Alternative Engine Conversions - A Closer Look at the Subaru

[Dave DND]

Whilst I am by no means a VW Purist, I fully respect that there are many out there that have a clear definition of what a Buggy should be and how it should look, and what follows here will have many of you grumbling and groaning. Personally, I just enjoy the randomness of each one that we see, and my only hope is that the "scene" will last for many years to come. We have many Body manufacturers amongst us to keep them all looking good, we have plenty of metal to keep patching up the old chassis, and there are a few spaceframes and bespoke chassis welders out there to keep us going on the new builds also. But what about the engines?

The original Air Cooled Type 1 engine ticks virtually all the boxes bar one, and that is that in its standard guise is woefully underpowered for today's high speed motoring. That said, it is exceptionally easy to bolt on some extra power in the form of larger barrels and pistons and twin carbs, and you only have to look at what some of the guys have done on here to realize that the Beetle engine can really scream if you want it to. Performance comes at a high cost though, and good parts are getting increasingly hard to find.

For those that want a bigger engine, then the Type 4 can provide fuel injection, and the 2 liter T25 engine has enough grunt to push the weight of a camper about, let alone a Buggy, and the conversion is also very simple to do. But, there is also a major downside in that shiney parts are non existent and standard parts prices are rocketing skywards at an alarming rate. Some have even opted for the Corvair 6 cylinder conversion which is nothing short of awesome. However, everything I have mentioned so far has the same achilles heel apart from very old technology. The ChineBay parts are of sub standard quality and the genuine parts are fast approaching the end of their serviceable lives.

Recent events with my own engine prompted me to see what else was out there, and one of the names that keeps coming up is that of Subaru. I used to own a Subaru Forester, and it was indeed fairly bulletproof. The in-joke amongst Scooby owners was that if it went wrong, you didn`t bother fixing it, because for a hundred and fifty quid, you just changed the engine. A beery chat with a mate of mine threw up that a friend of his was scrapping a Subaru H6, which has a 3.3 litre flat six engine, and apart from not knowing that such a beast even existed, I also wondered why I had never heard of it being put into a VW? There must be a good reason why it is not considered, and after much research indeed there was. Its physically too long for the campers and far too powerful for the VW Beetle gearbox and would break it the minute you tried to pull away.

It took me a while to find that bit of info though, and after a few nights trawling the interweb I was surprised just how much information is out there that all covers so very little. Loads of posts can be found about those undertaking the conversion, they all get hit by various stumbling blocks, wiring, oil sump conversion, fuel supplies etc, but very few threads seemed to cover everything. Most are putting the engines into Watercooled campers, so the major problem faced by us of radiators are seldom even mentioned. By this time, my mind was buzzing, and I thought I would have a detailed look at the Subaru conversion from start to finish, but with a bit of a twist - I`m not doing this in my Buggy - I`m going to convert a Subaru.

 

Ok, that has probably confused you, so let me explain better. With the exception of the gearbox adapter plate, I`m going to try and convert everything else to be completely stand alone within the Subaru shell, relocate a radiator in the back and rewire it all in such a way that it should be a little more understandable for those wanting to splice it all into a Buggy from start to finish.

[Dave DND]

So, where do you start?

You can buy an unknown engine on eBay for £150 which has so many pipes and cables hanging off it, that its actually a bit daunting. How do you know if you have all the bits needed? You can buy a ready made VW converted wiring loom for around £400, and an adapter plate is around £500. but is that all that you need? What does it actually cost? What is actually involved?

Well, the only way of finding out is to jump in feet first and have a bash.

The starting point is deciding which engine option you are wanting to go for. Ignore the 1.8 engine as it uses a very expensive adapter plate, whereas the 2.0, 2.2 and 2.5 all use the same one. There are single overhead cams, dual overhead cams and of course you will all be falling into the same old trap as I did by now of the word Turbo. Remember why I couldn't use the 6 cylinder engine, the Beetle gearbox just cannot take the power. Unless you want to spend a fortune getting the box drastically upgraded, the general consensus is that it is easily destroyed by anything bigger than 140BHp. Turbo is fast approaching 200, so for this experiment we will, ignore it. The 2.5 DOHC engine is around 165BHp and some of the 2.2 engines have stories of head gasket failure around 130K miles. The 2.0 SOHC engine seems to be generally regarded as the one to go for, because even in its standard form it is still over three times the power of a Beetle engine and there are many cars with mileages way in excess of 180K that are still going strong. At 135BHp it can still kill a gearbox, but so long as you do not drop the clutch and wheelspin everywhere, it seems to be regarded as ok.

So we have chosen the engine and now to find a donor vehicle. Too old a car, and it will be knackered high miler, and too late a vehicle, it will have the complex drive by wire systems that are a pain to convert. The Subaru Legacy is probably the one to aim for, as generally looked after, whilst the Impreza Saloon will have been thrashed by every Chav that has ever stolen it. The spectacularly bland Forester has probably had the easiest life, but I am unawares how different the ECU mapping would be for such a large old plodder compared with the racey Impreza.

As a confirmed Petrol Head, it goes against the grain somewhat to buy a perfectly good car and chop it up into pieces, but it was pointed out to me that a Brain and Heart transplant meant that the soul lived on and was ready for an adventure. The plan is to buy a car, strip everything off it and see if you can actually finance most of the conversion by selling the bits off. Looking at ebay prices, 4WD gearboxes go for £350, interior £150, door cards £75, Lights £50 each, wheels, tyres, switches, etc, etc, everything has a value. Theoretically its possible to end up with an engine for nothing, but I have never tried it - so here goes.

[simon-dubman]

Excellent post Dave

One of my buddies form some time ago had a 2.0 in a camper took a bit of fiddling but it worked and went like a train. i also saw a buggy with what sounded like a scooby engine at santa pod a few years back, it had some short type of wheelie bars hanging out the back.

I did toy with the idea of a V8 for my buggy as parts for the T4 engine are expensive even second hand, i did find a Porsche supplier 914 specialist and you would need to re mortgage the house for the parts.

Looking forward to reading through your findings. 

[snoopy]

Have you looked into fitting a scooby box with a 2wd conversion instead of a vw unit.

Should not have taken you for a spin in the kango and then spotting you in a purple n greenn buggy having a test ride with a scooby unit. Just think, heaters demisters and less servicing.

[Dave DND]

Have you looked into fitting a scooby box with a 2wd conversion instead of a vw unit.

I did have a look at that one, but the Subaru box goes backwards. Conversion prices are silly at around £2K and then you have to fit the box in place. Sure you would get a 5 speed box, but the VW Van box is also very strong and can be fitted for a lot less than the Scooby one. No, I wanted to see what the basic conversion would entail and what can be done with our existing setup and running gear.

Should not have taken you for a spin in the kango and then spotting you in a purple n greenn buggy having a test ride with a scooby unit. Just think, heaters demisters and less servicing.

Keith, your Fiat twin cam Kango pulls fantastically and shows what an alternative engine can do - I was mighty impressed. But don`t underestimate what a well set up Beetle engine can do either - Andy Robinson took me for a spin in his Buggy and it really shifts - And I have to say that my own T25 engine is certainly no slouch either and would give many a run for their money. But apart from the power and smoothness of the Subaru, you also have another few thousand useable revs from the engine, and that has to give us something to play with.

[Zip Buggy]

Just rang my parents as they had an old 2.0ltr Subaru Legacy with a good engine that had been sitting in their yard for a few years. They scrapped it last week

[fugglededumm]

Andy AKA The General has done this twice to his sandrail. Once to the 2L and then just now to the 2.5L . I have not driven it with the new engine but it was pretty scary with the last one! http://bajaclub.co.uk/forum/phpBB3/viewtopic.php?f=7&t=931 it starts a few pages in.

[Dave DND]

The aim of this exercise is not about power or speed, not your heavy Rover V8, the thirsty Mazda RX7, the old Lancia Twin Cam, the Mortgage requiring Corvair, but more about finding a modern solution. This is where the Subaru really comes into its own, as it uses a water cooled flat four engine, with pretty much the same one used over its entire model range, meaning that there is a plentiful supply. The conversion is certainly not straightforward though, nor for the faint hearted, and there are some serious negatives that must be considered before you hit eBay looking for some bits.

Negatives:

Well the most obvious one is the radiator. There are no more modern air cooled engines around, so any engine swaps you are looking at are going to involve finding a location for a radiator and the associated plumbing that goes with it. On a positive note though, you will also end up with a heater.

The engine is a very compact flat four, but as you can see from this picture, the sump underneath hangs down a very long way. Its not just a matter of chopping the lower 3 inches out either, as that can reduce the oil capacity by a significant amount. There are companies that will provide a modified sump and internal oil pick up, but these are not cheap and something that needs to be researched and factored in to your costs.



You will also need to have a bespoke exhaust made. This probably isn`t that much of an issue for us though, as most of us have already ditched the stuff available off the shelf, and have opted for bespoke systems from the likes of Beelzedub anyway.

The wiring is probably the bit that is commented about most. Everything, and I really do mean everything on the Subaru is controlled by a central Engine Control Unit (ECU) and this little box of tricks can have in excess of 100 wires going to it. The engine is quite complex with various crank and cam sensors, so it is no surprise to find that most of the wires will be used. If you source an engine on its own, then make sure that you also grab the ECU and all of the associated wiring looms. There are companies out there that will take your own loom, chop out everything that is not needed,and send you back a plug and play loom like this for around £400. I do have a few issues with this loom though, and that will become clear as the project moves forwards.




And finally, you will need to find a way to attach it all to the VW Gearbox and make it work. This will entail some form of adaptor plate, a modified flywheel and a heavy duty clutch system. All of which are readily available (mostly from the USA) but there are still a few pitfalls to watch out for.




From what I have read, the total conversion cost (excluding labour) can be done for under 2 grand. Not sure how accurate that is, but I guess we will soon find out in the months to come.


Positives:

OK, so why would we consider it then?

The Subaru engines are very reliable, and have a good supply of spares that are readily available. They are significantly more powerful than the air cooled engines and will return a far higher MPG thanks to modern technology. There are a few added bonuses too, such as the ability to have a heater and an alternator as standard. They rev a lot higher than the old air cooled motors do too. Imagine the extra performance and speeds you could have if your engine went up to 6500rpm instead of topping out at 4500rpm?

And whilst £2K is by no means a cheap solution, you wouldn`t actually get that much for your pound if throwing it at an air cooled lump, so in some ways it could actually be seen as good value for money and a viable proposition.

[fugglededumm]

Have you see the http://www.rjes.com/ bell housing solution for the engine/gearbox mating. Also lots of useful information on there too

[Dave DND]

Have you see the http://www.rjes.com/ bell housing solution for the engine/gearbox mating. Also lots of useful information on there too

There is indeed some brilliant info on their site and I have spoken to Rich at RJES a fair number of times, but they only really cater for Bus gearbox bell housing conversions, (which is the same as Andy has in the General) but unable to provide a solution for a Subaru on a Type1 Beetle box. That will have to be done with an adaptor plate sourced elsewhere.

[pepsi81]

Dave, loving your thread, something I've considered for a long time but not had the balls. There's a guy our way with a 3.3l which goes like stink in a camper😍
Why not go all the way, buggy 😘

[Dave DND]

For my own project, I have decided to use the Subaru Impreza GX on the basis that it will have the added ECU mapping and performance of the Chavtastic Impreza Saloon, but being the "unfashionable Old Man's estate" version, may not have been thrashed quite so much.

I don`t want to be messing about repairing anything for this experiment, so it was important that I started out with something good. I located a 52 plate Impreza GX AWD with the more desirable engine known as the EJ20 2.0 SOHC that was for sale with a full service history, a years MOT and a mere 100K miles on the clock for just £600. It is a lot more than you need to pay for a donor, but the 200 mile drive home confirmed that everything including the 4 wheel drive gearboxes worked brilliantly (and could therefore be sold for parts) and most importantly, demonstrated that the engine was silky smooth and very responsive.





Opening the bonnet reveals a flat four that looks very scary because of the number of pipes and tubes everywhere. Once the power steering and air con is removed, I`m hoping that a fair chunk of plumbing will also follow. One of the other reasons that I chose this engine is because it has a standard cable operated throttle. The later ones have motors operated by sensors on the gas pedal. They can still be used, but its a lot more work.





So over the next few months, I will bore you all senseless as I start to rip this apart and see what all the fuss is about

 

[Zip Buggy]

Watching this thread with keen interest Dave.

[pepsi81]

Dave, keenly watching your outcome. As always, from you the start of a brilliant and well thought out thread, packed with useful info . Best of luck. Save the steering wheel
🤑
Paul

[snoopy]

The project is under way and cheaper than an aircooled engine alone, now chop the body off the pan and fit the buggy body.

This will be a long interesting thread.