# Mk3 24v Swap?



## Ls1Mx5 (Jul 28, 2010)

What is needed for this? Will the stock 12v engine harness plug into the 24v? Can I use the 12v ecu? Can I use the stock 12v axles on the 6 speed trans? What about the mounts? I've searched but have found no answers to these specific questions. 

Thanks in advance guys, if this swap is not stupid hard I might keep my mk3 and build and 24v vr with really big cams.


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## Ls1Mx5 (Jul 28, 2010)

Bump this


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## GTIVRon (Jul 24, 2009)

I THINK you can use your trans. If thats the case then yea you can use the axles. Engine mounts are different. Not sure about how to go about that, look for a mounting kit? Your 12v harness and ecm will not work on the 24v valve iirc.


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## Ls1Mx5 (Jul 28, 2010)

GTIVRon said:


> I THINK you can use your trans. If thats the case then yea you can use the axles. Engine mounts are different. Not sure about how to go about that, look for a mounting kit? Your 12v harness and ecm will not work on the 24v valve iirc.


 Thanks, I want the six speed trans because I don't like the long gearing of the five speed. Would the axles from the mk4 fit into the mk3 hubs? Will the 24v engine harness plug right into my 12v chassis harness? How about the ecm, will that plug into the stock ports? Thanks


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## GTIVRon (Jul 24, 2009)

Hmm tough call, I haven't ventured that far into it myself... As for connecting to the chassis harness I'm sure adapters exist, if not, pin it out. And as far as axles, I believe you will need the MK4 hubs. 

To be honest though, your best bet would be to ask in the hybrid/swap forum.


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## PhReE (Sep 16, 2004)

Ls1Mx5 said:


> What is needed for this? Will the stock 12v engine harness plug into the 24v?


 No. 



Ls1Mx5 said:


> Can I use the 12v ecu?


 Yes, but you will need to modify a lot of stuff. Crank trigger and cam trigger stuff is different. Best to use a 24v ecu. 



Ls1Mx5 said:


> Can I use the stock 12v axles on the 6 speed trans?


 No. Axels must match the trans 



Ls1Mx5 said:


> What about the mounts?


 The 24v block has the old style mount holes on it so it can mount like a 12v in a mk3. The thing here is the trans mount, if you use a mk4 trans then you will need to do some custom crap to mount it in a mk3. However if you use a mk3 vr6 trans, and a 24v block then it will "bolt in" to a mk3. Any vr6 will mount to any vr6 trans. 

There have been O2M's mounted into Mk3's before, look around for that. The O2M is far beefier than the 5-speeds so if you want to make a lot of power and have it last thats the trans to use. However if you are going to go S/C or N/A then the 5-speeds are beefy enough and a lot easier to make work in a mk3.


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## Ls1Mx5 (Jul 28, 2010)

PhReE said:


> No.
> 
> 
> Yes, but you will need to modify a lot of stuff. Crank trigger and cam trigger stuff is different. Best to use a 24v ecu.
> ...


 I want a 6-speed for the closer ratio gears. Will the 6-speed axles fit into my stock hubs? I have no problem fabricating a mount, I however hate custom wiring. How difficult is the wiring aspect of the swap? Btw thanks for the info so far guys:thumbup:


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## mattinbend (Oct 12, 2000)

wiring is too hard if you hate wiring. wiring is pretty easy if you can read schematics and take the time to learn them. 

6 spd axles will not fit mk3 spindles. make custom axles.


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## VR6-GT42RS (Jun 4, 2008)

6speed axles will fit into stock vr6 hubs(splines on the outer cv is the same).. only the lenght in right side is differnt.


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## PhReE (Sep 16, 2004)

If you don't want to mess with wiring then just swap in the whole 24v ECU, cluster and engine harness. If you don't want the cluster, then it gets more complex.


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## TREKSportMK3 (Feb 1, 2009)

actually you can use the 12v ecu from model years 97 or 98 to 99.5, can't remember exactly, but it has to do with the with the cams, i've been researching this to as a possible swap and honestly it's a lot to swap but if you can get a good mk3 12v late parts car you'd be in awesome shape and if you wanted it to perform better than the 200hp 200tq u could prolly talk to c2 they might be able to make a custom chip, but anyways just wanted to say that certain late mk3 vr6 ecus will work with the 24v motor... yup


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## need_a_VR6 (May 19, 1999)

The later 12v (single chain) use the same cam trigger wheel and sensor, the change is in mid year 96 production, most are MY97+ but it's possible to have a late build 96 with it. Anyway, even if you use that, you lose VVT on both cams, as well as the intake changeover without additional hardware.


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## sdezego (Apr 23, 2004)

VR6-GT42RS said:


> 6speed axles will fit into stock vr6 hubs(splines on the outer cv is the same).. only the lenght in right side is differnt.


The D/S is close, but it should be shortened as well. 

To the OP: Of course if money is no object, DSS makes the custom axles


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## TREKSportMK3 (Feb 1, 2009)

need_a_vr6, youre pms are full... didnt know that was possible, but pm me when you get em clear lol


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## need_a_VR6 (May 19, 1999)

They're full constantly it can only hold 100 and I think I got half that from you yesterday alone


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## TREKSportMK3 (Feb 1, 2009)

need_a_VR6 said:


> They're full constantly it can only hold 100 and I think I got half that from you yesterday alone


awww jeez, make me feel bad  can't help it i full of questions and ideas


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## gtizzle67 (Mar 10, 2008)

you can use the stock 12v ecu, just use a giac 268chip with it, and use the o2a trans, it will bolt right up, if u want shorter gears use a differentrint and pinion ie:3.67 or 3.94


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## need_a_VR6 (May 19, 1999)

Looks easy..


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## PhReE (Sep 16, 2004)

Hell yeah, I want one in a mk2, fast as **** without even modding the motor. :laugh:


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## nothing-leaves-stock (Mar 1, 2005)

wow, lots of false info here...
pauls right in whats he's posted.

-mk3 VR6 hubs are 100mm. )2m mk4 and vr6 mk4 are 108mm
-no you can't use a 12v harness and ecu. vct will be lost, most sensors are not the same
-axle on d/s is a differnt lenght. DSS makes them
-mounts are differnt for the motor and trans
-you will have to have the ecu immo defeated to run. unless you do dash, key, cluster switch etc etc etc
-it takes skill to wire this up right..its not a obd1 aba swap.


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## nothing-leaves-stock (Mar 1, 2005)

oh and i have a full R32 motor, bolted to a built 02m and a c2 turbo kit at the shop if anyones interested...complete with everything


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## need_a_VR6 (May 19, 1999)

nothing-leaves-stock said:


> wow, lots of false info here...
> pauls right in whats he's posted.
> 
> -mk3 VR6 hubs are 100mm. )2m mk4 and vr6 mk4 are 108mm
> ...


To answer how I got around these, in order:

-I used an 02A
-I still used the obd1 VR6 harness and spliced in plugs for VVT, cam, injector plugs from the 24v, made an adapter for a Mustang TB and ran standalone. You COULD run a late OBD2 12v with that throttle body IF you care to lose VVT
-no axle changes if you use the 02A
-used stock 02A mounts, just need some shims between mount and bolt of front motor mount
-don't use the MK4 harness/ecu 
-if you do use the Mk4 stuff, good luck, I do a LOT of wiring and I wouldn't want to do it.

PS: if you use an 02A it's easier.. I run a 4.24 in my trans and a .755 5th it's like a 6sp but without 5th gear


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## Mk3vr97 (May 7, 2010)

need_a_VR6 said:


> To answer how I got around these, in order:
> 
> -I used an 02A
> -I still used the obd1 VR6 harness and spliced in plugs for VVT, cam, injector plugs from the 24v, made an adapter for a Mustang TB and ran standalone. You COULD run a late OBD2 12v with that throttle body IF you care to lose VVT
> ...


cant wait to do mine. damn can u do my swap lol


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## nothing-leaves-stock (Mar 1, 2005)

yes yes paul YOU can do that... "others" can't... they don't have the knowledge to figure out what can be swapped out, wiring and cam timing bs like you can! haha

i was responding to the op wants.
o2a is easy bolt in..o2m isn't.


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## need_a_VR6 (May 19, 1999)

nothing-leaves-stock said:


> yes yes paul YOU can do that... "others" can't... they don't have the knowledge to figure out what can be swapped out, wiring and cam timing bs like you can! haha


I can be bought


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## 2mAn (Oct 15, 2006)

getting some conflicting info here and im hoping the pros will clarify it. 

ignoring the transmission mounting issue, just focusing on the motor here, my understanding is that the rear mount is the same, but the front is slightly different and needs to be shimmed? am i right or wrong?


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## need_a_VR6 (May 19, 1999)

Correct, the rear mount bolts right on and the 02A front mount just needs a stack of washers (or similar) on the upper bolt hole:


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## VR6-GT42RS (Jun 4, 2008)

i did this swap with 02m.. 

97 obd 2 ecu 
custom trans mount 
modified front vr6 mount 
stock 02m axle DRIVERSSIDE 
shortnet stock 02m axle at right side 
when its done with the the obd2 ecu,the variabel intake cam,and the variabel intakemanifold lenght will not work..(on a 2001 vr6 24v) from 2002 both variabel cams will be lost. 

the only thing that will be a little lower is the power in the lower rpm..from mid range to top end power will be the same.. 

i will have my ecu custom chiptuned..then it will run great.


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## nothing-leaves-stock (Mar 1, 2005)

i have a full 02m swap with peliquin diff, spec clutch and flywheel and axles for sale


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## thomas514 (Jan 12, 2010)

heres a couple links i used durring the swap:

http://mk2vr6.com/board/viewtopic.ph...=8092&start=24
http://www.vask.org.nz/index.php?topic=5877.120
http://www.vwwatercooled.org.au/f47/...vr6-25960.html
http://www.vwwatercooled.org.au/f47/...6-25960-4.html
http://forums.vwvortex.com/showthread.php?2179594
http://www.montrealracing.com/forums...d.php?t=727238


02m tranny> 
http://forums.vwvortex.com/showthrea...Pictures-Fixed)
http://forums.mwerks.com/showthread....ated-8-May2003)
http://forums.vwvortex.com/showthread.php?3932040
i took vr6 12v axles, shortened them, as for the hub i kept 4 bolt: 
took 12v hubs, brought them to a machine shop and they drilled/tapped 4 bolt in to the 12v hubs: 
http://forums.tdiclub.com/showthread.php?t=261101 
http://forums.vwvortex.com/showthread.php?4799721
to mesure the axles: http://www.driveshaftspecialist.com/...asureList.html
more on axles: http://forums.vwvortex.com/showthrea...&highlight=02M
http://forums.vwvortex.com/showthread.php?3610564

fuse id http://forums.vwvortex.com/showthread.php?1797836

mkiv dash http://forums.vwvortex.com/showthread.php?4265758

02m internals http://www.zelek.com/vw02M_hard_parts1.htm

u can use the 2.0 maf much cheaper 
http://forums.vwvortex.com/showthread.php?773176

o2 sensors http://forums.vwvortex.com/showthrea...oxygen-sensors

trany removal (note this is 5speed, but the process if very similar) 
http://forums.vwvortex.com/showthread.php?2703042
http://forums.vwvortex.com/showthread.php?4045505

slave cyl.> 
http://forums.vwvortex.com/showthread.php?2970528/page1
http://forums.vwvortex.com/showthread.php?4376420
http://forums.vwvortex.com/showthread.php?4321537

Starter Grind Fix and Replacement 
http://forums.vwvortex.com/showthread.php?2269482

i took all mkiv wiring harness' all your gona have to splice is stuff like the tail lights, head lights, wiper motor, fuel pump, 

the cluster, ignition, and ecu wer from 3 different cars so i had to get Unitronic to do an immo delete, costed me 650$

common coolant fan BS 
http://forums.vwvortex.com/showthread.php?3126433
http://forums.vwvortex.com/showthread.php?3386797
http://forums.vwvortex.com/showthread.php?3844295
http://forums.vwvortex.com/showthread.php?3890491
http://forums.vwvortex.com/showthread.php?3126433

-there was JUST not enough room for the rad/coolant fans, you can shave down the "big" coolant fan with a wood file, about 8mm was enough. another way i could see working is taking the "cross member" where the hood latches into, and moving it forward a knotch... so pretty much where on either side there's three 10mm screws, you could move the intire thing forward, (so in the end youd only be using 2 screw on each side). then u re-adjust the hood.

-also the fuel lines on mk4 are quick connect, i just cut the quick connect tip off.. 
-same goes for the two hoses leading in and out of the heater core
-the stock air box didnt have room either, i was too lazy to relocate the battery so i just put a p-flow
-audi tt control arm bushings

heres a good site; you have to open with google chrome to translate into english 
http://volkswagen.msk.ru/index.php?p=vw_golf4_1j

coolant temp. sensor/ thermostat.... 
http://www.nime.co.uk/content.php?mk4fans
http://forums.vwvortex.com/showthrea...940-Fan-sensor
http://forums.vwvortex.com/showthrea...t)-housing-DIY
http://forums.motivemag.com/showthread.php?2385488



i got some more links, feel free to ask


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## Mk3vr97 (May 7, 2010)

thomas514 said:


> heres a couple links i used durring the swap:
> 
> http://www.montrealracing.com/forums/showthread.php?t=727238
> http://mk2vr6.com/board/viewtopic.php?f=21&t=8092&start=24
> ...


Some good stuff:thumbup:


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## thomas514 (Jan 12, 2010)

Mk3vr97 said:


> Some good stuff:thumbup:


*some of the links above dont work*, 
i fixed them in this thread: http://forums.vwvortex.com/showthread.php?5078746-mk3-vr6-24v-6-speed-02m-gearbox-swap-(LINKS)


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## vortexpert. (Sep 27, 2009)

:thumbup:


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