MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: Britishlion on February 23, 2011, 06:19:40 pm

Title: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: Britishlion on February 23, 2011, 06:19:40 pm

Evenin All !  :happy2:

Just bought Mandy's exhaust (Thanks Mandy) and noticed JKM have advised not to attach to standard back box ?

why would this be, as this was my plan ? surely if the down pipe is 2.75 and the back box is 2.75 what would the problem be ?

Anybody got any thoughts ?   :popcornsoda:

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: PDT on February 23, 2011, 06:20:56 pm

You will need a reducer  :wink:

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: Beddie on February 23, 2011, 06:24:50 pm

'Aparoon' on here ran a Pipewerx cat/DP on his standard cat back system with absolutely no problems, but did have to have a reducer as PDT says  :happy2:

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: Britishlion on February 23, 2011, 06:26:58 pm

Thanks guys, I guess the garage will have a reducer, i was sure i had read of people running just DP attached to standard !

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: Britishlion on February 23, 2011, 06:48:14 pm

Demon tweaks website also say DO NOT fit with standard !


 :confused: :confused: :confused:

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: martziniuk on February 23, 2011, 07:14:44 pm

I run a 3"decat down to a standard system with no issues. I had a cone reducer welded onto the decat pipe.

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: craig_t on February 23, 2011, 07:17:18 pm

It depend who you ask to which answer you get.

I am in a similar situation with a pipe werx down pipe. Some garage tell me that I really shouldn't mate it up to my stock cat back as it may bottle neck the gases at the reducer.

Other people say it will be completely fine and have had no problems.

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: Mandy on February 23, 2011, 07:18:00 pm

I think it will be ok, as lots of people do it with no probs. It's just not 'recommended' by Milltek, but obviously they'd prefer you to use their back box wouldn't they.  :smiley:

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: Janner_Sy on February 23, 2011, 07:19:51 pm

Quote from: Britishlion on February 23, 2011, 06:19:40 pm

Evenin All !  :happy2:

Just bought Mandy's exhaust (Thanks Mandy) and noticed JKM have advised not to attach to standard back box ?

why would this be, as this was my plan ? surely if the down pipe is 2.75 and the back box is 2.75 what would the problem be ?

Anybody got any thoughts ?   :popcornsoda:


nothing wrong with mating a 2.75" DP to a standard cat back. I had  a 3" dp mated to mine with zero issues.

the ONLY reason they say that is because they make more money when you buy a TBE system instead of a just a downpipe

the pipewerx DP has a built in reducer by the way so its a direct fit

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: TrickGTI on February 23, 2011, 07:19:57 pm

 :jumpmove:

Quote from: Britishlion on February 23, 2011, 06:48:14 pm

Demon tweaks website also say DO NOT fit with standard !


 :confused: :confused: :confused:

it will be just a case of DONT DO IT, and while your here why don't you just spend another 500 for the rest of the system its for the best really...

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: Janner_Sy on February 23, 2011, 07:21:11 pm

AMD tried getting me to fit a miltek cat back when they fitted my HPFP because it could release a good 10Hp :grin: :grin: :grin:

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: Britishlion on February 23, 2011, 07:36:00 pm

Quote from: Janner_Sy on February 23, 2011, 07:21:11 pm

AMD tried getting me to fit a miltek cat back when they fitted my HPFP because it could release a good 10Hp :grin: :grin: :grin:

Ha ha ! Am I right in saying any garage will have a reducer or do I need to find one ?

Will I get a sound change from the exhaust or is that only cat back that produces this ?

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: Janner_Sy on February 23, 2011, 07:37:44 pm

i had a notable change in exhaust note after fitting the downpipe.  Much deeper burble and slightly louder.  The cat back IMO ruined my car, all it does is let everyone within a 2 mile radius know when your speeding

i will never fit a cat back again

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: Britishlion on February 23, 2011, 07:41:44 pm

My old r1 was like that when I fitted an akropovic exhaust.

Sounded awesome, but when you let it go, everyone knew about it ! Including the police!

Not that I ever speeded of course  :innocent:

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: chungster on February 23, 2011, 07:53:22 pm

IIRC vRStu had a DP/Sports Cat with OE Cat Back on his S3 and made some mighty numbers with it at SRR.  :happy2:

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: martziniuk on February 23, 2011, 08:22:53 pm

The Fitting centre may need to order the reducer in before you go so check when/if you book in.

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: martziniuk on February 23, 2011, 08:25:55 pm

Quote from: Janner_Sy on February 23, 2011, 07:37:44 pm

i will never fit a cat back again

Seriously! Is it that bad?
I had nearly convinced myself the cat back would release a little extra power, especially the larger Miltek ones.  :surprised:

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: Britishlion on February 23, 2011, 08:33:08 pm

Quote from: martziniuk on February 23, 2011, 08:22:53 pm

The Fitting centre may need to order the reducer in before you go so check when/if you book in.

If both are 2.75, why do I need a reducer ?

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: martziniuk on February 23, 2011, 08:35:35 pm

I'm not sure what the diameter of the Gti cat back is but the Octavia vRS is 2.5"

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: Bernhard30 on February 23, 2011, 09:43:56 pm

Had the Millek DP and Cat fitted to a standard system last week. At PDT.
There's a def change to the engine note and sounds more burbley, not noticeable within the car except when opening up, but a def increase in tone from outside the car. I took note from posts on this forum on not getting a full system. Didn't want the Halfords car park Corsa style noise myself..

Title: Re: Milltek Sports Cat and Downpipe linked to a standard back box ?
Post by: Britishlion on February 23, 2011, 09:50:43 pm

Great news thanks mate !