If there is a VW engine available out there, you can bet someone has installed it in an A1 chassis car.  From the relatively simple 16v Scirocco engine swap to adding Mk4 1.8T engines and even VR6 plants, there are people out there willing to go through the time and expense of upgrading the power in their vehicle through the installation of later-date technology.

Listed below are some of the more common swaps in order of difficulty.  Although not intended to be a comprehensive "how to," this should give you a good idea of what is needed before you decide which route to take.  The swaps are listed in ascending order of difficulty.

Note that for any of these swaps, wiring is often the most difficult part of the task.  Be patient, go slow, and have wiring diagrams for both your recipient and donor vehicles available.  If doing it yourself is too much, you can contact Fast Forward Automotive, and they can create a wiring harness for you that will greatly simplify the job.

Upgrade to 2.0 Liters Using Your Existing Components

There are two types of 2.0 liter blocks that are easily adaptable to your existing head and anciliary components.  One is the Audi 3A "bubble" block that was installed in Audi 80 from 1988 to 1990.  The other is the VW ABA "tall" block fitted to many A3 Golfs, Jettas, and Cabriolets.  Both engines produced about 115hp in stock form, with the 3A making slightly less torque - 135 ft-lbs for the ABA, 122 for the 3A.

The ABA has longer rods and the same piston size as a 1.8L and the block is taller by about 16mm. The 3A "bubble Block" uses larger pistons, the overall engine height is the same as the 1.8L.  The ABA and 3A BOTH have the 82.5mm bore and 92.8mm stroke giving a displacement of 1984cc.  Both engines have a compression ratio of approximately 10.0:1, which necessitates the use of high-octane gas or the installation of a knock-sensing ignition to control detonation.

Since the ABA block is taller, you will need a custom downpipe to account for the added height of the exhaust manifold.  There may also be some clearance issues with items contacting the hood of the vehicle, for instance the cam belt cover will likely need to be removed.  When selecting an ABA block, look for one that was manufactured before 1996.  These blocks have forged internal components (as opposed to cast) and have piston oil squirters.

To perform this swap, note the following:

Adding a 16v Engine

People have been adding 16v engines to Rabbits since they became available back in 1986.  The easiest engine to use is one that is sourced from a 16v Scirocco, as it has many of the parts (such as the motor mounts and exhaust manifold) that you'll need for the conversion.  It is also configured for a driver's side fuel distributor location as opposed to the passenger side configuration found on A2 vehicles.

Before you start the swap, it is very important to have the manual for the donor and recipient vehicles.  This is the only way to cross-reference the parts and wiring necessary to complete the project.


What you do with the wiring is dependent on what you're starting with.  If you have an earlier car - i.e. a non-Westmoreland car, it will probably be best to swap out the entire harness with one from the donor car. If you have a post-1980 car without any electrical problems, you can get buy with just swapping out the engine harness as these cars have a better fuse box and wiring.  You can still swap the entire harness out if you so desire, but it will add complexity to the project.  If you swap out the entire wiring you can do interesting things like add a scirocco 16v gauge cluster to your dash (although to do so with a Westmoreland Rabbit would necessitate using a Mk2 or Cabriolet dash).


You can use CIS-lambda with a 16v engine.  You will, however, need to use knock-sensing ignition with this motor. Your idle will also benefit from adding the idle position switch on the throttle body.  The warm-up regulator can be bolted to the driver's side of the head as there are two unused bolt holes that are used for the warm-up regulator on European CIS 16v cars.   The the coolant temp, thermo time switch, and idle speed valve , and other senders from your existing motor should be swapped over to the 16v motor.

You can also upgrade to CIS-E or CIS-Motronic.  All Scirocco 16Vs came with CIS-E.  2.0 liter 16v engines came with CIS-Motronic.  Both systems are pretty much self-contained, and are relatively easy to wire.  Both only require switched 12v power to operate.  A good link for details can be found here.  For CIS-E, coming from your ECU you will have three plugs. Two of them have three wires and one  has two wires.  Look for the solid black wire. That wire needs a switched 12V from your ignition.   The other two plugs are for your AC idle and the oxygen sensor heater.

To make things easier, you should use the exisitng wiring for your various temperature and pressure senders.  Just swap senders from your original engine into the 16v and you will be fine.


If your engine came from a 16v Scirocco, the mounts on the engine will work for the swap.  If your engine came from any other car, such as an A2 GTI, then you will need to remove your old mounts and install them on the new engine.  They will bolt up directly with no modification.  Now would be an excellent time to change out the inserts.


Your stock transmission can be used with no issues.  If you can source a Scirocco 16V transmission you can use the Scirocco drive axles with the 100mm CV joints.  Many people have used the older 020 transmissions with 90mm flanges with no problems.  If you use the 16v transmission, you must use the 16v clutch and pressure plate as well, as the input shaft is larger.


You can use your existing driveshafts or the driveshafts from a 16v Scirocco.  The Scirocco units have 100mm CV joints, so if you have the 90mm flanges, you'll have to swap them out with the 100mm ones.  100mm CV joints are recommended.


You will need a Scirocco 16v exhaust manifold and downpipe.  You can also source a custom downpipe from Techtonics and use a Mk2 exhaust manifold, but this is a pricy option.  Your existing performance exhaust from the cat back will work fine.  If you have the stock Rabbit exhaust, you need to upgrade to a 2.25" cat-back system, which can also be sourced from Techtonics.


Your existing radiator should work if you are not using a/c.  With A/C, using a scirocco 16v radiator and a low temperature fan switch should be used.  


Your existing fuel pump will work fine.  You do not need to swap in a 16v fuel pump or worry about rigging up a tank transfer pump.  If your donor car is not a Scirocco, this means moving the fuel distributor over to the passenger side of the car.  To do so, you must fabricate an appropriate bracket and move the fuel lines from the driver's side to the passenger side.  Many people simply cut the metal fuel lines of at the firewall, use a flaring tool and attach high-pressure flexible fuel lines.  You will also have to cut/otherwise modify the air filter housing, as it will be too tall for the hood to close.  None of these are trivial issues, but not significant enough to cause major problems.

2.0 Liter ABA Engine Swap With Motronic

This is a medium-difficulty swap and involves a considerable amount of wiring to make the fuel injection system work properly.  This is where we start talking about things like OBD-I and OBD-II.

First, a note about OBD-I and OBD-II.  A Mk3 donor car manufactured before 1996 will have OBD-I.  This system is less complex than OBD-II, and is therefore easier to install in a Mk1 vehicle due to the reduction in necessary wiring.  This is not to say that an OBD-II swap is not possible, it is just more complicated.  In addition, the OBD-I ABA block has forged connecting rods, a forged crank, and oil squirters, while the OBD-II ABA has forged components and no oil squirters.  This makes the OBD-I engine a good choice.

Note that the 2.0 liter engine from the MkIV chassis is not a good swap candidate as the block is not configured for A1 compatible motor mounts.

As usual the first thing to do is buy the Bentley for the Mk3 donor car so you'll have access to the wiring diagrams.


Since the ABA can be used as a short block upgrade to your existing engine, the mechanical part of the swap is obviously the easiest.  All the items that apply to the short block swap apply to swapping the entire engine.  Your existing motor mounts bolt directly on, and the engine is taller so you'll need to use a dual-outlet manifold with the longer techtonics downpipe.  The only hood clearance issues are with the throttle spring return damper on the throttle body, and if this is removed this issue is resolved.


An 8v 020 transmission will bolt right up the the ABA if an 8v 020 clutch and flywheel are used.  This means your existing axles will work as well.  


There are two directions you can take when integrating the wiring from your Mk3 donor car into your Mk1.  You can splice the engine harness into your existing wiring, or you can elect to swap out the entire harness from the Mk3.  Having some experience with attempting to swap entire harnesses out, I would recommend just splicing what you need, but if you want to get complicated and install a Mk3 dash and other electronics into your car then swapping the entire harness could be the way to go.  For our purposes here, I will cover the splicing method.

The following links provide some good information in addition to what is available in the Bentley manual.

http://mysite.verizon.net/e.sese/x-flow_swap.html - An OBD-II swap into a Mk2 with some good info on how to deal with the VSS sender issue.  Also has good information on how to integrate air conditioning into the swap process.

http://scirocco.psycode.com/aba/ - A good source of information required to integrage the A3 Motronic wiring into your existing wiring harness.

http://www.selenengineering.com/ - Good all-around information regarding the 2.0 liter swap, including swapping your wiring out to Central Electric 2 (CE2).

This is a partial list of the OBD-1 connections needed to do this swap:




Black 12 Coil output stage - 12v switched power
Yellow/Blue 20 ECM T68/6 - Ground for Fuel Pump Relay(85)
Red/Yellow 14 ECM T68/54  - Needs 12v power
Blue/White 20 ECM T68/65 - Speed Input from Instruments
Yellow 20 20 ECM T68/21 - Transmit to data link connector
Grey/White 20 ECM T68/43 - Recieve from data link connector
White/Yellow 20 ECM T68/28 - Ground terminal for O2 Relay(86)
Red/Blue 20 Splice - to O2 Relay(85)
Red/White 16 O2 Sensor - O2 Relay(87)
Red/Yellow 16 Fuel Pump Relay 87 - O2 Relay(30)
Red/Blue 12 ECM Power Supply Relay(87)
Black/Brown 20 ECM T68/9 - ECM " "(85 as marked on relay)
Blue/White 20 Coolant Sensor - Temperature Gauge
Yellow 20 Oil Pressure F1 - Oil Pressure Warning Buzzer
Blue/Black 20 Oil Pressure F22 - Oil Pressure Warning Light
Brown/White 16 Engine Block GND
Yellow/Black 20 ECM T68/5 - Check Engine Light
White/Blue 20 VSS #2(signal) - to speedometer (if  A3 cluster installed)
Green/Black 20 ECM T68/22 - Tach output from ECM, to gauges.


This may be the most annoying part of this swap.  The Mk3 2.0 uses an 020 style gearbox but instead of having a mechanical speedometer cable it has an electronic sensor called a Vehicle Speed Sensor or VSS for short. The VSS sends a signal to the cluster which is then converted into a signal that continues onto the ECU.  If the ECU sees you accellerating in 4th or 5th gears and sees nothing coming in from the VSS, it cuts the the engine off.  The main issue is to get around this speed limiter/engine cut in fourth and fifth gear if the ECU is not provided with a proper speed signal.

One solution is to use the Mk3 cluster with a VSS sensor swapped in place of the mechanical speedo cable on the tranny. This completes the circut and gives the ECU the necessary signal. This is the route to take if you are swapping in the A3 dash and the entire wiring harness.

If you are pursuing the splicing method, you can use a mechanical speedometer cable driven cluster from a Mk1 or Mk2 that had cruise control or an MFA computer. You must splice a wire into the hall effect sender and run that to the ECU speed input from the cluster.  Another issue is getting a tach signal to the cluster - you can run a wire directly from the negative pole from the Mk3 coil to the tach input wire on the cluster. There is a small plastic cover on the coil which when removed allows you to attach a spade connector to the pole.  More information on this method of solving the VSS issue can be found here and here


The stock CIS fuel pump will provide plenty of fuel for this motor, so there is no need to swap. The stock routing of fuel lines on an an A1 is up into the engine bay from the passenger side then across the firewall to the drivers side where they exit by the CIS fuel distributor. The ABA fuel rail has it's inlets on the passengers side. The issue is then how to route the fuel lines back across the engine bay to the fuel rail. The easiest path is to cut the hard fuel lines about three feet from their ends, at the point about 8" after they bend behind the steering rack. The ends can then flared with a flaring tool and 3/8" fuel injection hose with fuel injection clamps can be used to extend the lines to the fuel rail.  IT IS VERY IMPORTANT THAT YOU USE FUEL INJECTION HOSE AND FUEL INJECTION CLAMPS. Don't use fuel line that's designed for carbs as it is not designed to handle the pressures invloved with fuel injected engines.

For a fuel filter, use the one from the Mk3.  It has barbed ends which allow the filter to be easily placed anywhere in the engine compartment, as long as it is in-line before the fuel rail.


Your existing radiator should provide adequate cooling, but it may be wise to upgrade to a Scirocco 16v radiator just for the extra safety margin.  To hook everything up, you will need a combination of  Mk1 and Mk3 coolant hoses.  As will all VWs, there are various radiators you can use which will change which hoses you will need. In addition, there are several different ABA lower coolant outlets for the water pump which may affect which hoses you use.  Get all the hoses from the donor vehicle to ease integration.  The main hose you will need is the upper Mk3 coolant hose. This hose has connections for the waterpump, the oil cooler, the top outlet of the radiator, and the side of the cylinder head. Try and get this entire hose from your motor swap source as it's not cheap.  The heater core lines uses the Mk3 hard line that runs around the base of the block to the heater core lines at the firewall.  Standard 5/8" hose can be used for the return line from the expansion tank.


This A great source for this swap is at http://www.funksoulkitty.org, especially the pictures of the various items that must be fabricated for this swap, such as mounting the hyrdaulic clutch mechanism.  The write-up below contains elements of her posts on VW Vortex.

Another good starting point is here.


There are several varieties of 1.8T engines.  The earlier version is engine code AEB and has an external water pump and was designed for longitudinal applications.  The later versions, such as engine code AWP, have an internal water pump and were designed to be transversely mounted.  The earlier AEB engine is the easiest to add to an A1 platform car.


There are several options for gearboxes into the A1. You can stick with your stock 020 or upgrade to the 02A or 02J.  While your existing 020 transmission will fit, it is not suited to the power output of the 1.8T and is recommended that you upgrade to the 02A or 02J unit.  Keep in mind, however, that the 02A and 02J are cable shifted and hydraulic clutches, so your existing shifter will not work, and you must fabricate the clutch pedal mechanism or convert the unit for cable shift.  I using the hydraulic clutch, fitment of these transmissions will require custom mounting of a clutch master cylinder to the fire wall (which must be reinforced properly) and custom mounting of clutch master to the clutch pedal arm.

There are kits out there to convert the hydraulic clutch to a cable clutch.  In addition, an early (1990 or 1991) 16v Passat or Corrado G60 will have a cable actuated clutch.  Performing this conversion requires much less fabrication than keeping the hydraulic clutch.

In order to swap over to a cable clutch setup, you will need the parts noted below, referencing the numbers on the picture:

European/UK Parts:

-OR- US Parts (from '92 Eurovan)

For the cable shifter, you can run the cables either down through the tunnel or out of the hole in the firewall that is already there for the automatic transmission linkage.  This hole is behind the gaffer tape & seam sealer, so you'll have to poke around with a screwdriver to find it.  Its best you mount the shift box inside your Rabbit otherwise you will be reaching to far down for the gear lever and it will feel awkward, also this will cause problems under the tunnel as it will sit in the path of the exhaust.


Depending on which 1.8T you decide to go with, you may or may not have to modify the passenger side mount. The AEB 1.8T can use your existing passenger side motor mount, although it is recommended that you use a heavy-duty insert.  The later style AWP 1.8T  will require modification of the passenger side mount  With any of these engines, the front motor mount remains stock, although strengthening of the front core support is recommended.  You can beef up this up with a purchased structural member from Black Forest Industries or you can fabricate one yourself.

The transmission you use will determine what type of driver's side mount you use.  If you use your existing 020 transmission, all of your exsiting A1 mounts can be used, including the rear one.  If you use the 02A or 02J transmission, then custom mounts will be required.  These can be purchased from Watercooled Racing Development, or from Patatron.com. These are not inexpensive - roughly $300 - so if you have the fabrication capabilities it will be cheaper to make these mounts yourself.


The drive axles obviously remain stock if you stay with the 020 transmission.  The 02A has 100mm drive flanges, so you can use the 16V Scirocco 100mm axles with it. Please note that  Mk2 drive axles will not fit.  If all you have is 90mm CV joints, then you can swap out the flanges with your 020 transmission and use them, although they obviously will not be as sturdy as the 100mm units.

The 02J transmission will only work with 100mm driveshafts, so you cannot use your existing 90mm units with it.  Keep in mind that some of the vehicles that used 020J transmissions actually used 108mm flanges, so if you happen to have one of these units, you'll have to swap for 100mm ones.  The part number for the 100mm flanges is 02A 409 355D.


The earlier 1.8Ts with the earlier version of Motronic engine management do not utilize an immobilizer. The later versions of 1.8T and Motronic implemented an immobilizer and also have a drive by wire throttle. Wiring the Motronic into your A1 is not a trivial undertaking, but certainly can be done. Another limitation with the Motronic is that you can only really tune it by replacing the ECU chip.

You can use aftermarket engine management  such as Megasquirt and modify the stock engine bay harness that will come with the 1.8T. You can also modify the stock wiring currently in your car and in the end, you will be able to tune the system to your liking.

To get around the drive by wire issue in terms of the mechanical component side of things, you can install a throttle body from an ABA engine and connect to the gas pedal with a VR6 throttle cable.

Adding a VR6 Engine

Let's start by saying this is not a bolt-in swap.  Significant fabrication is required as the VR6 engine mounts are completely different than the A1 mounting points.  In addition, the VR6 transmission is cable shifted and has a hyrdaulic clutch.  The VR6 engine is significantly heavier than any 4 cylinder VW engine, which will necessitate the use of a car that has no significant structural issues.  Many people use seam welds along all the joints in the engine compartment to supplement the existing spot welds.  There are those that don't recommend this swap due to the added weight of the VR6 engine, the idea being that the additional weight up front will so upset the chassis dymanics that the car will lose so much of its hadling abilitiy that it will no longer be fune drive.  Obviously, those that have gone though the pain and effort to complete such a swap would beg to differ.

The most compatible donor vehicles will be a 92-94 Corrado VR6, 95-99 Golf GTI or Jetta GLX,  or 93-97 Passat GLX. All of these vehicles will have Central Electric 2 fuse boxes and compatible front suspensions.  It would be best to have the entire vehicle so you can be certain to have all the parts you need.


The driver and passernger side motor mounts from the donor vehicle should be removed.  You can use a spot weld cutting drill bit to remove the spot welds that hold the mounts to the car, and then use a grinder to smooth them out.  The existing front core support of the car is insufficient to support the weight of the VR6 engine.  You can beef up this up with a purchased structural member from Black Forest Industries or you can fabricate one yourself.  You will also need to cut up the engine mount cups off of the donor car's engine mounts and weld them to the body.  To make sure everything fits properly, it would be best to "mock up" the engine in the engine compartment of your car by placing the engine in the car and temporarily bracing it in place.


It is recommended that a Corrado VR6 radiator be used for this swap, which must be installed at an angle so the pins will line up with the holes in the radiator support.  The fans, however, will not fit, so aftermarket cooling fans will be the easiest and quickest solution.


The existing A1 struts can be used, although the springs should be upgraded to compensate for the extra weight of the engine.  If you want a VR6 5-lug setup, you will have to accommodate the steering knuckles from the donor VR6 car.   For starters you must use A2 manual steering tie rods, which are a couple of inches longer than the A1 parts. The A2 tie rods will screw directly into your A1 steering rack.  The lower control arms need to be significantly modified to use the VR6 ball joints. For everything to line up properly, the mounting point must be moved towards the front of the car by about an inch and out from the sides of the car by about an inch.  For the A1 struts to mount properly to the VR6 knuckles, the tab on the VR6 knuckle can either be machined down to a smaller size, or you cut the lower mounting tabs off the strut and weld them back on to widen the distance between them.

If you do not care about the 5-lug setup, you can use your existing spindles, struts, and control arms, although 16v Scirocco spindles would be recommended as they will accommodate the larger outer CV joints.

In either setup, the driver's side axle must be cut down to fit properly.  This will require taking an existing drive shaft, cutting it in half, shortening it by about 1.5", welding it back together, and finally balancing the unit.  

Due to the additional weight of the car, it is recommended that you swap out the rear drums with rear disk brakes and upgrade your master cylinder to at least a 22mm unit.


The 020 transmission is not suited for the VR6.  At a minimum you should use an 02A transmission.  All the notes about this transmission lined out in the 1.8T conversion section apply to the VR6 as well.


This item is too complicated and lengthy to summarize here.  Suffice it to say it is easiest to use the entire harness out of the donor car and splice in your existing harness for such items as the tail lights, dash illumination, etc. Everything else from the donor car  can be made to work with sufficient effort, including such items as the turn signal/wiper stalks and ignition switch housing and the VR6 donor car's instrument cluster. Such things as your A1 fuel guage sender will work with adequate accuracy and can be retained.


Your existing CIS fuel pump will work fine.  As with all the other swaps, you will have to move the fuel lines over to the passenger side of the engine compartment and use an A3 inline fuel filter.


If you have a 2.25" cat back exhaust you can keep it in place.  The catalytic converter and downpipe from the donor car can be fitted with some fabrication.  A Passat downpipe will work with some modification to the point where it attaches to the catalytic converter.