• Hi Guest why not show off your SEAT! (now fixed)
    You can now share your favourite car photos in the new media gallery including embedding pictures from your Instagram account.
  • Hi Guest! New high quality keyrings are now available to pre-order: order yours now.

JackB's Mk3 Leon Cupra "400"

JackB

Active Member
Jan 18, 2020
92
55
Hi everyone, this readers ride is about my Leon Cupra 290, which I have owned for almost a year. It's my daily driver and only car on the road.

When I picked it up it had 1000 miles under its belt as a main dealer demo car... I'm sure it had the manufacturer recommended gentle break in (not)!

Over the last 8000 miles - I have got to know the car on the road - how it handles city driving, motorway miles and B road blasts. It's a huge step up from my old diesel clio, so I have gained much enjoyment from the stock car.

Whilst I didnt realise at the time I bought it, mine is a bit of a frankencupra, It is has the DNUC engine (adds gas particulate filter (GPF), removes port injection), 7 speed DQ381 DSG and standard digital dash, which you would expect for a 2019 car. But it also has the silver badges, red brake calipers and colourful cupra flags which you would expect for a 2018 car.

I actually love this combination, I prefer all of the elements it retained from earlier revisions of the car over the 2019 equivalent.

The Magnetic Grey paint colour looks ace too, shows up completely different shades in different lights, sometimes looks almost blue!

My plan for this thread is to document any changes I make to the car and the rationale behind those. I tend to do a lot of research before making decisions so hoping any findings I can share may be useful to others.

Looking ahead for 2020, I have a trip planned to the Nurburgring - which hopefully won't be the only track time I get. I'm not an experienced track driver so it will all be a learning experience for me :). Not going to be setting any lap records any time soon - but this interest may be an indication of the direction I am taking the car (though it will remain as my daily, so nothing too extreme).

I'm not going to preempt where the car is going as I am not 100% sure, so will post up as and when things happen & I get chance to write about it. My next couple of posts will cover things I have already done.

Any questions/comments welcome.
Cupra 1.png Cupra 2.png Cupra 3.png Cupra 4.png
 
Last edited:

JackB

Active Member
Jan 18, 2020
92
55
Ok, so before I move forwards, I figured I should cover historic changes made over the last year:

Disabled soundaktor

Even though the car is quiet, I prefer to hear its real soundtrack. I did this within a month or so of getting the car. I used a Carista beta testing trial to do this with an ELM327 OBD adapter I already had... so cost me nothing too.


Hardwired front and rear dashcam - Viofo A129 Duo

Another early 'mod' for me. Luckily not had to use it but I am pleased with the video and audio quality that it outputs. GPS info is a bonus too.

It was well worth hardwiring this, absolutely no visible wires so really clean and tidy.

I bought some trim tools which were a massive help and definitely stopped me damaging the various bits of plastic that needed prying.

I did end up braking the clip that holds the rubber conduit tight between the boot hatch and the body (I ran the rear camera wire through this). Replacement of the part is cheap from a main dealer (5G6971829B), but unfortunately you have to depin and remove all of the rear light wiring to do this. So I just sealed the original one up with black silicone sealant... which has served its purpose protecting against water ingress since (been checking on it through the winter). The 'repair' is only noticeable with the boot up and even then I doubt you'd spot it if I didn't point it out.


Rubber floor mats and Rubber boot liner tray

Bought these at the cars first service ready for the winter months. Plan is to run these through the winter (or on any camping trips etc), keeping the carpets nice for the summer.

The floor mats are a really thick, durable rubber. Easy to clean too. Would recommend to anyone with a Mk3 Leon. Part number ZGB5F0512041.

The boot liner tray is thinner and more plasticky. I'm still happy with it, just not as impressed as the floor mats. Would still recommend if you load your boot with muddy or wet items from time to time. Part number 5F0061205F.


MST Performance Intake Kit and Turbo Muffler Delete

Bought and fitted by myself recently - I'm not a mechanic by any stretch of the imagination but can handle a spanner, this job is fairly easy to do. Though one top tip is to make sure you have a 7mm spanner, I had 6mm and 8mm but no 7mm. This made the jubilee clips on the hoses a pain to undo - there wasn't enough access for a 7mm socket - it had to be a spanner.

Why did I do this mod?
- I wanted to be able to hear the intake and turbo a little more
- I'm going to be tuning further for performance soon

Why did I choose this over other options?
- It was significantly cheaper than the equivalent full Racingline setup (especially as I got it at a discount).
- I also considered doing a stock intake mod instead with a new filter and the MST pipe work, this would have met the same level of performance but wouldn't have provided the same uplift in sound. It didn't actually cost me that much more to get the full MST kit because of the offer I had.
- It uses a cotton cone filter, which is longer lasting and a better filter (i.e. capturing dust) than foam. It just flows slightly less.
- It topped this guys tests for flow (so the cotton filter cant be holding it back that badly!)

I'm very happy with this purchase, quality is nice. Can hear a nice amount of intake on throttle now and the turbo muffler delete lets out subtle sounds when lifting off. No noticeable increase in noise when cruising gently though. Pics attached with and without the box cover (i'm running it with the cover).

Cupra 5.png Cupra 6.png
 

JackB

Active Member
Jan 18, 2020
92
55
Audi RS3 Brake Cooling Ducts

So today, I fitted some cooling ducts for the front brakes, an Audi OE part for the RS3 that fits other MQB cars perfectly, part numbers are 8V0407811 and 8V0407812 (one for left, one for right). I got them direct from a local Audi dealer for £12.53 each... much cheaper than online resellers.

I have added these to provide additional cooling when pushing the car on the track... not sure they would be relevant on a 100% road car though.

Easy to fit - only tools required are those to take the wheels off and some pliers to cut the cable ties (which come with the ducts to secure them).

I also used the opportunity to give the front arches/brakes a bit of a clean... much easier than normal :D.

Cupra 7.png Cupra 8.png
 
Last edited:

JackB

Active Member
Jan 18, 2020
92
55
So I did my first ever track day on Saturday at Oulton Park.

The car drove perfectly considering it is in near stock form - the brakes, tires, oil etc all seemed to take it in their stride - though that doesn't mean there won't be upgrades following soon :).

Cupra 9.jpg Cupra 10.jpg

 

Jake_LHX

Active Member
Jan 9, 2020
34
8
Great video dude.

Mad how well I know that track having never actually driven it :p Spotting all the points I have stood for various events :p
 
  • Like
Reactions: JackB

The Daily Meme

Insta: @thatredcupra
Jan 3, 2018
883
444
Cambridge
So I did my first ever track day on Saturday at Oulton Park.

The car drove perfectly considering it is in near stock form - the brakes, tires, oil etc all seemed to take it in their stride - though that doesn't mean there won't be upgrades following soon :).

View attachment 13345 View attachment 13346

These cars were designed to be driven on a track, not suprising they handle it well even completely stock. I may take mine to Snetterton at some point but I don't trust myself not to ruin it. I'm usually a very cautious driver on the road.

I was given a track experience day for my birthday last week witht he choice of 3 out of 36 cars. Looking at the line up, they have a cupra. Might give that a go while I'm there to get a bit more confidence in my own car.
 
  • Like
Reactions: JackB

JackB

Active Member
Jan 18, 2020
92
55
Thanks for the comments @Jake_LHX and @The Daily Meme (keep us in the loop with your track experience day!). Now time for an update.

Bola FLC Wheels
Cupra 12.png Cupra 13.jpg
I now have new wheels fitted - a change i've been planning and researching for a little while now. Whilst I love the aesthetic of the standard wheels - they were not perfect for my purposes. I have laid out my considerations for this decision below:
  • The OEM wheels are diamond cut, which looks lovely when new, but is well known to degrade when exposed to our winter conditions. My new wheels have a more typical finish, which will be more durable and cheaper to refurb if required.
  • The OEM Wheels are really heavy, for normal road use this might not be a bother, but reducing this rotating and unsprung mass should deliver real benefits on the track. There should also be a small positive benefit on ride comfort and fuel economy. Total weight for my brand new wheel and tyre is 18.1kg, vs 22kg for the mostly worn OEM wheel and tyre.
  • My new wheels are 18in rather than 19in, allowing me to increase the sidewall (overall diameter is near identical). This has delivered an immediately noticeable improvement in comfort on the motorway and rough roads, and should also improve compliance in the wet. Sharpness in the dry will be slightly reduced vs a comparable 19in setup. Like for like tyres seem to be around 10% cheaper in my new size, and wheel replacement is around 20% less if ever required.
  • The wheel size I have gone with is 18x8.5 ET45. Aesthetically, this means the tyre contact patch is shifted out by 5mm each side and the alloy wheel face pokes out 11mm more than OEM. This minimises changes to the suspension geometry whilst still providing a more aggressive wider stance.
Something you should consider when buying aftermarket wheels is the wheel nut type. The OEM type is ball seat, but my new ones are cone seat. This is not a problem in day to day use, except for the fact that your new wheel nuts will not be an appropriate fit for your spare wheel. Because of this, I have put 5x of the OEM bolts in the spare wheel (using tape so they don't rattle). Should a roadside tyre change be required, the correct bolts are immediately on hand.

Ball vs Cone.jpg

I have also purchased an impact socket which is sheathed in plastic to prevent wheel damage when removing them. This fits securely in the spare wheel foam surround as per the below image.

Cupra 14.jpg


Michelin Pilot Sport 4 S Tyres

The original 235/35/19 contisportcontact 5 tyres were near the end of their useful life, and in my opinion, have been offering inadequate grip in the wet all along. For my new 18in wheels, I have treated them to a set of Michelin PS4S's (not to be confused with PS4's) in 235/40/18.

I chose these based on the outstanding reviews they receive both on here and elsewhere (I find https://www.tyrereviews.co.uk/ and their youtube channel is a great resource). I've not put many miles on them yet but they do feel like an instant improvement.

The only time I will be pushing these out of their element will be for track use, where a Michelin Cup 2 or similar tyre would be more appropriate... if I start taking track time more seriously, I may look at having a separate set of wheels with track day tyres fitted - but for now - I am happy with my PS4S's.
 
Last edited:

JackB

Active Member
Jan 18, 2020
92
55
I was going to be giving a bigger update this week, however my plans have been disrupted by garage closures (Bloody COVID-19)... I'm part way through a set of performance upgrades.
Cupra 15.jpg

In these COVID-19 impacted times - theres only so much you can do - so heres an update on a small mod completed today.

Fan Washer Jets

Theres not much I can say about these that is not already covered in this handy how to guide.

My car left the factory with pistol style washer jets (part numbers 5F0-955-985 and 5F0-955-986 for left and right).

Other VW Group cars come with a better fan style jet, which is a direct swap - 5M0-955-985-C-9B9 (same number covers both left and right).

Took me a couple of minutes to swap them over and another couple to adjust the height. I've not been able to use them on the go yet but they seem to provide broader and more even coverage of the windshield. Happy with the results.

Cupra 16.jpg
 
  • Like
Reactions: The Daily Meme

The Daily Meme

Insta: @thatredcupra
Jan 3, 2018
883
444
Cambridge
I was going to be giving a bigger update this week, however my plans have been disrupted by garage closures (Bloody COVID-19)... I'm part way through a set of performance upgrades.
View attachment 13895

In these COVID-19 impacted times - theres only so much you can do - so heres an update on a small mod completed today.

Fan Washer Jets

Theres not much I can say about these that is not already covered in this handy how to guide.

My car left the factory with pistol style washer jets (part numbers 5F0-955-985 and 5F0-955-986 for left and right).

Other VW Group cars come with a better fan style jet, which is a direct swap - 5M0-955-985-C-9B9 (same number covers both left and right).

Took me a couple of minutes to swap them over and another couple to adjust the height. I've not been able to use them on the go yet but they seem to provide broader and more even coverage of the windshield. Happy with the results.

View attachment 13896
Nice, this is one of my mods i plan to do. Its something that always irritated me about my last leon. I had triple jets, and one was going over the car, one was hitting the very bottom of the screen and one seemed just about normal. Whenever I went to adjust them they would end up in another weird configuration so i gave up in the end but never got round to swapping to fan jets before i sold the car. Will be doing it on the cupra at some point though.
 
  • Like
Reactions: JackB and Syphon

JackB

Active Member
Jan 18, 2020
92
55
Well it's been a while since I have checked in on here - thanks for the comment @The Daily Meme - I was lucky that my triple jets were configured fine when I got the car (and stayed that way whilst they were still on)... I definitely recommend the fan jets though when you get chance.

Unfortunately, the big performance upgrades I mentioned before are still on hold (COVID-19). I still want to give an update now I've had the car for just over a year. So what is new?

Car Insurance

Boring topic I know, but I do want to give my thanks to Adrian Flux - who have been able to provide a great level of cover, and the flexibility I need for mods at near enough the same price as the cheapest mainstream insurer quoted on a standard car. I've always been with 'normal' insuers till now so the customer service experience both on the phone and online was not something I've been used to.

Thanks to the team @[email protected] FLUX .

Forum Merch

I prefer to keep my car simple and clean, however as I won @Syphon 's recent "name that icon" competition and got some in the post free of charge (thanks!) - I couldnt resist. I'm going to see how I like them over the next few weeks - I might not keep the old logo in the rear window but I like the new one in the rear quarter.

Cupra 17.jpg Cupra 18.jpg Cupra 19.jpg
 
Jun 14, 2020
3
1
Great thread Jack, and nice to see so much thought going into each mod.
I'm going to make some mods soon to my car (once my insurance is up), so it's good to hear Adrian Flux are keeping things sensible.
Keep up the good work.
Phil
 
  • Like
Reactions: JackB

JackB

Active Member
Jan 18, 2020
92
55
Thanks for the kind words @360phil

There are more exciting updates to share in the days/weeks to come, I've performed a series of upgrades (final steps still to be completed in the next few days) over the last few months - and just need to get them written up to share with you.

Powerflex Hybrid Lower Engine Mount

First up is a new lower engine mount, in the form of the Powerflex PFF85-833. Wheel hop was a real problem in my car (if you read around, you will see I am far from the first person to have this issue), and I am pleased to say that this has completely resolved that. There is also a side benefit in the form of better feel when changing gears in M Mode (feels a bit more snappy).

The downside is a slight increase in NVH (noise/vibration/harshness) when sat idling - It's enough to be noticeable, even by a passenger that doesnt know the mount is installed - however I find it to be a very minor issue, and well worth living with for the associated benefits. You can't tell its there at all when moving along steadily.

There are lots of choices in the lower engine mount world, and it's hard to get any real information on how they all compare to one another. I opted for Powerflex as they are a well established name in the world of mounts/bushes, and went for their hybrid insert (over their cheaper standard insert) because it seemed like a better solution to me for a little extra cost and effort to install.


Wagner Intercooler

This should give you an idea of the further updates that are due to follow. When I posted the picture above back on March 29th, I was at Awesome GTI's garage getting this intercooler fitted (Wagner 200001048). Shout out to them for looking after me and my car well that day :).

The stock intercooler on our cars is adequate for most people, however it's effectiveness at removing heat from the air is limited, and it will start to become a restriction on tuned cars, or even a stock car in hotter weather or with continuous hard demand on the engine. Given my intention for some track use, an intercooler upgrade was a no brainer.

Aftermarket intercoolers provide more cooling capacity for the intake air, and thus support the engine in making more power, for longer (colder air = denser air = more in cylinder to go bang).

Like the lower engine mount above, there are lots of options for intercoolers, ranging from cheap 'no name' chinese imports to options such as the Wagner at double or triple the price. I have no doubt that the cheaper options perform well (i've seen dyno graphs from facebook groups where these have been sucessful), but because of my interest in extracting maximum performance with the minimum possible impact on reliability, I didnt want to take the risk (I realise this concern may have been overkill, but at least i have peace of mind).

It's worth nothing that fitting this to my facelift cupra required lots of cutting on/around the front bumper - none of it is visible from the outside but it does add to the complication of the install - Awesome did a great job of this for me and kept me updated as they progressed to make sure I was happy. Apparently the intercooler fits perfectly with no cutting on other MQB cars.
 
Last edited:
  • Like
Reactions: Jimbobcook

JackB

Active Member
Jan 18, 2020
92
55
BCS Powervalve Exhaust

I think its fair to say that the exhaust note on the newer GPF equipped cars is muted, and, whilst I'm not a fan of really loud exhausts, I did want something with a bit more character.

I researched the usual names (Milltek, Scorpion etc), and whilst the products seemed OK, I'd picked up mixed reviews of the quality of their products.

Whilst looking, I saw some posters mentioning BCS Powervalve Exhausts, although I hadnt heard of them, I couldn't find a bad word about them or their products. Their prices are very competitive for the quality on offer. After a few detailed conversations, these are the guys I went with to build and fit my system.

The options you can get (and my choices) are as follows:

Valved or Non Valved -
  • A valved system is the party piece in BCS's offerings. Unlike similar competing products, which are controlled by an electrical switch, the BCS system opens and closes based on how much boost the turbo is generating.
  • They also offer non-valved systems, which are like a normal sports exhaust, and a bit cheaper.
  • I went for valved and am blown a way by how well it works, it is as quiet as OEM on the motorway but opens up the sporty sound when you put your foot down.

Presitge, Sport or WRC -
  • This is the sound profile, prestige being the quiestest (two fairly large silencers), WRC being the loudest (straight through), and sport offering a happy medium of the two.
  • This is purely going to be down to personal preference, I went for the prestige system because I prefer a more subtle note, and also need to ensure I stay within noise limits for track days.
  • The system sounds nothing short of amazing. It's deeper than the stock exhaust, and has much more range in the sounds it will make, you can hear more of whats going on at the engine, without it being overly loud or droney.

Decat, 100 or 200 cell catalytic converter -
  • What you go for here really depends on your car and how you use it, I didn't consider the decat option as my car is a road vehicle first and foremost.
  • The choice between the 100 and 200 cell cats is based on how far you want to push the power envelope, both should pass MOT emissions tests, but the 200 cell will get through it a bit easier. The downside of the 200 is that it creates a little bit more restriction, vs the 100 cell which in theory flows just as well as a decat (BCS can explain the science of this to you if you are interested!).
  • I went for the 100 cell.

Downpipe wrap -
  • An optional extra is having the downpipe covered in a thermal wrap. The purpose of this is to keep the heat in the exhaust and out of the engine bay, allowing the engine to breathe cooler air and perform at its best for longer. It's a nice to have and not something that is needed.
  • I opted to have the wrap as it's not too expensive, looks great in the engine bay and should give some performance benefit.

Tips -
  • The final option is what tips you have on the exhaust, BCS will talk you through the options suitable for your car, there will be something to suit any taste (round/oval/single/double/quad/black/silver etc).
  • I went for ovals, which are effectively a bigger version of the stock design for my car. There was obviously a lot of attention to detail in this (in the whole system to be honest!), the guys were talking about how they worked out the shape and the angle of the exit, to compliment the lines of the car. It really does show in the finished product - which lines up perfectly with the OEM rear bumper, and looks great from every angle.
As a final word on the exhaust, I'd highly recommend BCS to anyone, both the product and their customer service is top notch. The guys are clearly enthusiastic about cars, and will treat yours with the same care as they would their own.

Here are a couple of pictures to show off the system.

Cupra 20.jpg
Cupra 21.jpg

My next post will be about the software changes made to my car, to compliment the hardware changes already mentioned ;)
 

JackB

Active Member
Jan 18, 2020
92
55
To kick this post off, I performed a mid year "mini service" myself recently:

  • Millers Oils NANODRIVE CFS 5w-40 NT+ (Expensive and higher viscosity than the OEM 5w-30, but widely recommended when running increased power)
  • Genuine oil filter and sump plug
  • NGK R7438-8 (4905) spark plugs (High end spark plugs that are a step cooler than the OEM plug, recommended by Unicorn for those running "stage 2" power on this engine)

Now on to the exciting stuff............

Unicorn Stage 2 ECU Software with DSG Map

All of the mods mentioned above have been building up to this!

I went with Unicorn because of their locality to me (although I would say they are worth travelling for!) and because of their excellent reputation for smooth, powerful maps. I prefer the idea of the map being tweaked for my car on the dyno as Unicorn do, rather than being a more 'off the shelf' flash of the ECU, such as those from Revo and the like.

On the flip-side, the likes of Revo's maps will have been tested on and applied to more cars, in a variety of conditions all over the world. There are definitely pros and cons to each option.

Here are the results:
Cupra 22.jpg


Unfortunately, I didn't get a run done with the car completely stock, so it was already making good power (325hp, 330lbft) before the software was applied. The official stock numbers are 286hp and 280lbft.

With the map applied, the car pulled an incredible 405hp @ 6000rpm and 415lbft @ 4000rpm. Perhaps more importantly, the car holds over 400hp all the way from about 5600rpm to 6700rpm.

The car has been absolutely transformed and pulls like a train now. You can see from the graph, its not peaky anywhere - it's just a smooth build of power across the rev band, and you can really feel that driving the car. By 3700rpm it is making more than stock power and it just keeps building from there.

I got Unicorn's DSG map at the same time to support this, which increases the clamping pressures, improves the shifts, raises the redline and allows a true manual mode (no automatic up-shift, no kick-down).

I need to get some more miles on the car to assess how well the DSG map works in a variety of conditions - but I've not ran in to any concerns with it so far - and it's definitely an improvement when "on it". Crucially, the car has not been turned in to a monster, and still feels just as driveable even at low speed / low throttle.

I'll give an update on how my recent changes are working out once I have been able to get some more miles on the car (hopefully some track time too!), I'm a very happy chappy in terms of first impressions though.
 
Last edited:
Jul 19, 2020
4
0
26
Leicestershire
Great write up. Have you got any planned brake or suspension mods? I've got the copra 19 model and some of the big brake kits appeal, albeit a costly upgrade so not sure if the improvement would only be marginally better on track.

Sent from my SM-G975F using Tapatalk
 

JackB

Active Member
Jan 18, 2020
92
55
Awesome car sir! Health to drive 🚗(y):D
Great write up. Have you got any planned brake or suspension mods? I've got the copra 19 model and some of the big brake kits appeal, albeit a costly upgrade so not sure if the improvement would only be marginally better on track.
Thanks both :). Good question @Jbrad94 on further mods, to address suspension - I'm leaving it as it is for now, as it drives and corners well from the factory in my opinion. Asethetically, it would be nicer a bit lower, but theres some pretty bumpy roads I have to traverse regularly which make me appreciate the stock height. If I were to upgrade, I'm tempted by full coilovers of some description rather than just springs (I have reservations about how well the dampers will work and last with lowered springs).

Regarding brakes, I agree, the big brake kits look lovely. I am particularly taken by the Reyland kits (AP Racing 6 Pots + 362mm floating rotors specifically), however I am conscious that I am not on an unlimited budget with this car - and am also very much aware that doing one upgrade can make another necessary (e.g. because I have added power, and am going to be using the car on track, I may need to improve my oil and/or water cooling), raising the cost even further.

With that said, I do think the stock brakes could be improved, and I needed to replace the stock pads anyway after taking them way outside of their comfort zone and destroying them at Oulton Park (above). Rather than go straight to a BBK, I have decided to see how the stock braking system can perform with some modest upgrades - all of the below has been done both front and rear

Ferodo DS2500 Pads

These pads (part numbers FCP4425H for front and FCP4697H for rear) should offer an increase in performance over the OEM parts, although choosing the right set was really difficult - and I won't know if I have got it right until I have fully utilised these ones.

The OEM brake pads are designed to work well from stone cold - and survive only standard road use. This allows them to be made quite cheaply and still perform adequatly for the majority of customers.

On the other hand, high performance brake pads are designed to survive the hot conditions created on track (with some being fine to 1000c+). The problem with these are is that they are much more expensive, and most are not suited for road use - as they do not work optimally until they have been warmed up.

I needed to find a happy balance with my car doing double duty on both road and track, and so enters the DS2500 pad from Ferodo. This compound offers a better than OEM friction coefficient all the way from 20c to 500c (unfortunately, I dont have specs for OEM to compare - but this should be confirmed by their overall stopping power and resitance to heat).

Additionally, these come with a larger surface area to the OEM pads from the front, which should increase the amount the pads can clamp on the disc, and also help the pad to last longer.

It is worth noting that these do not come with a wear sensor. To avoid a warning light on the dash, I cut the plug off the old pads and joined the wires by hand, then reconnected to the plug on the car - easy job. I also had to use Carista to fully release the rear electronic parking brake - which is important to avoid damaging the mechanism when replacing the pads.

To confirm, I am still using the original discs that came on the car, as they still have life in them. I have inspected them for wear/cracks, and cleaned them up - before bedding in the new pads.

Cupra 23.jpg

HEL Braided Brake Lines

Braided brake lines (part number SEA-4-209 used here) are a nice mod to do for any car driven hard. Whilst the brake fluid runs in hard lines all the way out to each wheel, the final leap from the chassis to the caliper must be done by a flexible line for obvious reasons (the caliper can move up/down/left/right relative to the chassis).

The OEM lines are rubber, cheap for the manufacturer and perfectly adequate for most drivers. The problem with this is that they can expand under hard braking, creating a softer pedal and reducing the pressure that actually gets transferred to the brakes.

Braided lines are still flexible, but a metal sheath stops them from expanding under pressure, creating a more direct braking feel, and allowing all pressure to get to the brakes. Their hard outer coating also improves durability over time vs rubber lines.

Cupra 24.jpg

Motul RBF660 Fluid

The car is almost two years old, so it was sensible to replace the fluid anyway, but it was a necessity after replacing the lines and letting air in to the system. After doing a bit of research, I decided it worthwhile to replace the brake fluid to a more performance oriented specification OEM.

I'm not sure of the exact OEM specs, but to meet the DOT 4 specification, the dry boiling point (when the fluid is brand new) has to be at least 230c, and the wet boiling point (when the fluid has aged and absorbed water) 155c. Whilst I didnt boil earlier this year at Oulton, the ambient temps were cool and I may have been pushing them close to the limit. Boiling brakes are dangerous brakes (gas compresses, so when you press the pedal - all it does is compress the gas rather than press the pads against the caliper), stopping you from... stopping.

All of my research pointed to Castrol React SRF as the best, but it is very expensive. May be worth it in a BBK but with my stock brakes, I felt it overkill.

The next best seemed to be Motul's RBF range, available in a few different 'grades': 600, 660 and 700.

The key specs compare as follows:
NameDry Boiling Point (C)Wet Boiling Point (C)
Castrol React SRF310260
Motul RBF 600312205
Motul RBF 660325204
Motul RBF 700336205

I opted for Motul RBF660 as it was practically the same price as RBF600, whilst 700 was a jump up in price (for a minor spec bump I probably wouldnt use) and Castrol SRF as mentioned above is way more expensive.

I used a pressure bleeder kit to bleed the fluid and found it both easy and efficient to use, well worth buying and will hopefully serve me well for many changes to come :).



As an overall comment for all of these upgrades together, I can tell you that the brakes now feel sharper in initial bite, and the pedal is firmer when stepping on them hard. I look forward to giving them a proper go at the track.

As a closing note, my car is currently making a strange noise - which I have posted details about here. Hopefully It's nothing too serious and I can get it sorted soon :)
 
Christ Knott Insurance - Competitive quotes for forum members