MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: jaylufc17 on November 17, 2016, 09:14:29 pm

Title: Which Downpipe?
Post by: jaylufc17 on November 17, 2016, 09:14:29 pm
own a mk5 gti dsg with stage 1 map... looking to change the downpipe... any recommendations?? do these make much difference sound wise too?

can you get anything decent for under 150ish?
Title: Re: Which Downpipe?
Post by: RetroRaz on November 17, 2016, 10:26:10 pm
U can get the cheap ebay ones for that budget, not sure how good they are though

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Title: Re: Which Downpipe?
Post by: slix on November 17, 2016, 11:15:30 pm
Look at this on eBay  http://www.ebay.co.uk/itm/390464426028

Been running this for a month or so with no problems. Sound is pretty much the same as stock but only slightly louder on WOT. Sounds better on idle too.
Title: Re: Which Downpipe?
Post by: ROH ECHT on November 18, 2016, 03:29:34 am
It's all about the welding and material with a DP. I spent $450usd for my DP and still the weld sheared off about the turbo flange...but it was still able to be re-welded. Given that...you shouldn't need to worry about price because all can be re-welded if broke. So find what you can in Stainless on ebay knowing if it breaks it can be repaired.
Title: Re: Which Downpipe?
Post by: pudding on November 18, 2016, 09:49:01 am
Make sure the really cheap ebay ones actually have a 3" - minimum - inside diameter before you fit it.   There is some far eastern crap being sold as 3", but is actually only 2.5" ID, which causes massive back pressure.  Ask R Tech about it!

The turbo outlet is approx. 84mm ID, 3" is 76mm, so ideally the bigger the better to avoid a step in the flow.  Relentless performance on the TFSI facebook group sell a 3.5" DP which gets around that problem, and looks well made.

Another option is to bash out the first cat in the OEM DP, but make sure you do it facing the floor to avoid clogging up the second cat with crumbs.   I put mine in a B&D workbench facing down and hogged it out with a 32mm wood drill.   Took all of 2 mins  :smiley:
Title: Re: Which Downpipe?
Post by: ROH ECHT on November 19, 2016, 06:34:10 pm
Make sure the really cheap ebay ones actually have a 3" - minimum - inside diameter before you fit it.   There is some far eastern crap being sold as 3", but is actually only 2.5" ID, which causes massive back pressure.  Ask R Tech about it!

The turbo outlet is approx. 84mm ID, 3" is 76mm, so ideally the bigger the better to avoid a step in the flow.  Relentless performance on the TFSI facebook group sell a 3.5" DP which gets around that problem, and looks well made.

Another option is to bash out the first cat in the OEM DP, but make sure you do it facing the floor to avoid clogging up the second cat with crumbs.   I put mine in a B&D workbench facing down and hogged it out with a 32mm wood drill.   Took all of 2 mins  :smiley:
I have, and I'm not alone in having, a 2.5" turbo-back(by Techtonics Tuning) with a K04 and aggressive K04 tunes that run up to 25 psi of boost...I never experience "massive back pressure" or spool interference. I think it is safe to say a 2.5" is safe for up to a K04. I would have opted for a 3" if I thought there was a chance I might select a Big Turbo sometime in the future but I won't. Having said that...a 3" won't hurt either.
Title: Re: Which Downpipe?
Post by: RetroRaz on November 19, 2016, 10:01:11 pm
if ur going for just noise, just do a resonator delete. I did mine for 90 quid at EMP Performance in St Albans, Hertfordshire. Sounds crazy!
Title: Re: Which Downpipe?
Post by: LencTPH on November 19, 2016, 10:20:38 pm
Try Relentless tuning DP.
Title: Re: Which Downpipe?
Post by: pudding on November 21, 2016, 09:50:23 am
Make sure the really cheap ebay ones actually have a 3" - minimum - inside diameter before you fit it.   There is some far eastern crap being sold as 3", but is actually only 2.5" ID, which causes massive back pressure.  Ask R Tech about it!

The turbo outlet is approx. 84mm ID, 3" is 76mm, so ideally the bigger the better to avoid a step in the flow.  Relentless performance on the TFSI facebook group sell a 3.5" DP which gets around that problem, and looks well made.

Another option is to bash out the first cat in the OEM DP, but make sure you do it facing the floor to avoid clogging up the second cat with crumbs.   I put mine in a B&D workbench facing down and hogged it out with a 32mm wood drill.   Took all of 2 mins  :smiley:
I have, and I'm not alone in having, a 2.5" turbo-back(by Techtonics Tuning) with a K04 and aggressive K04 tunes that run up to 25 psi of boost...I never experience "massive back pressure" or spool interference. I think it is safe to say a 2.5" is safe for up to a K04. I would have opted for a 3" if I thought there was a chance I might select a Big Turbo sometime in the future but I won't. Having said that...a 3" won't hurt either.

I meant the turbo flange, not the exhaust system  :wink:   I'm sure you can appreciate an 84mm turbo outlet hitting a 2.5" brick wall is going to restrict flow?

I agree, a 2.5" system is fine for this application.  I imported a Techtonics system with dual borla mufflers some years back for my Corrado VR6 Turbo, and it was a superb exhaust.  That car put down well over 400hp through a 2.5" system.  I didn't (and still don't) believe 3" was necessary for a 3.0 V6 turbo, let alone a 2.0 4 pot with a tiny little cotton reel turbo, and I like the extra refinement of small diameter exhausts.