MK5 Golf GTI

All Things Mk5 => Modifications & Technical Area => Performance Modifications => Topic started by: Gti_Mad on October 25, 2011, 09:23:00 pm

Title: Running a decat
Post by: Gti_Mad on October 25, 2011, 09:23:00 pm
hi lads can any1 tell me if running a decat brings up any fault codes on the dash????

also any1 ever seen or heard an apr exhaust running a decat ???
Title: Re: Running a decat
Post by: Saint Steve on October 25, 2011, 09:27:29 pm
i doubt it mate, that would be too loud!!!!! :signLOL:

Title: Re: Running a decat
Post by: Gti_Mad on October 25, 2011, 09:40:29 pm
well im gonna give it ago and see how she sounds dude  :evilgrin:
Title: Re: Running a decat
Post by: Weston on October 25, 2011, 09:45:44 pm
When I had mine done the EML came on within 100 miles but hasn't returned since being mapped out.
Title: Re: Running a decat
Post by: Gti_Mad on October 25, 2011, 09:51:31 pm
ok dude cheers
Title: Re: Running a decat
Post by: Weston on October 25, 2011, 09:53:27 pm
Car feels like it accelerates quicker now as well, definitely worth it  :happy2:
Title: Re: Running a decat
Post by: Gti_Mad on October 25, 2011, 10:16:31 pm
isit much louder tho dude???

as the apr is pretty loud already  :signLOL:
Title: Re: Running a decat
Post by: kevinm on October 25, 2011, 10:47:18 pm
I'm running gutted cats and it is a good bit louder, especially on high idle when the car is cold.
Title: Re: Running a decat
Post by: DJM on October 26, 2011, 01:34:49 pm
I got decat downpipe onto standard system, no real noise change inside the car. Abit louder on acceleration. Meant to sound real nice but not had chance to let someone else drive it passed me yet lol.

EML came on as said about 100miles. Will be getting mapped out later this week.
Title: Re: Running a decat
Post by: Weston on October 26, 2011, 06:41:35 pm
isit much louder tho dude???

as the apr is pretty loud already  :signLOL:

Idle is louder in startup but the same when warm. It's a bit louder driving & much deeper. Also there's more popping etc
Title: Re: Running a decat
Post by: Fcan_PT on November 03, 2011, 10:59:25 am
The benefits with decat original exhaust are good? it approves?

I already thought build an custom exhaust in a exhaust house, inox 3" decat only with final resonator or 3" only with middle ressonator, what do you think about it?
Title: Re: Running a decat
Post by: Fcan_PT on November 05, 2011, 01:21:57 pm
up
Title: Re: Running a decat
Post by: dockermel on March 07, 2012, 09:59:40 am
how much to get it mapped out??
Title: Re: Running a decat
Post by: LC_15 on March 07, 2012, 10:04:02 am
I am buying one very soon as just bought a milltek, will be going for a tube for my rear box so its just got one silencer in it then.
Title: Re: Running a decat
Post by: Weston on March 07, 2012, 10:28:51 am
how much to get it mapped out??

Ask your tuner. I didn't pay any extra, just went back.
Title: Re: Running a decat
Post by: Weston on March 07, 2012, 10:41:39 am
Whats the difference between a large bore downpipe and decat?

A large bore down pipe will be wider than standard, 3" v. 2.75" I believe. A decat means the cat material from within the DP has been removed so essentially it's just an empty pipe. Both allow greater flow through the exhaust.
Title: Re: Running a decat
Post by: pd9264 on March 18, 2012, 05:56:43 pm
i put a decat on my gti and my eml hasnt come on, iv done about 500 miles. also iv got an extension piece on my second lamda sensor. its got a little hole in the bottom where it enters the exhaust. it stops the sensor picking up too much exhaust gas so it doesnt relise its got a decat. its only a cheap toyosport decat though.
Title: Re: Running a decat
Post by: nezquick on March 19, 2012, 02:56:49 pm
Just a quick question, I have a decat downpipe (3") mated to a resonated milly, the check light came on but cleared with vagcom - I am expecting it to come back within the 100 miles again. Is this potentially a MOT failure recipe? I love the sound of mine, really nice and quite when you want it to be and then when you give it some boot it sounds   :drool:
Title: Re: Running a decat
Post by: Tamiyoman on March 21, 2012, 03:16:44 pm
No CAT= MOT FAIL, light on or otherwise  :happy2:
Title: Re: Running a decat
Post by: nezquick on March 21, 2012, 03:27:21 pm
 :happy2: thought as much, thats alright I have a friend in the business so im sure he can help  :innocent:
Title: Re: Running a decat
Post by: Tamiyoman on March 21, 2012, 03:39:40 pm
:happy2: thought as much, thats alright I have a friend in the business so im sure he can help  :innocent:

Like most folks on here just stick it back on for the day, get MOT done then take off afterwards, only trouble is you will face fines etc if pulled over by the Highway Wombles (They operate regularly on A17).
Title: Re: Running a decat
Post by: nezquick on March 21, 2012, 04:02:23 pm
Yeah I think Ill do that although he passed me last time with a previous car that maybe shouldn't of passed. hmm, my car is quite enough not to draw attention to it if im gentle on the pedal so hopefully shouldn't have much of a problem thats why im tempted to just weld in a highflow sports cat but christ they're expensive
Title: Re: Running a decat
Post by: Tamiyoman on March 21, 2012, 04:10:59 pm
Yeah I think Ill do that although he passed me last time with a previous car that maybe shouldn't of passed. hmm, my car is quite enough not to draw attention to it if im gentle on the pedal so hopefully shouldn't have much of a problem thats why im tempted to just weld in a highflow sports cat but christ they're expensive

I have been pulled over by the highway wombles 5 times in 6 years always on A17 (At least they are not shutting the road!!), when you pull in its usually wagons, Vans, HGV's (Checking weights, dipping tanks etc as lots of Pikeys round Cambridgeshire/Lincolnshire using red diseasal) and Sports cars (clearly looking for Cat removals, tyres etc), had the pipe up my cars exhaust every time, they actually tried to stop me another time and started waving me in, just drove past them as I was in a bit of a hurry and no time for them messing about!!