what can I expect to get as MPG for an entirely stock 73 2.0L w/ stock FI -- if I keep my foot out of it all the time

120 mi / 6gal=20mpg with my 2.0 (worn out heads)

Last time I calculated mileage with my 1.7 i got 22mpg.

I bet its a bit better niow

that sucks!! my 6 cyl acura gets 25

well...i like my cars a little richer than usual....

but I dont believe (until I see it) that a aircooled engine (stock FI) could get 40MPG and not cook heads.


Your acrua is probably just a tad newer than 30 years old....and I bet that your car is OBD I or II, which helps keep everything in check, not to mention its probably not 2nd gen FI either.

hmmm very true ... but still a might disapointing

Yeah tell me about it....especially when you plan trips and have to pay double when you drive the 914 :garhhh:

ooo yeah ... I gues that nixes my road trip home to texas

I had one time where I could drive more than 100 or so miles on less than between 1/2 tank and 1/4 tank



I just had the singe carb installed and adjusted by the local Porsche mechanic

Oh, and I drive my 914 every single day....

been through one 2.0 and 2 1.7 engines (all used--2.0 was original engine)

owned and driven almost daily for five years

I usually get between 25 and 30 MPG
bored 1.8 L-Jet
running pretty rich to boot (waiting on the O2 setup to tune it right)

my engines are used, I know on one trip I got 22MPG

with my 1.7

Your results may vary, but I wouldnt expect 40MPG

I drove from Marietta Georgia to Potomac Maryland, 682 miles, & stopped once for gas in my mostly stock 74 2.0 D-jet. I have OEM euro pistons & a Bursch exhaust. I made the trip in 10 hrs averaging 65 mph. When I made it home I still had 1/2 a tank. That's 682mi/24gal = 28.4mpg on the highway... I don't drive her in town, ever .

I've suspected that my '73 2.0 mileage is around the low twenty's with a Bursch and no other mods and with moderately aggressive driving. That said, I remember Porsche used to advertise that you can drive a 914 from San Francisco to Los Angeles on one tank of gas - something that my father said he did when he owned the car.

My Dad had gotten over 40 on his 1.7L. I know this for a fact, he's not the type to care about gas mileage. It just amazed him. I know Joe Sharp tuned a car that was getting 49mpg too, but that 914 had single barrel Solex carbs.

I think that a 2.0 should be getting somewhere around 26mpg or so.

Not to bash Britt, but there is no reason a stock 1.7L should be getting under 30mpg unless he drive it like its a raped ape all of the time. It just doesn't make sense. The 2.4L /6 in our 911 gets better mpg than that.

There are many apocryphal tales of 914 and VW gas mileage - stories of T1's that got 40+ MPG on mountainous freeway drives, 1.7L 914's with FI that never got less than 36 MPG, etc. It's hard to sort out what's true...

I've had two engine configurations in my 914. The first was a 2.2L with 40IDF's built by Garretson's. I kept regular records of my mileage, I never got more than about 22 MPG on the freeway and as low as 17 MPG in town. With my 2.0L stock D-Jet FI motor, I got about 20 MPG in town, and I think I saw 24 MPG once on a freeway run. I recently got that motor rebuilt, still at the shop, so I don't have any data on it yet. YMMV.... as they say.....

BTW, as a point of reference, last weekend, I went camping with my family. We drove from Phoenix to south of Tucson, gaining over 3000 feet in elevation, and driving at 75 to 80 MPH (on cruise control), in a fully-loaded 2004 Toyota Sienna with the A/C on. Round-trip gas mileage was 26.4 MPG. IMO, modern cars are far, far better than these ancient carb and early FI cars.....

I could consistently get 36 hwy with my 1.8. My six gets about 13 MPG.

yyyeah....\

forgot about that, my aftermarket exhaust does take away MPG

I've never gotten good mileage. With my old 2056 (stock cam & compression, djet) I averaged about 20mpg. With my rebuilt 2056 (#73 webcam, 8.3:1 compression, djet) I now average 24mpg.

Demick

Stock 73' 2.0 with D-Jet

32 highway
28 city

I took precise measurements of mine years ago when it was driving great and had 65,000 miles on it. And I kept verifying the result for many years afterwards- cause I'm a dork like that. All stock except for my tires- I was running 185 60 Michelins with the correct pressure. But actually those 'slightly larger then stock' tires should have theoretically worked against the MPG. Also having the top on gives better mileage. Oh yeah, and 86 octane gas.

I make it a habit to measure the mileage almost everytime I fill up- when the gas light comes that's my starting mark, reset the trip Odometer, fill it up, note the exact amount of gas added and so on.. I was always surprised by the 'greeness' of the car, especially with the 1970's technology.

Betty gets around 28 to 30 mpg on her 1.8L.

I get around 18 to 20 on my 2.4 MFI six. But MFI is notorious for being a gas hog. And I do drive it like a madman all the time. I just cannot keep from running it up to redline at every gear. It just sounds soo nice.

I got 32 with my early 1.7L car was about 2250 pounds 205/60-15
29 MPG with carbed 2.0L before A/F meter tweek and Tangerine. with dragging rear brakes. 195/60-15

Now 1800 pounds 225/50-15 tweaked out as much as I can 13.5:1 A/F cruising I am doing much better if I would ever keep my foot off the floor (ain't gonna happen).

Still gotta stop to pee way before I need gas.

30 - 35 mpg with my 1.8 with stock D-Jet
30 - 35 mpg with my 1.7 with stock D-Jet

Andy

1.8 with D-jet....

must have been optional?

I never got more than low twenties and usually high teens. After 3 years of ownership I found a fuel link and started to get around 25mpg. (BTW, I never smelled fuel or would have ever guessed that I had a slow leak.) I'd recommend that if you don't know how old your soft lines are then just replace them.

nope. but you'd be surprised how easy it is to put a 1.7L D-Jet system on a core 1.8L motor ...
Andy

Irrelevant, but I get 6-7 from a wild 2056 on the track. That's at $7.00 a gallon!

I did a mileage check when I drove up to Garold's last fall for his BBQ party. My 2.0L w/Weber 44s got between 27-29 mpg (had to estimate some of the off-interstate distances).

On track? No idea. I can fill up near my house, drive to the track. Run my lapping sessions and then get back home w/o needing to fill up...

30-35 MPG with a very old 110k miles stock 1.7 that has serious blow by.

I figure with a heavier flywheel, a new 1.7 rebuild, 35 solid MPG should be fairly easy, and consistent.

But, I did not set out on this adventure with MPG as my first objective...
So I will not be heading down that road...

If I were to build a high MPG 1.7,
I would do alot of the same HP tricks, but with the mindset of higher MPG.

For instance.
Lighten everything up inside the motor.
a Lighter crank, and valve train just simply will take less fuel to move around and produce the same power.

I would start with the 1.8 heads, for the better flow and port angles, and weld them up for the smaller cylinder diameter,,,or make a spacer like Chris did CFR...

Just go down that road of pure efficiency, and you end up with the same needs as a high horspower motor...all except the big valves big pistons big stroke and big everything else.

I think that Britt should build a 40mpg 1.7.
It can be done, and it will happen eventually...it just needs some head tuning and a bit more of Jakes time to look it over...he was really close, but gave up for other projects.

I am sure its coming from Jake, but it should be something that the average guy can figure out, given a bit of advice and the right parts...

Rich

Id freak if I had a powerful but yet efficient 1.7

Right now im skeptical that it could be done.

Everybody that gets *good* mileage, what exhaust are you running?

Stock or Non-Stock.

i ran non-stock. the captn calls them boat-anchors. mine was a manta 4-tip ...

the key here is, all FI components, including the engine harness were in very good shape (rebuild), valves and timing adjusted, new fuel & vacuum lines.
jada jada ...

made a world of a difference ...

the motor itself was tired and had some oil blowby on decel. but the mpg was great on the street and the highways.
Andy

very intresting!

I have the manta, its one rusty muffler, I want a coated stock exhaust to run

Wouln't a high performance exhaust help mpg? efficiency is efficiency right?

I did not say powerful.

But that is truely a matter of perspective.

The truth of the matter is if you look at the original design, it was always a compromise, kinda a middle of the road split between good mpg, and power and longevity.

Properly done, with some chamber work on the head, a 1.7 liter could be the most efficient aircooled motor.

You would need to take alot of time to measure and balance the motor, blueprint it, get a lighter crank, redo the heads...it certainly can be done..

Rich

Anthony, I've just got to do the math on that...

Let's say you drive your 100 miles a week. At 20 MPG, that's 5 gallons a week, at 25 MPG, that's 4 gallons a week, so if this difference was due to a gas leak, you'd be leaking a gallon a week. If the leak was in an unpressurized part of the system, then this would be over the full course of the week, if it was in a pressurized part of the system, assuming an average speed of 33 mph, it would be over 3 to 5 hours (since the system bleeds down from high pressure). Either way, a gallon leak per week is a LOT from my experience - you'd see and smell gas easily. Even if it was a steady leak of a gallon over the course of a week, that's 128 oz / 168 hours, or about 0.76 oz/hour - you'd definitely see and smell that! I've got a leak coming from my tank fittings right now that's about a drop or two a day, and it stinks up my passenger compartment....

Not saying it didn't happen - just saying the numbers are hard to understand. Maybe you drive a lot less or more than I'm suggesting here....

Ya know, it's hard to find info on what the volume of a "drop" is, leave it to Wikipedia....

Given a couple of the measures given, a drop is somewhere near 1/300 of an ounce - so there are about 300 drops in an ounce. If that's the case, if you have a leak of 0.76 oz/hr, this would mean you're leaking about 228 drops per hour, or one drop every 16 seconds - that would be a very smelly leak....

What about an opening somewhere allowing gas to evaporate . . . it evaporates pretty fast, not that fast but still pretty quick.

My brand new 73 1.7 got 34 in town and 42 on the highway. the national speed limit was 55 mph then! At 55 in 5th ( thats about 2800 rpm) 40 plus mpg should be expected from a well tuned 1.7L. My 75 2L FI gets 22 in town and 30 at 75mph

Brit, Maybe theres a reason why you've been through 3 motors in two years and your mileage sucks?

Yeah, I already know I dont know much about cars. I'm a computer geek, and taught most of what I know myself.

Now I understand things like timing and fuel mixtures---something that would keep an engine alive.

Not everybody knows everything the first time around

And because I now know about timing and its effects and learned from running a single carb---this engine has been VERY dependable for a used engine.

A former NASA astronaut found a rather inventive way around this problem.

I've been driving the car more like 1500 miles per year. Does that work with your math?

My numbers are really off the top of my head because I never made mileage records. Then there is also the issues of smaller than normal tires (195-60-15) and inaccurate 30 years old odometers.


The bottom line for me is that I noticed a tank last a lot longer after fixing the leak.

My first 2.0 was AX modified by PO and it got 22-26mpg. My 1.7 got 32-36. My current 2.0 gets 27-29.

Makes more sense, it's sitting more, so it's got more time to drip and evaporate. 1500 mi/year is only 28 mi/week, so it's taking you nearly a month of driving to notice a 1 gallon difference.

I just thought that if it was a gallon a week that it'd be noticable....

I drove my 74 2.0 FI from Moab Utah to Draper Utah coming back from Red Rocks "06" and went 208 miles on 5.52 gallons. The car has 61K original miles on it.

Yesterday I got 29.5 MPG @ 80 MPH loaded down with AX tires jack and all kinds of other stuff.

Guess that big ass wing ain't so bad after-all.
225/50-15 Hankook R2 sticky street tires.

The best method I have found to get a more realistic figure is to buy 10 galons of gas when the light comes on. Repet 5 times, then divide the acccumulated mileage by 50.

When i used to have taller 195/65/15 tires on my unmodified 1.8 I would get about 33-35 all highway. Around town I would get about 28-30. Now I get about 20-25 with 195/50 tires.

Well thats mighty intresting....

I have 195/50s and I get 23.75MPG on the highway(200 mile trip tested--with sun poisioning!)

Where does one find 195/65/15 tires?

Local tire shop... I had Bridgestone Potenzas on there before, switched in favor of the fuzions.