gas mileage

In my '68 coupe, I initially had a holley 4 bbl, points distributor. I think other than the holley everything was stock except the intake. It did and dos have something slightly less (numerically) than 3.00 gears. I also had a C-4. I've since put in a pertronix setup, replaced the holley with an newer edelbrock (because of the holley catching fire haha read post: car caught fire) and I've replaced the C-4 with a T-5. My gas mileage has easily doubled. I can now go almost a week of driving back and forth to school everytday and Lawrenceville twice a week without filling up. That's as good as my last car which had a 3.0liter V-6, but with a smaller tank. The V-6 car got about 22 mpg. I'm guesstimating 15-17 for the mustang but I haven't tested it.
 
:shrug: Well, maybe either my head is stuck up my ass, or you guys just aren't really getting the better MPG's you think you are. OK, so my car isn't exactly stock, but it's not overbuilt by any means either, it has only the basic upgrades and enhancments. I still have my 2:79 gears as well. It is only a 3spd which is fun in town but hard on the highway. I'll have to check it again this summer with a pertronix, but I'm pretty sure I've averaged around 8 in the city and 10 on the highway using super all the time. I do lean on it from time to time istead of running steady simply because I bought it for fun not economy, but I don't think granny shifting is going to double my results either.
 
One thing about the fuel gage: car companies deliberately make the fuel gages read non-linearly (is that a word? :rolleyes: ).

When you fill it, the gage won't move off full for a while. It will move slowly for the first "1/4" indicated (not really first 1/4 of tank though). Then it will move fast down below 1/4 full to almost empty. Then it slows down again.

The car companies do this deliberately because of human psychology. People don't like it and get upset when the gage moves in a true linear fashion representing how full the tank is. They get a feeling that the tank immediately isn't full (which is true) and they don't like it. So the car companies changed how the gage reads so that people will feel better about the "fuel economy" of the car.

Sorry, got OT there, but I think it's interesting. If you pay attention to your gage (in any car you own) you'll see what I mean.

So any test of mileage has to start and end with a full tank. The gage won't give you a true indication, even if it's a new car/gage.
 
Pakrat said:
:shrug: Well, maybe either my head is stuck up my ass, or you guys just aren't really getting the better MPG's you think you are. OK, so my car isn't exactly stock, but it's not overbuilt by any means either, it has only the basic upgrades and enhancments. I still have my 2:79 gears as well. It is only a 3spd which is fun in town but hard on the highway. I'll have to check it again this summer with a pertronix, but I'm pretty sure I've averaged around 8 in the city and 10 on the highway using super all the time. I do lean on it from time to time istead of running steady simply because I bought it for fun not economy, but I don't think granny shifting is going to double my results either.
I'm sorry that your car gets such crappy mileage but I know for a fact that I was getting the mileage I claimed because I used to check it religiously.....this was back in the late 70's early 80's just after the second gas crisis and we all kept an eye on mileage. I even verified that my speedometer was correct. When my car was bone stock with the 2 barrel carb and crappy single exhaust the best I could get on the highway was 15-17 mpg....so the mods I spoke of earlier netted me about 7 mpg on the highway. My driving style was also fairly conservative and when I beat on the car the gas mileage dropped accordingly....but the numbers I reported were my averages during normal to and from driving.
 
well i know my stang buddy gets 17 in his with 3.50 gears and i KNOW I was getting at least 18 in the 289 stock 65 FB with 3.00 gears because I could drive forever before filling up. So I know 18 is feasable, its just getting rid of this crappy rear gear.
 
Ronstang said:
I'm sorry that your car gets such crappy mileage but I know for a fact that I was getting the mileage I claimed because I used to check it religiously.....this was back in the late 70's early 80's just after the second gas crisis and we all kept an eye on mileage. I even verified that my speedometer was correct. When my car was bone stock with the 2 barrel carb and crappy single exhaust the best I could get on the highway was 15-17 mpg....so the mods I spoke of earlier netted me about 7 mpg on the highway. My driving style was also fairly conservative and when I beat on the car the gas mileage dropped accordingly....but the numbers I reported were my averages during normal to and from driving.

:shrug: You guys are lucky, maybe it is my driving habits then. What I'll have to do is try a different technique at next fill up and see if it makes a difference. No slight revving at lights, no WOT bursts and then drifting along, just a steady pace. I'll report back in a few weeks and we'll see. At the least I think this will be a worth while experiment for sure. :)
 
Pakrat said:
:shrug: You guys are lucky, maybe it is my driving habits then. What I'll have to do is try a different technique at next fill up and see if it makes a difference. No slight revving at lights, no WOT bursts and then drifting along, just a steady pace. I'll report back in a few weeks and we'll see. At the least I think this will be a worth while experiment for sure. :)



NO BS Pak. And that was going over the Continental Divide and some in Denver traffic. I did hold my speed to around 60 most of the way.
 
I went as low as 8 MPG carbed c-4 in the city and as high as 15 MPG with an efi t-5 combo in the fastback on 3.00 gears. My coupe well I haven't driven that car more than 5 miles away from my house in 6 years.

My 90 with efi and t-5 3.55 gears. gets 14 city and about 21 highway. Although I have managed 24 city/highway.

In comparison the acura legend gets 21 city with the ac on. CRV 28 city.