Title says it all..
What I'm working with,
'71 1.7 F.I. Yellow 914
Recently yank dual carbed 1.7,(smokes)Oh really?

anyhow I've installed another good used motor, with complete F.I.
Pertronix ignition and Stainless Steel Heat Ex's.
Bursch exhaust.
Sorry, no K & N, staying with Oil Bath Air cleaner
The guy has to drive thru a couple miles of dirt road.

Any other tricks to help with getting the 40 MPG goals?
I said he'll have to stay with those skinny tires though.
Am I correct?

I've over 30yrs of "Practice" on 914.
One thing struck me, I found some SOLID alum. motor mount.
I know it helps with shifting but
Kinda of "tighen" up the motor to the car.
Worth the trouble?

Let me hear it people!

I one tanked it from Castle Rock to Albuquerque one year. I think about 37 mpg in the Copper 2.0

40mpg isn't out of reach on a good strong 1.7 or 1.8 for freeway traveling.

I'd think it'd have to be FI and tuned 100%.

I've had a couple of stock 1.7's that always seemed to pull mid 30's even after calculating how far off VDO speedo's always seem to be.

Dave (DraperJoJo) got 37 in his 2.0 coming back from RRC. 40 should be doable in a 1.7 but, I'm thinking you'll need all the help you can get (tailwind, downhill, etc.)

I did a "best mpg" 74' super beetle a few years back. Being carb'd it had it's limits, but I learned alot from it:

Disc brakes have less drag than drum (Not a 914 issue I know)

Tire size has a lot to do with it. For a mpg 914, I would go with 185/65/15's pumped to almost 40psig.

Fuel delivery, no carbs, keep it stock FI with good clean working components

Strong spark and plugs, like the old DTC's, loose the points etc

Healthy engine, 60lbs comp isn't going to help you in your quest for mpg

Good alingment, this added 2.2mpg to my Bug.

I almost bought the yellow 1.8 CAMP914 has for sale just to do a mpg 914. But everyone knows yellow is just too fast.

High pressure in the tires. Like the "MAX PRESSURE" rating on the tire sidewall.
Low speeds. Rolling resistance goes up linearly with the speed, aero drag generally with the square of the speed.
Tall gearing. You want the RPMs to be as low as you can live with. (NOTE: This can be a problem in air-cooled cars, where the RPM determines the fan speed!) It is better to be at 1/2 throttle in a very tall gear than just off-idle in a lower gear.

So pump the tires up to 40+ PSI, and run the car at the lowest speed you can stand in 5th gear. Keep a close eye on the head temps, and if they get hotter than you like either downshift or speed up. (The latter by downshifting then speeding up then upshifting, of course.) And avoid slowing down and stopping if at all possible! If you're driving in the city, this means "timing" the lights so you hit as many of them green as you can.

In a more modern water-cooled car, you can shut the engine off and coast, but I think that opens up the door to the possibility of significant problems in an air-cooled car.

--DD

Aerodynamics:
Diffusor tabs on the trailing edge of the roof.
Front air dam to keep air out from under the car
Remove rear valence or put a sheet of somethnig under the rear of the car (careful with cooling)
Remove the mirrors and use a single small F1 stlye rearview mirror
Remove the antenna
Put skirts over the rear wheels
Chrome dome wheels

Weight reduction
Replace bumpers, hoods with glass or carbon fiber
Remove sound deadening materials
Go with early style doors
Plexiglass rear window
Strip the interior as much as comfortable


More advanced:
Replace motor with small displacement Subaru and custom EFI tuned for low fuel consumption.

With all of that you could get 60 mpg I bet.

I have heard of a stock 1.7 (carbed) 914 getting 49 mpg on a long highway trip, driven very carefully.


-Tony

Would a thermostatically controlled electric fan work? In theory, it would only run fast enough to keep the cylinder heads (or oil) in the correct range. I've never heard of that used on air-cooled cars before but I'm pretty sure that's how most/all late model water pumpers work. (Of course the heat transfer properties of water are better than air. That might have something to do with it.)

I've been told exactly opposite. You want the engine to be at cruise speed about 40-60% of your max horsepower RPM. Thats why those little fuel efficient Hondas and such run a fairly high RPM on the freeway.

I recall seeing a Raby 50mpg 2.0 advertised (or perhaps under development?). Is anyone here running that motor?

Update:

A quick google search turned up:

http://www.aircooledtechnology.com/r_d_sds_efi.htm

From the last paragraph of above page:

"'Super 2 liter plus' 2016cc RAT R&D engine that’s working toward a 50MPG fuel efficiency while making 110+ HP with a flat torque curve"

That's a motor I would love for a daily driver!

Found another discussion:

http://www.914club.com/bbs2/index.php?s=&a...st&p=401255

Great tips guys!

I knew there's a few more ideas.

My very first trip in my first 914, (bought in '85)
Made a trip from Denver, to ASPEN!
Work related
I tell everyone to take a drive in the twisties as soon as possible,
cause I did!
4 hr trip in three
and after getting home, on same tank!
I figured around 40 +!
All this during ski season.
Think the COLD air helps?


When I change tires for handling (wide)
there went the mileage.

Yup....the 914 only restarts 60% of the time.

914 restarts?

Go downhill. Alot. Throw that baby into coast mode.
Find the right hill, and the sky's the limit. lol
Joe

Hiya Kevin,
I averaged 32 mpg in the silver car from Denver to Seattle. Average speed about 68 mph dial it in, inflate the tires and go for it.
In driving my wifes jeep I found that I could squeek out a couple of more miles per gallon by shifting to netrual and coasting down hills, up off ramps, to a stoplight. No reving the motor unless necessary, and long un intrupted highway driving. 60 mph may be slow when the speed limit is 75, but that extra 15 mph cost a lot of fuel. and the puppies may have to deal with the windows up during free way driving.

I haven't had to fill up in a week. Jack stands get great fuel economy.

Got 44 mpg from NorCal to Denver in a 1.7 and I was haulin ass every chance I got. It's easily do-able.

Cold air is BAD for MPG - kills the vaporization. The mileage nuts put manual choke cables on the heated air coming from the exhaust manifold that is usually only on only during cold starts. Claims of several MPG are claimed. Skinny tires are good. On my 8000 pound truck going from 235/85's back to 265/75's (same brand and type, same diameter) cost me a about 1 - 1-1/2 mpg 24 down to 23 or a bit less.

How did you stay awake?

Ah, the crisp morning air and a bunch of 914's racing through the Rockies on thier way to RCC. Then just wedge the foot and headed for home. I started about 4am and had to stop at 11pm due to weather in Idaho. Then back up at 6 and home. Way to much Mt. Dew.

Practice your technique.

Watched a myth busters last night where they proved significant milage improvement from texturing the body surface like a golf ball. Not for the CW's

Convert to diesel - good for about 25-30% milage increase.

To be blunt, you've been told wrong. The Hondas that get better mileage have taller gears. The CRX HF, in particular, has exceedingly tall gears. That's one of the things that helps it get good mileage. And a number of people have switched to taller gears in several different types of cars, and all have gotten better economy.

--DD

I haven't measured it scientifically, but I think I get about 10mpg...LOL

Kevin you are a pisser

I did that drive but the other way around from Abbotsford BC to Colorado Springs being chased by a storm in November with near bald tires on my old truck. Got new ones in the Springs. Damn long drive by yourself.

I was able to get 34-38mpg consistently in my well-tuned 1.8.

Okay, it wasn't well tuned. Just tuned.

205/65/15 tires. Good fuel. Clean filters. Clean injectors. Good spark (MSD). Good induction and exhaust. Keep it at 3000-3200 rpms for long distance drives.

40mpg is not unattainable. You could re-gear 5th so that you cruise at 2600rpm in 5th doing 75. There may be cooling issues but... You would get good MPG.

My 84' Civic with a mild cam and simple header got 54MPG on the freeway at 70MPH. This was with a CARB and that silly extra valve thing that Honda used to do. After I swapped the 130HP Integra engine and trans (lower final drive) my mileage dropped to the mid 40's but never less than 30 even when beating the living crap out it (like running at full tilt to see just how fast it would go - M on the speedo, think to the left side of the odo!)

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

Programmable EFI

Skinny tires will help. Go for the original 155 or 165 x 15
High pressure will also help
The slower you drive, the best milage you will get. Going 60 instead of 65 will help.
No cooling issue because your engine will not generate a lot of power. 15 hp are enough for 60 mph.
I owned a 1964 Citroen 2CV. It was rated for 18 HP and could reach 60 mph with a bad aerodynamic shape.

Remember as a general rule:

Torque = Acceleration
HP = Top speed

Lazy, higher torque engines with taller gear get better mpg than high strung short geared cars do.

I know, there are about a million exceptions to this.

I had a 4.5 V8 Fiero that always touched 30mpg averaged with a good tall geared 5spd.

I've also had a 77' 911S all stock that got low 20's for mpg at best driven normally. So much of it has to do with fuel delivery. CIS doesn't compare to EFI systems.

My current 914-4 2.0 with carbs probably gets upper teens. And I baby it. Worthless.

So if you want that 40mpg 914, get any stock FI 914-4, make sure it's tuned 100%. Good alingment, tires (no 205's either) and drive it easy. I bet you'd get darn close in any stock 914-4 FI to 40mpg. Even if you never made it, you'd get close.

Our little CRX ran about 2.5K at 65 MPH, so I wouldn't call that real tall gears. I mean, if you've got to keep your foot in it to keep going, your putting more air through the motor, causing the ECU to add fuel to compensate. Doesn't make sense to me. The HF CRX was like 1.3 liters, thats why they got good mileage.

Coming back from the Route 66 in 07 Linda used 6 gallons to go 295 miles. She was running 205-50's and stayed above 70 most of the way. She was running twin Solex's with a D-Jet cam. 49.16 MPG
Thomas ran twin 34 Webers and was getting 44 all the time.
If you want to get good mileage cheap look into putting the 34's on your D-Jet and you will smile at the Pump. You will suffer from the lack of head-jerking preformence that you lost from the conversion of the 1700cc's. I have to admit that I did notice a loss of power but the MPG is there if someone wants to do it.
Just from my experience I would do an L-Jet and put it in an early car with the tallest tires I could find. Put in all new wheel bearings and clean and grease the C/V's.
I THINK 60 MPG is waiting for one of Us.

I've always wanted to build a 50mpg 914.

I was really on the fence about the yellow 1.8 CAMP914 has. I think that would be a great platform to start with.

my old 1.7 914 would do about 35 mpg driven HARD round trip to yosemite (about 500 miles) lots of hills and windy roads, really had my foot into it, (really hit 100 mph and caught air on a hill) this with 195 50 tires (stock gears) so my rpms were a bit high. this was an ealry car (lighter doors)

i assume if I had high pressure tires that were skinny i would have done better, also would have done better if I had actually tired to go slow


this was the early high comnpression 1.7 with stock FI system. good old real 92 octane gas (now days expect 10-15% lower milaegae on the "new" oxygenated gas shit that the nazi smog folks force on us. I noticed the drop in MPG in all my cars when they switched to the shit gas. just as they said it would do, 10-15% reduction in mpg. dam the californianazi government


keep in mind, depending on the attitude of the jack boot thugs that run your state, your milage may differ with their "new ' gas. (plus it cost more!!!)

You want a high mileage car?

Saw a 80-115 MPG Mustang once at an American Society of Mechanical Engineers meeting. It was built by one of the Ford GT engineers that built cars for the 1960's Lemans races. He went into exactly what he did in front of a pack of initially critical engineers, and how he allowed several packs of reporters to beat the crap out of his car for several days to verify his results. Basically, he handed them the keys on Friday and said "Bring it back on Monday". They verified the mileage.

How did he do it?

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.

For today, new engines are available and maybe you should look at Kubota garden tractor engines. I think there is a 2-3 cylinder diesel engine that meets the high mileage requirements and it would sip even less fuel than a 4 cylinder. Not much on acceleration but high mileage.

Go with the proper gearbox gearing to have the max engine torque at 1200 RPM to coincide with 60 MPH.

Use special high pressure tires.

No muffler to impede back pressure.( ie use straight pipes ) Why? With a max of 1800 rpm, it's a little faster than idling and the engine it doesn't make much noise.

A little bit of aero ( plex headlight covers) and that was it.

A high mileage gutlless wonder that never exceeded 1800 rpm.

Wit the normal teener engine, you should never put your foot down on the accelerator or your mileage goes to heck. Put in a rev limiter that kicks in at peak torque. This will cause your top speed to go down becasue you can't exceed peak torque, but hey, your stated goal is simple- high mileage which means not fast.

And I agree with Mark. Why turn a great handling sports car into a low revving gutlless wonder? Wouldn't a garden tractor engined Yugo work about as well or maybe better?

"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.

You can have both.

Yup, and gutless at normal teener RPM's too

That's just sad....

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.)

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

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.

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......

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.

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

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.

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.

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

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.

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.)