Project GTI: Realising Potential
Straight Into It

I typically like to open a post with an anecdote or a thought. I won’t be doing that today because we’ve got a lot to get through.

Despite it being the holiday season, progress on Project GTI was pretty damned steady; steady to the point that I now have a backlog of information and updates that I want to get through. When we last spoke, I had just finished my first track day with the car and everything had gone swimmingly. It did leave me with an itch to extract just a touch more power from the EA888 motor however…

2015 Project GTI Scorpion Exhaust by Paddy McGrath-2

And that’s pretty much where we’re going to pick up the story. In a previous update, you might remember that I addressed the complex and seemingly restrictive intake side of the engine with an APR Carbonio induction kit. This was really only done as one part of a couple of steps that I wanted to perform before having the ECU remapped.

2015 Project GTI Scorpion Exhaust by Paddy McGrath-1

The real restriction on the factory setup is the stock exhaust system, as it typically is on most production cars for emissions requirements.

2015 Project GTI Scorpion Exhaust by Paddy McGrath-3

The standard exhaust pipe diameter is around 2.5-inch, but it’s the factory catalyst that really restricts power. You’ll notice here that I did previously remove the factory resonator to give the GTI a little bit more of an entertaining soundtrack, but that was just noise with no performance enhancement. That being said, if you have a stock GTI and want to liven up the melody, it’s a great, cheap modification.

2015 Project GTI Scorpion Exhaust by Paddy McGrath-4

For what I want from this car, noise and sound is only a by-product or a happy bonus. I want to extract the full potential of the highly underrated 2.0-litre EA888, and this is where Scorpion Exhausts came into the fray…

Red Power
2015 Project GTI Scorpion Exhaust by Paddy McGrath-5

Scorpion is a UK-based manufacturer with massive motorsport experience; British Super Bikes, British Touring Cars and something called the Gobstopper represent just a tiny part of its portfolio.

2015 Project GTI Scorpion Exhaust by Paddy McGrath-7

I could have just gone for a turbo down-pipe, but instead opted for a full system. There was a lot of packaging and I may have temporarily taken over half of Flip’s workshop.

2015 Project GTI Scorpion Exhaust by Paddy McGrath-14

Whilst Flip worked on removing the stock system, I set about unpacking and photographing things. Nice festive underwear, bro.

2015 Project GTI Scorpion Exhaust by Paddy McGrath-10

Flip is very much a hardcore JDM guy, but I did find this on his work bench. That’s it, come to the dark side…

2015 Project GTI Scorpion Exhaust by Paddy McGrath-11

With everything unpackaged, I was able to figure out what was what. Sadly, despite the immense packaging, my courier managed to leave a nice dent on one of the back boxes. It wasn’t going to affect performance and when fitted wouldn’t be visible, so we decided to proceed with installation and worry about it afterwards.

2015 Project GTI Scorpion Exhaust by Paddy McGrath-8

This piece right here is what I was really interested in though…

2015 Project GTI Scorpion Exhaust by Paddy McGrath-9

The first section of the exhaust connects directly to the exhaust side of the factory K03 turbocharger. It’s 0.5-inch larger in diameter compared to the stock section, so the exhaust gases can be expelled with more freedom. Part of my ethos for building this car is to keep it as civil as possible. With regular emissions and roadworthiness tests a reality of running a car in Ireland, I decided to opt a for catted system. This is a high-flow, 200-cell catalyst which is far less restrictive than the factory cat. This should comfortably see me through any emissions tests without having to reinstall the factory down-pipe section, whilst still offering a significant improvement in performance.

2015 Project GTI Scorpion Exhaust by Paddy McGrath-6

Hopefully no one notices this bit when it’s being tested…

2015 Project GTI Scorpion Exhaust by Paddy McGrath-12

I also chose to go with a resonated system. The non-resonated stock system I was previously running was fine about town, but the drone on motorways started to become an annoyance. I use the GTI everyday – I’ve already run up 12,000kms since I bought it six months ago – so I want to keep the car as civil as possible when required and to maintain its ability to be ‘one car to do all things’.

2015 Project GTI Scorpion Exhaust by Paddy McGrath-13

The final option I chose was to have the Daytona-style tips ceramic coated black. The tips are much larger than stock (3-inch versus 4-inch), so the black finish helps to keep them subtle looking. I’m a big fan of trying to disguise a car’s performance potential so as to not attract attention on the street, and these really play a nice role in this.

Bolt On, Drive Away
2015 Project GTI Scorpion Exhaust by Paddy McGrath-15

Removal of the factory system was pretty much straightforward, with only one bolt being a bit stubborn and requiring access from the top of the engine. Other than that, it was plain sailing and nothing needed any significant amount of force to be removed.

2015 Project GTI Scorpion Exhaust by Paddy McGrath-16

This is the stock down-pipe and catalyst section.

2015 Project GTI Scorpion Exhaust by Paddy McGrath-17

You can immediately see the difference between new and old here; the Scorpion system’s larger diameter tubing with a much slimmer catalyst. The bolts before and after the cat on the Scorpion system are for pre- and post-catalyst sensors, but the GTI only runs one post sensor from the factory.

2015 Project GTI Scorpion Exhaust by Paddy McGrath-18

You can also see the difference at the business end, with the Scorpion system forgoing the muffler at the turbocharger. All the sensors were easy to remove and reinstall, which stops the car’s ECU from having a meltdown.

2015 Project GTI Scorpion Exhaust by Paddy McGrath-19

At this point, there was a part of me that wanted to take the car off the lift and bring it for a quick drive just to see how loud it was. Flip did not agree and we continued with the installation.

2015 Project GTI Scorpion Exhaust by Paddy McGrath-20

Installation is the opposite of removal.

2015 Project GTI Scorpion Exhaust by Paddy McGrath-21

Pretty quickly, it was all back together. We double-checked everything and I took it for a quick drive around the block. First impressions were that it was much quieter than the non-resonated setup, but it produced a far more interesting sound as opposed to a noise. The top-end felt much freer too, even on the stock ECU map.

2015 Project GTI Scorpion Exhaust by Paddy McGrath-22

Once back from the test drive, we put it back up on the lift to triple-check that everything was still secure and to listen for any blows from the exhaust. Everything was perfect. As an aside, how good do the black tips look? I’m very happy with that particular detail.


This was about as straightforward an installation as one could have hoped for. It’s always a testament to a good product when no modifications of any sort have to be made. Bolt off, bolt on.

2016 Project GTI Scorpion EXTRA-2

This is a huge piece in the puzzle of unlocking the GTI’s performance. It’s one of those things that regardless of how much power I decide to chase in future, the exhaust system will be up to task. In stock trim, the engine puts out around 210hp and 207lb-ft, but with the intake and now the exhaust sorted, I can finally push forward with having the ECU remapped and improving upon those figures. I’m going to bypass the ‘stage one’ tune and go straight to ‘stage two’.

I’ll leave you with this short video to give you an idea of how Project GTI (yes, it still needs a better name!) sounds now. It’s likely the last time you’ll hear the car making standard-ish levels of power…

Paddy McGrath
Instagram: pmcgphotos
Twitter: pmcgphotos



Comments are closed.


by Oldest
by Best by Newest by Oldest

so shiny so chrome!


Dat, my friend, is how you make a lovely exhaust!


Love the black tips, much nicer.
I'd be careful of that Motorsport Use Only bit on the  exhaust. You mightn't want to but I know a lot of people grind that off...
I'm not sure how it is down south but I know in Armagh at the MOT centre if they see that, it's an automatic fail. Just keep it hidden... ;)


The Katakana "Supidohantasu" on the rear window looks right at home. I like it!
The GTI is looking good so far! Now time for some body-kit action and 18" chrome spinners! Wait. It's not '01 anymore is it? Just tell us how much more power it'll be packing after the tune! A nice detail would also be to take it to the track before the tune and then see how much better the car performs with one.


"What exhaust warning officer? It was Lava rock wrapped when I collected it after installation"
I'm yet to see someone get caught with a properly, tactically wrapped exhaust..... ;)


Lovin the set up! Just did the same to my MK6 TDI. Sounds surprisingly similar for being worlds apart.. Keep up the good work!


super jesus Much wow. Many noises.


Mayank0809 It is quite good, in fairness.


Tomo Pattison Should be fine, not a big issue to remove it either. Once its emissions are in check, it should be alright. I hope.


TarmacTerrorist I like how you think.


Dimitry Mochkin I think that can be arranged...


Diesel Dude Pretty sure the TSI is based off a TDI design, or something like that. When it comes on boost now, there's just a little difference :)


The Chrome Spinners? Sweet!


On to the REVO wizards!


Paddy McGrath 
Careful there, you should never go full Retard....


Damn, why didn't Flip agree with you? Haha


Mmm love how it farts between gears. Earvana.  Very nice sound not too buzzy for a 4 banger.  Guess the turbine helps with that too.


Can you ask to Scorpion to learning about making Mondeo XR5 systems? Totally undriveable  :(


Love that crack between changes these cars have, that's now amplified with the addition of the exhaust.


SnoozinRichy I just like that it's a proper 'pop' now and not a fart.


Dimitry Mochkin What else?


pimstoop You've read my mind :)


Bima Leksono Right? Damn his sensibleness.


bluestreaksti Yeah, it was previously quite high pitched in comparison with the resonator removed. Much prefer the deeper sound.


Just a tip, get the SPS pro!!
Got it on my Seat leon cupra, best thing i've bought for my car thus far.
Playing with the settings you can really change your cars behavior, plus the extra data read-outs are really cool.


Why you didn't go for an APR ??


God dammit Paddy, How am I going to get a shine on those exhaust tips now???? :)


I really enjoy reading your updates on your car Paddy, I can't wait to see further updates!


Tim Oliva Thanks, Tim. The next one's a good one :)


LarryKehoe I have faith in you.


Antonis_K Honestly, APR isn't really represented that well on this side of the world. I went with Scorpion because exhausts are their business. They design and manufacture everything in-house, so that for me is good enough.


Paddy McGrath pimstoop Good job sir!


...the next steps as preparing for the mapping. Nice.any further hardware updates coming before your session ending with ~ 280ps/380nm  :) ?


Someone help. I know this issue was solved before but I can't figure it out. 

I'm not getting new articles when I go to the SH homepage. Even when I press the 'Latest' button some of the current articles are missing. 

What do?


johnbezt I'm having the same problem, only with SH other sites are fine. I'm have to go to options, adnvanced, cache, the hit clear cache....then next time I go back the SH I get the latest articles


@383Coupe johnbezt You need to force-refresh the front page. We're aware of it and the IT team are working their hardest to sort it. Sorry!


Riddlah Just an upgraded spring for the Forge diverter valve to handle more boost. You're not too far off with your numbers either... ;)


Gotta force a refresh.. Just hit Ctrl + F5.


Paddy McGrath Riddlah for the moment at least :). You´re package will bring you so much fun


At first I was pretty leery with the watchword swirling around "civil", and I mistook that for a plaintive stealth-mode. Definitely more than pleasantly surprised with the results, it sounds great Paddy! And those black tips are the perfect touch, bang on.


Can always upgrade to the Revo intake at a later date U0001f609


I really like your MK6 GTI, for me it is really a joy to read your article.
Hope that your wish of your perfect GTI come true