Yeah my thought too, didn't the rabbit come optioned with a purpose built deisel?? and that was the basis for the vanagon diesel.

my dad test drove a vanagon deisel back in 1986 he bought the gas one. with only about 55 hp it was less HP to lbs ratio than his old 63 microbus.



Now when the rabbit deisel came out, during the gas crunch when I was a kid, it was known to be very reliable. unlike some American deisels cars that actually were nothing more than gas engines modified to run deisel, they had short life spans, and were a joke. Thats what I recall, detroit offered a lot of gas engines convereted to deisel and it was a disaster. VW had a great reputation for its diesel rabbits

I am enjoying finally getting my 914 on the road, but I too am interested in getting more MPG's out of her. My other toy is a 88.5 Suzuki Samurai that I transplanted a VW 1.6L turbo diesel into. Even though it is a junkyard dog pulled from an 85 Jetta, it is on the low end of acceptable compression, and Samurais have all of the aerodynamics of a brick, I get 29 MPG while driving mostly in the 45-50 mph range.

Really makes me interested in what one of those 1.6L TDi engines would do for a 914.

My youngest son had a 98 integra type r when he went to a&m in 99. It was geared about 4:44 with a 5 spd. We had put a 4-2-1 header on it and a cold air intake. It sounded like a early z28 at about 6k-8k. He drove it 80 and that was 4k, it got 35-38 all day long with the ac on. That was a great little college car. We made a mistake and he traded it on his 05 sti after he graduated, it only had 60k on it. Then he started hot rodding the sti and he bought a suzuki sidekick 1.6 with auto and ac and 4wd for a commuter. It got 28 at 75 with the ac on, he wanted a 5 spd but the auto one was priced right. He drove it three years and got back what he paid for it. We got it wholesale in oklahoma on the net. I worked on it two weeks after we got it home doing the belt and plugs and checking the valve lash and etc. He did have to put tires on it while he had it. My opinion only is that a air cooled motor will always need a richer ratio to run cool enough to be safe than a water pumper.

All I can say is: having lived through the Rabbit era, the original Rabbit diesels used the same engine block as the gasoline engine ( aka - a cost cutting measure), but bolted a higher compression head on them. Same rod bearings as a gas engine, but with knock loads applied to the same bearing surface area. It was a topic of discussion one night in my Graduate level college class ("Combustion Engines") complete with math analysis. The classmate that that brought up the topic had owned one, hads lost an engine, and insisted it was a POS. The math showed why using a different block with wider bearings is a good thing for diesels to survive the higher loads from knock.

Another friend lost an engine too. So, two of my friends owned them, both lost an engine, and both thought they were a POS. Not to mention the other "fun" problems they were notorious for. So, BS to yer BS, I got pissed Engineer friends to argue design flaws with you, and the professor that did the analysis was reasonably competent. He did the landing gear on the Apollo lunar lander.

My Diesel Rabbit kicks ass! When I bought it, I pulled the 4-speed gearbox and replaced it with a 5-speed, which was an option. I looked around and found that VW sold a half-dozen variants of the transmission with various gear ratios. I went with the one with the tallest 5th gear. I average 50mpg. It's not stylish, but it puts me in the good graces of the local Diesel crowd. I fill up every .. month. Those diesel motors started off with the lousy 1.5 motor, but it improved every year. The best ones are from 1983-1985, especially if you're lucky enough to find an EcoDiesel model.

Besides, what's the worst that can happen? Changing the head gasket could take you, I don't know, ALL MORNING to change out thanks to the uncluttered, simple layout.

I got theese figures from a french magazine called "Autojournal". The figures come from three different issues from 1970 to 1973.
The test was always made at the same place: Montlhery speed track.

Mpg are mesured at constant speed in fifth gear, so they are the best you can reach.
The tests are made with regular cars with regular tires at regular pressure (the 1.7 had 155 tires).
Targa top in on, windows closed, headlights are turned off and there is only the driver on board.

These figures are for european cars wthith slightly higher compression and may be a little better than the US cars...

As you can see, you better drive slowly if you want to achieve 40 mpg, but it is doable with a regular 1.7 914.

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That is a interesting chart and yes, my 2056 gets 30mpg going 75mph on long trips!
I had a new 84 Rabbit diesel and it got a easy 50mpg when new on trips! Totally gutless like a 30hp 57 bug.....I never had a engine problem and sold it when it had 75,000 miles for a POS Colt Vista 4 wheel drive that the tranny blew up at 25,000miles....

My orginal 1.7 not in particularly good condition. Tuned well, stock size tires,(

any bigger throws off the trip odometer ,& speedometer ) . I could make the

trip from Toledo to Tweeks Fur Fest on 1 tank of gas . It was just ofer 400

miles with a little remaining . This i credit to the punny 34 itc's i had a it then.


Damn thing would run 90 mph all day long, ( but It took a half hr. to reach that

) . I still think a well tuned F.I. is the over all best for performace and mileage

you can do a lot to increase mpg but at a big price in driveablty . I feel the

reason I have this car is to drive the curvies with wild abandon.

Dave

I didn't read the whole thread, sorry if I'm repeating anything. If I were going for max highway MPG from a 1.7 w/D-Jet, here's what I'd do:

1. Drive with the roof on, windows up, no passenger-side mirror. Use interior ventilation.
2. Change to narrow, stock sized-tires. Inflate to spec pressure for the 914. If you want, experiement with higher pressures up to the max recommended pressure, be aware this could negatively affect handling
3. As the chart from the French magazine showed, lower speeds equal higher mileage. Avoid driving 5 - 10 mph over the speed limit.
4. Engine in perfect mechanical condition (incl. valve adjustment). Timing and dwell spot-on, plugs perfect.
5. Verify injector spray patterns are perfect, fuel pressure at 2 atm.
6. Fuel and air filters clean
7. Use the procedures on my page to set the part-load adjustment of the MPS to the leanest tolerable mixture. In a cooler climate you will be able to get away with lower CO. Start at 2.5% and work downward. I've had good results with 2.0% in cooler weather, and the car even ran decently at 1.5%. Invest in a CHT meter and oil temperature gauge to make sure your engine temperatures aren't too hot.

Yes.......what a bloody sacrifice?.....gas milage over raw unchained
*POWER*

I think most also don't factor in cost of this high mpg figure.

A 40-ish mpg 914-4 isn't going to break the bank by any stretch.

A 45mpg Prius will set you back what, $45-50k?

Umm, gonna never see a return on that fuel savings vs another new car for $25k that would get 35mpg and be twice as fun let alone a decent little 914 for $5-8k.

although the VW TDI contingent might not agree.

Way back when...

I drove my 72, 1.7, which was about 2 or so years at the time, from Portland O, to the SF Bay area, a distance of about 640± miles. Tuned regularly, all stock, lowered slightly, 165 x 15 tires, top on, driving in the 60 to 65 mph range...many miles of straight line driving, weather was generally cool. Left about 7 am, got in about 8 pm, I-5 wasn't quite complete then...the mileage: 41.5± mpg. I was amazed...beside the mileage, I drove straight through...with one or two p stops.

As road trips go it was not as much fun as the drive up...many more stops!

Back in the 70's there were several articles in "Hot VWs and Dunebuggies" on high mileage Type 1s. I still have some of these. The one I still want to build is a 2 cylinder. Very easy to do using the rear two jugs. Some airplane engines I'v seen use two on the same side. They bolt a plate over the other side. Cooling no issue as they are "slipstream" cooled. The other thing I remember from those high mileage engines is that you want a lot of rotating weight, IE heavy flywheel and front pully. I'll build a 2 cylinder one of these days.

My 2nd-gen Si runs 3000 RPM at 60 MPH. Short gearing. (0.771 5th, 4.25 final drive)

The 2nd-gen HF runs about 2000 RPM at 60 MPH. Much taller gearing. (0.695 5th, 2.95 final drive)


...An as I said, it is one of the reasons. The 2nd-gen HF had a 1.5L engine, but only made about 60 HP. The 1.5L "DX" (or standard model) made about 90 HP. The Si only had 100cc more displacement, and made 108 HP. Much worse mileage; EPA rating of about 30 on the freeway as opposed to 50 for the HF.



One reason that we don't see high MPG simple cars any more is because nobody will buy them. They fold up like accordions in a wreck, they don't carry much stuff or many people, they don't have 67 cupholders, there are no airbags, no ABS, no air conditioning, they accelerated from 0 to 60 MPH in about a month... They made compromises that were acceptable in the 60s, or 70s, or 80s, but that nobody is willing to make these days.

Don't blame today's cars for not being yesterday's cars.

--DD

I got 42mpg driving from L.A. to Las Vegas in my 1.7 once.
Just once...
A head melted on the trip back.

I think only one post even mentioned aerodynamics, which plays a huge roll in gas mileage. I like to run my car with roof off and windows rolled down as much as possible. With the 3.2 liter car I get 23 MPG with that configuration. With the roof on and at least the passenger side window up I get 26 MPG. A 3MPG difference just for putting on the roof and rolling up a window.

Cheers, Elliot

They did another series not to long ago as well. I believe they produced a Super Beetle with 100hp that was touching 40mpg averaged out. Pretty impresive.

If I remember correctly, the best combo they got was using little dual 34's, not the EFI kit, single carb combos or dual 36's or 40's etc. I wish I still had the magazine. I probably still do somewhere.

I think the EFI tunned for mpg lost power over the 34's, but only yeilded like 1mpg better than the carbs. Tuned for the same power as the carbs, it lost 2-3mpg vs the little carbs. It was a really good series. I read through it the same time I was building my mpg super beetle. It really brought to light the significance of tire size, pressure, alignment, body CD, brake drag etc. Lowering the beetle too much didn't help, but some did and so on.

Very good series. It's probably online somewhere.

remember to subtract about 4-6 mpg from the peak value shown onthe chart to account for todays oxygenated fuel that has about 10-15% less energy content per gallon than the typical fuel found when this report was written.

that 40 mpg quoated could be translated to low as 34 mpg with the "improved " gasoline forced on some of us.

all my cars dropped this percentage in mpg when they switched to the reformulated fuel. (plus the price per gallon went up )

Ain't the green thought process wonderful.

You go to a lot of trouble to figure out how to to better yer mileage, and they diddle the fuel to reduce your mileage.

ain't that the truth. so many shades of green. Sustainability versus air quality versus global warming. only answer is going back to living in caves. I'm working on converting my old teener to the fred flintstone look. rust is doing most of the work for me.

Somebody say RUST?

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This 914 wasn't getting 40 MPG!
Time to lighten her up
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This thread has peaked my curiousity.
As many of you know, I have a stock 1.8 ljet with an Audi automatic. I've never checked the gas mileage. Now the tub is a 75 and currently has the anchor bumpers and is completely stock, except it does have an early 2ltr exhaust system (exhchangers, banana muffler, no cat).

Any predictions for gas mileage?

1st = 2.71
2nd = 1.50
3rd = 1.00
Rev = 2.43
Final = 3.45