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

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.

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.

 

I didnt see the damage on the cupra fr but i would have fixed that if it wasnt too serious ! Anyway, a nice project you have going on there ! Should be a hoot when finished ! Good job !

 

I'll upload a picture when I'm at a pc, but the damage was very minor and could have easily been repaired safely. However, the insurance assessor categorised the cupra as Cat B which means that although it can legally go back on the road, the DVLA will never issue a log book for it again. As I wasn't the owner when it was written off I can't get a log book for it. Shame as it was in mint condition pre accident and only has 34k miles on it.

Picture of the damage to the Cupra



Very minor damage to the edge of the sill where the hub snapped and pushed the tyre into it



Snapped rear hub (second hand replacement fitted for transport)



Some apparent damage to inner arch



and some slight damage to the rear of the inner arch



Crazy that this shell is essentially scrap, but as it was not my insurance claim, there is no way for me to appeal it and therefore I am left with no choice but to re-purpose the parts in one way or another.

 

Very nice, I've got a fr st in grey as the normal car, just lowered it and remap on the diesel, love it.
So is everything cupra going into the shell?
Are you fitting all the active dampers etc too?

 

Nice project.

 

This looks like its going to be a fun build, good luck getting it running.

 

That sounds like the perfect daily!

No I'm not fitting the DCC suspension simply because it's prone to leaking and then I'd have excess connectors/wires if I ever removed it and went aftermarket. I have swapped in the following:
- Engine
- DQ250 gearbox with VAQ differential
- front panel/rad/intercooler
- additional radiator
- washer bottle
- front subframe, steering rack, ARB, hubs and brakes

The rest is stock FR, and internally it should look like an FR other than Cupra instrument cluster.


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! Got to send the ECU's off next week for some work, I just want to get it started with the Cupra engine in beforehand if I speed up a little bit.

 

Nice update, getting there @Mjj4 .
Yeah the estate is a great car, nice size and decent room to carry stuff, yours is going to be fantastic with the upgrade.

 

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.

 

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!

 

Ticking it all off there @Mjj4 ,
Strangely was looking at exhaust today as got offered an early mk3 cupra system from a 3 door to go on my St, thinking it may just need extension bits in the rear bits to tailpipes, but a quick look underneath I'm not sure it would fit with the estate due to room between subframe and spare wheel well, needs further investigation, plus have to cut bumper as pre face lift isn't a separate valance either.
Was surprised how cheap alloy front subframe is, nearly got one when looking for hubs for my fr, might be a future swap, think there is a problem if fit the uprated dog bone mount with it due to clearance looking on audi forums, but not 100% on that.
There are different front wishbones, but aftermarket that alter geometry, whiteline possibly.

 

Yeah slowly getting there, I'm nervous I'll have some coding or module issues to get it running properly, and hoping I can avoid all component protection issues by sticking with all of the facelift modules bar the main ECU and possible ABS unit. At least it will look pretty cool if it doesn't run!

Unfortunately the hatchback exhausts don't fit the ST for the exact reason you mention. The stock Cupra ST system has a silencer each side of the spare wheel well compared with the single silencer on the hatch. I looked at so many pictures of the underside of ST's as I was originally planning on getting a standard exhaust and modifying it to look more OEM for an FR. I'm glad I didn't now because of the whole rear diffuser spacing from PFL to FL.

Well I've just ordered a billet dogbone mount insert from the well known performance company aliexpress for £9.77 posted, which seemed the cheapest way to see if there are any clearance issues. I also ordered an offset twin exit exhaust tail pipe thingy from the same website, it wasn't cheap and it may not fit, but it's a 63mm inlet, 89mm outlet which makes the total width 190mm and this is very very close to the stock overall width.





Fingers crossed it fits!

With the alloy subframe swap it really isn't that bad. I did mine on my own on a gravel drive in a couple of hours. I left the steering rack in and undid the 3 x 16mm for the ball joints, exhaust support bracket, 4 main bolts, 4x support bolts for the rear brackets and the dogbone mount x2. What hubs are you after? I'm not sure what the differences are to be honest! I thought my FR hubs and Cupra hubs looked exactly the same, not that I looked too closely.

 

Aliexpress is fantastic for some bits, and if doesn't work you've not spent too much.
Was after a set of alloy hubs which are standard on the fr, cupra, s3, golf r etc but got over that problem now, had 2 bolts shear when garage fitted the front shocks, long story.
Might do the subframe in time but at moment it's house stuff and recommission the mgf, house move planned so need to get it done.
Was a shame about the exhaust, might be a future purchase, where did you get yours?

 

Yeah that's exactly what I thought. I wasn't going to pay £40-50 for a potentially rebranded chinesium one to find out there's clearance issues. It's also fun to see what stuff is like when it comes from Aliexpress. Ah OK that doesn't sound good at all! I have a set here if you do need some, but sounds like you've got it sorted. The subframe is something I'd only do if you had any reason for taking the old one out, or you were working in the vicinity such as wishbone bushes.

Exhaust was from Demon Tweeks eBay outlet. It was £200 less than anywhere else because it was listed as New (other). But it arrived fully stapled and sealed with Scorpion tape so that was a result as I was expecting a customer return or similar. Also bagged £45 in nectar points on it because I bought it during the Valentines day 30x nectar points offer - it's the little things!

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!

 

Mmm. Brake envy.
Might need some spacers to clear them, possibly 10mm at most hopefully for you.
Macan 4 pots with the 345 mk6 discs is an option I'm considering, have found some 340mm s3 front discs and calipers locally but they are at that sort of pivotal price of " buy or hold on for 4 pots"

 

Well the brake test hasn't gone to plan! The issue with brake upgrades for me is the price of discs. These calipers were considerably cheaper than a set of OEM or 2 piece 370mm discs, which then makes it an expensive consumable in essence. The Macan 4 pot option was my original plan, but these were always the perfect caliper (if they'd fit!). You can buy brackets to fit these 4 pots to 340mm discs for £140 which then means the discs are actually affordable. This may be the route I have to go as the caliper actually rubs on the barrel.

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!

 

The 280mm calipers I put on my mk2 golf cleared when cold but after a bit of heat expansion from braking they rubbed the inside of the borbet spokes so used a 5mm spacer.
I've ground the outside of 4 pots I the past, metro 12" APs under 10" mini wheels, (plug and redrill mounts and lathe vented discs down) and had one start to weep on an mot test! Be careful.
Wheel cover looks good, let us know how it fits.

 

That sounds interesting with your old 4 pots!! I think grinding the calipers is off the cards for a few reasons including the risk of any failure/leaking. I will be putting my family in the car and need insurance to be proper too!

I may have an alternative solution in the 360mm region, but not 100% sure yet as some parts haven't arrived yet.

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!!

 

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!

 

Nice job there.