Decats

[LSBasi]

Thanks to people like like ******** and Tartaris, I now know which direction I’m going with Tuning+mods (DP+Midpipe+MRC map) and what colour to order my car in today (Java Green).

My question is probably flogging a dead horse to most of you guys but I’ll ask it anyway.

Apart from the usual MOT issues and voiding warranty, are their any other cons to a decat over a sports cat?

Does anybody regret going decat?

Are the fumes and smells that extreme when stationary that it stinks the car out with windows down or sunroof open?

Would anyone advise me against going decat?

 

[Tristan]

Thanks to people like like ******** and Tartaris, I now know which direction I’m going with Tuning+mods (DP+Midpipe+MRC map) and what colour to order my car in today (Java Green).

My question is probably flogging a dead horse to most of you guys but I’ll ask it anyway.

Apart from the usual MOT issues and voiding warranty, are their any other cons to a decat over a sports cat?

Does anybody regret going decat?

Are the fumes and smells that extreme when stationary that it stinks the car out with windows down or sunroof open?

Would anyone advise me against going decat?

Hi, I went from just decat downpipes fmic and intake w/ mrc stage 2 map TO all the stated plus milltek non res catback.

With the downpipes fmic and intake setup, everything was fine there was a clear noticeable difference with pops and bangs with the car in dynamic.

Going to comfort mode (with the decat downpipes) was basically the same as stock comfort mode. Switching from dynamic to comfort felt like pressing a mute button ideal for when you are approaching a destination or your own neigborhood.

You will need a map to soften the harsh cold starts though but since you're looking to get a map I would say full steam ahead with the decat downpipes. The non res cat back would be a step too far for you because being in dynamic is almost identical minus the higher revs as being in comfort mode with the cat back.

 

[LSBasi]

The car will be a weekend toy so a loud startup and lots of 5 cylinder noise sounds great. Don’t get me wrong guys, if it wasn’t for the glorious 5 cylinder I wouldn’t be overly keen on increasing the volume

Danny, seems I got the wrong end of the stick with the decat fumes

Do you guys reckon the RS3 would pass an MOT with sports cat and no GPF filters? If yes, I’ll 100% head down the sports cat path

 

[Beebee-one]

Thanks to people like like ******** and Tartaris, I now know which direction I’m going with Tuning+mods (DP+Midpipe+MRC map) and what colour to order my car in today (Java Green).

My question is probably flogging a dead horse to most of you guys but I’ll ask it anyway.

Apart from the usual MOT issues and voiding warranty, are their any other cons to a decat over a sports cat?

Does anybody regret going decat?

Are the fumes and smells that extreme when stationary that it stinks the car out with windows down or sunroof open?

Would anyone advise me against going decat?

If you are contemplating going for decat downpipes then I would assume you are going to get the car mapped? Just needed to ask as some people seem to think they can just fit the decat exhaust and that's it job done.
As for the cons you are asking about......
Firstly it's not a cheap job to do as it involves around 3 to 4 hrs of workshop time to fit a downpipe. Some garages will drop the front subframe and leave you with the extra hassle (and cost) of having to get a wheel alignment check afterwards (MRC use pins to reposition it so it is usually not a problem). Obviously if you are keeping the car past MOT time then choose your exhaust system wisely. There are a number of them where you can retro fit a sports cat without having to remove the whole damn thing and refit the OEM part to pass an MOT.
I have a Scorpion full decat downpipe (FL car) but also bought the 200 cell sports cat which can easily be swapped in and out again with just two bolted clamps (see pics below). Prior to the Scorpion I had a Milltek decat installed on the car which can also have the sports cat section retro fitted but it aint cheap.
Noise: You have a certain amount of control over the noise (either ASBO loud or subdued) by using the Dynamic or Auto/Comfort modes. Be warned that by adding a downpipe it will amplify the wastegate tinny rattle you get at coldstart and below 2800rpm in Auto or Comfort mode. Dynamic mode and any engine revs above 4000rpm will open the exhaust flaps and give you (and surrounding population) the glorious 5 cylinder noise we all love.
Smell: Yes there is a smell of pungent exhaust gas/unburnt fuel but only in certain circumstances such as idling or queuing in traffic, multi-storey car parks and other enclosed spaces. When the car is moving there is no noticeable smell in the cabin.

The Scorpion decat DP....... the red circle is the decat section that can easily be removed and replaced with a sports cat (see other pic below)

.....and the 200 cell sports cat that can be inserted inserted into the DP for MOT time or if you dont like the smell of the full decat exhaust.

 

[LSBasi]

If you are contemplating going for decat downpipes then I would assume you are going to get the car mapped? Just needed to ask as some people seem to think they can just fit the decat exhaust and that's it job done.
As for the cons you are asking about......
Firstly it's not a cheap job to do as it involves around 3 to 4 hrs of workshop time to fit a downpipe. Some garages will drop the front subframe and leave you with the extra hassle (and cost) of having to get a wheel alignment check afterwards (MRC use pins to reposition it so it is usually not a problem). Obviously if you are keeping the car past MOT time then choose your exhaust system wisely. There are a number of them where you can retro fit a sports cat without having to remove the whole damn thing and refit the OEM part to pass an MOT.
I have a Scorpion full decat downpipe (FL car) but also bought the 200 cell sports cat which can easily be swapped in and out again with just two bolted clamps (see pics below). Prior to the Scorpion I had a Milltek decat installed on the car which can also have the sports cat section retro fitted but it aint cheap.
Noise: You have a certain amount of control over the noise (either ASBO loud or subdued) by using the Dynamic or Auto/Comfort modes. Be warned that by adding a downpipe it will amplify the wastegate tinny rattle you get at coldstart and below 2800rpm in Auto or Comfort mode. Dynamic mode and any engine revs above 4000rpm will open the exhaust flaps and give you (and surrounding population) the glorious 5 cylinder noise we all love.
Smell: Yes there is a smell of pungent exhaust gas/unburnt fuel but only in certain circumstances such as idling or queuing in traffic, multi-storey car parks and other enclosed spaces. When the car is moving there is no noticeable smell in the cabin.

The Scorpion decat DP....... the red circle is the decat section that can easily be removed and replaced with a sports cat (see other pic below)
View attachment 193406

.....and the 200 cell sports cat that can be inserted inserted into the DP for MOT time or if you dont like the smell of the full decat exhaust.
View attachment 193407

Yes I’m well aware I’ll need a map to remove the CEL after removing the cat lol

That’s a smart bit of kit from Scorpion! Very clever.

In all honestly would you not find it easier to slip your MOT man an extra 50 quid come MOT time?

I think removing the OPF and a sports cat down pipe will be sufficient, along with the MRC remap.

This Apr system is what I have in mind

 

[Beebee-one]

Yes I’m well aware I’ll need a map to remove the CEL after removing the cat lol

That’s a smart bit of kit from Scorpion! Very clever.

In all honestly would you not find it easier to slip your MOT man an extra 50 quid come MOT time?

I think removing the OPF and a sports cat down pipe will be sufficient, along with the MRC remap.

View attachment 193408
This Apr system is what I have in mind

The APR DP is a pricey bit of kit but looks good.........whatever you fit has to be better than the stock DP (pic below).
When I choose the downpipe I was unsure about the smell so rather than being stuck with it and trying to find an MOT guy who likes performance cars I went for the option of being able to swap out the sports cat.

The stock DP (FL car). Not great gas flow and has the cat right next to the turbo outlet.....good for emissions but not so good for thermal management when mapping.

 

[LSBasi]

The APR DP is a pricey bit of kit but looks good.........whatever you fit has to be better than the stock DP (pic below).
When I choose the downpipe I was unsure about the smell so rather than being stuck with it and trying to find an MOT guy who likes performance cars I went for the option of being able to swap out the sports cat.

The stock DP (FL car). Not great gas flow and has the cat right next to the turbo outlet.....good for emissions but not so good for thermal management when mapping.
View attachment 193410

It’s more an Mot guy that likes money rather that performance lol

APR is pricey but all I’m buying is downpipe, midpipe and the APR panel filter (something about K&N panel filters look like they don’t catch the smaller partials). Then the MRC map. Once it’s all done I’d like to think I’ll never have to spend another penny on performance.

Well I say that but gearbox mapping is something I know nothing about. I can’t see any reason to get this done as the RS3 I “THOROUGHLY” test drive gave me instant up and downshifts (Much better gearbox than on my M2 Comp)

 

[banny650]

Got an STM decat for my OPF car

 

[LSBasi]

Got an STM decat for my OPF car

How much difference to sound did they make?

Was that the only hardware replaced?

Who mapped your car, how were the results?

cheers