
  • Thank You
  • -Given: 125
  • -Receive: 248
  • Posts: 4165
Re: Pre-cat. . . . . REMOVED!
« Reply #17 on: January 22, 2012, 12:14:00 pm »
Nope  :smiley:

The ECU adjusts to the extra flow of the exhaust and the cooler EGT's and all is well - as long as you don't damage the lambda sensor when removing the pre-cat
NOW: 2015 Golf R DSG 5 Door, Lapiz Blue, 19s, Discover Nav, Reversing Camera
GONE:2007 Black GTI Edition 30 3dr

Offline GrayMK5GTI

  • Global Moderator
  • Just look at my post count
  • *
  • Thank You
  • -Given: 125
  • -Receive: 248
  • Posts: 4165
Re: Pre-cat. . . . . REMOVED!
« Reply #18 on: January 22, 2012, 01:17:44 pm »
Can also confirm that this mod releases around 6bhp  :star: this was confirmed on the dyno
NOW: 2015 Golf R DSG 5 Door, Lapiz Blue, 19s, Discover Nav, Reversing Camera
GONE:2007 Black GTI Edition 30 3dr

Offline GarethB

  • Won't Shut up.
  • *****
  • Thank You
  • -Given: 10
  • -Receive: 16
  • Posts: 628
Re: Pre-cat. . . . . REMOVED!
« Reply #19 on: January 22, 2012, 02:21:20 pm »
Nice  :happy2:

Best get the hammer out  :evilgrin:

Offline GrayMK5GTI

  • Global Moderator
  • Just look at my post count
  • *
  • Thank You
  • -Given: 125
  • -Receive: 248
  • Posts: 4165
Re: Pre-cat. . . . . REMOVED!
« Reply #20 on: January 22, 2012, 02:34:20 pm »
Nice  :happy2:

Best get the hammer out  :evilgrin:

DO IT! Will help it on the RR at JKM  :smiley:
NOW: 2015 Golf R DSG 5 Door, Lapiz Blue, 19s, Discover Nav, Reversing Camera
GONE:2007 Black GTI Edition 30 3dr

Offline GarethB

  • Won't Shut up.
  • *****
  • Thank You
  • -Given: 10
  • -Receive: 16
  • Posts: 628
Re: Pre-cat. . . . . REMOVED!
« Reply #21 on: January 22, 2012, 02:40:30 pm »
booked in at my mate's garage in a couple of weeks for a few bits - I shall have to see if we've got time to whip the downpipe off and remove the pre cat.

How long did it take to do? once the material is cracked/broken, does all it all kind of 'fall' out, or does it require extra work?

Offline vRS_Pagey

  • Just look at my post count
  • ******
  • Thank You
  • -Given: 66
  • -Receive: 59
  • Posts: 1577
Re: Pre-cat. . . . . REMOVED!
« Reply #22 on: January 22, 2012, 02:46:51 pm »
I'm really keen to do this when the weather warms up. One question though, are there any sensors i have to worry about that might not make it run smoothly??


If you DIY this, just be careful of the O2 sensors directly after both the pre-cat and main catalyst, if you damage them they're not cheap!  My advice, remove the one nearest the turbo before you start...... :drinking:

His: MK2 Black Magic Skoda Octavia vRS Estate
Hers: MK5 Graphite Blue Pearl VW Golf GT140 -

http://www.mk5golfgti.co.uk/forum/index.php/topic,32783.0.html

Offline GrayMK5GTI

  • Global Moderator
  • Just look at my post count
  • *
  • Thank You
  • -Given: 125
  • -Receive: 248
  • Posts: 4165
Re: Pre-cat. . . . . REMOVED!
« Reply #23 on: January 22, 2012, 02:55:02 pm »
booked in at my mate's garage in a couple of weeks for a few bits - I shall have to see if we've got time to whip the downpipe off and remove the pre cat.

How long did it take to do? once the material is cracked/broken, does all it all kind of 'fall' out, or does it require extra work?

It took my local garage an hour to do, not sure on how hard it is, just got to make sure you turn it upside down after and shake all the bits out.

I'd advise ordering a new gasket and nuts from vw first, only cost about £8 total.
NOW: 2015 Golf R DSG 5 Door, Lapiz Blue, 19s, Discover Nav, Reversing Camera
GONE:2007 Black GTI Edition 30 3dr

Offline sideshowfred

  • Always Involved
  • ****
  • Thank You
  • -Given: 7
  • -Receive: 2
  • Posts: 115
    • Email
Re: Pre-cat. . . . . REMOVED!
« Reply #24 on: January 22, 2012, 04:23:30 pm »
Definitely going to get this done once the weather warms up a bit. I like cheap and easy mods  :grin:

Offline Timvgti

  • Always Involved
  • ****
  • Thank You
  • -Given: 0
  • -Receive: 5
  • Posts: 192
    • Email
Re: Pre-cat. . . . . REMOVED!
« Reply #25 on: February 26, 2012, 03:48:56 pm »
Can also confirm that this mod releases around 6bhp  :star: this was confirmed on the dyno

6BHP?? Wow NiCE!
Do you have a dynoplot from this?
Going to ask my garage/tuner to remove the pre-cat tommorow.
How much would this cost?
Think of doing this together with a exhaust tip swap.
The tips on my stock exhaust look rusted and ugly.
Maybe someting like the milltek gt80 tips look?...

Offline GrayMK5GTI

  • Global Moderator
  • Just look at my post count
  • *
  • Thank You
  • -Given: 125
  • -Receive: 248
  • Posts: 4165
Re: Pre-cat. . . . . REMOVED!
« Reply #26 on: February 26, 2012, 05:47:43 pm »
Can also confirm that this mod releases around 6bhp  :star: this was confirmed on the dyno

6BHP?? Wow NiCE!
Do you have a dynoplot from this?
Going to ask my garage/tuner to remove the pre-cat tommorow.
How much would this cost?
Think of doing this together with a exhaust tip swap.
The tips on my stock exhaust look rusted and ugly.
Maybe someting like the milltek gt80 tips look?...

Yeah I got 204 on JKM's dyno before then got 210bhp on R-Tech's dyno. I know it's not ideal to compare one reading on one dyno against another reading on another but it's there or there a bouts.

It cost me about an hours labour at my local garage (could cost more if your turbo bolts are tight).

Have you tried Autosol from Halfrauds on the tips? Cleaned mine up nicely  :notworthy:
NOW: 2015 Golf R DSG 5 Door, Lapiz Blue, 19s, Discover Nav, Reversing Camera
GONE:2007 Black GTI Edition 30 3dr

Offline dannychapman2007

  • Taking part
  • ***
  • Thank You
  • -Given: 0
  • -Receive: 1
  • Posts: 32
    • Email
Re: Pre-cat. . . . . REMOVED!
« Reply #27 on: February 26, 2012, 06:21:36 pm »
Will this be in the same location for my cupra with a ko4? Anyone done it with an eddy?


Sent from my iPhone using Tapatalk

Offline GrayMK5GTI

  • Global Moderator
  • Just look at my post count
  • *
  • Thank You
  • -Given: 125
  • -Receive: 248
  • Posts: 4165
Re: Pre-cat. . . . . REMOVED!
« Reply #28 on: February 27, 2012, 07:00:51 am »
Will this be in the same location for my cupra with a ko4? Anyone done it with an eddy?


Sent from my iPhone using Tapatalk

Yes mate the K04 downpipe is exactly the same as the Ko3 (standard GTI) one. Would probably give slightly better gains on an ED30 too!
NOW: 2015 Golf R DSG 5 Door, Lapiz Blue, 19s, Discover Nav, Reversing Camera
GONE:2007 Black GTI Edition 30 3dr

Offline smee

  • Taking part
  • ***
  • Thank You
  • -Given: 1
  • -Receive: 2
  • Posts: 49
    • Email
Re: Pre-cat. . . . . REMOVED!
« Reply #29 on: February 27, 2012, 09:58:59 am »
i know the cat will obviously slow down the gases but isnt the main restriction on the standard down pipe the bend?? it goes from 2.75 inch to about an inch within that bend. thats where i would say the big restriction is. hence why the aftermarket jobs have no precat and full 3" bend.

nice work im sure it sounds nicer and louder but to me this is like drilling the engine cover from the 80's and 90's just sound and no gains.

would love to be proven wrong (yes i have seen the 6bhp figure quoted but i can get that by farting in my car ;) )