Diesel Conversion

[raver_boi_88]

yeah but one of the fastest trucks in the world is a diesel, It can be made faster and more throttle response just from the switch of ecu's, it just depends on how much you want to spend...

[Joe_Black]

Americans in general have a very dim view of diesels as whole based mostly on sheer ignorance and ill-concieved bias. Your average citizen takes television as gospel, and last time I paused to consider the tube there wasn't anyone talking diesel. Many here are still smarting over GM's diesel-converted 305 that spontaneously self-destructed in many Oldsmobiles and the lackluster performance of miserly VW Rabbits sold en masse during the last fuel crunch.

Now, the Italian ride mentioned previously was almost certainly a normally aspirated economy car. So of course it left you feeling flat. I've got an '82 Mercedes 300D Turbo with a manual tranny and that thing scoots. And I haven't even turned up the injector pump yet, which would turn that 2-ton sled into an actual drag car. Diesels are amazing in that all you really need to do to get more performance out of them is get more fuel and air into the engine. That's it.

Diesel fuel also has benefits as there's more energy in a given volume of diesel than gasoline, one reason they typically get much better economy than gas vehicles. Throttle response has much to do with the configuration of the engine and vehicle as well. Turbo and supercharged engines drive much like a gas vehicle in responsiveness. My big International has a supercharged 2-cycle V8 and it responds VERY quickly! A friend has a new VW Golf TDI and the VX has a time keeping up with it, and it's not even tuned.

Now of course that kind of performance comes at the price of economy, much like any combustible-fueled vehicle. But the nice thing of a diesel is that if you don't drive it hard you keep almost all the original economy, which isn't typical of gasoline engines. And if you use B100 economy isn't as much an issue if you need the speed. You can then not only beat cars light-to-light, but also pump-to-pump.

[Maugan_VX]

Hey Joe,

Don't get me wrong here, if Isuzu made a diesel VX (for all I know, they did overseas, I have no clue) I'd considering trading-up. However, I just question the cost/benefit ratio of performing this aftermarket modification to a perfectly well-functioning VX.

How much is a new Isuzu diesel engine with a blower these days anyways? Can't be less than $5k....

[PeteVX]

This has been on my mind for some time too, i grew up in England, i reckon there are now more diesel cars there than gas, the europeans have invested heavily in developing diesel over the last decade, and it shows! All my family over there drive turbo diesels, they are quick, quiet have tons of torque and get great economy (they also dont have that wait for the glow plugs to heat annoyance anymore either), my dads Renault wagon gets 45 mpg and just flies along, oh and they usually run for 300,000 plus miles so long as you keep the oil clean.

Joe you sre so right that here in the US diesels have a bad name, noisy, smokey old tubs with the performance of a tractor! Sure diesels are not gas engines, they have very different charicteristics, but that doesnt make them bad, i love driving a diesel, specially a turbo. I dont see media influenced public opinion changing anytime soon either but that doesnt mean we cant take advantage.

We used to be able to get low milage used engines complete ready to drop in very cheap in the UK, they came from Japan i beleive where they used to scap cars after only a few years, something to do with very heavy registration taxes as a vehicle gets older or something like that.

Not sure of the federal mport restrictions on bringing a motor in, i know its not easy any more to bring whole vehicles, i just scraped by with a handbuilt motorcycye when i moved here 8 years ago but almost had to send it back again.

I'd be very interested in a turbo diesel conversion though if anyone figures out the logistics (too busy/lazy to do it myself, hey at least i'm honest!)

Pete

[Joe_Black]

Diesel engines and heavy trucks have been Isuzu's bread-n-butter business all along, they do cars and light-trucks as a secondary market. They're recognized world wide as making the best diesel engines on the planet. You can find them in everything from small reefer units, lift-trucks and power units on up to semi-trucks and heavy mining equipment.

As for importing a used (or new) engine it's pretty much just crate-n-ship. You can usually find at least one intercooled turbo-diesel from the late model Trooper on eBay at any given time. People that are re-selling them here are asking up to $4500 for a low mileage engine, usually the 4JG2TC model. But as I've been watching these for about 4 years I've learned it's more economical to import yourself, some I've seen just in the last few days for around $1000. The JDM engine market is commanding quite a premium, especially with the tuner and drift crowd, and that affects all imported engines.

The beauty of converting the VX is that since this is what the Trooper comes with overseas, all the mounts and such fit our chassis. Literally a plug-n-play installation, with the exception of the very latest diesel which is electronic. Isuzu is well know for their reluctance to re-engineer anything that works, so more than likely the harness could be easily integrated. Remember, the diesel Troopers came off the same assembly line but just received a different engine option and corresponding hood for the intercooler scoop. And the Trooper had the same 6VE1 3.5L engine as the VX.

[Maugan_VX]

Joe,

Thanks for enlightening us (me).

At ~$1000 and "plug and play" functionality, whats the downside? Does that price include the ECU? Will it behave with TOD and the 4L30E like the 6VE1? What are the changes needed to the fuel delivery system? Exhaust? Are there any resources online that you'd recommend concerning diesel conversions in general?

what kind of emissions regulatory implications are there?

Curiosity is killing me.

[Joe_Black]

Joe,

Thanks for enlightening us (me).

Well, I first got interested in doing this prior to getting a VX when I wanted to build an '89 Trooper RS into the ultimate road and trail rig. I had been reading a lot about the then-new 4BD2TC as used in the NPR medium duty trucks and that a few HD Troopers came with the same engine. So I got really interested in fitting an intercooled turbo-diesel powerhouse into an RS, complete with the big ole hood scoop.

At ~$1000 and "plug and play" functionality, whats the downside? Does that price include the ECU?

From what I've learned only the very latest engine is (4JX1 IIRC) electronic with common-rail fuel delivery. All previous models are fully mechanical.

Will it behave with TOD and the 4L30E like the 6VE1?

I'm pretty certain you'd have to baby it if retaining the 4L30E, but it may just survive normal driving as it's not that bad of a tranny. Just not well-suited for high-torque offroad use. I still haven't fully deciphered the connection between the TOD computer and the ECU, but know only minor changes were made to the rally VX's which had 5-speed manual transmissions. My hope is to confirm soon that the TOD transfer case will mate with the diesel auto and manual trannies.

What are the changes needed to the fuel delivery system?

Diesels use a non-pressurized system with a vent and a return line. Our system is already plumbed and you'd need to just change the tank-mounted fuel pump.

Exhaust?

A new exhaust would be needed from the manifold to the cat since it's an inline 4-cylinder and diesels use a different cat/particulate filter set-up. Everything after the cat would work fine as diesels are pretty flexible with exhaust and not as sensitive as gas engines.

Are there any resources online that you'd recommend concerning diesel conversions in general?

I've found a lot of folk converting a variety of vehicles to diesel or US spec vehicles to domestic diesel spec, but nothing specific comes to mind. I'd just Yahoo! or Google "diesel conversion" and browse. There was a '98 Trooper on eBay twice recently that had a well done Mercedes OM617 conversion, and that is a potential back-up in the event Isuzu diesels proved too difficult to obtain.

what kind of emissions regulatory implications are there?

That I'm not 100% sure of as Florida is pretty lax in that department and I haven't really looked at other states requirements. It shouldn't be too difficult to poke around your particular state's DMV or DOT web pages to glean any local emissions regulations.

Curiosity is killing me.

Yeah, it's been getting me for years as I keep generating about 2 more questions for each answer I get. LOL!