MK5 Golf GTI

All Things Mk5 => Modifications & Technical Area => Performance Modifications => Topic started by: CarlW on October 27, 2015, 12:47:26 am

Title: Exhaust..
Post by: CarlW on October 27, 2015, 12:47:26 am
From what i've read i think i'd like to get a 3" decat downpipe and have this matched to my stock cat back.. What's making me wonder is the fact most people are doing this paired with a remap as this is best for power gains and also rules out the EML or CEL lights coming on..

My questions are.. Is there another way of having the 3" decat installed without the remap as well as getting the EML / CEL lights coming on and also would i still benefit at the same time although not a lot until i can afford to have a remap doneat a later date?

The end result being slightly more performance until it's mapped but also the car being louder which is what I'd like but without the problem of warning lights..

Are there any other drawbacks that i haven't yet read or heard of with having just the 3" decat downpipe installed? Not including the MOT fail as i know a friendly MOT'er in my area.
Title: Re: Exhaust..
Post by: Greenman on October 27, 2015, 03:36:51 pm
I would be interested to hear replies to this also.

I have been thinking the same CarlW - downpipe/200cel sports cat and stage 2 map, or cat back and leave the standard box as i don't want it massively loud and stick with the stage 1.

I have heard the de-cat/sports cat only option will give you some nice pops, but isn't that loud.
Title: Re: Exhaust..
Post by: Paradox1 on November 04, 2015, 04:03:04 pm
You can usually fit a spacer to the lambda sensor which is supposed to prevent the CEL coming on the Dash.

Fitting a Decat to the standard catback will sound not much different to stock unless you boosting it may sound a bit louder and sporty.
check Youtube for an idea of the sound.
Title: Re: Exhaust..
Post by: Powervalve Nige on November 05, 2015, 03:46:35 pm
I think you'll find that with a sports 200 cell cat installed, the lambda spacer enables the lambda probe to be pulled out of the gas flow, negating the velocity reading, which triggers the CEL. However, the Co levels will still be well outside of OEM parameters and will still trigger the CEL.
Our De cat with Mini 200 cell cat screwed into the lambda boss is the way forward  :happy2:
Cheers
Nige

(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FVW%2FMK7%2F_DSC0554_zpsuzz885ex.jpg&hash=ea069a5ca04cd1188f9c99204fc5e246e190724c)
Title: Re: Exhaust..
Post by: samiul11 on November 05, 2015, 08:29:48 pm
I think you'll find that with a sports 200 cell cat installed, the lambda spacer enables the lambda probe to be pulled out of the gas flow, negating the velocity reading, which triggers the CEL. However, the Co levels will still be well outside of OEM parameters and will still trigger the CEL.
Our De cat with Mini 200 cell cat screwed into the lambda boss is the way forward  :happy2:
Cheers
Nige

(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FVW%2FMK7%2F_DSC0554_zpsuzz885ex.jpg&hash=ea069a5ca04cd1188f9c99204fc5e246e190724c)

Price?
Title: Re: Exhaust..
Post by: AIR_CHILLED on November 22, 2015, 08:29:11 pm

I think you'll find that with a sports 200 cell cat installed, the lambda spacer enables the lambda probe to be pulled out of the gas flow, negating the velocity reading, which triggers the CEL. However, the Co levels will still be well outside of OEM parameters and will still trigger the CEL.
Our De cat with Mini 200 cell cat screwed into the lambda boss is the way forward  :happy2:
Cheers
Nige

(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FVW%2FMK7%2F_DSC0554_zpsuzz885ex.jpg&hash=ea069a5ca04cd1188f9c99204fc5e246e190724c)

Nige,
 I've had your 200cell downpipe fitted for well over a month now, 1000+ miles and the CEL has not come on yet?
The car's APR 1+ (hpfp) so I don't know if this has anything to do with it but a stage 2 is normally when it's mapped out.

Any ideas?
Title: Re: Exhaust..
Post by: CarlW on November 22, 2015, 09:41:28 pm
Isn't that a good thing? Surely you don't want a CEL warning dash light on whilst driving?
Title: Re: Exhaust..
Post by: AIR_CHILLED on November 22, 2015, 11:06:52 pm

Isn't that a good thing? Surely you don't want a CEL warning dash light on whilst driving?

Yes it is a good thing.

I'm wondering if there's anything inherent in the BCS design which helps prevent the CEL coming on?

As we know a 200 cell sports cat will pass MOT emissions but the lambar sensor should see out of parameter values and throw the CEL. Generic stage 2's map out this issue but I'm not at stage 2.
Title: Re: Exhaust..
Post by: CarlW on November 22, 2015, 11:23:17 pm
Ahh.. i see :happy2: Would be handy to know this. Can both these EML and CEL lights cause any further damage or prevent any performance if you are totally stock? Can they cause limp mode etc? Or is it simply a warning light you have to put up with until you get them both mapped out?
Title: Re: Exhaust..
Post by: Powervalve Nige on November 23, 2015, 10:11:03 am
The characteristics of the DP/Cat are borderline CEL triggers - some cars will set it off, others are fine.
Generally its after spirited driving that it can illuminate.
The cheapest option is to go for the dog leg lambda spacer (around £10.00) as a means to defeat the CEL until you get it mapped out.
Cheers
Nige
Title: Exhaust..
Post by: AIR_CHILLED on November 23, 2015, 09:36:44 pm
Ahh.. i see :happy2: Would be handy to know this. Can both these EML and CEL lights cause any further damage or prevent any performance if you are totally stock? Can they cause limp mode etc? Or is it simply a warning light you have to put up with until you get them both mapped out?

No performance related issues with the EML / CEL when triggered by the sports cat or de-cat it just masks any other faults that may occur.