Post by: GrayMK5GTI on January 18, 2012, 01:07:58 pm
After a bit of ECU - adapting (on the bypass) I'm happy to report the following:
- More turbo sound :drool:
- slightly deeper exhaust note :smiley:
- faster turbo spool up :happy2:
- pulls harder in the higher revs :driver:
So to sum up, it's a win-win for me :star: I'll report back on the MPG effect at a later date.
I should also point out that this WILL NOT CAUSE YOUR CAR TO FAIL AN MOT! (unless the requirements change again). VW fit it to aid cold-start emissions which isn't tested as part of the uk MOT.
It's worthwhile changing the manifold gasket and the nuts while your doing it (parts are only about £8 from vw)
See here for more info, part no's and photos: http://briskoda.net/forums/topic/197778-pre-cat-removed/
Cheers,
Graeme
Post by: sub39h on January 18, 2012, 01:10:25 pm
Post by: GarethB on January 18, 2012, 01:19:40 pm
depending on whether you remap beforehand, it would interesting to see if you achieve any power gains on JKM's rollers next month
Post by: Tfsi_Mike on January 18, 2012, 01:21:36 pm
i'm guessing if you have an aftermarket exhaust, a Milltek or similar, that these don't have pre-cats in anyway?
My Miltek didnt :happy2:
Post by: GrayMK5GTI on January 18, 2012, 01:24:18 pm
i'm guessing if you have an aftermarket exhaust, a Milltek or similar, that these don't have pre-cats in anyway?
No mate, standard exhaust. Didn't want to go all out for a full exhaust system with a cambelt change due
Post by: GrayMK5GTI on January 18, 2012, 01:25:59 pm
Sounds good Graeme.
depending on whether you remap beforehand, it would interesting to see if you achieve any power gains on JKM's rollers next month
Funny you should say that, it's booked in at R-Tech on Saturday - should get a dyno run before as a comparison though! :happy2:
Post by: GarethB on January 18, 2012, 01:33:21 pm
I'm sure that you'll be happy with the results. Is it just booked in for a map, or are there other goodies in store?
Look forward to seeing how it does on JKMs RR. My car should perform a little better than last time too :evilgrin:
Post by: GrayMK5GTI on January 18, 2012, 01:39:33 pm
ohhh, R-Tech. I've never used them personally, but they've always had a great rep across all the forums.
I'm sure that you'll be happy with the results. Is it just booked in for a map, or are there other goodies in store?
Look forward to seeing how it does on JKMs RR. My car should perform a little better than last time too :evilgrin:
Yes I've heard a lot of good things about them, seem to know a lot about the TFSI's and do full diagnostics before the map.
Nah not going in for anything else, just the custom stage one :happy2:
Yours should be up on last time with the revo map. Have you got any other mods yet?
Post by: GarethB on January 18, 2012, 02:01:45 pm
Got several parts sat waiting to be fitted, but finding the time to fit is tricky - especially being an accountant in january!
Hopefully will have a few bits sorted by 11 February in time for the RR day.
Post by: GrayMK5GTI on January 18, 2012, 04:36:56 pm
Yes, it should hopefully perform a little better than before.
Got several parts sat waiting to be fitted, but finding the time to fit is tricky - especially being an accountant in january!
Hopefully will have a few bits sorted by 11 February in time for the RR day.
Awesome you will have to take me out for a spin!
Post by: vRS_Pagey on January 18, 2012, 10:35:53 pm
Post by: meady on January 19, 2012, 06:15:44 am
Post by: GrayMK5GTI on January 19, 2012, 07:04:35 am
So ur telling me the golf gti has a pre cat and a main cat? I thought i had goten away from that when i sold my astra :(
That's right, at least its easy to remove bud :grin:
Post by: vRS_Pagey on January 19, 2012, 10:45:19 am
So ur telling me the golf gti has a pre cat and a main cat? I thought i had goten away from that when i sold my astra :(
Yup, the pre-cat filter is located directly after the turbo, so all the hot gases are slamming directly in to a wall!! It's only there for the European cold emissions test, not a requirement in the UK so no issue with removal! By getting rid, the gases movement is not as restricted which results in quicker spool up etc. Obviously the ideal is to change the down pipe which increases diameter, and reduces catalyst material but the pre-cat removal on the OE exhaust is the next best thing. :wink:
Post by: Bogwoppit on January 19, 2012, 08:22:54 pm
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fpeter0976%2FOctavia_vRS%2FP1050722-Copy.jpg&hash=89cad05facb0ad0b3c1f5b22944f9241da949939)
Post by: jon-tfsi on January 19, 2012, 08:32:41 pm
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fww123%2Fjon-tfsi%2FIMGP2718.jpg&hash=89f81e60da40afa475352a99da084969aba75f62)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fww123%2Fjon-tfsi%2FIMGP2722.jpg&hash=eaf2c4d56d1bf8c8f2f30d0d4ee53515da2d070d)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fww123%2Fjon-tfsi%2FIMGP2724.jpg&hash=64e6f11a4f4645bf0b17a5950ba579cb419e4f0e)
Post by: sideshowfred on January 21, 2012, 10:15:40 am
Post by: GrayMK5GTI on January 22, 2012, 12:14:00 pm
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
Post by: GrayMK5GTI on January 22, 2012, 01:17:44 pm
Post by: GarethB on January 22, 2012, 02:21:20 pm
Best get the hammer out :evilgrin:
Post by: GrayMK5GTI 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:
Post by: GarethB on January 22, 2012, 02:40:30 pm
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?
Post by: vRS_Pagey 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:
Post by: GrayMK5GTI 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.
Post by: sideshowfred on January 22, 2012, 04:23:30 pm
Post by: Timvgti 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?...
Post by: GrayMK5GTI 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:
Post by: dannychapman2007 on February 26, 2012, 06:21:36 pm
Sent from my iPhone using Tapatalk
Post by: GrayMK5GTI 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!
Post by: smee on February 27, 2012, 09:58:59 am
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 ;) )
Post by: Timvgti on February 27, 2012, 10:22:02 am
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:
6BHP gain is nice. Maybe the highest, looking at price versus gains!
Guess a twintake/air intake gives about the same gain, but costs way more.
Any other that did a dyno run with the pre cat removed?
And who experiences better mpg? (Not the main reason why I want it, but would be great!)
Post by: Bazgti on February 29, 2012, 03:47:00 pm
You take off the pre cat which is connected to the turbo...
Theres then a chalky lookin substance inside...
You knock it out wi a chisel n hammer...
Re fit n hey presto?
Sorry for bein a tard by the way, jus wana get this right cos may av a bash on sunday.
Post by: 56OctyVRS on February 29, 2012, 04:08:49 pm
Post by: Bazgti on February 29, 2012, 04:19:55 pm
Post by: vRS_Pagey on February 29, 2012, 04:51:48 pm
Post by: Bazgti on March 07, 2012, 03:23:14 pm
Post by: Bazgti on March 07, 2012, 10:36:12 pm
Post by: alackofspeed on March 07, 2012, 11:19:12 pm
Just bought my gasket. What tools do i need?
Decent socket set, maybe a ring spanner (depending on your socket sets ability to reach / grip some of the flange nuts), hammer, cold chisel, radial wire brush head in a drill (or similar to remove material from the inner wall of the pre-cat pipe), and a dust mask. Obviously a jack and axle stands too. Easy job, at most an hour for a competent DIY mechanic.
Post by: malaroo978 on March 14, 2012, 10:39:13 am
I'm thinking about doing this on my 1.4 tsi. Couple of stupid (really stupid) questions but try not to judge... :signLOL:
Right, firstly do I need specific o2 sensor adapters to remove?
Secondly I assume I need the gasket (do I just ask for a turbo to downpipe gasket?) But can I just reuse the rest (nuts/bolts etc)? My engine was replaced 1200 miles ago so I'm hoping that will make it easier.
Last stupid question, wheres the best place to put axle stands? I was going to buy ramps but I've already got stands. Is it ok on the sills using wooden blocks with cut outs? Don't fancy a car on top of me...
Cheers
:drinking:
Post by: ssed30 on August 13, 2012, 02:09:39 pm
The exhaust note is a lot more 'burbly' too and sounds great, really nice when backing off the throttle.
I can report more on mpg later, at the moment it's definitely better but maybe only by 2 mpg. I did my usual route to work today where I always get 33 to 35 mpg. I got 36 mpg for the first time ever, but was driving slightly faster today. So it's good.
I reused all original bolts, nuts, and gaskets.
It's a difficult job on the driveway and took nearly 3 hours, not including food and drink breaks. It would have taken less time had I not dropped a nut into the engine bay... and then a socket. Both of these each took around 30 minutes to locate and recover. lol
The penetrative oil is a must for releasing any seized bolts/nuts.
So in my opinion it is absolutely definitely worth doing.
Post by: JMP on August 13, 2012, 02:23:18 pm
Post by: Black9 on August 13, 2012, 02:40:39 pm
Post by: GrayMK5GTI on August 13, 2012, 06:33:39 pm
Post by: ssed30 on August 15, 2012, 07:21:30 am
I always get 33 - 35mpg on the way to work, I'm now getting 35.5 - 37.5mpg.
On the way home from work I always get 38 - 40mpg, I'm now getting 42 - 44mpg.
Pretty good result!
Post by: zerolag on November 27, 2012, 07:18:30 pm
Does anyone have any before and after EGT readings by removing the Pre-Cat?
I've gone Stage 2 ECU and don't yet have a downpipe, wondering whether you can get away with just removing the Pre-Cat to keep the temps down? I'm not overly concerned with the extra HP, but want to keep the extra torque Stage 2 has made but keeps temps down also.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fwww.voodish.co.uk%2Fmisc%2FStage2GTIFSI-stockDP.jpg&hash=94374cfad57da5088065619625685a2ac27b6dc2)
Post by: daz_pd on November 27, 2012, 07:20:05 pm
Post by: GrayMK5GTI on November 27, 2012, 07:29:35 pm
Ideally you need a free flowing (decat) exhaust for best gains
Post by: zerolag on November 27, 2012, 07:32:13 pm
@GrayMK5GTI: Thanks... definitely, but want to keep those costs down if possible :)
Guess I'll just get it done then do some logging on VCDS... is the VCDS EGT calculation accurate? I'm peaking at 900*C at 22PSI, eek.
Post by: daz_pd on November 27, 2012, 07:37:13 pm
Post by: PDT on November 27, 2012, 07:42:45 pm
Post by: zerolag on November 27, 2012, 07:44:32 pm
Thanks for the link to that DP... my only concern is the emissions for MOT.
PDT: Cheers, that would be really helpful... The spikes of 900*C worry me a bit.
Post by: GTI-Ross on November 27, 2012, 07:46:13 pm
Post by: RobboGTI on November 27, 2012, 07:52:16 pm
More info on mpg gains:
I always get 33 - 35mpg on the way to work, I'm now getting 35.5 - 37.5mpg.
On the way home from work I always get 38 - 40mpg, I'm now getting 42 - 44mpg.
Pretty good result!
Wtf??!!! On my commute to work I average 30-33mpg at best. Makes me feel like something is wrong with my car now :/
Post by: GrayMK5GTI on November 27, 2012, 07:57:28 pm
I regularly get 40+mpg on the motorway if I set the cruise control at 69-70mph (on the speedo).
Anyhooooo there's plenty of MPG threads on the forum to discuss this on :grin:
Post by: zerolag on November 28, 2012, 11:10:30 am
There's one on the forsale section but can't respond due to being too new. :driver:
Post by: GrayMK5GTI on November 28, 2012, 12:59:30 pm
Post by: zerolag on November 28, 2012, 01:03:16 pm
Post by: zerolag on January 17, 2013, 09:17:07 pm
You definitely hear the turbo more, and there is some degree of bass to the exhaust now. I have a carbonio in there too since, but I don't think this adds very much tbh.. perhaps a few hp. Will have to do some more runs with VCDS>
Post by: GrayMK5GTI on January 17, 2013, 09:40:46 pm
Glad more people are getting some benefit from doing it too :smiley:
Post by: 56OctyVRS on January 18, 2013, 09:18:24 am
@daz_pd: Mostly mixed driving but like boosting quite a bit, don't see much high revving.
Thanks for the link to that DP... my only concern is the emissions for MOT.
PDT: Cheers, that would be really helpful... The spikes of 900*C worry me a bit.
When I had my standard dp with the pre cat delete it still sailed through the mot on emissions. Most people dont take the car for a blast and get the cat piping hot before mot's. The mot doesnt test cold start emissions so just get the cat warm and all will be fine.
Post by: GrayMK5GTI on January 18, 2013, 12:13:33 pm
@daz_pd: Mostly mixed driving but like boosting quite a bit, don't see much high revving.
Thanks for the link to that DP... my only concern is the emissions for MOT.
PDT: Cheers, that would be really helpful... The spikes of 900*C worry me a bit.
When I had my standard dp with the pre cat delete it still sailed through the mot on emissions. Most people dont take the car for a blast and get the cat piping hot before mot's. The mot doesnt test cold start emissions so just get the cat warm and all will be fine.
Emissions have been discussed plenty earlier in in this thread, I can't believe folk are still bothered about failing an MOT when loads of us have got through ok. :grin:
Post by: ArildStavrum on January 22, 2013, 03:09:28 pm
Normally he is spot on with everything and has a gti stage 3+ himself so this has really confused me!
Post by: GTI-Ross on January 22, 2013, 03:29:07 pm
Trust me you wont fail it.
Post by: ArildStavrum on January 22, 2013, 04:05:38 pm
Is he 100% sure you meant the PRE-cat, not justthe normal one. Pre-Cat is only for cold starts, not even checked in the UK.
Trust me you wont fail it.
You see this is where I got completely baffled as he said I dont have 2 Cats.....
As i said he is normally spot on but this has thrown me.
Post by: GTI-Ross on January 22, 2013, 04:10:25 pm
Is he 100% sure you meant the PRE-cat, not justthe normal one. Pre-Cat is only for cold starts, not even checked in the UK.
Trust me you wont fail it.
You see this is where I got completely baffled as he said I dont have 2 Cats.....
As i said he is normally spot on but this has thrown me.
Unless you have a custom Downpipe that has no Cat in it, then you defo have 2 cats cats (pre-cat and normal cat) the Pre-Cat is worthless and restrict airflow
Your guy does sound, but he defo wrong on this occasion mate :fighting:
Post by: ArildStavrum on January 22, 2013, 04:38:00 pm
Is he 100% sure you meant the PRE-cat, not justthe normal one. Pre-Cat is only for cold starts, not even checked in the UK.
Trust me you wont fail it.
You see this is where I got completely baffled as he said I dont have 2 Cats.....
As i said he is normally spot on but this has thrown me.
Unless you have a custom Downpipe that has no Cat in it, then you defo have 2 cats cats (pre-cat and normal cat) the Pre-Cat is worthless and restrict airflow
Your guy does sound, but he defo wrong on this occasion mate :fighting:
I dont have a custom downpipe - all I have is the Milltek Catback, the remaining exhaust is stock.
is the pre cat seperate to that which would have come with the milltek catback?
apologies if that is a retarded question!
Post by: GTI-Ross on January 22, 2013, 04:53:43 pm
Post by: GrayMK5GTI on January 22, 2013, 06:40:21 pm
It WON'T fail an MOT without it as it's not required for an MOT. if you are really worried, make sure the car is warm when taking it in for the MOT. none of us have had a problem :smiley:
Post by: ArildStavrum on January 22, 2013, 07:53:58 pm
There is a precat right of the turbo and there is another cat that is part of my milltek catback??
Again apologies if I'm being a muppet.
Post by: woky on January 22, 2013, 07:58:26 pm
Ross has it covered - All GTI's (Inc edition 30) have a pre-cat right off the turbo at the top of the downpipe.Does removing this cause any warning lights to appear on the dash ?
It WON'T fail an MOT without it as it's not required for an MOT. if you are really worried, make sure the car is warm when taking it in for the MOT. none of us have had a problem :smiley:
Post by: 56OctyVRS on January 22, 2013, 07:59:03 pm
Ross has it covered - All GTI's (Inc edition 30) have a pre-cat right off the turbo at the top of the downpipe.Does removing this cause any warning lights to appear on the dash ?
It WON'T fail an MOT without it as it's not required for an MOT. if you are really worried, make sure the car is warm when taking it in for the MOT. none of us have had a problem :smiley:
None at all mate
Post by: woky on January 22, 2013, 08:22:10 pm
Post by: smee on January 22, 2013, 09:09:10 pm
So....just to be crystal clear.
There is a precat right of the turbo and there is another cat that is part of my milltek catback??
Again apologies if I'm being a muppet.
No. Engine to turbo. From the turbo cones your exhaust. Literally on the down pipe right next to turbo is the pre cat. The pipe bends 90 dehree to go down tje back of the engine here there is a flexi pipe. This ot bends again to run under the car. There is the bracket which goes in to sub frame and then the main cat. Out the other sode of the cat your miltek starts
Post by: Moz on January 22, 2013, 09:23:39 pm
is it an easy job? i,m thinking about getting the car remapped in the spring. Is this worth doing before i get it mapped ? cheers.
Yes it's an easy job. Just a few bolts to remove and then a hammer and a flat driver or chisel to do it.
Worthwhile doing, it doesn't add much BHP but does sound better and also if you're having a MAP it can be taking into account.
Post by: GrayMK5GTI on January 23, 2013, 06:50:25 am
is it an easy job? i,m thinking about getting the car remapped in the spring. Is this worth doing before i get it mapped ? cheers.
All your questions are answered earlier in the thread :happy2:
Post by: skard on January 23, 2013, 11:14:32 am
Post by: Meallbhan on January 24, 2013, 05:57:07 pm
Thought I'd post up my Briskoda photo on here if it helps:I'm not understanding exactly how the standard exhaust separates. You undo the four bolts at the turbo to release the exhaust, thats all good but then do you take the whole exhaust off, do you split it after the main cat, or does the pre cat come off the exhaust by itself? I've seen a couple of photos with the precat on its own, but how does it come off?
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fpeter0976%2FOctavia_vRS%2FP1050722-Copy.jpg&hash=89cad05facb0ad0b3c1f5b22944f9241da949939)
Post by: JMP on January 24, 2013, 06:41:28 pm
Post by: Meallbhan on January 24, 2013, 07:05:35 pm
So the whole front section has to come off like in the pic above and its not possible to remove the precat by itself?
I suppose some exhaust paste would be a good idea when putting the sleeve back together?
Post by: GTI-Ross on January 24, 2013, 07:06:52 pm
There's a sleeve connection between downpipe and catback. It has a couple of bolts which are usually rusted and I had to cut them to separate dp from catback. After unbolting it, you just push the sleeve over the back section and downpipe drops down.
Yeah the DP and Main cat is one section, (quite long, bad design) so take it al off, then just knock out the pre- cat, these is pics of mine.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fk489%2Frocketrossuk%2FIMG_0517.jpg&hash=255f9ea0a957b036ad015f98ecdd9318306c85a2)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fk489%2Frocketrossuk%2FIMG_0518.jpg&hash=4124476409105809056ef77ac08386581a371768)
Good luck...( you wont need it, easy as hell)
Post by: Meallbhan on January 24, 2013, 08:14:06 pm
Post by: GTI-Ross on January 24, 2013, 10:36:49 pm
All cleared up, cheers. Wot a pain in the hoop!
So what did your guy say, does he know what he is doing now :happy2:
Post by: 18Edition30 on January 31, 2013, 08:15:26 pm
Only downside I notice is bad smell when sitting stationary for period of time, an reversing. All used to be stopped by pre cat I spose. Anyway round this?
Post by: Meallbhan on January 31, 2013, 10:07:47 pm
Post by: Kinks on January 31, 2013, 11:14:00 pm
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Post by: Kinks on January 31, 2013, 11:17:18 pm
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Post by: camfollower on January 31, 2013, 11:23:44 pm
Post by: Kinks on January 31, 2013, 11:30:36 pm
Cheaper to buy a second hand Standard TBE on here, I bet there's loads about, smash it out yourself then take it to the garage. Probably do that for a tonne all in, and an exhaust to sell on.Not a bad idea wonder what price they go for? although if more money is involved then might as well look into a Miltek? does anyone know if the Miltek can mate upto the standard back section :driver:?
Post by: GrayMK5GTI on February 01, 2013, 07:24:04 am
If its an eggy smell isnt that a sign of your main cat has gone?
Sent from my GT-N7105 using Tapatalk 2
The main cat sometimes makes that smell especially from cold. Most cars don't have a pre-cat so would have that smell anyway
Milltek TBE doesn't have a pre-cat either so you would get that smell with that also.
Post by: GrayMK5GTI on February 01, 2013, 07:26:09 am
Been looking for someone in stockport to do it but no luck! The guy at audi doctor who is fab wanted to open the pre cat up and weld back together due toxins in material? Wanted £200 to do it :-( so anyone know of anyone in the area who isnt that cautious? Ill even provide a dust mask ???
Sent from my GT-N7105 using Tapatalk 2
I used ABP Motorsport in Shavington (Crewe) - Jn16 M6. It was about £60 IIRC
Post by: 18Edition30 on February 01, 2013, 07:34:44 am
Its worked a treat on the eddy anyways!
Post by: Kinks on March 25, 2013, 07:29:37 pm
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Post by: GrayMK5GTI on March 25, 2013, 08:06:12 pm
There is definetly a few horse power in it, R-Tech nick said EGT's were lower and there was much less restriction in the exhaust
Post by: Kinks on March 25, 2013, 08:22:29 pm
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Post by: akbarirfan on October 30, 2013, 01:00:46 pm
Is this a mod that you would inform the insurance company about? (I mean would it be classed as a mod type thing, it's not aftermarket but is a modification to the standard system :scared:)
Thanks
Post by: GrayMK5GTI on October 30, 2013, 04:53:55 pm
Hi All,
Is this a mod that you would inform the insurance company about? (I mean would it be classed as a mod type thing, it's not aftermarket but is a modification to the standard system :scared:)
Thanks
As it will increase power then you ought to. Although it's about the same gains as you get from using super unleaded over stock unleaded. Unless the insurance company understands what you are doing they may confuse it for removing the actual cat (illegal) so you may be best saying "modifying the downpipe on the exhaust to free up a few HP"
Post by: GTI-Ross on October 30, 2013, 05:39:05 pm
Hi All,
Is this a mod that you would inform the insurance company about? (I mean would it be classed as a mod type thing, it's not aftermarket but is a modification to the standard system :scared:)
Thanks
nah man, i wouldnt even mention it, its just a way to bump up your premiums for no apparent reason. most people dont even knw it there.
Post by: akbarirfan on October 31, 2013, 02:41:17 pm
I know they do what they can to get out of paying a premium, but still!
Post by: micaerin on October 31, 2013, 11:20:37 pm
Post by: akbarirfan on November 01, 2013, 03:01:10 pm
Post by: Simon_2.0t on November 01, 2013, 04:47:20 pm
Post by: phem0r on November 01, 2013, 06:15:57 pm
Post by: GTI-Ross on November 01, 2013, 10:23:34 pm
Having a milltek cat back fitted on the 8th, reckon it's worth having them take the downpipe off and removing the pre-cat?
Simple answer - Yes !!!
Roughly 5 bhp more and a slightly deep tone and throttle response.
Post by: darren4 on November 18, 2013, 03:51:24 pm
Post by: GrayMK5GTI on November 18, 2013, 04:23:59 pm
I never noticed any strange smells :happy2:
Remember Milltek turbo back exhausts don't have pre-cats and you never hear people complaining of smells from those. It's just the same with this
Post by: darren4 on November 19, 2013, 10:05:01 am
You may get a slight smell from cold start, but that's it. Remember the main cat is still there. . .
I never noticed any strange smells :happy2:
Remember Milltek turbo back exhausts don't have pre-cats and you never hear people complaining of smells from those. It's just the same with this
Ah thank you, so it's like normal them thanks for the info :smiley:
Post by: N8KOW on November 19, 2013, 03:03:49 pm
Post by: munny on November 19, 2013, 06:18:34 pm
Post by: GrayMK5GTI on November 19, 2013, 08:23:02 pm
You could gut the existing downpipe and have a stage 2 map to get the best benefit from it.
Post by: munny on November 19, 2013, 09:09:17 pm
A decat pipe removes both cats and will bring on your EML as well as cause your car to fail an MOT.
You could gut the existing downpipe and have a stage 2 map to get the best benefit from it.
Looking to go Decat, evoms intake and dv. everyone says best to just renew with the revised original version of a dv rather than aftermarket. and a remap soon. just wanted to get a decat in the mean time but dont want it to be stupidly loud with both cats removed.
Post by: 56OctyVRS on November 21, 2013, 10:05:23 am
Post by: Arnoldc1990 on July 06, 2014, 05:48:14 pm
Post by: GrayMK5GTI on July 06, 2014, 05:50:02 pm
Make sure you buy a new gasket and nuts (£8) from VW first
Post by: raven8472 on March 17, 2015, 12:49:31 pm
So standard exhaust with precat removed, does the car drone on motorways. While stopped at traffic lights with windows open can you smell extra fumes.
Also throttle response how much better is it. Had my standard GTI DSG on surrey rolling roads setup and it made 213bhp which seems to be top end of standard figures.
Post by: Wash on March 17, 2015, 02:19:37 pm
Thinking of getting this done and my only experience of Decatting cars was a DPF removal on a E90 330d Beemer.
So standard exhaust with precat removed, does the car drone on motorways. While stopped at traffic lights with windows open can you smell extra fumes.
Also throttle response how much better is it. Had my standard GTI DSG on surrey rolling roads setup and it made 213bhp which seems to be top end of standard figures.
I had the pre cat removed in my old GTI with the rest of the system staying standard and it didn't drone at all. It sounded pretty much the same as before tbh.
With regards to smelling fumes, my current GTI has a 3" decat Milltek TBE and I only smell fumes on first start up when the car is cold.
Post by: raven8472 on March 17, 2015, 02:33:18 pm
Post by: numec on March 17, 2015, 03:55:44 pm
The standard exhaust does have a nice tone to it and the DSG farts between gears are :happy2:.Cant get enough of that sound
Post by: patpong_pete on April 06, 2015, 05:04:57 pm
in east or north london thats had this done
thanks in advance gents
Post by: Kam88 on June 10, 2015, 06:10:18 pm
Post by: dazza on June 10, 2015, 06:14:09 pm
Post by: scopes on June 10, 2015, 06:16:25 pm
Post by: dazza on June 10, 2015, 06:22:56 pm
Post by: Kam88 on June 10, 2015, 06:23:45 pm
Post by: StuF on June 10, 2015, 06:51:14 pm
Please don't go under the car with just the widowmaker supporting it. :mad:
x2 :scared:
Post by: dazza on June 10, 2015, 06:58:49 pm
http://www.sgs-engineering.com/jsr2-axle-stands?___SID=U
I usually put the stands under then leave the jack just touching.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fecx.images-amazon.com%2Fimages%2FI%2F719f8WIyKVL._SL1400_.jpg&hash=8b45c8536462c47e45591b580fa623a74addbe33)
Post by: Kam88 on June 10, 2015, 07:25:23 pm
Post by: GTIEagles on June 10, 2015, 09:26:28 pm
Post by: Flyingscotsman on June 10, 2015, 09:32:54 pm
Seriously mate, use axel stands you are literally playing with death just using the standard jack
X 2
Axle stands all the way. Saved my life once!
Post by: Paulo P on June 11, 2015, 09:28:49 am
Post by: Dan_FR on June 11, 2015, 09:34:02 am
To @Kam88 (http://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=11200) Never EVER go under the car supported by the scissor-jack in the boot. it is designed to change wheels at the side of the road i.e. you are not under the car! One sharp pull on a spanner and you could pull the whole car off the jack. Seen it happen and fortunately they were close calls without serious injury. The above post proves that people are not always lucky and it can and does happen, even on axle stands which are 100% safer than the scissor-jack.
Post by: dom069 on June 11, 2015, 12:58:03 pm
Post by: Kam88 on June 11, 2015, 02:54:57 pm
I went this morning and picked up my axle stands and my low profile car that i left at my parents house so it all sorted guys thanks for looking out for me but all good this was i was just being lazy yesterday :rolleye: have to say car does sounds a fair bit better
Post by: GTIEagles on June 11, 2015, 03:02:44 pm
How did you find removing the downpipe? Is it really awkward to do or am I better leaving it to a garage?
Post by: Rampage on June 11, 2015, 07:07:54 pm
sorry to hear about your friend.
I went this morning and picked up my axle stands and my low profile car that i left at my parents house so it all sorted guys thanks for looking out for me but all good this was i was just being lazy yesterday :rolleye: have to say car does sounds a fair bit better
Have you found any performance gains? Etc
Interested in doing this, had a go but couldn't get the nuts off. Looking for a garage in S. London to do this... AMD wanted £240+Vat!
Post by: Kam88 on June 11, 2015, 10:59:06 pm
:happy2: Glad to hear you are still in one piece.
How did you find removing the downpipe? Is it really awkward to do or am I better leaving it to a garage?
To be honest bit fiddly all in all about an hour to take off and about 45 to put back on not so hard much easier on ramp but i did in on my drive way. what did help was the fact that i caked the bolts with wd40 day before i did think about paying a garage but at the prices they quoted i done it myself.
Post by: Kam88 on June 11, 2015, 11:02:14 pm
sorry to hear about your friend.
I went this morning and picked up my axle stands and my low profile car that i left at my parents house so it all sorted guys thanks for looking out for me but all good this was i was just being lazy yesterday :rolleye: have to say car does sounds a fair bit better
Have you found any performance gains? Etc
Interested in doing this, had a go but couldn't get the nuts off. Looking for a garage in S. London to do this... AMD wanted £240+Vat!
To be honest didn't really realise any gains but i only had remap on it a week prior so getting used to the power as it is at moment :signLOL:
Does sound much better splutters sometimes i love it and seems to pick up little bit better. Just do it yourself cake it in WD40 the night before.
All bolts can be accessed from under the car apart from one at top that has to be done demo top. Remove engine cover and if you stick your hand round the back you be able to feel the nut. all of them are 17mm so for the one on top use a deep 17mm socket with two long extensions which will bring the ratchet near bater tray and you then have much better access :happy2:
Post by: GTIEagles on June 12, 2015, 08:19:18 am
:happy2: Glad to hear you are still in one piece.
How did you find removing the downpipe? Is it really awkward to do or am I better leaving it to a garage?
To be honest bit fiddly all in all about an hour to take off and about 45 to put back on not so hard much easier on ramp but i did in on my drive way. what did help was the fact that i caked the bolts with wd40 day before i did think about paying a garage but at the prices they quoted i done it myself.
Doesn't sound too bad then. How does it separate from the exhaust end?
Post by: Rampage on June 12, 2015, 08:40:46 am
sorry to hear about your friend.
I went this morning and picked up my axle stands and my low profile car that i left at my parents house so it all sorted guys thanks for looking out for me but all good this was i was just being lazy yesterday :rolleye: have to say car does sounds a fair bit better
Have you found any performance gains? Etc
Interested in doing this, had a go but couldn't get the nuts off. Looking for a garage in S. London to do this... AMD wanted £240+Vat!
To be honest didn't really realise any gains but i only had remap on it a week prior so getting used to the power as it is at moment :signLOL:
Does sound much better splutters sometimes i love it and seems to pick up little bit better. Just do it yourself cake it in WD40 the night before.
All bolts can be accessed from under the car apart from one at top that has to be done demo top. Remove engine cover and if you stick your hand round the back you be able to feel the nut. all of them are 17mm so for the one on top use a deep 17mm socket with two long extensions which will bring the ratchet near bater tray and you then have much better access :happy2:
Thanks dude, may give this another go then. Thanks for the tips! :happy2:
Post by: Kam88 on June 12, 2015, 09:57:49 am
:happy2: Glad to hear you are still in one piece.
How did you find removing the downpipe? Is it really awkward to do or am I better leaving it to a garage?
There is 2 13mm bolts undo them and Steve slides off that's it's splt
To be honest bit fiddly all in all about an hour to take off and about 45 to put back on not so hard much easier on ramp but i did in on my drive way. what did help was the fact that i caked the bolts with wd40 day before i did think about paying a garage but at the prices they quoted i done it myself.
Doesn't sound too bad then. How does it separate from the exhaust end?
Post by: Kam88 on June 12, 2015, 09:59:06 am
sorry to hear about your friend.
I went this morning and picked up my axle stands and my low profile car that i left at my parents house so it all sorted guys thanks for looking out for me but all good this was i was just being lazy yesterday :rolleye: have to say car does sounds a fair bit better
Have you found any performance gains? Etc
Interested in doing this, had a go but couldn't get the nuts off. Looking for a garage in S. London to do this... AMD wanted £240+Vat!
To be honest didn't really realise any gains but i only had remap on it a week prior so getting used to the power as it is at moment :signLOL:
Does sound much better splutters sometimes i love it and seems to pick up little bit better. Just do it yourself cake it in WD40 the night before.
All bolts can be accessed from under the car apart from one at top that has to be done demo top. Remove engine cover and if you stick your hand round the back you be able to feel the nut. all of them are 17mm so for the one on top use a deep 17mm socket with two long extensions which will bring the ratchet near bater tray and you then have much better access :happy2:
Thanks dude, may give this another go then. Thanks for the tips! :happy2:
If any other questions let me know what I did is unplugged the lambda sensors rather then undoing them that might help aswell
Post by: Rampage on June 12, 2015, 10:35:47 am
Post by: Chris92 on June 13, 2015, 06:03:17 pm
Can't say I've notice any difference apart from more turbo noise inside the car but it's very faint and I always have my music on so never hear it anyways. Would I do it again? Hmmm probably not unless I was going stage one.
Post by: rdfcpete on June 19, 2015, 01:29:47 pm
What's economy like further down the line now, has the MPG still stabilised with continued better figures? Must equate to 50 miles or so per tank, on average?
Seems win win this mod :happy2:
Post by: GrayMK5GTI on June 19, 2015, 01:52:40 pm
It's not designed to catch carbon like a DPF (as petrol engines don't make soot like diesel), it's so close to the turbo so it heats up quickly to do its job within 30secs of engine start (ecu dumps fuel into combustion chamber to heat both cats up quickly from cold).
I noticed much better turbo spool and a marginal mpg increase over the 18months I kept the car for. It's worth remembering that anyone with a Milltek, BCS (or any aftermarket downpipe) will NOT have a pre-cat either.
For a "free" mod, it's definetly a win win :happy2:
Post by: GTIEagles on June 30, 2015, 09:11:11 am
Post by: Kam88 on June 30, 2015, 09:42:01 am
Post by: Amir32 on June 30, 2015, 09:11:26 pm
Post by: raven8472 on July 02, 2015, 07:13:52 pm
1) Small increase in exhaust note maybe 10% with Turbo whistle more noticable
2) Improved throttle response and turbo feels likes its coming in earlier along with butt dyno feels slightly better pull in acceleration.
3) Too early to tell on MPG but for the small cost and if done with care (Had the gasket and some difficult bolts replaced) well worth it. Will be getting Stage 1 sorted soon.
Post by: patpong_pete on July 02, 2015, 11:07:53 pm
small fee ? how much was it in total ?
your in safe hands with AKS -Alex
Post by: raven8472 on July 03, 2015, 01:05:40 am
Post by: rdfcpete on July 30, 2015, 09:53:39 pm
The pre-cat is soley to reduce cold start emissions, which is a requirement in some countries (NOT UK).
It's not designed to catch carbon like a DPF (as petrol engines don't make soot like diesel), it's so close to the turbo so it heats up quickly to do its job within 30secs of engine start (ecu dumps fuel into combustion chamber to heat both cats up quickly from cold).
I noticed much better turbo spool and a marginal mpg increase over the 18months I kept the car for. It's worth remembering that anyone with a Milltek, BCS (or any aftermarket downpipe) will NOT have a pre-cat either.
For a "free" mod, it's definetly a win win :happy2:
:happy2: :happy2:
So most or nearly all turbo petrols on the market would have this part, including the M135i perhaps, for example?
@GrayMK5GTI (http://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=2907)
Post by: Scottymon on July 30, 2015, 09:59:06 pm
Post by: GrayMK5GTI on July 31, 2015, 09:02:40 pm
The pre-cat is soley to reduce cold start emissions, which is a requirement in some countries (NOT UK).
It's not designed to catch carbon like a DPF (as petrol engines don't make soot like diesel), it's so close to the turbo so it heats up quickly to do its job within 30secs of engine start (ecu dumps fuel into combustion chamber to heat both cats up quickly from cold).
I noticed much better turbo spool and a marginal mpg increase over the 18months I kept the car for. It's worth remembering that anyone with a Milltek, BCS (or any aftermarket downpipe) will NOT have a pre-cat either.
For a "free" mod, it's definetly a win win :happy2:
:happy2: :happy2:
So most or nearly all turbo petrols on the market would have this part, including the M135i perhaps, for example?
@GrayMK5GTI (http://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=2907)
I'm pretty sure all VAG turbo petrols do (mk7 has main cat near to turbo so doesn't have one)
Astra VXR does. . . Likely lots of others.
Post by: Lewo on March 21, 2016, 06:57:12 pm
Took mate and me about an hour to do mine today, the turbo nuts came off easier than I expected which was my only worry.
He managed to get them off without any spray whilst engine was still warm, took me 10 mins to knock out the pre-cat and clean up with drill and wire brush.
Only done a short drive home, so hard to tell any difference at the mo.
Just relieved it went without any problem. :happy2:
Post by: shoaybmakda on March 21, 2016, 07:28:09 pm
Post by: l2azvan on April 02, 2016, 09:11:01 pm
Post by: rdfcpete on November 20, 2016, 01:07:10 pm
Has anyone done this to any of the MQB platform cars yet i.e. 8V S3, 7R or MK7 GTI/clubsport etc?
:happy2:
Post by: GrayMK5GTI on November 20, 2016, 09:02:00 pm
Got the thread spade out. Tooooo relevant though :wink: :evilgrin:
Has anyone done this to any of the MQB platform cars yet i.e. 8V S3, 7R or MK7 GTI/clubsport etc?
:happy2:
Ahh my old thread :innocent:
The latest platform cars have the main cat right up by the turbo, rather than having a pre cat.
Post by: rdfcpete on November 20, 2016, 10:01:01 pm
Got the thread spade out. Tooooo relevant though :wink: :evilgrin:
Has anyone done this to any of the MQB platform cars yet i.e. 8V S3, 7R or MK7 GTI/clubsport etc?
:happy2:
Ahh my old thread :innocent:
The latest platform cars have the main cat right up by the turbo, rather than having a pre cat.
Oi oi Gray :drinking:
So with these, Sports cat/cat mods etc would be the alternative to the original precat mods talked about on this thread?
Wonder what the BMW turbos are like... :thinking:
Post by: MKDK on April 26, 2017, 08:36:20 am
I'm getting my GTI mapped... Only things done so far: Carbonio intake (just the box - got that dirt cheap!), GFB Diverter Valve, noise pipe delete with a new throttle body and the pre-cat removal.
I'm wondering what effect a 3" downpipe with 200 cell cat. would have versus a stock downpipe with the pre-cat removal done?
Any experience on this matter?
Post by: pudding on April 27, 2017, 11:32:10 am
So I'm having the thread spade out as well... :grin:
I'm getting my GTI mapped... Only things done so far: Carbonio intake (just the box - got that dirt cheap!), GFB Diverter Valve, noise pipe delete with a new throttle body and the pre-cat removal.
I'm wondering what effect a 3" downpipe with 200 cell cat. would have versus a stock downpipe with the pre-cat removal done?
Any experience on this matter?
Noise pipe? I take it you're not from the UK as we didn't get that on our GTIs :smiley:
I found much more of a gain from a 3" downpipe. The main restriction in the factory downpipe isn't actually the pre-cat, but rather where the gases converge at a rather nasty and acute angle, which is a weird triangle shape and quite restrictive.......plus the narrow bore once it leaves that restriction.
On top of that, the pre-cat carcass is very thin steel, so it sounded a bit blowy on mine after bashing the cat out, which was irritating. It wasn't a leak, just the exhaust noise being audible through the empty cat shell.
Post by: JMP on April 27, 2017, 12:26:03 pm
I'm wondering what effect a 3" downpipe with 200 cell cat. would have versus a stock downpipe with the pre-cat removal done?
Any experience on this matter?
I first had a precat delete and after a while switched to 3" 100 cell sports cat ebay downpipe. I got more topend power with the aftermarket downpipe, however the turbo spools earlier with the precat delete. It felt better and felt like it had more torque in daily driving with the precat delete.
I didnt do dyno, but measured 80-120kmh pulls and I got about 2/3s of the performance gain from precat delete in comparision to the downpipe.
This was with k03 GTI revo stage 2.
Post by: RetroRaz on April 27, 2017, 04:19:50 pm
Post by: golfmck1980 on April 27, 2017, 07:35:28 pm
Post by: MKDK on April 29, 2017, 05:33:09 pm
You are correct, sir. I'm across the water to the east, in Denmark ;-)So I'm having the thread spade out as well... :grin:
I'm getting my GTI mapped... Only things done so far: Carbonio intake (just the box - got that dirt cheap!), GFB Diverter Valve, noise pipe delete with a new throttle body and the pre-cat removal.
I'm wondering what effect a 3" downpipe with 200 cell cat. would have versus a stock downpipe with the pre-cat removal done?
Any experience on this matter?
Noise pipe? I take it you're not from the UK as we didn't get that on our GTIs :smiley:
I found much more of a gain from a 3" downpipe. The main restriction in the factory downpipe isn't actually the pre-cat, but rather where the gases converge at a rather nasty and acute angle, which is a weird triangle shape and quite restrictive.......plus the narrow bore once it leaves that restriction.
On top of that, the pre-cat carcass is very thin steel, so it sounded a bit blowy on mine after bashing the cat out, which was irritating. It wasn't a leak, just the exhaust noise being audible through the empty cat shell.
This horrible thing (http://i7.photobucket.com/albums/y295/Raven6t9/246.jpg - not my pic) had to go. Replaced the throttle body pipe, so all the air goes to the engine. Definitely gave a better throttle response!
I have noticed that blowy sound on mine too after the pre-cat delete... was actually pondering changing the gasket. Didn't do that after the pre-cat delete, as the existing one looked fine.
Post by: acko2204 on October 20, 2017, 02:40:49 pm
But if anything goes wrong which it has for me! Then the job can quickly escalate out of control especially when car is only on axle stands.worst nightmare as I had the stud hardest to get at snap on me 😡
Thought no problem I’ll remove downpipe & carry on & try and remove stud, nope it was stuck like a ‘mo fo’
I’ve put everything back together and everything tightened up minus the one nut, car sounds same( but deeper tone) so don’t know whether this is good enough.
Just priced studs up at VW and £1.46 inc VAT each..part nu N 044 520 3
So it’s maybe off to a local Indy & have job re done & get them to remove all studs & put new ones on turbo manifold then refit downpipe..grrrr
Post by: acko2204 on October 20, 2017, 02:44:32 pm
Post by: GTI DAZ on January 04, 2018, 03:02:03 pm
Post by: f00glee on January 04, 2018, 03:28:20 pm
anyone know the part no. for the gasket and for the nuts?
1K0 253 115 AB & N10286108 I believe. Please do check for yourself but I think this is right. I can dig my TPS receipt out later if you want confirmation :happy2:
Post by: GTI DAZ on January 04, 2018, 03:33:53 pm
Post by: pudding on January 04, 2018, 03:34:41 pm
Post by: GTI DAZ on January 04, 2018, 03:51:06 pm
Yeah do check. I used internet part no.s for these and got the smaller manifold nuts instead of the much bigger turbo flange nuts :grin:
N10286108 - https://www.urotuning.com/Turbo-to-Downpipe-Self-Locking-Nut-M10-p/n10286108.htm
Post by: GTI DAZ on January 04, 2018, 05:03:26 pm
spoke to VW Letchworth they confirmed that...
1k0253115AB, turbo / cat gasket £8.35 (1 Required)
N10286108 (turbo / cat nut M10 self locking) £1.14 (4 Required)
total cost £12.91 ( price Jan 2018, inc VAT)
Post by: pudding on January 05, 2018, 09:33:48 am