Trev's VWRX Project
Engine-Transmission

Engine-Transmission
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3-6-2003:
Engine:
After ages and ages of pie in the sky "what if..." type of dreaming I took the plunge and bought myself a stomper of an engine: a 2.0 Turbo from a '99 Subaru Impreza. As far as I can gather, these are rated as having about the 210BHP mark when in the Impreza, but that's while running a power steering pump and air-con, and all the exhaust gasses having to pass through a catalytic converter. That figure should work out a few BHP higher by the time I've fitted it in a beetle as power steering and air-con won't be much use to me and I won't be required to run a catalytic converter. Plus I'll be pushing it all through just 2 wheels as opposed to the Impreza's 4WD. That means there will be slightly less frictional losses without the extra differential and shafts. The engine is known as an EJ20T to those in the know (wink!). I had to ask to find this out! (Thanks Rich!)
I bought the engine in Co. Cork, and was able to see and hear the car running before the engine was removed. The car was written off at 26,000 miles by its insurance company as it was subject to salt water flooding over its back half (it was parked on a boat ramp and the tide came in!) It wasn't crashed and had the proverbial single lady owner to boot!
The engine came from one of these:

pic: ISDC www.555club.com
Subaru 2.0 Turbo
The gold coloured bit on the left is the inlet from the intercooler, the red bit on the right is the exhaust outlet from the turbo

Transmission:
The engine will be fitted to a stock Porsche 915 transmission via an engine adapter kit. The transmission will have to be raised and moved forward in the chassis. The raising will allow extra ground clearance for the extra low sump and exhaust pipework that the engine is fitted with. The moving forward is necessary because I want it to fit under a stock engine lid. It will also move some weight forward in the car, making for less tail-happy handling! Moving the gearbox forward may necessitate chopping the centre out of the torsion tube. Since this is the anchor point for the torsion bars, the bars and inner anchor points will have to be refitted further outboard in the chassis. The transmission came from a 1974 2.4 litre 911.
Porsche 915 transmission
Comparison between VW transmission (top) and Porsche

Cooling:
Cooling will have to be addressed soon. Whatever happens, the radiator will be mounted in the front of the car, in the spare wheel well, and air will be ducted up from a scoop in the floor of the well. Copper pipes will run the length of the car, probably along the central tunnel and join up with the engine. The engine has an intercooler, and I will have to figure out the best place to locate this to get a good flow of air through it.

28-7-2003:
Engine:
I've sent away the cheque to DS Tuning in Germany to have the adapter kit made, it should arrive within the next week. To have the kit made to suit the Porsche transmission I had to first locate a flywheel to suit the gearbox. Mike Ghia came to the rescue, he had one in stock, and as soon as I received it from him, I sent it off to DS for modification. I'm not entirely sure why the Porsche flywheel was required instead of the Subaru item, but I'm sure that when the kit arrives it will be obvious. Because the Porsche gearbox is being used, I will have to get a clutch kit to suit. This I will get from a motor factors like German, Swedish & French or similar. The Porsche flywheel is a plain disk with no toothed edge. Apparently the starter ring gear bolts onto the clutch cover. I don't know whether this comes as part of the clutch kit or not. If it doesn't, I'll have to go hunting again!

Transmission:
When I bought the gearbox, it came with the gear selector rod, gear lever and the big bracket that bolts to the Porsche central tunnel. Normally if this transmission was to be used in a beetle the Porsche selector rod would need to be lengthened by a few inches. I will be moving the gearbox forward as much as the CV joints will let me in an effort to move the centre of gravity forward and make the car a little less tail heavy. However, the 'box was missing the output shafts that the CV joints bolt onto so I had to locate a replacement pair. After discovering there was an independent Porsche specialist in Ireland I gave him a call to see if he had anything to suit. It turned out he did and he supplied them to me. He's Howard Langridge of Langridge Porscha in Kildare.
I still have to see which CV joints will bolt onto the output shafts, I remember hearing somewhere that VW Type 2 CVs can be used, but I'll have to do some more research to verify this.
Driveshafts will have to be uprated over the stock VW IRS items. Porsche 944 shafts seem like a logical way to go, they're the same length as the VW ones and are made of sterner stuff, so should be more capable of transmitting the power.
Output shafts for the 915 transmission.
9-8-03:
Engine & transmission:
I received the engine adapter from DS Tuning in Germany in the post on Wednesday 6-8-03. It included a large adapter ring with 4 studs sticking out, one of which was longer than the rest, a flywheel to suit the Porsche transmission and some shorter studs for fitting the plate to the engine. The flywheel was the one that I had sourced from Mike Ghia and posted over to them to modify for the Subaru engine. They either welded on a thick boss onto the engine side of the flywheel or made a completely new flywheel to the correct specs. I can't see any signs of welding, so I presume they made a whole new one. Either way, it's got the correct bolt pcd for the end of the Subaru crank and the correct bolt pcd for the Porsche clutch. The gearbox input shaft support bearing was retained in the stock position.

I got the adapter home on Saturday 9-8-03 and proceeded to fit it up to the engine. It needed a small amount of clearancing to it's outer edge to fit it around the turbo bracket, but nothing a short zap with the grinder didn't sort out. The two long lower studs on the Subaru engine had to be removed and replaced with the shorter ones supplied in the kit. The other two studs supplied were fitted to the top of the engine. The adapter plate slipped on easily then, being located by the 4 studs and 2 dowels protruding from the case. The oil drip tray had to be removed from the bottom of the engine to facilitate fitting of the adapter. The flywheel was then bolted onto the end of the crank via the original 8 bolts and then the gearbox was fitted to the 4 studs that protrude from the adapter. One stud is longer as I said, this is because it secures the starter along with another stud on the gearbox. I haven't got a clutch, ring gear or starter yet so obviously they weren't fitted. Incidentally, I trial fitted an old beetle starter motor I had lying around and it fits the gearbox alright, but I'm not sure if it would be compatible with the Porsche ring gear. Also, the Porsche transmission doesn't have a starter support bush so the beetle starter probably won't be suitable.

Here are some photos of the fitment of the adapter and then joining the engine to the gearbox. They're of really bad quality because the only camera I had at the time was a mobile camera phone. I'll get better pics soon... (better pic below! 18-7-04)
The adapter ring and flywheel
raised boss on flywheel
Subaru engine with stock flywheel removed
with adapter ring fitted
 
with modified Porsche flywheel fitted
engine and gearbox meet for the first time!!
plate can be seen between gearbox and engine
  

12-1-04:
Engine & transmission:
I got a single 944 Automatic drive shaft with the rear brake and suspension parts. It's the wrong length to be of any use to me but at least it will yield a pair of CV joints to use while setting up the location of the gearbox in the chassis. It remains to be seen if the bolt pattern of the cv joint is the same as that of the output flange. Fingers crossed!

Cooling:
The Subaru engine will probably need more air to cool itself than the stock VW engine, so I will place the radiator up front in the spare wheel well as originally planned to get the coolest air. I will weld in the slotted front apron from an air-conditioned 1303 to keep it all looking factory. The apron is holed from rust so was going to be replaced anyway.

27-1-04:
Transmission:
As rotten luck would have it, the bolt pattern of the output flanges I have didn't match the 944 CV joints! The CV joint had a bolt pcd of 6x86mm and an outside diameter of 100mm, the 915 flange had a bolt pcd of 6x94 and an outside diameter of approx. 110mm. While there were 6 holes on the flange pitch circle, only 4 were fully drilled and tapped, the remaining two being intended for a pair of dowels to help locate the CV on the flange. See the pic below for more detail.
I managed to locate a pair of earlier 901 gearbox output flanges on Ebay.com thanks to a tip off on the Germanlook.com forums, and I won the auction for them. They look smaller in diameter than the ones I have, and have 6 fully drilled holes. Hopefully they will be more suitable for the job at hand. I don't know what to do with the first pair of output flanges now. Anyone need a pair? Contact me ;-)
The first set of output shafts that I subsequently discovered are the WRONG ones!!
Another pair that I hope are the RIGHT ones!! Note 6 holes drilled and tapped.

21-4-04:
Transmission:
Oh nuts. This is becoming a bit of a habit...
I got the 901 output flanges in the post today from Canada. The pcd is 6x77mm and the outside diameter is 88mm. Wrong again. Maybe they'll fit beetle CV joints, but even that will be a stopgap measure, the beetle CV's won't be strong enough for the power output of the Subaru motor. More research will have to be done...
Well, at the very least, now I should be able to start fitting the gearbox to the chassis. Waiting on these components was stopping me from doing any real work on the project. Time to break out the angle grinder!
Turns out these ones are probably wrong too. D'oh!!

4-7-04:
Transmission:
Well, the first meaningful work has begun. I've fired up the trusty grinder and started fitting the 915 gearbox to the 1303 chassis. While I could have fitted the gearbox in the stock location with minimal fuss, I decided it would be best to jack it up and install it higher in the chassis. The main reason for this is the depth of the Subaru sump. If you measure how much of the VW engine hangs below the axis of the crank and how much of the Subaru motor hangs below, you'll find the Subaru is approximately 130mm lower than the VW motor. So, if I was to fit the Porsche 'box where the VW one was, and bolt the engine to it, the sump would be 80-90mm lower than the VW one. Not good. So, the transmission had to be mounted higher. The initial idea was to mount is so high that the selector rod into the Porsche box would be in the same location as the VW one. Only problem is, the selector rod on the Porsche box is lower down on the gearbox than the VW one, so the gearbox would have been too high for my purposes. The CV joints will limit how high I can mount the gearbox as they only have a certain range of angular movement. Lift the box too high and you risk locking out the CV joints.
In cutting the centre out of the torsion tube, I cut off the centre mount for the torsion bars. The back suspension collapsed onto the bumpstops. The initial plan was to do this and then cut the centre mount in half and reweld the halves further outboard in the chassis and use shorter torsion bars from a swingaxle beetle with the IRS springplates. You can see below how much shorter the swingaxle torsion bars are compared to the IRS ones. From there you can see where the mounts would need to be welded back in. To be honest, it looks like a LOT of work to get them back in securely and lined up properly, and coilover shock absorbers are available to dispense with the torsion bars altogether. I will probably end up opting for the coilovers. I will also build up a tubular framework to strengthen the back end of the chassis enough to carry the heavier engine and provide solid location for the gearbox, engine and back suspension.
After talking to Mike Ghia, and about the amount of work involved in strengthening the back end of the chassis, using coilovers etc, he suggested chopping off the chassis horns altogether as they would be pretty much defunct. It makes sense that a well thought out and well engineered rear suspension system using a custom built frame and coilovers would give better adjustability and handling than a system based around torsion bars and constrained by obstructions like chassis horns and a torsion tube.
However, if you're going to go to all that trouble to effectively design and build the rear of the chassis, then you might as well dispense with the VW floorpan as it forces the use of a rear engined layout. If the chassis was designed to mount the engine in a mid-mount setup, then handling could be dramatically improved with less of the weight bearing on the rear axle. And if you're going to dispense with the VW chassis, and mid mount the engine, then why stick a big 1303 body on top? Why not go for a sleek Karmann Ghia body or for the oddball factor, maybe a type 3 body. NOBODY would expect a car with looks like a Notchback to go at performance car speeds!
But that's getting a bit excited about the whole thing. I'll probably stick with the rear engined layout because it'll mean I can retain the stock back seat, and keep the car looking stock from outside. Besides, not many people are going to expect a street sleeper 1303 to outperform many big buck luxury cars either, are they?
Gearbox, welcome to your new home!
Sitting the gearbox above the torsion bar: too high for me
Starting the cut the centre out
Centre of the tube cut free
Swingaxle torsion bars (bottom) are shorter than IRS ones
cut, fit, cut, fit, cut, fit
Throttle and clutch cable guides temporarily bent out of the way
Gearbox moved forward a bit, note angle of drive shafts. Needs to go further.

18-7-04:
Transmission:
While I still have to make up my mind about spaceframing the back end of the chassis, I decided I'd better get on with getting everything lined up and a trial assembly of the engine and gearbox in the chassis. I've decided to retain the rear engined layout, it's still a VW, even if it has had a heart transplant. I also want the car to retain some level of practicality and with that in mind, it'll be more practical to service the engine from outside the car than climbing inside to change the oil. I also want to be able to lift the engine lid and see an engine that sits in place nicely.
More metalwork had to be removed from the back end of the central tunnel to make room for the gearbox to be moved forward some more. That hole is just getting bigger, and the clutch and throttle cable guides have had to be moved further out of the way. Now there's room to move the gearbox forward considerably, so much so that I'm worried about the rather extreme angle the drive shafts are in at the moment. I think I might start chewing up the CV joints with them so far out of line. I know the Porsche 944/Type2 CV joints offer a wider arc of movement, so for the same location they should be under less pressure, being a bit further from their limit.
Gearbox now futher forward again, the driveshafts are getting a bit out of line...

Engine:
With the gearbox bolted up to the CV joints, I was able to figure out roughly how far forward and upward I could go before straining them too much. The time had come to introduce the engine to the gearbox and chassis and see how things were going to fit. Using a hoist, I was able to swing the engine into place easily. Having the hoist available to me made the job of fitting the motor much easier, I generally work alone, and trying to manouver the engine balanced on a jack and into the chassis would have been a real pain in the ass. So with the engine bolted to the gearbox via the adapter plate and hanging from the hoist, it became apparent that the stock Subaru engine mounts lined up pretty well with the stock VW rear gearbox mounts.
Making an adapter plate to bolt one directly to the other would have ended up in the engine being too high (!) and there would be a lot of movement in the engine as it would have a doubly thick engine mount, so I decided to cut the top off the VW mounts leaving the steel base bolted to the chassis and then extend the base to pick up the Subaru mounts. As you can see from the pictures below, the location was approximately right, but the angle was wrong. I toyed with making a "wedge" to join the two, but a simpler solution was at hand. After removing the stock brace from between the frame horns the VW mounts could be rotated individually to bring them into line with the Subaru mounts. They would still need to be extended by some flat plate.
The plate was cut to size and welded to what was left of the VW mounts and a hole drilled in each where I thought was right. It turned out I was wrong and I had to drill another hole further down, you'll see that in the pics. I don't mind as I'm not trying to get it right first time with these, they'll serve as a template later on when I reinforce the back end. When that happens, these mounts will be incorporated into the framework.
While it is very convenient that the mounts lined up nicely, and the engine is quite balanced on the mounts without much pressure on the gearbox nosecone, I'm still very much aware of the severe angle of the driveshafts. I need to find some gearbox output flanges from a 911SC (thanks for that piece of info from Mike Ghia!) and the correct length drive shafts from an early 944 Turbo to see EXACTLY what range of movement the 944/Type2 CVs give. If I need to move the engine and gearbox back to save the CV joints, it will simply mean extending the VW mounts further back to meet the Subaru ones. I can afford to move the assembly back a bit as the location of the rearmost point of the engine (the crank pulley) at the moment is actually aboput 40mm FORWARD of where the VW pulley would be.
A better shot than those above of the adapter and flywheel on the engine.
The hoist was like having a second set of (very strong) hands!
Subaru mount (top) doesn't quite line up with the base of the VW mount.
Same, but the left side...
 
After extending the VW mount, note the bottom bolt hole doesn't line up as the mount has been rotated around the big bolt.
Same on the other side.
Where it's sitting at the moment, the dreaded low Subaru sump is no lower than the brace between the frame horns.
 


21-3-05:
Transmission:
Since I discovered the flanges bought from Ebay were actually designed for type1 size CV joints, and the bigger ones I bought locally in Ireland were designed for the much bigger 930 style CV joints, the only thing to do in the absence of type2/944 size flanges was to have the 930 flanges drilled out to suit the type2/944 bolt pattern. After dropping them into my friendly neighbourhood precision engineer along with one of the type2/944 CV joints to work from, I collected them a few days later all freshly resized. You can see below the difference in the diameter of the flange and the 944 CV joint, the flange overhangs it by about 5mm each side.
I have also sourced a pair of early 944 turbo drive shafts complete with CV joints from Ebay UK and I now have enough parts to get back into assembling the rear axle. Once I have the redrilled flanges plugged into the gearbox and the 944 axles and trailing arms installed I can FINALLY determine how far out of line I can safely run the CV joints without causing them to wear out prematurely.

944 CV and 930 flange
Note redrilled flange
930 flange much wider than 944 CV
The redrilled holes. M8 to match CV bolts
     

Gotta love all the shiny new parts...

      


7-5-05:
Transmission:
After having the output flanges machined to suit the 944 CV joints, the next thing to do was to plug them into the gearbox to see if the drive shafts worked any better than the stock VW ones. I have installed the 944 trailing arm on the right side now and everything is in place for a trial assembly. Once the output shafts were plugged in and bolted tight, the drive shaft slipped into place perfectly! The shafts are the correct length for the type of trailing arms being used, you can see the difference in length between the 944 Turbo shafts and stock VW shaft below. Because of the extra length of the shaft, the difference in the angle of the shafts from the stock angle is less then with the VW shafts. Truth be told, the VW CVs were "popping" when moving the car around the garage, that's how extreme their angle was. Luckily the 944 shafts and CVs are well within their safe range of movement with no strain whatsoever.

944 Turbo shaft (top) compared to beetle shaft (bottom)
901 output flange (left), 915/930 output flange (right)
944T shaft installed, angle is within safe range


4-7-05:
Transmission:
With the body off, it's easy to see the longer Porsche drive shafts are at a more acceptable angle than the VW ones were. The shift rods can be compared too, since I'll be using the Porsche shifter, the matching shift rod will have to be lengthened to meet up with the transmission.
Since the nose of the transmission is currently sitting inside the central tunnel, it makes sense to use a single front gearbox mount on the nosecone inside the tunnel. I've ordered a Ford Fiesta engine mount to do the job, it has a single stud on either side. I'll make up a mount to adapt it to the transmission.
The starter from a VW automatic transmission was supplied by Britt from California (thanks!) and fits nicely in the transmission. A self supporting starter like this is required because the Porsche gearbox has no bush in the bellhousing to support the starter pinion shaft like the VW transmission has. I still haven't checked whether it meshes with the Porsch ering gear, so fingers crossed it does!
The stock Subaru intercooler and air filter have been offered up in their stock locations just to see how they'll fit with the space available. The intercooler will need a decent feed of cool air so I'll have to figure that bit out yet. I reckon the filter will have to be relocated, but I'll check that when the body is put back down.
The Subaru wiring loom has been taken out of storage to see what bots are required and what bits need to be cut away. I'll fit it up to all the parts I have like the ECU and gauge cluster to see which plugs are used and then compare it to a wiring diagram and see what's not necessary.
911 shift rod (top compared to beetle shift rod (bottom)
Old pic of the angle of the VW shafts.
Drive shaft angle now more reasonable
915 gearbox just resting inside tunnel at the moment
 
Self-supporting starter fitted
Stock Subaru instercooler and air filter fitted to engine
THE WIRING LOOM!