Back in November 2020, we purchased our brand new Volkswagen MK8 Golf GTI development car to begin working on our performance upgrades for this platform.
The visual appearance of the front end seemed to divide opinion across the world. But regardless of whether you’re a fan of that (or not) there’s no doubt a significant amount of tuning potential underneath the bonnet (or hood), if the VW MK7/7.5 platform is anything to go by.
Coinciding this new project with a significant investment in an all-new array of high-end scanning and printing machinery we have been able to get straight to work. And, in a more efficient way than ever before.
New Turbo – Does this mean more performance potential for the MK8 GTI?
The MK8 GTI uses the well-proven formula of FWD with a 2.0T 4-cylinder engine, but with a new Garrett turbocharger unit. Could this new turbocharger unit mean more potential from ECU calibration? It will be interesting to see the results compared to previous models.
After some road testing in standard form (watch that VIDEO HERE), we got straight to work and no sooner was the car up on the ramp than the front end was off! This gave our in-house engineers the opportunity to compare this latest version of the famous Golf GTi model to the previous MK7.
The all-new scanning equipment allows a 3D image to be created – in this case, the engine bay of the GTI Mk8. This means there’s no trial and error fitment like in the past. The scan builds an incredibly accurate replica, which allows the engineering department to use all of the available space for uprated parts.
Our also-new Stratasys F370 3D printing machine then allows sample parts to be printed. Generated in-house so we can crack straight on with trial fitment, too. Not only that, but these parts are also capable of withstanding heat. Meaning the car(s) can be test driven on the road and dyno for development before we put the final pieces into production.
So what have we learnt so far about the GTI Mk8
Well, the good news is that our uprated MQB intercooler fits straight on to the Volkswagen GTI. But that’s about all from a direct fit hardware point of view. New throttle and charge pipes, as well as a completely new intake system, is needed. Which is what we’re currently busy working on.
As always we focus on Stage 1 development first. But at the moment the software tuning side of things is impenetrable. No one yet has full access to the latest ECU that the Volkswagen GTI MK8’s are now using. However, understanding how the stock car performs and feels is essential. Providing our calibration engineers data for future areas of improvement.
No doubt there will be some significant headroom for impressive gains over the stock GTI’s 245PS output. We are excited to see what we can achieve… and will keep you updated.
Continued Volkswagen GTI MK8 Development
Thanks in part to the new machinery we have been able to make some significant progress. Starting with the OEM+ intake, replacement airbox lid, turbo muffler delete and the throttle and charge pipe kit.
As with everything we do, extensive development is critical. Over the coming weeks and months, we’ll be able to make some significant advancements with the hardware.
We haven’t even touched on the uber-modern interior, digital dash, 7-speed DSG gearbox (or 6-speed manual) and expected GTi refinement yet. Suffice to say it’s a lovely place to be. Yet still divides opinion on social media.
Could this be the best GTi to date? Well, that’s one for you to fight out. The purist love for this platform is strong – but the Volkswagen group continue to amaze with their progression.
We’ll keep this blog updated so you can follow progress.
LIVE UPDATE 17/2/21 // OEM+ Development
Thanks to the 3D scanning advancements we have been able to push on really quickly with some sample air box lids and a 3D printed back hose.
We are prototyping two types of the lid, one based on the OEM style to retain that uber-subtle OEM look and one based around our Carbon Series shape, which features a much smoother design to optimise airflow.
This is a style that is proven on our Volkswagen Golf MK7 (MQB) platform and so we were able to set to work straight away with it on the MK8 GTI.
We will be heading to our external testing facility to flow test both very soon to get some scientific results.
The increased diameter bore at the back of the lid (where the back hose connects to) is less restrictive than the OEM alternative, therefore allowing more air to be fed to the turbo. More air equals more power potential. And, as soon as we can get into the ECU, our software engineers will be able to make the most of all that extra airflow.
We have also been able to press forward with the turbo muffler delete and machined turbo inlet to suit the new turbo that’s used on the MK8 GTi.
We’re pressing forward quickly with this project and will have another update for you soon. We’re working on some more 3D printed test parts and we have some more upgrades going on the car very soon.
Check back here for updates.
LIVE UPDATE 3/3/21 // Bilstein Evo S & RF0 Alloys for the MK8 GTI
So while we’re busy working away on some further hardware parts for the car it was time to get it sitting, handling (and looking) a little better.
Let’s face it – there’s always room for plenty of aesthetic improvement over the factory-spec look. Well in our opinion anyway.
To improve the ride quality, handling and ride height we’ve opted for a set of Bilstein Evo S ‘street’ suspension. These allow a ride height drop of up to 70mm (not that we’re going that low on ours).
Evo S also boasts improved ride comfort over the factory suspension, too, with fixed damper settings designed for “sporty handling” say Bilstein.
For us, Bilstein is always the number one choice. Our Volkswagen 7R sits on the more track-focused Bilstein B16 set-up, while the MK8 GTi is more road-biased making the new Evo S perfect for what we need. Also finished in this stunning new grey colour.
Straight forward install in our HQ Performance Centre with a few alterations at the end to adjust the ride height as preferred, with roughly a 30mm drop over factory.
Wheel & Tyre Upgrade
In addition to that, we fitted our ‘lucky’ MK8 GTI out with a brand new set of our 18” RF0 Flow Formed alloy wheels and 225/40ZR18 Nankang NS-2R tyres. These are spec’d to give the perfect fitment without spacers AND thanks to the Flow Forming technology the rims are super-light.
Big Weight Saving
Placing both the Volkswagen OEM GTi wheels on the scales and the 18” RF0 it soon becomes apparent just how much of a saving! The RF0 rims are 2.75KG lighter EACH (per corner), giving an 11KG total ROTATIONAL weight saving – that’s huge. And something you’ll really be able to feel on the road..
The more performance-focused tyre will also add additional stability (due to the stiffer sidewall) and improved dry weather grip over the OEM-spec Bridgestone.
Of course the final step before taking it out on the open road is to get the geo done and the alignment dialled on our in-house equipment.
What A Difference!
What a difference a drop makes! Not to mention a set of stunning (we are biased of course) 10-spoke rims. A vast improvement over the OEM set up.
Next up will be some more 3D printed parts to compliment the larger diameter air box lids that we are currently testing. Stay tuned…
What do you think to the ‘NEW look’ then?
LIVE UPDATE 23/3/21 // Big Brake Kit
As with most of our development cars they’re used for high-speed testing and track work. The GTi is no exception and, as such, we’ve treated it to our 355×32 big front brake kit.
The kit offers a substantial visual upgrade tucked away behind the 18″ RF0 wheels. However, most importantly, is the increase in braking performance to cope with harder, prolonged performance driving.
The kit comes with everything you need including the 6-pot Alcon calipers, handed rotors, bells, brackets, pads, bolts, braided lines and Motul performance Dot 5.1 brake fluid.
There are a couple of different pad options – this time we’ve opted for our Ferodo DS Performance pad.
The replacement is straightforward once the car is up on the ramp, but is something you can get done at your local Revo Authorised Dealer. And, while the OEM brake kit was off the car we took the opportunity to compare the weights.
So, a 6.15kg saving PER SIDE equating to a ~12kg saving overall just in the brake kit.
Add that saving to the saving with the RF0 wheels (11kg) and you get a combined saving of 23kg! Much of which is also rotational – which you will definitely feel the benefit of.
We’re leaving the rear brakes OEM for the time being. Unlike our MK7R, which has an uprated 356mm rear kit and is more track focused, running our 500bhp Stage 3 ETR turbo package.
So that covers the brake upgrade on our MK8. All that’s left here is to bed them in following the correct procedure.
Next we’ll be back at our flow-testing facility analysing the various air box test lids discussed earlier in this blog post.
LIVE UPDATE 30/3/21 // FLOW TESTING THE DEVELOPMENT 3D Printed PARTS
We thought we’d bring you an exclusive, behind the scenes look at our flow testing practises. And what better way than with our 3D printed parts for this GTi.
We are going to test 4 variants today so you can see for yourself the benefits of each. Hang tight, this is going to get a bit techy.
The testing was carried out in a 3rd party test facility in a temperature controlled room with an ambient temperature of 13.7°C and pressure reading of 1013.62hPa. The test pipe used is 76mm I/D with a 3D printed adapter to accept the intakes.
Each intake was run at full capacity first to see what the maximum CFM (Cubic Feet per Minute) it was capable of running. Once a max for each unit had been set the test was carried out taking measurements every 50CFM to allow for a broader range of readings. Each time allowing flow to settle correctly before taking the reading.
The restriction for the test was measured in mmH2o. We also calculated roughly what the MK8 Golf GTI would require in terms of airflow in CFM on Stock ECU software, this worked out at around 460CFM.
While this is what the car would need to run efficiently, removal of any restriction within the system will only benefit the car further in terms of spool time, power and torque. Each test is carried out 3 times in the same controlled maner and then we take the average from each test for the final figures to ensure continuity.
Stock Intake system
The first test was to get a base line by running the complete stock intake system using the airbox with OEM filter, corrugated plastic intake hose and plastic turbo inlet adapter. The stock system was able to achieve a maximum CFM of 609 but we only recorded data to 600 as we used increments of 50 units. This gave a maximum restriction value of 1126.73 mmH2O @ 600CFM.
It was evident that the OE system, while capable of supplying the airflow the car needed on stock ECU tune had its limitations.
Revo OEM+ Intake
The OEM+ system utilises the factory airbox but replaces the paper filter inside with a high flow foam version. It also replaces the corrugated plastic hose and plastic turbo elbow with a smoother higher flowing Silicone unit designed to remove the turbulent ridges found in the OE version and a fully machined inlet adapter which allows for a much larger intake volume with a smooth tapered reduction matched to the turbo ID.
As can be seen in the testing the combination of the high flow air filter and smooth silicone turbo pipe reduced restriction well, allowing the kit to reach a higher maximum CFM of 657 (only published results to 650CFM). This showed that the OEM air filter and hose would become a restriction, even more so when you start to tune the car with the corrugated hose causing excessive turbulent airflow and the plastic turbo elbow proving to be a chocking point.
The Revo silicone hose clearly smooths the airflow out allowing for faster airspeed without large pressure increases due to the tapered hoses with stepped internals, combined with the machined inlet. The Revo OEM+ kit had a maximum 1032.63mmH2o restriction at 650CFM, at 600CFM the OEM+ unit showed a restriction of 902.03mmH2o. This is a difference of 20% between the stock system, not taking into account the OEM+ was capable of achieving a higher CFM while still remaining less restrictive.
The next point of restriction within the stock system we wanted to look at was the airbox itself, in this case the lid section which has the outlet.
Revo OEM Lid and Back hose kit
We decided to replicate the design of the OE airbox lid but with the added benefit of a larger outlet hole to the back pipe. The outlet diameter being increased meant we also increased the silicone back pipe to match giving a larger volume of airflow from lid to turbo. The machined turbo inlet stayed the same as was used in the OEM+ kit as space restrictions within the engine bay hinder any further increase in size there.
The increase in flow was instant, even being able to give flow readings as low as 100CFM. Something that the previous two tests were unable to do due to the restrictions in the OE lid and pipe size.
The increase in flow continues all the way through the test up to the recorded 650CFM, with the unit actually achieving flow to 667CFM. At 650CFM we saw an average restriction of 1003.97mmH2o, once again removing more restriction from the system in both previous tests and giving a 23% reduction in restriction at 600CFM compared to stock.
You can see from the graph though that due to the design of the lid, while we see a good reduction in restriction at the higher CFM the low down and mid range flow are very similar to that of the OEM+ kit. This is due to the OE lid style having very sharp corners and edges the air is having to navigate around, reducing efficiency and limiting the extra restriction we have gained with a larger outlet. Something that is tackled on the next design.
Revo Carbon Lid & Back hose kit
Our final test was carried out using a similar design of lid to the very successful unit we use on our MK7 MQB platform.
Applying what we learnt from the MK7 carbon intake we constructed a much more free flowing ergonomic replacement lid to that of the OE design. Using flow channels built into the lid to guide and ultimately speed up air flow to the outlet we were able to release the final bit of restriction from the airbox setup.
Once again combined with our larger back hose and machined inlet you can see from 300CFM the carbon lid design pulls away from the previous tests all the way through to the recorded 650CFM. With the carbon lid actually achieving a maximum of 681CFM reading.
As before looking at the restriction compared to the OE set up at 600CFM the carbon kit had a restriction value of 835.70mmH2o which is 26% less than the OE and a continued improvement in the 3 iterations of intake we have tested.
While all the above is ‘only’ bench flow testing we will continue to test on the car with both road and Dyno testing to ensure the data we are collecting is as accurate as can be.
We will also be flow testing the front section of the MK8 GTI with revisions we have made against OE as this is also another restriction point within the system. However, so far the data captured is promising and gives us a good idea of what we would like to have as an end product. We can now clearly see where the main points of restriction are on the OE system and as a result can target those areas with further R&D.
The Revo OEM+ intake kit looks like it will be the perfect accompaniment to stage 1 software once its underway with the Carbon variation being suited to higher power where more flow is required at stage 2 and above.
So there you have it. Just to reiterate this is simply our findings so far from very early testing and development parts. Nothing is signed off or finished as yet, these are just some baseline figures to help us work out where improvements need to be made.
Lots more testing and analysis to go yet.