Fuel Mileage and your GT

[mr_udy]

I've got a stock '73 GT that is barely adequate as far as regular daily driving but have little money for upgrades. I figured with the gas prices the way they are now, maybe I could look forward to enjoying some decent gas mileage with some regular maintenance. I believe I checked it last year and only got 17mpg with a 4spd manual stock GT (poor runnning Solex). What about others?

[73Manta72gt]

last I check my mileage 72 gt with 1.9/weber was 37mpg. My 73 manta with a 5spd/weber/1.8 get 31.8 these were highway trips.

[Tire Fryin GT]

Currently my GT doesn't even use gas, but some day I hope to get it down to about 10 or 15 MPG, And if I can squeeze more horsepower out of it, I would like to drop it even more.

I guess we have differant goals in mind with the GT's

[greensmurf20]

i get 26.5 with a 71 GT with weber, larger camshaft and a 4 speed trans on stock height tires.

[baz]

Originally Posted by Tire Fryin GT Currently my GT doesn't even use gas, but some day I hope to get it down to about 10 or 15 MPG, And if I can squeeze more horsepower out of it, I would like to drop it even more. I guess we have differant goals in mind with the GT's

dito for me but i will be happy to get 10 mpg and we have a bigger gallon here 4.45litre insted of 3.8 litres in the states

[Old Hippie]

Please correct me if I'm wrong but wasn't the stock rating 30 mpg? I would think with a good stock motor, high-fire ing sys and a newer carb, you should be able to pull 35 to 40 mpg's. Depending on your drive habits.

[greensmurf20]

MPG is reflecting my driving habbits, cuz on the highway going to vickis house i got 31 MPG, overloaded by 380 pounds!!!, 2.0 complete in the back too! got 38 on the way home on a stock solex and points ignition still.

[Gary]

I "think" I remember getting 40+ MPG with my 1.9 '69 GT W/Solex on a trip back from Canada back in 1979.

Haven't checked it in it's current state: 38 DGAS, ported intake, Compufire, C&R cam, High comp Jahns pistons, Getrag, etc. Then again, I only gas it up a couple of times a season... (Too many toys...)

[nobody]

21 if I keep my foot out of it, around 17 with my foot in it.

11:1 w/ twins and roller s and a bit of cam, 5 speed.

Ok I get 15, big heavy feet. I drive comfy tho " both feet flat on the floor".

[hrcollinsjr]

When I was still driving my GT the best I ever got was a trip from Atlanta to NC, 33 mpg. My lowest speed was 70 mph but more like 80 to 85 mph with a stock engine, a header, electronic ignition, 32/36 DGEV, clutch fan and 4 spd. My typical mileage was 30 mpg if it dropped to 25 mpg it was time for a tune up.

Harold

[GoinManta]

I averaged 25 MPG in my Manta (2.0L With a 40FAV).

I used to get in the 28 range with my Kadett in H.S.

When delievering Pizza in my old beater Manta (back in the early 90s') I used to get 24 around town (Heavy foot AND stop and go).

From what I have heard the GT gets about 15-20% better than the Kadeet or Manta, ESPECIALLY on the highway, due to aerodynamics.

40 MPG highway is not uncommon on a well put together high compression motor, with a good Carb (Even Solexs in proper tune can be considered a good Carb) .

As for Points VS Pertronix.. the Pertronix will NOT get you better gas mileage NOR will it get you more power. IT will save you the maintenence of dealing with points though, and it will make the motor (and thus popwer and MPG)consistant.

From what I have heard, the Low compression motors suffered in MPG. IT doesn't help that your foot has to be in them a lot more due to lack of power.

Charles

[RallyBob]

Used to get 5.5 to 6 mpg in the old 2140 cc Opel race car at racing speeds. 75% 93 octane pump gas, and 25% 114 octane leaded race gas mix.

Not cheap to run, but worth every penny on the 'fun' scale.

[hrcollinsjr]

Ditto what Charles said about the Pertronix. The change that I noticed was that it ran the same way EVERY day. The plugs seemed to last longer but the mpg still seemed to drop off after 5000 to 6000 miles. I would almost regain the cost of the sparkplugs on the first fillup after there replacement. At todays prices it would be even more important.

Harold

[nbrcrnchr]

When my 70 gt was my daily driver in the early 80's, I would average 32 to 33 going back and forth to school. Teenage driver, with a lead foot. This was a 1970 1.9 liter 4 speed manual and it was in great tune at the time. I got as good as 37 MPG on the highway. Today, I'd like to say that it’s still in as good a shape, but that would be a lie. Now, I'm somewhat afraid of checking mileage and I need to do some work to get it up and running as well. Have a 38 dgas waiting to install. I need a new radiator core, probably new gaskets, it leaks all over the garage, etc. It's been sitting awhile and has been neglected.

[Paul]

FWIW,

The EPA rating on a 75 Manta was 19/27, 19 mpg in Town and 27 on the Highway. In the days of the 55 MPH speed limits, cruising I-40 at 63 mph would get me 29-30 depending upon wind direction.

[mr_udy]

WOW! Guess it makes sense that an underpowered car would require more foot...thus more gas but something must really be wrong with mine at 17mpg mixed city/highway. I could handle 17 if I had say 200HP or something but this is rediculous...slow car with poor mileage! I will verify it again come better weather then give her some plugs, wires, cap, rotor, points (never done this...oldest car previously was a '69 chevy P/u with an aftermarket HEI system) then see what she'll do. Probably need some carb work (solex) too.
Not sure of the maintenace history since I Just got the car in Fall and simply wanted to drive it a bit before put'n her away for the winter. Thanks for the insight!

[Old Hippie]

Well, on average, Opels sound the same or better than rice cars AND much more fun to drive! The electronics I was taking about was some gaget that is supposed to increase mpg w/ a slight increase in power. "Double shot" or "Double Fire" ing. Something like that. I need to ask a guy at work who has one.