MK3 Leon ST FR 400BHP Sleeper Project - Cupra Engine and DQ250 Swap

[mjj4]

Evening all.

I thought I would share my current project because it is already turning out to be slightly more complicated than I thought it was going to be, and that always makes a more interesting read!

Last year I purchased a 2016 Seat Leon Cupra 290 DSG off a friend that was a Cat B write off with minor damage to the offside rear. The plan was to use the engine in my Mk2 Golf that has been sat dormant in a garage for near on 10 years, but I'm renovating a house so knew that the Mk2 would be out of action for several more years yet. So rather than having this Leon sat around on the driveway, or the engine sat in the garage for years, I thought I would do a quick and easy project to essentially re-shell the car and have some use out of it.

The 290 Cupra

To make it easy I thought I would only search for a petrol and DSG Leon, which will also make the insurance and DVLA situation more simple, but I wanted to go for an estate for practicality which really narrowed down my options. I found this 2015 Leon 1.2 TSI DSG ST from Copart in Sandwich, which wasn't accident damaged and said it ran and drove. I thought this would make an epic sleeper so I won it and bravely took the 4 hour train journey prepped with a tow rope, tyre pump and boost pack. Out came the Leon on a forklift and I nervously got in and turned the key. To my surprise it started straight up and the engine was near silent. From the outside the car looked good with just 1 tyre slightly flat. I drove down the road waiting to find out why it had been put through Copart, but the gearbox went through all the gears and it drove in a straight line. It had only done 78k miles and had full stamped up service history in the glovebox, winner!

Now is where it gets a little more complicated. I can only imagine this happens to everyone, but as soon as I got home, another Leon was listed on Copart with the front end missing, but it was a 2018 FR, 1.8TSI DSG in purple which I thought looked amazing. It was a Cat N with only 47k miles and the whole front was missing, so I thought I could get a bargain and I have a spare front end from the Cupra so this wouldn't be an issue for my project at all. So you guessed it, I won the facelift Leon, and a few days later it was delivered via Shiply.

I thought that buying the 1.8TSI Leon would make the swap really easy as both the 1.8 and 2.0 engines use the same SIMOS 18.1 ECU, where the 1.2TSI doesn't (so would require a full loom swap). However, being a facelift non Cupra model, the wiring looms are fairly different; headlight loom, washer bottle loom/location, lack of DCC etc... and the huge headache (for me at least) of component protection. But I'll go into that when it's more relevant.

Unfortunately, Copart damaged the bonnet and bottom of the A pillar when moving it out of the yard, which isn't surprising, but there was an almost undamaged LED headlight in the boot which made up for it slightly. More on that later when I get to the bodywork stage.

 

[mjj4]

So I started this at the end of December 2022, the perfect time to do a project on the drive/half in the garage when its constantly cold, wet and dark. That has been the biggest hold up really, but hopefully we will get past this cold snap and I can get back on with it next week.

So I cleared the front half of my garage and began by taking the engine out of the Cupra.

I also picked up a 4" trackslag downpipe as it seemed an obvious time to change whilst putting the engine back in.

Then I started on the 2018 Leon ST, which didn't take long considering the whole front was missing.

I also swapped the subframes over as I wanted the Cupra front brakes, and wasn't sure if the steering rack and anti-roll bar were different. Turns out the anti roll bars are the same, so maybe I should have checked these first and saved myself a load of time and hassle by just swapping the brakes.

Cupra engine and 6 speed DQ250 installed

Front going on from the Cupra, but with the correct facelift headlights, one of which was in the boot and one was an ebay find.

Current priorities are:

- Re-pin the DQ200 connector to a new DQ250 connector
- Wire in the VAQ differential
- Sort out the ECU/VIN/Immobiliser/Component Protection issues

Basically get it running!

More soon.

 

[H Rafiq]

Looks very exciting! That 18-reg Leon ST donor car you’re using is my ideal car colour, purple. If only that was a Leon Cupra colour… Is your Leon Cupra engine cover spare? If so, I’ll have it please

 

[MoToJoJo]

Loving that purple colour, really cool

 

[mjj4]

Looks very exciting! That 18-reg Leon ST donor car you’re using is my ideal car colour, purple. If only that was a Leon Cupra colour… Is your Leon Cupra engine cover spare? If so, I’ll have it please

Thanks, yes it was the colour that did it for me. And although it's pretty pointless creating a cupra powered FR, at least it's a non cupra colour.

I haven't decided whether I'm going to run the cupra cover or not yet so I'll have to let you know on that one.

 

[mjj4]

Not a huge update, I have pretty much finished stripping the Cupra down and it should be going for scrap on Monday/Tuesday. Other than that I have been buying shiny bits for the ST as that's always fun and takes little effort. What takes more effort is taking the front end back off and cutting a fair bit of the rad support out to fit this beast.

Wagner intercooler

Front end coming back off

Sandwiched in between the air conditioning condenser and radiator.

Trimmed down radiator support frame

Also got a facelift front bumper delivered with correct FR spec grills (excuse the mess)

Lastly for today (there is more) I got this Scorpion non-res 3" Cupra ST exhaust system. I'm not 100% sure if I will end up using this, but I will try it and see as the price was good and I have a plan to keep the system looking OEM.

The front is back on now with the intercooler installed, but no pictures as it was dark by the time I put it back together. I must have had the rad surround on and off 10 times to get enough trimmed for it all to fit nicely.

Hardware wise it's definitely ready for 400bhp!

 

[mjj4]

So I still have a fair few bits to do, but thought I'd get on with some of the bulkier tasks before getting down to the fiddly stuff like wiring and washer hose changes that I'm not overly looking forward to.

I started off by taking the last of the bits from the Cupra shell, and getting that collected for scrap. My mate works for a local scrap/skip company so it seemed more sensible to use a skip lorry than to try and winch it onto a recovery truck.

The shell weighed 400kg, so I removed a ton of stuff from it. Such a shame as the shell wasn't really damaged, but I'm sure there will be a dynamic grey washing machine coming to Argos shortly!

First job was to sort the rear end, so I started by removing the rear springs and ARB.

Built up and installed with the VWR 25mm springs from the Cupra

I then fitted the Scorpion 3" system to the 4" Trackslag downpipe. I had to cut the stock exhaust off as it goes above the rear subframe and I wasn't prepared to drop the subframe.

Here is the one of the first problems I've come across with this engine swap. I purchased a 280/290 estate exhaust, which said something like 2015-2018 model year. I didn't consider that this estate is a facelift and there is no facelift Cupra estates that are FWD (unless the super rare manuals are? Either way no one seems to make an exhaust for a FWD facelift off the shelf). The tailpipes on a PFL Leon ST sit wider out than on a FL ST, which is a pain really as I couldn't use a 4drive system either. Either way I wasn't going to use the Scorpion tail pipes as I want this to look fairly stock, but will have to get a custom twin tail pipe made due to the offset I'm faced with.

Also makes it a bit more awkward for my plan on the right hand side exit as it sits wider than I was expecting.

Rear end pretty much done now, and back on the floor with 20mm spacers installed. It's not on level ground at all so not sure how it will actually look, but I'm happy with the way it's going.

On to the front end next.

 

[mjj4]

When I swapped the engine into the Leon I also swapped the subframe in as I wanted the brakes and steering rack and thought that would be easier than swapping the individual parts. I also thought the wishbones may have been different between FR and Cupra (turns out they aren't). So when I purchased the SuperPro ARB's which was not part of the plan but I got them for a cracking price brand new on eBay, I was upset that I'd have to drop the subframe down again. To make this worth it I thought I'd upgrade the subframe with an Audi aluminium subframe from an A3 8V.

£65 delivered from eBay, couldn't resist!

New vs the original FR steel subframe

Also notice how the dogbone mount has additional reinforcement on the aluminium subframe.

I gave it a quick clean with some Bilt Hamber alloy wheel cleaner and it was good enough to start building up. Installed the new SuperPro ARB and FR wishbones.

Also whilst the subframe was out I took the front shocks out and installed the VWR springs up front. I think my favourite thing is that the blue on the springs and ARB matches

All done and dusted for now. Pretty pleased with this and definitely feel it was worth the few hours on my back in the rain on gravel

Need to work out what's next and write a to-do list.

- Wire in DQ250
- Wire in VAQ differential
- Change ambient temperature sensor plug and extend wires
- Install Cupra clocks
- Install Cupra pedals
- Possibly change ABS pump for Cupra (if necessary)
- Bleed brakes
- Paint front calipers
- Buy longer front wheel bolts
- Finish exhaust
- Sort washer bottle wiring and plumbing (Cupra bottle is on the opposite side to the FR due to the Cupra's additional radiator).
- Install washer jets in bonnet
- Install front bumper
- Get front end painted

That will be a good start anyway!

 

[mjj4]

Not much of an update, my auto headlight switch from an Ibiza showed up yesterday, along with a 2.5" downturn tail pipe. As with most of my plans, this isn't going to be as straight forward as I dreamt, but the idea was to have a downturn tip on the right exit and only have to cut a tiny bit of the rear diffuser so it couldn't be seen easily. Because the exhaust is wider than I anticipated being for a PFL, the exhaust sticks out too far. I may be able to cut the downturn at a 45 degree angle and just cut a small section of diffuser but haven't looked at it properly yet. I put it on the left side and it *looks* like the Aliexpress tip may actually fit, so I'm excited for that to arrive.

On the left side for alignment checks

This project is definitely getting a little out of control. I'm glad that I'm set on the sleeper vibe, otherwise I'd be looking at seats, coilovers, splitters etc... This was supposed to be a real budget build and to use as much of the Cupra donor vehicle as possible to save costs. Either way, found these 370mm TTRS/RS3 calipers for a good price. My mate picked them up for me so I haven't got them here yet, but hopefully they'll fit under the stock wheels as that is something I really don't want to change as I think aftermarket wheels will immediately give the game away.

They need to be black obviously!

 

[mjj4]

As far as an update goes it's nothing big. I tried the caliper on over the stock Cupra 340mm disc to see if the wheel would fit. I tried it with both a 15mm and 20mm spacer and it unfortunately fouls on the barrel of the wheel.

Clears the face with 15mm spacer which was ideal

Touching the barrel unfortunately

You can see the 2 contact points from the caliper here

I then added a 20mm spacer and the wheel just spins, but you can see from the clean patch on the barrel where it's making contact

This may be fixable with a little grinding on the caliper, but 20mm spacer is too much on the front anyway I think, and I don't think I'd be happy with the end result. Hard to tell at the moment with it not movable with no front bumper.

So I may go down the 340mm bracket route, as the 340mm discs are almost new anyway. I was tempted to use the whole stock cupra brake setup on my girlfriends TT so that's the only downside if I decide to use these discs. The other option is 19s, but that's more expense and less sleeper!

I did order something else from AliExpress though, in the form of an alcantara steering wheel cover. I was going to go for grey stitch, but went red in the end. Not that I particularly like the red, but because the stock FR wheel has red stitching, along with the seats and gear gator.

Grey version

Red version

Lastly, ordered a tight pie cut 2.5" downturn. I'll get someone to tig this to the right hand exhaust outlet which should then hide behind the rear diffuser and means I wont have to chop up the diffuser.

Hopefully it'll run soon too as an added bonus!

 

[mjj4]

Not at a lot been going on and now we have about 2 weeks of rain forecast, but my first AliExpress order arrived with my exhaust tailpipe.

The pie cut 90 degree bend also turned up as well so I placed it on to see if it's going to work. Ignore the clamp it will be tig welded on and I'm going to cut ~2" off the Scorpion exhaust so I won't have to cut the rear diffuser at all.

Obviously it will sit much higher too, but I don't have the right hand exhaust to chassis hanger yet.

Looks like the exhaust woes are over though other than a mount to buy and a bit of tig welding. Not considering its a pre facelift cupra system on a facelift fr!

Hopefully ECU's will be back soon and I can get it started!!

 

[mjj4]

Very little update, the downturn tip and right hand exhaust section is off for tig welding, and the steering wheel cover turned up so fitted that in the last couple of evenings. Started doing both bottom sections, and then did the top section from the red stripe outwards either side so the stitching is symmetrical. I'm not super hot on the red stitching but it matches the FR spec interior and gear gator so all in all I'm very pleased with it. Especially for ~£18!

I had to add a washer behind each paddle shifter fixing to accommodate for the additional thickness of the wheel now. I also added the AliExpress billet paddle extensions which I think are pretty cool.

Sorry for the pic overload, got nothing else to post at the moment! Let me know your thoughts, good or bad!

 

[H Rafiq]

Very little update, the downturn tip and right hand exhaust section is off for tig welding, and the steering wheel cover turned up so fitted that in the last couple of evenings. Started doing both bottom sections, and then did the top section from the red stripe outwards either side so the stitching is symmetrical. I'm not super hot on the red stitching but it matches the FR spec interior and gear gator so all in all I'm very pleased with it. Especially for ~£18!

I had to add a washer behind each paddle shifter fixing to accommodate for the additional thickness of the wheel now. I also added the AliExpress billet paddle extensions which I think are pretty cool.

Sorry for the pic overload, got nothing else to post at the moment! Let me know your thoughts, good or bad!

It looks very good, and you’ve done a good job on it but, personally, not for me. Don’t like the feel, especially when hands get sweaty. Prefer a leather one myself.

 

[mjj4]

Not been up to much on the Leon the last couple of weeks as I'm fitting out both bathrooms at home. Mainly been messing around with different brake setups as I got hold of a load of Racingline brake stuff - 3 calipers, 2 fixed bells with no discs and 2 floating bells with 355mm discs. Turns out the Brembo 4 pot/TTRS setup does fit under the stock wheels with 15mm spacers, but I hadn't seen that someone had added spacers between the calipers and carriers - oops!

So currently setup with the 355mm floating Racingline discs with TTRS calipers to check out the fitment, and it looks almost perfect bolt on if Reyland can make me some 370mm discs to fit the Racingline bells.

Also got the exhaust back from being tig welded and that fits a treat, just need the Cupra ST exhaust bracket to fix it on properly.

Raclingline bits and pieces:

Older 6 pot monoblock caliper - 360mm on the newer 355mm disc

Latest 6 pot stage 3 355mm caliper but only have one unfortunately!

This was the setup I was going to go for, until 1 of the 4 bleed nipples snapped and I then snapped a torx bit in it! Haven't got that out yet.

This was when I realised there were additional spacers between the caliper and carrier on the TTRS setup, so chucked one on to check the offset with the disc and inner pad clearance which is perfect.

So going to try and get some 370mm discs made and go with this setup as I think it will be the most reliable caliper wise.

Right hand exhaust outlet sorted which I'm very happy with.

Hopefully ECU's and DQ250 de-immobiliser will be sorted next week, so I better pull my finger out this week if it stops raining!

 

[thatslowk1]

Some great progress here mate, looking forward to seeing the build come together.

 

[Hassan0113]

Hi pal, where have u reached with sorting out the dq250?

 

[who.am.i]

Nice job mate,subbed

 

[Bluepower]

Not been up to much on the Leon the last couple of weeks as I'm fitting out both bathrooms at home. Mainly been messing around with different brake setups as I got hold of a load of Racingline brake stuff - 3 calipers, 2 fixed bells with no discs and 2 floating bells with 355mm discs. Turns out the Brembo 4 pot/TTRS setup does fit under the stock wheels with 15mm spacers, but I hadn't seen that someone had added spacers between the calipers and carriers - oops!

So currently setup with the 355mm floating Racingline discs with TTRS calipers to check out the fitment, and it looks almost perfect bolt on if Reyland can make me some 370mm discs to fit the Racingline bells.

Also got the exhaust back from being tig welded and that fits a treat, just need the Cupra ST exhaust bracket to fix it on properly.

Raclingline bits and pieces:

Older 6 pot monoblock caliper - 360mm on the newer 355mm disc

Latest 6 pot stage 3 355mm caliper but only have one unfortunately!

This was the setup I was going to go for, until 1 of the 4 bleed nipples snapped and I then snapped a torx bit in it! Haven't got that out yet.

This was when I realised there were additional spacers between the caliper and carrier on the TTRS setup, so chucked one on to check the offset with the disc and inner pad clearance which is perfect.

So going to try and get some 370mm discs made and go with this setup as I think it will be the most reliable caliper wise.

Right hand exhaust outlet sorted which I'm very happy with.

Hopefully ECU's and DQ250 de-immobiliser will be sorted next week, so I better pull my finger out this week if it stops raining!

Bumping this thread, any new updates??

 

[mjj4]

Bumping this thread, any new updates??

Sorry for being so quiet!

Well unfortunately not much of an update car wise. There were some issues with both the ECU immobiliser and DQ250 immobiliser that were looked at in May, and unfortunately we haven't managed to have a second go at it yet. So at the moment the furthest I've achieved is having the car run on the original ECU, but not been able to move it with the gearbox immobilised. I'm waiting for these 2 issues to be sorted which will hopefully be soon as its been several months now.

Other than that, I purchased a brand new bonnet and bumper from Seat, but haven't had these painted yet as I wanted to get them done with the a pillar repair. The car is back together and complete other than the bumper missing all of the grills as it seemed a waste of time installing them when it needs painting, and its currently on the stock Cupra calipers as I haven't got the right discs yet - mainly due to lack of motivation as it doesn't run/move currently.

I will post a small update next week - life is a bit busy at the moment with a house renovation and 3 month old baby, but once I get the engine ECU back and gearbox immobiliser sorted I will put some hours back into the Leon.

Current list to do:

- Finalise front brake setup
- Refurbish front brake calipers in black
- Fit right hand exhaust heat shield
- Fit 370mm disc guards (bought from a TTRS part no and they don't fit!!)
- Fit Virtual Cockpit (purchased) and MIB2 unit with MOST port
- Get engine/gearbox immobiliser sorted
- Get CP removed for front assist sensor and virtual cockpit
- Try and code the car to remove any faults
- Send to body shop
- ENJOY (one day hopefully!)

 

[mjj4]

It's been a while, but progress has finally been made!

Last Sunday I loaded the Leon onto a truck and took it to have the gearbox de-immobilised.

Exhaust shot - just need to trim the end off from the downturned tip as it's visible from behind.

Things went well and after an hour of so the Leon moved under it's own power for the first time in a while!

The dashboard was lit up with a whole host of errors.
- Horn didn't work
- ESP fault
- Hill start assist
- Auto hold
- Parking sensors

After some VCDS coding I managed to get most of the faults sorted

This was all down to the VAQ being connected to the can-bus but not being coded in. Once that was coded in, everything else started working.

Almost a clear instrument cluster

Off to get MOT and tracking done so I can at least drive it whilst getting everything else sorted. I've only driven it in the damp on the Bridgestone S001 tyres that it came on, and it is lively to say the least!

So finally it's road legal and all working bar some minor niggles - there's a gearbox DTC that needs deleting, it needs a service and the front sensor CP needs removing, then it'll be error free and onto the nice to have things, like Cupra Drive Select, virtual cockpit etc...

It's booked in at Seat for CP removal on the front sensor, although they said they've never been asked to carry out a CP removal. I think the Cupra Drive Select may be an issue as I think it's something to do with the MIB software and not a coding option, but we will see.

Need to get it into a body shop ASAP too!