Author Topic: Final push for the MK5 GTI  (Read 601 times)

Offline paulmcgrath

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Final push for the MK5 GTI
« on: January 02, 2019, 03:01:06 AM »
So I bought the dsg GTI this time last year and the turbo was goosed!
Straight away I ordered a turbotechnics turbo with a 360-degree thrust bearing.
As it has the 360 bearing it's technically a hybrid and my mechanic is saying that it's very torquey with more power than a standard GTI,
Has anyone any experience or comments on that?.
He says that a remap will do it the world of good.

Before the remap I want to get an injector and inlet clean.
I've been advised that for the best bang for your buck stage 1 upgrade I should get R8 coils, NGK BKR7EIX sparks and a stage 1 full exhaust system.

Is it worth getting a full exhaust system or would a downpipe be enough?


Current mods - Typhoon air intake, GoFastBits Diverter Valve, Porsche front calipers, H&R springs, Whiteline anti-roll kit, Powerflex lower engine mount.





Offline colesey

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Re: Final push for the MK5 GTI
« Reply #1 on: January 02, 2019, 08:30:36 AM »
Is it possible that the turbo is a full hybrid with K04 internals? TT sell those for @£700.

I found the R8 coils & NGK plugs worthwhile for responsiveness though changing the stock downpipe would technically make it stage 2 rather than stage 1. The downpipe is however where the power is to be found rather than in the back section, so better to put that money towards a remap and VIS hpfp internals. You will likely also benefit from upgrading the stock intercooler to S3 version.

Offline AJP

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Re: Final push for the MK5 GTI
« Reply #2 on: January 02, 2019, 05:15:38 PM »
Is it possible that the turbo is a full hybrid with K04 internals? TT sell those for @£700.

I found the R8 coils & NGK plugs worthwhile for responsiveness though changing the stock downpipe would technically make it stage 2 rather than stage 1. The downpipe is however where the power is to be found rather than in the back section, so better to put that money towards a remap and VIS hpfp internals. You will likely also benefit from upgrading the stock intercooler to S3 version.
Yeah x2.

With the vast majority of tuners an aftermarket downpipe (with sport cat or decat) is the key qualifying hardware for a Stage 2 map. A Stage 1 map is typically a map for a car with totally stock hardware. Completely agree that mating an uprated downpipe to the existing catback is the way to go. The catback flows well enough for k03, k04, and probably only becomes a real restriction at k04 hybrid or BT power levels.

There's more benefit to an uprated fuel pump than just the extra power. Sometimes (actually quite often) a Stage 2 map can push the standard fuel pump past its limits. In this case, at best you're losing out on power, and at worst you'll get fuel cuts. Which are not fun. Nothing like ignition cut - if you get a fuel cut it can be like hitting the brake suddenly when you're on the power.

I'd argue that on tuned TFSIs an uprated pump ranks right up there with a bigger downpipe in terms of essential mods. Your intake for example might open up an extra 10bhp... but only at peak power. An uprated pump however will give you extra torque right from spool up all the way to high revs. As the pump is cam-driven its ability to deliver high fuel pressure is dictated by revs. So with a standard pump you lose out at lower revs, until the revs climb and the pump is able to deliver more fuel pressure. An uprated pump gets around that problem. A good supporting mod (especially if your turbo is capable of a bit more boost than a vanilla ko3) is an RS4 fuel return valve. It'll help the uprated pump hold the higher pressure better than the standard valve. The RS4 valve is arguably only of full benefit at k04 boost levels and beyond, but if your inlet mani is coming off at any point it's maybe worth sticking one in as part of the job.

I noticed a big difference having a Loba pump fitted. It was primarily to cure the fuel cuts I was getting after going Stage 2 R-Tech. I knew anecdotally the car should feel a bit stronger, but it delivered much more torque than I ever expected. Basically the thing spools and boosts much harder at low revs. The way I see it, I'm now getting the full benefit of the punchy little k03. Obviously for peak power and top speed a k04 simply moves more air and a k03 can't compare, but there's something very satisfying about the way a properly set up k03 car can shift its weight from low revs.

Sounds interesting in terms of the spec of your turbo anyway. If it's anything like a proper k03 hybrid you should be able to crack 300bhp with all the right mods and a good map. I'd suggest a custom mapper like R-Tech or Unicorn to get the best out of your chosen mods.

Offline paulmcgrath

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Re: Final push for the MK5 GTI
« Reply #3 on: January 02, 2019, 07:50:18 PM »
Thanks for the replies @colesey @AJP really helpful and informative.

No, I just double checked with turbo technics, the turbo has stock internals with "a customer requested 360-degree thrust bearing" But that's two separate people that are clued up about GTI's that said mine is very powerful.
The second guy that asked if mine was remapped actually owns a GTI himself that he's plundered loads of cash into. He's done the camshaft, then redid the camshaft job when the cam chain started acting up and replaced everything again.

I'll be very interested to see what BHP my GTI is putting out when I go on the rolling road day which is happening around my way in the next month.

The inlet manifold, injector clean and thermostat change are costing 360-420 euro.
Should I fit an Oil catch can after this or is that just a piece of useless petrolhead tat?

I'll be getting a custom map on a rolling road in Ireland BUT the Fuel quality over here isn't as good as the UK (low quality 95 ron) so gains won't be as high as expected over on your side...

So far between you guys @AJP & @colesey you've added to my basket a HPFP, a S3 intercooler, an RS4 return valve and removed that turbo back exhaust which I wasn't too keen on.

Are used S3 intercoolers ok to fit?

Thanks.

Offline AJP

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Re: Final push for the MK5 GTI
« Reply #4 on: January 02, 2019, 08:06:27 PM »
Thanks for the replies @colesey @AJP really helpful and informative.

No, I just double checked with turbo technics, the turbo has stock internals with "a customer requested 360-degree thrust bearing" But that's two separate people that are clued up about GTI's that said mine is very powerful.
The second guy that asked if mine was remapped actually owns a GTI himself that he's plundered loads of cash into. He's done the camshaft, then redid the camshaft job when the cam chain started acting up and replaced everything again.

I'll be very interested to see what BHP my GTI is putting out when I go on the rolling road day which is happening around my way in the next month.

The inlet manifold, injector clean and thermostat change are costing 360-420 euro.
Should I fit an Oil catch can after this or is that just a piece of useless petrolhead tat?

I'll be getting a custom map on a rolling road in Ireland BUT the Fuel quality over here isn't as good as the UK (low quality 95 ron) so gains won't be as high as expected over on your side...

So far between you guys @AJP & @colesey you've added to my basket a HPFP, a S3 intercooler, an RS4 return valve and removed that turbo back exhaust which I wasn't too keen on.

Are used S3 intercoolers ok to fit?

Thanks.
I've no experience of catch cans personally, maybe someone else can help on that one.

As for the intercooler - yes, second hand is fine but obviously check for any damage to the fins etc.

Which uprated HPFP are you going for? Complete units like the Loba or APR are more money, but take out the risk of installation issues that come with fitting uprated internals (eg VIS) to your existing pump. The install in that case has to be done quite clinically from what I gather, but if you have the resources to achieve that there's some money to be saved over a Loba or APR pump.

And which downpipe? If you're going decat there's theoretically less to worry about and for example the Relentless decat downpipes have a decent reputation, but if you want to go for a sport cat it's important to note that it's well worth spending a little extra to ensure you're getting a potentially longer lasting cat. The cheaper the materials for the innards, the quicker it'll degrade and potentially cause issues. The BCS (aka Powervalve) sport cats are some of the best in terms of quality and flow.

Offline paulmcgrath

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Re: Final push for the MK5 GTI
« Reply #5 on: January 02, 2019, 10:55:21 PM »
I've no experience of catch cans personally, maybe someone else can help on that one.

As for the intercooler - yes, second hand is fine but obviously check for any damage to the fins etc.

Which uprated HPFP are you going for? Complete units like the Loba or APR are more money, but take out the risk of installation issues that come with fitting uprated internals (eg VIS) to your existing pump. The install in that case has to be done quite clinically from what I gather, but if you have the resources to achieve that there's some money to be saved over a Loba or APR pump.

And which downpipe? If you're going decat there's theoretically less to worry about and for example the Relentless decat downpipes have a decent reputation, but if you want to go for a sport cat it's important to note that it's well worth spending a little extra to ensure you're getting a potentially longer lasting cat. The cheaper the materials for the innards, the quicker it'll degrade and potentially cause issues. The BCS (aka Powervalve) sport cats are some of the best in terms of quality and flow.
[/quote]

I was looking at the scorpion DownPipe and also the stainless steel t304 decat and downpipe made in the uk sold on ebay which is 120 and alot cheaper.. any comments on that mate?
the powervalve one is out of my budget if I'm honest.

Regarding the sports cat and decat option. I've been told that sports cats last only a year or 2 and the decat option doesn't appeal to me at all cause I don't want to smell fumes in the cabin.

I briefly looked at the VIS hpfp and the autotech internals option and as you say there fiddily to fit correctly but I'd be quietly confident that my mechanic whos also a VAG enthusiast would be capable of sorting it.

Again any advice on the above would be much appreciated.

Thank you.

Offline colesey

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Re: Final push for the MK5 GTI
« Reply #6 on: January 03, 2019, 08:20:50 AM »
Some good points there Paul.  Cheap cats don’t last since they only have a thin coating of precious metals, however decat is illegal. Need a good quality cat like HJS and I sould second the BCS recommendation. Build qual is up there with the Termignonis on my Ducati.

If you want a new HPFP, you can buy them for @175 and can ask VIS to install the kit and test. The seals of my original pump were quite knackered after just 25k miles, so this approach is good for peace of mind and the original pump can be easily resold to offset some cost.

Another option you might like to consider instead of upgraded intercooler, catch tanks and octane boosters is Water Meths Injection. That will keep the motor cooler, run cleaner and able to run more ignition advance. The beauty of the K03 is its quick spool and torque band for fast road driving, rather than top end BHP, and WMI will help broaden the curve.

Offline AJP

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Re: Final push for the MK5 GTI
« Reply #7 on: January 03, 2019, 10:34:06 AM »
Scorpion are a decent brand, and been around for years, although I couldn't confidently say just how good their cats are. I think it's safe to go with the 'you get what you pay for' approach. It's a shame you say the BCS downpipe would be out of budget as it's not just the materials they get right, but flow as well. The BCS cat on mine is huge - marketed as 'oversize' IIRC. I've seen graphs showing these BCS cats making equal power to a BCS decat (which should theoretically flow more) on identically specced cars. Nige at BCS puts a lot of time and research into his work. It shows.

A decat downpipe is indeed 'illegal' but in practice it's a case of being on good terms with the MOT tester or swapping it for a standard downpipe on test day. I've never heard of anyone actually being charged with an offence for running a decat - although I'm not saying it'll never happen. I personally investigated all those options and decided that the extra cash for a well-flowing sport cat would be wise money.

I'd be looking at things in terms of priority right now. Like I mentioned, the downpipe and pump are the two biggies if you're wanting to make good power. A bigger intercooler isn't something I'd call essential at this stage. You really need to look at what say an S3 cooler will do for your particular setup that your standard cooler can't. So if you're experiencing bad heat soak causing the ECU to retard the timing and therefore lose power, a bigger cooler becomes a priority. But if your standard cooler is doing a decent job of keeping IATs down, there's so much less / nothing to gain from a bigger cooler. Obviously there are other factors such as marginal flow gains from the S3 cooler, but for me I'd only make it a priority if I knew the standard cooler was struggling and the ECU was pulling timing. That's only something you can ascertain fully once you're modded up with all the bolt-ons and mapped up to suit, by means of live data logging with VCDS. Ok, fitting an uprated cooler now will arguably safeguard you from potentially large increases in IAT that comes from running big boost at Stage 2+, but in terms of budgeting the build and prioritising mods, it won't kill you to get round to the cooler after you've done the downpipe & pump, and done those properly. If you're serious about this it's crucial not to cut corners with those two mods.

As it happens, I'm still on the standard cooler. I can feel it pull timing a tiny bit during the summer if I've been stretching the car's legs. But nothing alarming. Spec is K03, full BCS, Loba pump, Stage 2 R-Tech (I could go back down to R-Tech for the tweak to 2+ now I have the pump but I haven't yet bothered) and Ramair intake. Heatsoak isn't a big concern for me - at this stage. If and when I decide to fit a k04, an S3 cooler will be going in at the same time.

Water meth is also one of those interesting mods I have my eye on for the future!

Offline colesey

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Re: Final push for the MK5 GTI
« Reply #8 on: January 03, 2019, 12:33:30 PM »
@AJP, what power / torque are you making? It’d be good to see a dyno chart if you have one.

Offline AJP

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Re: Final push for the MK5 GTI
« Reply #9 on: January 03, 2019, 03:36:17 PM »
@AJP, what power / torque are you making? It’d be good to see a dyno chart if you have one.
The last time I got the car on the dyno was at R-Tech getting the Stage 2 map a good couple of years ago. Only mods at this stage were the full BCS exhaust, and a drop-in Pipercross panel filter. It made just shy of 270bhp and 345lb/ft.

Since then I've had the Loba pump fitted, and also a Ramair intake. It's still on that Stage 2 map although does feel noticeably stronger since the additional mods. I'm guessing peak bhp well into the 270s now with perhaps a fatter/wider torque curve.

I do have a graph somewhere - bear with me and I'll see if I can find any pics.

Offline AJP

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Re: Final push for the MK5 GTI
« Reply #10 on: January 03, 2019, 03:42:50 PM »
Here you go. Lower graph is with the existing Stage 1 R-Tech map with BCS and Pipercross panel filter. Obvs the upper graph is with Stage 2 and same hardware. Decent numbers, but I've always wondered if those torque figures a little on the optimistic side..!

Offline paulmcgrath

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Re: Final push for the MK5 GTI
« Reply #11 on: January 03, 2019, 04:31:06 PM »
@colesey The tip on supplying HPFP to VIS for them to install it is a great shout!! I was reading on this forum that you can find them for 200-230 on ebay but the only ones I can see for sale for the MK5 is the internals for sale on their main website at 350 euro?

@AJP the BCS DownPipe is very expensive so maybe its best I wait another 6 months to save up the pesos, so I can afford the Downpipe & cat, Inlet & injector clean, HPFP upgrade and Map all at once. Over 2k of bills there  :surprised:

On the one hand, the car has 167000 kilometers so I don't know if throwing over half the value of the car is worth it for the best quality products when it has such high mileage...

Offline colesey

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Re: Final push for the MK5 GTI
« Reply #12 on: January 03, 2019, 04:33:23 PM »
That’s pretty grunty! The hpfp map tweak should add nicely to the midrange, holding the torque longer.  I need to get my car to Rtech some time to have the inlet clean and stage 1+ remap, though I have been saying that for over a year!

Offline colesey

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Re: Final push for the MK5 GTI
« Reply #13 on: January 03, 2019, 04:36:38 PM »
Paul, there’s some brand new vis internals just listed on the TFSI for sale Facebook page for £200 - https://www.facebook.com/groups/424358197750803/ otherwise just email Ovidiu and I’m sure he can make you an offer.

Offline AJP

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Re: Final push for the MK5 GTI
« Reply #14 on: January 03, 2019, 07:51:12 PM »
That’s pretty grunty! The hpfp map tweak should add nicely to the midrange, holding the torque longer.  I need to get my car to Rtech some time to have the inlet clean and stage 1+ remap, though I have been saying that for over a year!
Yeah it's really strong from low revs. Plant it in 3rd at 2500-3000rpm and it pins you in the seat. Around this time of year it'll sometimes spin up even in 3rd, and that's with Michelin PS4!

For the bit of extra grunt a 2+ map tweak would unlock I'm probably going to hold out and put future funds into a k04. If I was staying with the k03 that tweak would have been done a long time ago! I think with all that torque from low revs and the meaty spool up it's really made the k03's inability to hold boost at higher revs much more noticeable. Hence my plans for a k04.

Anyway, I don't want to derail this thread. As you were ☺