The following write-up is an article S. Lucas Valdes (President & Resident Mechanical Engineer of GoWesty) wrote to illuminate our experience and opinion on diesel power and its application to the Vanagon platform.
We have installed 1.9 liter turbo diesel engines in six Westys, all 1982 vehicles that were already diesel powered, except for one which started out its life as a 1985 gas model. The engine that is easiest to install is the AAZ engine code type. It is 1.9 liter and turbo charged like the TDI, but is not a TDI. Instead, it is the earlier generation and simpler "pre-chamber"-type with no electronic controls. This power plant puts out about the same torque (120 ft-lbs.) as a stock 2.1 liter waterboxer, but only about 75HP instead of 90HP. They get about 25 mpg on the highway if driven conservatively. I have a 1990 Doka Syncro with one of these engines in it, and when driven "normally" I get around 22 mpg. The TDI is a way cooler engine (about 160 ft-lbs. and 90 hp) and more fuel efficient, but extremely complicated to install with all the electronics involved. On top of that, the TDI has the turbo mounted below the intake manifold, so when it is leaned way over to fit into a Vanagon, the oil won't drain out of the turbo. So, you have to convert the turbo and exhaust manifold to a different type. On top of that, you have to run an intercooler... all of which make the TDI a very difficult and expensive installation, indeed.
Basically, the negatives to installing a diesel engine in your Vanagon are vibration, gearing requirements, and cost. There is no way around the vibration. In-line 4-cylinder engines vibrate... and diesels? Forget it! That is just the nature of the beast. You can expect about 10 times more vibration than a waterboxer. The cost is high, especially given the gearing requirements. A proper AAZ 1.9 turbo diesel engine installation alone into an already diesel-powered Vanagon is about $7500. Then, on top of that, the gearing in the transaxle needs to be MUCH taller than for the waterboxer or stock 1.6 diesel in order to fully take advantage of the 1.9 liter torque and fuel economy. The best choice is a 5-speed with a 4.57 final drive, and a .70 5th gear. That puts the engine rpms at about 3000 @ 70mph. The cost of that gearbox is about $5000.
Now, I love diesels. I have a 1998 E300 Mercedes turbo diesel, four 1982 VW Rabbit diesel pick-up trucks, a 1984 Jetta turbo diesel, a 1999 Jetta TDI, a 2002 Golf TDI, a 1990 Doka Syncro turbo diesel, and a 1979 Kubota 3-cylinder diesel tractor. My first Vanagon was a 1987 Wolfsburg Weekender I bought in 1996. The first thing I did was buy a complete TDI engine and wiring harness for it. I built that super high-geared 5-speed for it like I describe above (which is still in it), and got ready for the TDI conversion. In the meantime, we did the six aforementioned diesel installations and started our more powerful and more efficient waterboxer program. Long story short, the TDI engine sat on the shelf for about three years. Based on the knowledge we had gained from doing the six diesel installations and the success we were having with the waterboxer program, I just could not fathom the work it would take to do a correct, good-as-factory installation of a TDI in a Vanagon. I ended up selling the TDI, and installing a 2.4 in my Vanagon, which is still in there today. The 2.4 liter, 9.65:1 compression ratio waterboxer motor we installed runs just fine down the road at 65 mph in 5th at 2800 rpm, and gets 18-22 mpg at that speed. It is as smooth as glass, and took just one day to install. ONE DAY. Since then we have built over a thousand waterboxers for customers all over the country with great success. A fresh GoWesty waterboxer engine can be installed in one day, and the cost with installation is really reasonable. Our waterboxer engines also come with a 48 month/48,000 warranty. Okay, it's not a diesel, I know. And that's a bummer, I agree. But hey, there are a lot of other things to worry about that are much more worthy of our limited capacity for anxiety...
So, what about all those advertisements you've read about in-line gas or diesel installation “kits"? From the ads you’d think they install in a weekend, and are simply turn-key. Yeah, right. Now, keep in mind, we at GoWesty have done SIX turbo-diesel in-line four cylinder engines in Vanagons, all of which (except for one) were already set up from the factory with that type of power-plant. My Doka diesel was already a factory 1.6 TD, so the installation of the 1.9 TD was not too much work. Even still, I am on the FIFTH exhaust system design: The thing keeps rattling apart! Good thing I love working on my own vehicles. It's fun, right? Right... One of our top technicians, Randall, put a TDI in his 1986 Vanagon Syncro. Randall is one of the most experienced, smartest, and talented technicians I have ever known (that is why he works at GoWesty!). He has been working on his TDI Syncro for the last five years, and still the bugs are not all worked out (thank goodness those hours were off the clock!). And, what about those in-line 4-cylinder gasoline "Jetta" engine conversions? Well, we have converted six back to waterboxers so far... thank goodness they FINALLY went out of business! So, believe me, we're speaking from experience. Diesel engines are not simple to install, are not trouble-free, and are certainly not “turn-key." If you have the time, tools, talent, and experience, and simply must have a diesel, go for it. But don’t be surprised when the thingamajig won’t fit where it's supposed to and the whatchamacallit keeps rattling off!
Now, if you already have a factory installed diesel engine in your Vanagon that needs to be replaced anyway, and it has a tired gearbox, it just doesn't make sense to overhaul what’s there. Going with a fresh 4- or 5-speed with taller gears and updated shifting system, and a fresh 1.9 turbo diesel instead of just overhauling the original trans and stupid 1.6 non-turbo engine, makes a lot of sense. You might spend twice as much, but you would have 4 times more vehicle to show for it when done.
That's our story, and we're sticking to it.
From a customer:
As far as I know they did a good job, and we have a well converted van. For us the problem is that on almost any incline we have to down shift to 3rd and can only go 40 mph until you are done climbing. This is hard for us as we live in a very hilly part of the world and like to play in the mountains. What would you suggest? Do you ever buy these kind of rigs from folks like us? We're looking for advice.
S. Lucas Valdes
GoWesty! Camper Products is a privately owned company specializing in parts, accessories, sales and service of Volkswagen (R) campers. It is not affiliated in any way with Volkswagen of America or Volkswagen AG. "Vanagon", "Bus", "VW", "Volkswagen", and "Eurovan" are registered trademarks and should be considered as such throughout our entire website.