Going for 40 MPG, Let me hear your 2 Cents worth Options

[Porcharu]

"First thing- replace the V-8 motor with a small displacement 4 banger turbo diesel that had high torque at low revs . That's a max torque at about 1200 rpm and never run it above 1800 RPM. It was rev limited to 1800 rpm."

There you go, torque = acceleration coupled with tall gears and low revs, you've got the formula for high mpg. That's exactly why my old POS V8 Fiero was quicker and got better MPG than any CIS 911 I've ever had. Just the way of things.

I agree, while it would be cool to have a 914 that got 40-50mpg, what would that do to the "fun factor" of the car? If I can drive a 914 like I want and still get 30's mpg, I'd be happy.

(IMG:style_emoticons/default/driving.gif)

Sounds like my truck. 8000 pounds empty, with 3-5 people and a bed full of crap it consistently gets 23-24 MPG on trips to our house in the mountains. Big lazy diesel that never sees over 2000 RPM. The same truck with the gas V8 gets half that if your lucky.
I bet a VW TDI swap (maybe the 3 cylinder one) would easily get 50 MPG - and be fun to drive (same HP much more Torque.)

[Root_Werks]

Didn't the later Vanagon's have a 2.5 diesel? That'd be a cool swap.

[underthetire]

I think a VERY small diesel hybrid would be very cool. I figure if you can get 50MPG on a prius with a gas hybrid, a 914 diesel hybrid should get 100MPG.

[Katmanken]

And very, very, very, gutless...

To do this right, it's idle to max torque in 300 RPM,

And a whole extra 600 RPM beyond that so you can pass....

Wooo whoooo...... (IMG:style_emoticons/default/smilie_pokal.gif) (IMG:style_emoticons/default/blink.gif)

VW van diesels were the stock VW Rabbit gasoline block with a diesel head. All the durability of a block designed for gas engine forces, with the extra shock loading from diesel pinging. None are rumored to survive.

[orange914]

The HF CRX was like 1.3 liters, thats why they got good mileage.

honda (80's anyway) ... small displacement + lightweight = M.P.G.

[Root_Werks]

Hybrids these days chant about 45-50mpg figures. Big deal, my folks bought one of those Geo thingies in the early 90's. It got 45mpg with 5 people crammed in it while driving in town. They took it on a weekend trip shortly after getting it and I can remember my Dad getting all excited when they came back. Almost broke the 60mpg mark with all the freeway driving they did.

Slow, small and ugly sure. But they bought it just for commuting. Didn't care what it looked like.

[realred914]

funny how big and fat "small cars" these days are, compare the early civic to the latest. the mpg is horrible, back int eh 1970's/80's we all thought mpg would go up to double or triple of 30 mpg, instead it has not, cars are bigger with more power crap in them, yet the mpg is about the same or worse

the new hybrids gets near 50 mpg. my old 1958 VW bug got about 35 mpg, so I am not impressed with all this wizbang tech giving a less than 50% boost in mpg.
the old Triumph Spitfires with Overdrive would get 40+mpg


50 years and no real progress in mpg of the average car. oh well, the arabs love it.

[effutuo101]

I remember when oil companies like oh, ELF were major shareholders in the car companies...

[Porcharu]

And very, very, very, gutless...

To do this right, it's idle to max torque in 300 RPM,

And a whole extra 600 RPM beyond that so you can pass....

Wooo whoooo...... (IMG:style_emoticons/default/smilie_pokal.gif) (IMG:style_emoticons/default/blink.gif)

VW van diesels were the stock VW Rabbit gasoline block with a diesel head. All the durability of a block designed for gas engine forces, with the extra shock loading from diesel pinging. None are rumored to survive.

Sorry I call BS - they are dimensionally the same but the blocks are stouter, the cranks are different and the rods are much bigger. Some VW peeps are up to 200HP with the turbo 1.6 @ 6000RPM. I have no idea how they do it. Those engines last a long time if maintained.

[Porcharu]

Didn't the later Vanagon's have a 2.5 diesel? That'd be a cool swap.

The euros had a delivery van that had a 2.5 TDI. 140HP with a safe for for big loads tune. If I can find one it is going into my Volvo (I have the special bellhousing for the diesels - Volvo used a 6cyl version of the VW diesel so the bolt pattern is the same.)

[realred914]

And very, very, very, gutless...

To do this right, it's idle to max torque in 300 RPM,

And a whole extra 600 RPM beyond that so you can pass....

Wooo whoooo...... (IMG:style_emoticons/default/smilie_pokal.gif) (IMG:style_emoticons/default/blink.gif)

VW van diesels were the stock VW Rabbit gasoline block with a diesel head. All the durability of a block designed for gas engine forces, with the extra shock loading from diesel pinging. None are rumored to survive.

Sorry I call BS - they are dimensionally the same but the blocks are stouter, the cranks are different and the rods are much bigger. Some VW peeps are up to 200HP with the turbo 1.6 @ 6000RPM. I have no idea how they do it. Those engines last a long time if maintained.

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

[BiG bOgGs]

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.

[charliew]

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.

[Katmanken]

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.

[r3dplanet]

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.

[johannes]

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.

[Bleyseng]

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.

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....

[BarberDave]

(IMG:style_emoticons/default/smilie_pokal.gif)

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.

(IMG:style_emoticons/default/driving-girl.gif) Dave (IMG:style_emoticons/default/slap.gif)

[pbanders]

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.

[Drums66]

I find trying to make a high mileage car out of a sports car just sad.
Buy a Honda.

Yes.......what a bloody sacrifice?.....gas milage over raw unchained
*POWER* (IMG:style_emoticons/default/boldblue.gif) (IMG:style_emoticons/default/thumb3d.gif)