***Subaru Diesel??!

[blatant]

I know other countries are really big into diesel. Why is the US NOT?! Has anyone heard of subaru coming out with a diesel for the US? How reliable are the subaru diesels, if they exist?? Do they make them or does someone else make them and brand them as a subaru?? Anyone want to speculate? I searched but found nothing on this...oddly enough.

 

thx just figured I'd get a discussion going...i buy one in a second if it were available here.

[Andyjo]

i don't know any answers to your questions... but... it seems to me that the amount of torque coming from as diesel would torque your little unibody in half if you pegged it. just a thought....

[RavenTBK]

This has been discussed I dont know how many times here on USMB. Most of the users feel like you.. would buy a diesel in a heartbeat. Is it going to happen? Who knows.

[blitz]

IMO the long stroke & long connecting rod requirements of a diesel design run contrary to the width constraints that currently force Subaru to use the shortest stroke and shortest rods possible in their gasser engines.

[Buddythedog]

I just drove the new Jetta Diesel Station Wagon. I didn't buy it, I bought a FOrester XS instead, really because I've had 2 Subie's already, it had awd, which I need here in the mountains at 8000 feet. That said, I fell in love with the VW diesel. It had plenty of torque (190 ft/lbs I think) yet only 100 hp. It drove beautifully, and got 43 mpg!! If only Subie would make one with that kind of mpg's I'd buy one and save several thousand a year.

[cookie]

are gas and you need to run a particulate trap to clean up a diesel for US standards. I am running 34 Diesels with traps at the moment on small vans.

At US prices we don't save enough to justify a diesel. Places where Diesel is a lot cheaper have used them in autos for years. In New Zealand my brother in law dropped a Nissan into his Range Rover.

It would take a complete redesign for the flat four to run a diesel, and now that Subaru partners with GM odds on it would use one of the Diesels they already have for corporate use.

If gas became very expensive here diesels would be quickly available like they were in the last energy crisis. Last time Mercedes cleaned up and a few good JDM diesels made it here. GM made a rather lame attempt at a converted Olds gas engine.

There are some very nice european diesels that have come a long way from taxis in driveability, power, and noise.

Don't hold your breath for a Subaru diesel.

[blitz]

It would be kinda neat if Subaru somehow did a diesel. It would put back the cool quirkiness that used to set Subaru drivers aprart from the herd.

[Scottbaru]

It's primarily due to the California Air Resources Board. They've set particulate emission standards for California that can't be economically met in passenger cars with the standard US diesel fuel. Carmakers don't want to sell a car in the US if it can't be sold in California. Gas engines produce more total pollution, but they won't budge. Cleaner diesel fuel would help, but would cut into oil companies profits. We're approaching the point where we'll have to go to diesel, there's been a surge of diesel offerings in new vehicles, and pressure to have cleaner diesel. I love diesels, drive them often overseas, can't wait to have an awd diesel wagon. Diesels are very popular overseas, but I don't think Subaru offers one, so I wouldn't hold my breath for them to lead in that area.

[rizzo]

the one thing that would make that jetta diesel wagon even better is if they offered 4motion on it. but VW only offers 4motion on their more luxury cars. it seems that subaru is the only "working man's" car that offers awd on the whole line. i probably would've gone for a jetta tdi wagon if it came with 4motion, but for the model years i was looking at, you could only get it on the passat, which i don't believe they offer tdi.

 

however... at least here in the northeast, diesel prices aren't cheaper than gasoline prices, which makes me curious if you would really save all that much on gas money by having a diesel engine (is 15 more mpg worth the extra cost of gas?).

[Diesel]

Here is the engine.

 

http://www.smaengines.com/enginesr.htm#technical

 

Too bad its a 4 stroke.

[Scottbaru]

Here is the engine.

Nice! I've heard of small planes running diesels. I wonder why it's so altitude limited?

[blitz]

Nice! I've heard of small planes running diesels.

Yeah, the diesel has the high torque/low RPM characteristic perfectly suited to a direct-drive prop arrangement. EJ-25 Subie motor is 28.5" wide at the valve covers, that motor is 36.3".

 

I wonder why it's so altitude limited?

Looking at the power vs altitude graph, it appears to be based on turbo sizing. To keep (thermal) efficiency as high as possible the turbo is sized no larger than necessary.

[KStretch55]

I've owned a diesel and never will again. They're great for heavy work, when they'll pay for themselves. But, for light duty applications the cost of parts and maintenance far exceeds any benefit in my book. I shudder to think what they are wanting for one of those aircraft diesels.

 

Also, I suspect the altitude limitations are more because you need a very large turbo to push enough thin air into the engine to keep a fuel/air ratio that'll detonate and still have power. The Russians and Germans both used diesels for some aircraft during the WWII and I believe that was the problem they ran into also. They did have some success with them in ground attack aircraft because they stayed at relatively low altitudes.

[Diesel]

The altitude limits are set at a point where the engine can be restarted without descending. A diesel needs lots of air to start. There are some turbos that are electrically driven so they can produce enough boost to start at higher altitude.

[Diesel]

I shudder to think what they are wanting for one of those aircraft diesels.

Don'y know but prolly 35-40K

[KStretch55]

It's been a few years since I worked on light planes, but I'd guess that's pretty close to double the price of a comparable gas aircraft engine. Anyone know for sure?

[Diesel]

It's close to nearly double. The nice thing about having a diesel is you can run 1/3 longer befor it has to be torn down and inspected.

[KStretch55]

But, the kicker would be will that 1/3 longer TBO (Time Between Overhaul) save you anything. Probably not for a general aviation application. Maybe, and I'd say just maybe, if you are using it for commercial aviation. Still I doubt it or we'd see more of a push from the freighthaulers to go that direction, after all they are in the business of making money. Just a rough estimate, but I'd say it wouldn't be comparable until you could get 50% more TBO. Then you might make up the cost, depending on the price of parts when you do the teardown inspection, cuz' you can bet the diesel parts are going to be much, much more expensive.

[KStretch55]

Another problem with diesel at altitude is cold. Diesel begins to gel at a relatively high temperature, compared to gas and you can only add so much deicer before you start to change the cetane rating of the diesel. Diesel will start to gel pretty bad at around 10 degrees F. Any colder and you just about have to have deicer. It's a constant -65 F at 25000 feet. Some larger and military aircraft use oil/fuel heat exchangers to keep the fuel relatively warm and help cool the engine oil and/or hydraulic fluid. But, this probably wouldn't be very affordable for general aviation uses.

[Buddythedog]

If you drive 20K per year, an extra 15 mpg will save you approx. 3000$$. If you have the car 5 years, that's 15K just in fuel savings. Maint. costs are higher in a diesel, but not that much.. FTW

[NorthWet]

A couple comments about diesels...

 

Having lived through the 70's diesel craze, I am not surprised that diesels are not popular today. A diesel engine should be built stronger (ie heavier) than a comparable-power SI engine, and due to the limited speed capability of current diesel designs, you need a larger, heavier-yet engine to match performance with a SI engine. Back in the 70's GM decided that all they had to do was slap different heads on their small-block V8 and it could be diesel. What a disaster.

 

Since our fuels in the USA are minimally taxed (relative to most of the world), the price of diesel is pretty close to that of gasoline, and both are priced as market commodities. When the demand for diesel increases, either from motor fuel use, heating oil use, or both, then the price of diesel goes up. When a whole bunch of cars start using diesel, then the price increases pretty dramatically. This quickly wipes out any perceived cost advantage.

 

There is only so much diesel fuel (or gasoline) that just "sits" in a barrel of crude oil, and if you want more from that barrel than you have to do more processing of the crude, and that processing uses material that would go to make something else, causing a reduction of supply of that distillate. So, commonly, to produce more diesel there is a drop in how much gasoline is produced, increasing the cost of both.

 

CI engines really only have one thing going for them, and that is thermal efficiency, and it is something that SI engines cannot match. But they use a dirtier fuel (though use of supplimental propane can help this), and due to their greater thermal efficency, produce more of a difficult to control pollutant (NOx).

 

Just a little reality check.

[vic/se]

A good diesel engine, is very reliable you can go a 1000,000km quite easy with normal maintenance and 40% better mileage when you compare to same displacement gas engine, and you can run them on almost anything even vegetable oil!!!! Do you think oil corp. going to like that???

That's why they're popular only on oil satarving countries

[KStretch55]

Check the price around for diesel lately? You'll find it is at or higher than the price of regular unleaded, at least in my area. Three years ago, when I owned one it was routinely .20 cheaper than regular unleaded. Demand has gone up and hence so has the price, even though it's cheaper to produce. Good ol' principal of supply and demand.

 

You think a blown headgasket on a Soob is a PIA. I was cruisin' down the freeway when my diesel blew one. Trashed the engine and turbo before I could even pull over to the side. A used engine cost me $2800 (no, that's not installed, just the cost of a JY engine)!!! Couldn't afford to replace the aftermarket turbo, too. So, had to make it normally aspirated after that. Same vehicle had the water pump seal go out one time, that was $400!! $365 just for the pump!!

 

They've got their uses and are stupendous for some applications, but I'll never buy another one for what I do.

[outback_97]

Buddythedog said:

 

If you drive 20K per year, an extra 15 mpg will save you approx. 3000$$. If you have the car 5 years, that's 15K just in fuel savings.

 

 

I'm having trouble with that math; doesn't seem right. Say a gas engined Subie gets 25 mpg. That's 800 gallons in a year, if we assume 20K miles a year. At $2.25 a gallon, that's $1800. Say a diesel VW gets 40 mpg (extra 15 mpg as stated above). That's 500 gallons of diesel. Even if diesel was only $2 a gallon (it's higher, right? I don't know ATM) that's $1000, for $800 a year savings, not anywhere near three large. If you drive fewer miles, or diesel is more comparable in cost to gas, then the savings go down from there.

 

Just trying to clarify.

 

Steve

[friendly_jacek]

I am surprised no one mentioned noise. I personally can't stand the noise of idling diesels. I drove my share of small diesels in Europe and just couldn't get used to. Even the advanced VW's TDI is unpleasant to my ears.