MK5 Golf GTI
All Things Mk5 => Modifications & Technical Area => Performance Modifications => Topic started by: vRS_Pagey on July 25, 2011, 07:36:15 pm
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Hearing good things about upgrading downpipes on the TDi, most of the info is about Decats though, obviously an MOT failure on a petrol but what's the rule on diseasals?
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Diesels will pass mot's without a cat,
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For now the soot chucker doesn't need a cat as the MOT but I read that the new laws that are coming in,any car fitted with a cat that is made after 2008 have to have it fitted
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For now the soot chucker doesn't need a cat as the MOT but I read that the new laws that are coming in,any car fitted with a cat that is made after 2008 have to have it fitted
I love my MY2007 Golf GT even more now! :innocent:
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I was also worried about this.
Had an mot the other day (so thats re-mapped from a 105 to 170) and also a decat.
Got a rating of 0.44 (and I beleive it needs to be under 3.5 to pass)
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Surely if you keep oem cat swapping once a year isnt too much bother, if need be?
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I was also worried about this.
Had an mot the other day (so thats re-mapped from a 105 to 170) and also a decat.
Got a rating of 0.44 (and I beleive it needs to be under 3.5 to pass)
Hmmm, thats interesting. What de-cat are you running mate?
Surely if you keep oem cat swapping once a year isnt too much bother, if need be?
I have thought about this on the vRS, but it seems that it's not a problem on the diseasel. :happy2:
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Rightly enough the diseasel won't need a cat to pass mot if registered before 2008 :happy2:
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It was just a custom stainless steel pipe.
The cat was cut out and the pipe welded in place....rather then a full downpipe but its essentially the same thing! (unless you get bigger downpipe but this still doesnt cause a failure in MOT)
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When I got my Milltek downpipe I wanted the sports cat but I was told Milltek only do a decat for the diesel and that it will pass an MOT with no problem :happy2:
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It was just a custom stainless steel pipe.
The cat was cut out and the pipe welded in place....rather then a full downpipe but its essentially the same thing! (unless you get bigger downpipe but this still doesnt cause a failure in MOT)
This was also an option I looked at for the vRS, but like Sy and Hurdy did, I would have the delete pipe and cat fitted with flanges so they could be changed with ease at MOT time. Obviously with this not being an issue on the Golf, I may get my mechanic to do it when he fits the new back box. :happy2:
Am I right in thinking this will effectively take the car to stage 2 (as with petrol) and as such will require a modification to the remap to eliminate CEL for lamba sensors etc??
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Hi mate,
The basic diesel emissions test involves testing the amount of smoke not co, often by shining a light through it and measuring what makes it through.
The de cat shouldnt put any lights on as its not a proper closed loop system and has nothing to monitor the other side. eg petrol appliations the first sensor makes sure the lambda is good and the second, after the cat checks the cat has done its job. If you see what I mean :happy2:
Im also thinking of the decat for my gt. I have come across 2 off the shelf options, milltek or THS. The milltek is left 63.5mm at the end wheras the THS includes adaptors to take it down to the 2 available sizes of centre section if need be. The THS is significantly cheaper and quality looks just as good but nowhere has any :surprised:
TBH I doubt there is much changed on the map for this. Maybe a good question for your mapper, I also wouldn't mind knowing what they change.
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Thanks for that mate, I will fire off the question to my tuner later and give you the heads up on the response. If you come across a supplier for the THS De-cat let me know, and out of interest what sort of money are we talking?
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also interested in that info!
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THS all seem to be £145 but can't find anywhwere which has any stock :sad1:
http://www.thsperformance.co.uk/category/Downpipes_Decats,b.html
Cheapest I have found on Milltek is from jabba sport.
http://www.jabbasport.com/store/index.php?app=gbu0&ns=prodshow&ref=MSAU282
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I bought my downpipe off ebay in Jan for approx £110 and it fitted perfectly, I'll try to find some info on it.
When I had my stage1 map done (Shark Performance) Ben mentioned he needed to tweak the map for the de-cat, from memory it was something todo with the speed of the spool up of the turbo.
Matthew
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It was bought from Performance Pipes and Tuning http://myworld.ebay.co.uk/performance_pipes_and_tuning/ they don't have anything for sale at the moment but could be worth asking them when they are making their next batch.
The item description was SEAT LEON 2.0 TDI DECAT, also GOLF MK5,A3,and OCTAVIA
Matthew
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Something I'll be looking to do in the future.
I've read that it makes quite a bit of difference. :smiley:
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Please could someone give me some advice.
I am looking to get the decat downpipe for my 140 tdi, I have a standard system down to the backbox which is from a GTi, my mechanic had to play around to get the backbox to fit. I have no idea what size downpipe I need, can someone please help.
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The larger the bore the better really, but generally they range from 2.75 to 3". The down pipe will join to your OE centre section though so no need to worry about the back box.
Out of interest what was the problem in fitting the back box? I have just sorted a GTi one from another member for my GT TDi.
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Different size, think he just put the backbox over the OEM and welded it, he said it wasn't much of an issue
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Different size, think he just put the backbox over the OEM and welded it, he said it wasn't much of an issue
Phewww!
I've got this one coming from JackG -
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fi936.photobucket.com%2Falbums%2Fad203%2Fpagey1255%2FRandoms%2F83eea3f5.jpg&hash=0ef19459b7dc6f12df55766e24cdec73429e34ca)
Based on what my mechanic did with the OE back box, I don't fitting this will cause him much of a headache. :happy2:
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Something I'll be looking to do in the future.
I've read that it makes quite a bit of difference. :smiley:
I found with my PD140 that just the decat pipe (staying OEM size) didn't give any increase in power but smoothed the power delivery out and also gives a nice little whistle :happy2:.
Would I do it again? if having a remap then No, unless I'm replacing the whole system replaced or the CAT failed.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FCar_Stuff%2FPD140_Octavia_Elegance%2Fbhpgraphs.jpg&hash=2354d82a9fa9589964abe27643c63a31597003c8)
(ignore the numbers, They are very optimistic with vcds logging.) All runs were done after fitting each component on the same stretch of road on the same day.
However, on my old PD130 I had a Turbo back Miltek system (De-cat/resonated) fitted, the exhaust gave 11bhp more and gave me another 23ftlb :driver:, that was running a generic Jabba remap and it wasn't altered after the exhaust was fitted.
Matthew
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Thanks for that Matt, its interesting that you didn't see any improvement with a decat fitted, even if it wasn't any larger bore the increased flow with no CAT material slowly it down should have been greatly improved. :confused:
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It felt different but the figures would say otherwise. It felt like it spooled up quicker which made it feel faster but the smoothness was the best thing about it although I only did 10-15miles before I went to the Shark Stage 1 :happy2: so maybe it would have been better over time.
Here is said Decat
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FPD140_Octavia_Elegance%2FDecat_Pipe%2FIMG-20110117-00134.jpg&hash=61bf5d4f66ad8687ab48a2f0766b96189c99443a)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FPD140_Octavia_Elegance%2FDecat_Pipe%2FIMG_0303.jpg&hash=aec6a1dc192501161723dd7a4f57e67eb78f88e3)
Matthew
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How does the pipe fit to the turbo, it doesn't have a flange?
Do you think having a decat fitted may cause the turbo to fail, I know this is common on the PD140! :scared:
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How does the pipe fit to the turbo, it doesn't have a flange?
Do you think having a decat fitted may cause the turbo to fail, I know this is common on the PD140! :scared:
It uses kind of a large jublee clip
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FPD140_Octavia_Elegance%2FDecat_Pipe%2FIMG_0304.jpg&hash=240d39d2eb09dce79f381858006f948da996220e)
With regards turbo fail, I don't know, My turbo failed at 55k and was replaced with a rebuild item from a VW dealership, it's now upto 70k and been on the decat since 67k in May.
I would say if your getting one fitted speak with Ben, he said to me that my map would need to be tweaked to suit the decat. Better safe than sorry :happy2:
Matthew
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Thought the turbo failure was linked to the variable vanes in the compressor housing sticking due to carbon build up???
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I think that is one of the factors, but I just thought with a decat the spool up would be quicker and potentially more intense weakening an already flawed turbo......
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the easier the turbo get's rid of the air the lesser stress you put on it. :happy2:
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the easier the turbo get's rid of the air the lesser stress you put on it. :happy2:
Of course, less restriction = less stress........!
Have you fitted the mounts yet buddy?
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Did anyone manage to get any answers on this subject?
Maybe one of the tuning firms on here would be able to clear a few things up?
1) Will the de-cat cause the turbo to fail? (Can't see why it should myself)
2) When remapped what is changed for the de-cat? Boost control? A few adjustments to the fuelling?
Cheers
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Did anyone manage to get any answers on this subject?
Maybe one of the tuning firms on here would be able to clear a few things up?
1) Will the de-cat cause the turbo to fail? (Can't see why it should myself)
2) When remapped what is changed for the de-cat? Boost control? A few adjustments to the fuelling?
Cheers
1) Mines been running a decat since May2011 and covered 3000miles, no sign of turbo failure (yet :grin: )
2) I'll ask the guy who did my map on sunday when I see him, what is changed with a decat on the map :happy2:
Matthew