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The MK4 Golf/Bora Dash Conversion

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So after getting a bit peeved with the crap Corrado heater controls and the pants brittle crumbly plastic I've decided to try and do the MK4 dash conversion. I have a full donor car and I have:


The bulk head support bar

the dash

all the lower dash parts

the switches

center console

radio cage

all wiring

steering column

dash to tunnel support bars

mounting brackets from the MK4 A pillars.

MK4 airbox, cables, wiring, and air ducting channels.


I'll get some pics of all the bits later.


I'll be documenting everything as I go along. A lot of this will be trial and error mainly due to lack of info about this swap. I have seen it done but info is still very sparse. I have no intentions of keeping any secrets or hiding any info. I intend on doing the full conversion including having all dash buttons and switches fully functional.


The main thing about this swap is that due to the amount of modifications currently going on in my engine bay I won't be keeping the AC part of the system. This may involve chopping it out or swapping the box and controls for a non AC setup but I'll try and work with what I've got. I have a fair bit of experience with wiring so that should be 'do-able'.


I'll also be attempting to keep the OEM look by having genuine MK4 clocks. The main issue with this may be the rev scale on mk4 clocks. I'm confident I can make everything work properly but the average mk4 won't have enough rpm on the dial. I have a bit of help with this and I think we can recode something like non-can mk4 clocks and have everything running sweet. But we'll worry about that after we get the actual dash and everything into place first.


Another nice mod would be using a MK4 fuse box and relay plate but we'll keep that on the back burner until I can make the rest of the stuff work.


I'll apologise in advance for any slow progress but I will try and update as much as possible. I already have a handful of other projects and a business to look after so i'm kept on my toes all the time.


Any help, advice, support, or comments are always welcome.

More info coming soon.



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didnt you retrofit the Mk4 climatronic into your car?


I'm actually in the middle of a full rebuild of my car (bora) in which I'm retrofitting it. I've helped about a dozen or so people to do it to their cars but I'm only getting round to doing my own now so I'm dragging my heels and lagging behind badly. lol

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OK so it begins. Basically this is trial and error and I expect to have a lot of errors along the way. I'll tackle them one by one as I go.


Firstly, The parts from the donor car. Airbox with AC blank although I'll probably remove the AC parts completely.





Lower dash parts.



Steering Column












Center Console Radio Cage



Lower center console and gear surround



And onto the corrado dash and removal. 2 10mm nuts in the scuttle panel about a 3rd of the way across from each side, a 10mm nut on a bracket on the center console behind the shifter box, and a couple of screws on brackets that you'll find as you go. Basically, if there's a screw in it I took it out and with a bit of flexing and testing I soon found everything i needed to take it out. Lets face it, it's corrado dash plastics as well, chances are it'll crumble like biscuit and fall out with the slightest pressure.





Dash out


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And lets have a look in below.







Luckily I have a few extra mk4 parts so I might make some mistakes and hack some bits off I didn't want to but as this is purely just me winging it, I need a few spares.

Time for a test fit.... FITS LIKE A GLOVE!!!

Ok so it's a big ill fitting creepy peado style leather gimp glove but it still makes it between the A pillars.











Doors are a bit of a squeeze. As I'd like to keep the original dash shape I'll be modifying the doorcards as they're grey anyway and I might as well do something with them.




Corrado teering rack is a bit tight. Here's how it fits with the dash and how it's attached.





OK so the first real task is to have a look at fitting the center console. to get a few angles and fitments worked out to see how I can fit everything in.

Radio cage slows into the gear surround plastics.


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First small problem. Gear surround plastics don't fit very well dur to the height of the tunnel. Bye bye front ashtray brackets.






And in it goes for a test fit.


Radio cage also needed a bit of a trim to even get it fitted in. The screw left on the left side is for the glove box but I think i'll need to chop it off as well.



First main problem.

That Corrado tunnel is huge where the shifter box is fitted. The gearstick fits very far forward and very high. So basically although the gearbox and linkages aren't in, it's obvious to see that the throw is too long at the front and hits where the AC controls are. I've seen a couple of attempts at a MK4 dash in a corrado and to be honest, the attempts to solve this problem have been poor or non existent. I'll go and have a word with my engineer pal to see if we can make an offset shifter so the mechanism will stay where it is and the knob and half the bar on top will pretty much move about 2 - 3 inches back. I did say it was trial and error. :)






Cross member is a bit wide with the standard MK4 brackets.


Off they go:



Stay tuned for more as I'll be continuing some work today.

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OK back at it for another day yesterday and made some major progress.


First I did a quick test fit of the mk4 steering column on the original bracket. It doesn't even nearly fit but I wanted to see how it







Next thing was to get the steering rack and bracket out of there. I messed about with a cheap air cut off tool for quite a while and also


a dremel. After breaking several blades and making no progress it was time to speed things up and bring the grinder in. A few seconds


later and a couple of agricultural cuts the original steering column bracket was out of there. This will be tidied up and seal seamed and


painted etc at a later date.






Tool of the day Winner!!!



Then the original airbox had to be removed. I had considered keeping this but to be honest, I might as well do the full swap.

You'll probably find 1 of the screws will seize. I cut 2 slots in this one with a carbide bit on a drill and after that i could loosen it


enough to unscrew it.




Another quick test fit to suss out where I'd like it to sit with the doorcards.




There's a massive amount of space behind the mk4 dash with the airbox out of there.



Then onto fitting the MK4 bulkhead crossmember. The main reason I want to use this is so I don't need to make a load of custom brackets


and everything screws onto it including the steering column and dash itself.

I trimmed about 1/4" off the bar at the sides just to give a tiny bit of extra clearance while fitting.




I also trimmed a couple of gaps at the side where the mounting holes are for clearance as the corrado has an annoying metal bracket poking


out of the A pillar at each side. As I'll be making mounting brackets for this I wasn't too bothered about cutting the existing ones. I


made these a little deeper later on as shown.





There's a bracket on the right hand side which holds the MK4 relay plate. I had to trim a tab off this to stop it hitting my fuse box


during test fitting. It was irrelevant whether it stayed or not as nothing bolts to it. As far as I'm aware it held a wiring clip so no


need for it. As you can see i cut out a little more to clear the bonnet latch release for test fitting.




I also trimmed a bit out of the latch pull bracket. Just a little off the edge.


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After some test fitting it was clear that the relay plate bracket was going to be too wide and get in the way.



It's spot welded on so I decided the easiest way to deal with it was to drill it out with a spot weld bit. This way I can reuse it if I


want to put the mk4 plate in. I'll just make a new brack to fit slightly different. Luckily I have a full set of Dormer spot weld drill


bits sharpened professionally. Expensive as hell but I got a batch of blunt ones cheap on ebay and had them sharpened by a mate.






This is the bracket on top of the dash that holds the crossmember steady in the middle. It matches up well with the existing hole where


the corrado dash was screwed on. Only problem is that the angle is a bit wonky.



A little clip with the grinder blade and we can bend it into shape and trim a couple of mm from the top to clear.





After all the trimming I wanted to fit the cross member to the dash to see how well it fitting and to make sure everything still lined up


when the 2 were put in together.





Some trimming was needed to get the dash sides past the corrado A pillars and brackets. I wanted to make sure I got rid of anything that


wasn't structural or holding something onto the dash.

As you can see it's very tight.



Here's where the bottom of the side panel clips on the drivers side.


And where the side clips on the passengers side.



MK4 fuse box mounts.



And drivers side trimmed and sanded down whilst keeping the Fuse box mounts.



Passengers side with all the crap hacked out.


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Test fit time again.

Loads more space now at the passengers side.





Getting there.




The bracket at the tunnel is a bit wonky. I might have to bend this and redrill it to make it fit. I'd like to keep it for extra





Time for a test fit of the MK4 steering column.

As you can see I have it mounted right at the front of the mounting bracket and not on the proper places. We have a slight length issue.




You can see how little overlap there is.



This is going to take a little bit of reworking. The rack overall is a similar length but because the dash sits further out we need to


fid an extra 4-5 inches probably from somewhere. This will be easier to work out when the dash is in it's final mounting place.



This needs to be altered as well. The mk4 linkage hits the firewall so I need to make it a little longer. As you can see it fits straight


on as they have the same splines but doesn't come through into the cabin at the same angle due to the length.




Back of the column where it mounts to the pedal box doesn't fit either. I'll make brackets for this. I'll try and use the original


holes, bolts and bushes.




Here are the 2 airboxes side by side.




Big cable tie style thing around the MK4 box. Cut this off, it can be replaced later.



The airbox is split by unclipping the zinc coated clips vertically around the middle of the box and then unscrewing about 11 screws around


the horizontal middle of the airbox on the fan side. The screws might be a bit crusty. Use a good screwdriver. The AC core can just be


lifted out. If you want to save any hassle try and get a non AC mk4 airbox.




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This is the remains of what is left sticking out after removing the AC pipes and core. This has to go as it won't fit against the


firewall when the airbox is fitted.



Bits to cut off. The big round bit sticking out the back. The large mount above the fan. And the AC outlet part. Remember there is a


screw behind this. Take it out first. Shave back as much plastic as you can from where the AC pipes came out. You can take off the MK4


kick panel white clip, the wiring conduit on top, and the AC surround, basically bit you don't need. You can also remove all the bolts on


the back. Only 1 lines up, the rest get in the way. I'll explain it when I get round to making the new mounts.






You can remove the relay holder above the airbox as it won't be needed.




Test fit. lol



Whilst test fitting you'll find that the incredibly heavy, thick, old, smelly, soundproofing will get in the way and make life difficult.


As some stage I will change this for dynamat but for now I trimmed a couple of places to allow the box to sit closer to the firewall and


line up better. Couple of pics during the trimming. The bits cut out only remove the top layer of thick leathery stuff. That's all


that's needed.




You want the water pipes to line up exactly like this.


And the air intake should be pretty close if you've trimmed enough off where the AC pipes came out. If you haven't the box will rock on


that point against the soundproofing.


And it should fit in just lovely.



Full MK4 wiring loom. This will be fun splicing a lot of this in. I'll list up the switches, connectors and wiring pin numbers and


colours shortly.



Next jobs.

Work out the wiring for the switches and buttons.

Post up connector lists and wires for corrado.

Post up connector lists for MK4.

Get wiring diagram for MK4 airbox.

Make mounts on back of MK4 airbox for corrado firewall.

Possibly make mount for front of airbox to support weight.

Remove corrado doorcards and remove speaker pods and pockets.

Test fit door cards without speaker pods.

Mark out doorcards for reshaping.

Somehow extend steering rack to fit standard column mounts.

Make brackets to fit bottom of rack to pedal box.


And so on and so on. More to come soon hopefully.

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Spoke to the engineer tonight and got some stuff sorted.


Simple fix for the gearstick. Basically 4 inches or so cut off the top of the existing shifter and the center bored and threaded internally and a flat piece of metal bolted to the top of that which will extend about 2 - 2.5 inches back (undecided yet) and the piece we cut off bolted or welded to the end. The result will be a gearstick which feels and operates completely normally but just sits back a little.


Steering column - The bottom where it mounts to the rack will be extended by around 1.5". And just below the middle universal joint will be extended by about 4-5 inches. Both should be totally unobtrusive to the function of the column and rack and allow it to mount properly at the top. Mounting brackets will need to be made for where it mounts at the pedal box but the extra length will allow for more flexibility with this.


Wiring diagrams coming soon.

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MK4 Golf/Bora Wiring Lists.


Ok here is the MK4 dash wiring for the switches. Firstly I'll apologise at the confusion I'm about to cause. All wire weights/sizes are listed by number as they are on the vw software.

Also, all colours are listed as they are on the VW software and they're in german. Sorry about that but that's what I've got used to. If a wire has 2 colours they are usually divided as follows. Main colour first/stripe second.


Wire colours.

sw - black

ws - white

gr - grey

gn - green

bl - blue

ro - red

li - lilac

ge - yellow

br - brown


+ = additional connection

-> = connected in serial to the following.

nc = no connection

T12a/3 = T12a is the connector name and overall number of pins (12) and the second number is the pin number on that connection/wire.


Each wire is shown as follows:

Connector point or pin - wire size, wire colour - Connections



Ignition Switch - D

30 - 2.5, ro -> 6.0 ro -> Connection 30 on relay plate

30 - 2.5, ro -> 6.0 ro -> Connection 30 on relay plate

75 - 2.5, sw/ro -> S1/5 connection on relay plate -> X-contact relief relay 8/75 + Dual tone horn relay 4/75

50b - 2.5, ro/sw -> T6/3 (brown connector in plenum) -> B/50

50 - nc

15 - 2.5, sw -> Positive connection A2 in dash harness

P - 1.0, gr -> Parking light switch E19 - T12/4

86s - 1.0, br/ro -> 10A fuse 37 (S237)


Immobiliser reader coil - D2

1 - 0.35, gn - T32a/2 -> J362 immo controller

2 - 0.35, sw - T32a/17 -> J362 immo controller


Indicator switch E2, headlight dipper/flasher E4, Parking light switch E19 - T12

1 - 1.5, ro -> Ignition switch 30

2 - nc

3 - 1.0, sw/ws -> T32/18 left turn bulb in clocks + left turn bulbs M5 (front) and M6 (rear) + Hazard switch T8d/3

4 - 1.0, gr ->Ignition switch P

5 - 1.0, sw/ws/gn ->Hazard switch T8d/1

6 - nc

7 - 1.5, ge/ro -> light switch T17/4

8 - 1.5, ge/gn -> 56b in interior harness -> 15A Fuse 21 -> left headlight dip beam bulb M29

9 - 0.5, gr/br -> Light switch T17/13 + 57L in dash harness + 5A Fuse 23 -> T32/27 (parking light left)

10 - 0.5, gr/li -> Light switch T17/14 + 57R in dash harness + 5A Fuse 22 -> T32/26 (parking light right)

11 - 1.0, sw/gn -> T32/2 right turn bulb in clocks + Hazard switch T8d/2

12 - 1.5, ws/gn -> 56a in dash harness + (10A fuse -> left main beam bulb M30) + (10A fuse 18 -> T32/17 in dash main beam indicator bulb)


Light Switch - E1 - T17

1 - 2.5, sw/ro -> Connection 1(X) in dash harness + ignition switch 75

2 - 1.0, sw/ws -> 15a fuse 36 (S236) -> 1.5, sw/ro - ignition switch 75

3 - TFL

4 - 1.5, ge/ro -> left stalk T12/7 headlight dipper

5 - nc

6 - B

7 - 1.5, ge/gn -> 56b in dash harness + left stalk T12/8 headlight dipper

8 - nc

9 - 1.0, gr/ws -> connection RFL in dash harness + T32/14 + NSL T6a/6 (L46 rear left fog light bulb)

10 - 0.5, br -> Earth

11 - nc

12 - nc

13 - 0.5, gr/br -> left stalk T12/9 parking light left

14 - 0.5, gr/li -> left stalk T12/10 parking light right

15 - 1.5, ro - ignition switch 30

16 - 0.5, gr/ge - (5A Fuse 3 -> 58a dash harness) + (5A fuse 4 -> number plate lights)

17 - 0.5, gr/bl - illumination


Ciggy Lighter - U1

1 - 1.5, br -> Earth

2 - 1.5, ro/sw -> 15a Fuse S241

3 - 0.5, gr/bl -> illumination


Glove Box Light - W6

1 - 1.5, sw/br - 10A Fuse 1

2 - 0.5, br -> Earth


Heated rear window switch - E15 - T7

1 - 0.5, gr/bl -> illumination

2 - 0.5, br -> Earth

3 - nc

4 - nc

5 - 1.5, ws/ge -> 25A Fuse 26 (S226) -> 10.0, sw/ge -> 75X

6 - 2.5, ws -> Heated rear window positive side.

7 - nc

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Nice work. Glad someone can be bothered to write all this up. The number of times people have asked me and to sit and write it all out is a major effort so nice work.



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Corrado Wiring List NOT FINISHED YET


Headlight and dimmer switch

1. 0.5, gr/bl - illumination

2. 0.5, gr - Relay Board R/3 -> 10A Fuse 3

3. 0.5, br - Relay Board R/8 -> line 31

4. ge

5. nc

6. ws

7. 2.5, sw/ge - Relay Board R/10 -> Load Reduction Relay 4 1/88

8. 1.5, ro - Relay Board R/5 -> line 30

9. 0.5, gr/gn - Relay Board R/2, R/6, R/7. (R2 -> 10A fuse 8 -> K/3 -> left brake light)(R/6 -> 10A fuse 7 -> K/2 -> right brake light)(R/7 -> (10A fuse 3 -> R/3)+(relay 10 point 1))

10. gr/sw^

11. gr/ro^


Rear Window Heater Switch

1. sw/ge - Relay Board P/2 -> 20A fuse 3 -> Line X

2. ws/gn - Relay Board P/3 -> Relay Board K12 -> rear window heater

3. gr/bl - Relay Board P/7 -> illumination

4. br - Relay Board P/5 -> Relay Board Z2 -> Battery -

5. nc

6. nc


Fog Lights switches

1. 1.5, gr/ge - Relay Board P/4 -> 15A Fuse 10 -> fog light relay 3/87

2. 1.0, gr/ws - Relay Board P/6 -> illumination

3. 0.5, gr - Relay Board P/9 -> illumination

4. 0.5, br/ws - Relay Board P/8 -> line 31

5. nc

6. 1.5, ws/ge - Relay Board P/1 -> A2/8 -> (T2f/1 -> left fog light)+(T2g/2 -> right fog light)


Ciggy lighter

1. 1.5, br - Relay Board Q1 -> line 31

2. 1.5, ro/gr - Relay Board Q5 -> 15A fuse 21

3. 0.5, gr/bl - illumination


Ashtray Light

1. gr/bl - illumination

2. br - Earth


OBD Port

4. 0.5, br -> Earth

5. br

7. 0.5, gr/ro -> TV14 data link connector - T2a/2

14. ge/bl

15. 0.5, ge -> TV14 data link connector - T2a/1

16. 0.5, ro -> Q3 -> 10A fuse 22 -> line 30


IGN Switch

15. 1.5, sw -> Relay Board H1/4 -> line 15

50. 4.0, ro/sw -> Relay Board H1/1 -> line 50

R. nc

30. 4.0, ro -> Relay Board H1/2 -> line 30

P. gr

X. 2.5, sw/ge -> Relay Board H1/3 -> load reduction relay 1/88

S. 0.5, br/ro -> Radio T8/4


Steering column connectors x 5

Black - 5 large pin - T5b

1. 1.5, ws/ge -> Relay Board J/8 -> Hazard Relay 6 4/49

2. 1.5, ge -> Relay Board J/3 -> 10A fuse S1 + S2 -> (A1/1 -> left headlight)+(A2/3 -> right headlight)

3. 1.5, ws/sw -> Relay Board J/2 -> Relay Board R/9 -> light switch 2/56

4. 1.5, ws -> Relay Board J/1 -> (10A fuse 12 -> T19/4 -> Main beam right bulb) + (10A fuse 11 -> T19/6 -> main beam left bulb)

5. 1.5, ro/ge -> Relay Board J/4 -> line 30


Black - 5 small pin - T5c

1. 1.0, gn/ge -> Relay Board J/10 -> Relay Board S/5 -> Wiper Motor 2/53b

2. 1.0, sw/gr -> Relay Board J/7 -> Wash/Wipe Relay 8 3/15 +(Relay Board S/1 -> wiper motor 1/53a)+(15A fuse 5 -> line X)

3. 1.0, gn -> Relay Board J/10 -> Wash/Wipe Relay 4/53s (relay 8 )

4. 1.0, gn/sw -> Relay Board J/9 -> Relay Borad S/4 -> Wiper Motor 3/53e

5. 0.5, br/sw -> Relay Board J/6 -> Wash/Wipe Relay 8 2/J


Red 4 pin - T4d

1. 1.0, gn/ws -> Relay Board H1/9 -> (Rear wash/wipe relay 2 4/L)+(Relay Board C/7 -> washer pump pin 2)

2. 1.0, gn/ro -> Relay Board H1/8 -> (wash/wipe relay 8 6/T)+(Relay Board C/2 -> washer pump pin 1)

3. 1.5, br -> Relay Board H1/6 -> Line 31

4. sw/bl


Black 7 pin - T7

1. 1.0, br/bl -> Relay Board H2/1 -> Horn Relay 11 4/85

2. 1.0, sw/gn/ws -> Relay Board H2/8 -> Hazard Relay 6 2/49a

3. 1.0, sw/ws -> Relay Board H2/6 -> (Relay Board A1/2 -> left front turn signal)+(Relay Board K/1 -> left rear turn signal)

4. gr/sw -> parking light switch PL

5. gr -> parking light switch P

6. gr/ro -> parking light switch PR

7. 1.0, gn/sw -> Relay Board H2/4 -> (Relay Board A2/4 -> right front turn signal)+(Relay Board K/7 -> right rear turn signal)


Brown 4 pin - Indicator switch - T4a

1. 0.5, br/ws - Relay Board V/2 -> Earth

2. 0.5, ro/ws - Relay Board V/1 -> U2/4 -> clocks T28/15

3. 0.5, bl/ge - Relay Board V/3 -> U2/8 -> clocks T28/6

4. 0.5, ge/ro - Relay Board V/4 -> U2/14 -> clocks T28/4


Fresh Air blower Switch

1. 1.5, sw - Blower resistors T5/3

2. 1.5, ge/sw - Blower resistors T5/4

3. 1.5, ge - Blower resistors T5/5

4. 2.5, ws/ge - Blower resistors T5/2

5. (+) 1.0, sw/ge -> T1A -> Fan control module T8e/4 + 3rd Fan Speed Module pin 1



---------- Post added at 8:04 PM ---------- Previous post was at 8:03 PM ----------


Nice work. Glad someone can be bothered to write all this up. The number of times people have asked me and to sit and write it all out is a major effort so nice work.




No problem. It's always good to have everything written down and documented as it gives a good reference to go back to should anything need to be fixed or modified.

Edited by Bazmcc

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I won't be able to do any more work until Monday but I should have a decent update on monday evening. I plan to work on the airbox mounting a little more and also I'd like to see if I can get brackets sorted to hold the crossmember. I'm also waiting on a bentley wiring diagram for the corrado rather than use the crap diagrams I have at the minute.


If I get the rub of the green I might be able to get the engineer to sort the steering rack on monday or tuesday but time will tell.


But here's a wee bit of progress I made last night. Not much but it helps.

Door cards removed and speaker pods/pockets taken off. The speaker pods are the main reason for the door not closing. The bottom of the dash hits the corner of the pod but has plenty of clearance from the dash itself. These should be easy enough to modify and recover. I have spare 3dr MK4 doorcards and I'm giving serious consideration into trying to graft them in but I'll worry about that another time. They might be more hassle that they're worth.



Set of Bora vents for the dash.



And I'll also be going with brushed aluminium for the dash trim. Believe it or not that's a sticker. This the new 3M di-noc brushed aluminium vinyl. Same sort of stuff as the carbon effect vinyl. Very easy to work with and unless you pic and poke at it, you can't tell the difference in it and real metal. Granted the real R32/anniversary trim is lacquered but this is as close to the real thing as I've seen.



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Spoke to the engineer tonight and got some stuff sorted.


Simple fix for the gearstick. Basically 4 inches or so cut off the top of the existing shifter and the center bored and threaded internally and a flat piece of metal bolted to the top of that which will extend about 2 - 2.5 inches back (undecided yet) and the piece we cut off bolted or welded to the end. The result will be a gearstick which feels and operates completely normally but just sits back a little.


This is exactly what the Audi TT shifter is like. They moved a MK4 golf one back an inch or so for the TT by putting a plate at the bottom of the shaft which steps it back.



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Corrado dash wiring list on page 2 updated. My diagrams are very limited but I have most wires in there. There are 1 or 2 missing links but most stuff is there.

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So yesterday I made some more discoverys and made a bit more progress. It would appear it's not a massive amount but it took a lot of fiddling around.


The task was to get the wiring figured out for the corrado, which was done in the morning, and to fit the MK4 airbox.


First thing was to hold the airbox up in place and mark where the threaded holes needed to go for the double ended screwsto hold the airbox to the firewall. I simply got it into place and put a pencil through the hole as straight as I could and marked the box. It was right at the top edge of the box directly above the existing hole. Another option was to drill the firewall but as you can see the pipes between the ABS controller and servo were exactly where the hole would be and I didn't want the pipes rubbing a threaded stud or nut.




So I can use the existing threaded hole on the box if I cut it off and flip it upside down. Shown in the pics below.






Then I started thinking about using parts of the corrado box to make mounting easier. I took the heater matrix out to have a look at it.

This is the MK4 one out. Looks suspiciously similar to a MK2, 3, Corrado matrix....






Decision made. I'll use the corrado pipes. As you can see from the pics above there's a little more clearance at the top.



Box test fitted again and re-marked with where the bolt hole is.




This even got me thinking about the other similarities between the Corrado and MK4 parts.

Main central airbox. Looks like the fittings are all in the same places and are the same size ....



I even compemplated this to make things easier.




But that would have been backing out of the project. Not only that, I would loose the recirc flap function and the fan control may be different as the MK4 uses a much bigger fan.



IMPORTANT: There are 2 threaded studs on the firewall on the cabin side of the car just where the air intake is in the scuttle panel side. Cut both of these off. They'll just get in the way and stop the box fitting tight.


I also had to mark the place for the hole behind the ABS unit on the passengers side. I just marked it with a pencil and cut a notch so it didn't rub off.


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Back to making the mounts for the mk4 box. Luckily I happened to have another mk4 airbox here to butcher but if you don't you can just use the bottom threaded hole from the corrado box. I also cut a flat piece of plastic. I used 5mm ABS because it's very very strong and solid and I happen to have some laying about. This is basically to screw onto the airbox as a mount to hold the threaded hole. The reason I'm screwing a piece on it because the mount will be right on the seam of the airbox where it can be split and I don't want to permanently fix that together. The bottom pic is a quick mock up of where it'll go.





PLASTIC GLUE: I only use LORD Fusor 142. It's made in the states and it's a dedicated plastic glue and is pretty much the strongest plastic adhesive available. It's the only glue I'd trust for this sort of work but there may be others available. It's strong, cures quickly, can be drilled, sanded, cut about 30 minutes after working with it. However, it's extremely expensive compared to others and requires a dedicated fusor adhesive gun to pump it out of the tubes and mixing tips to make sure it's mixed properly.


Here it is all glued up. And also screwed into place on the box.




Quick test fit to make sure the hole is in the right place.



Then I moved onto sorting out that bottom mounting point. Although this bolt actually lined up it was three quarters of an inch too short to fit exactly where it should be.

I used the tube which was cut off the box earlier in the project. I wanted to push this onto the existing mount, and fill it with plastic adhesive and rethread it. Basically this can be made to be exactly the same size as the corrado bottom mount. That makes it fit perfect. See pics below. While I was gluing this I also fixed the top mount in place. I used plastering/drylining scrim cloth for extra reinforcement in the glue to help hold everything solid.










Another test fit and everything seems to line up nice.




With the box now fitting I wanted to see how well the floor/foot vents fitted to the box. The corrado lower vent adapter looks like it might just match up with the mk4 airbox.





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And also with the corrado top window vent adapter on top. The MK4 one doesn't even nearly fit as it's a completely different shape.



While I was waiting for the glue to dry earlier I got a couple more things out of the way.

This is where I trimmed the middle bracket that fits the main crossmember to the tunnel.





I also marked out where the dash met the doorcards. Speaker pod brackets had to be removed to allow the door to close enough. This will be worked on at a later date when everything else it fitted.





That's all for now. More coming soon.

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