fratzog lover
Well-Known Member
Thats pretty impressive.
Miles/gallon: Newer vs Older Cars
- Thread starter g413
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GeorgeH
Well-Known Member
Agree. Kinda hard to cheat the physics. It's going to take x power to push x weight x distance.
GeorgeH
Well-Known Member
I might be mistaken, but I believe the stock cam in a 273 had a really low torque peak something like 23-2400 rpm.
That engine was "stock" only about a month after I bought it, about 1972. Best mileage was with 1972 340 heads cam and valve train, 1971 340 intake and TQ, and 273 with TRW forged 10.5 pistons with windage tray. The 72 heads were not untouched stock either.
A efficient combination. If you had a o/d back then you would probably pick up another 5 mpg. Stock engines with a low rear gear or a regular gear and o/d make a difference.
A buddy has a basically stock slant in a 42 Plymouth Coupe. A o/d 4 speed with a 4:10 rear gear and tall tires gets him 27mpg/hwy.
mopowers
Well-Known Member
Yes. And I'd say computerized fuel injection caused a great improvement in combustion efficiency. Others would probably include improvements in cylinder head design, intake/exhaust tracts, turbos/supers chargers, etc.
spl440
Everybody's Fool
And as more safety equipment is added to new cars, you know, 12 airbags, backup camera's, press brake to start car etc.. the weight goes up so mileage goes down. With the performance and mileage that exists now, the mileage with about 800 to 1000 lbs less of all the extra safety equipment would be that much better, but us dumb drivers can not think for ourselves, can we?
How sweet! What carb and intake?
pishta
I know I'm right....
show me that carb. I got a 1970cc Mazda motor in a 2600 lb truck, 5 sp w/.73 OD, 3.37 rear, new rings and NOS carb. It ran like a top, passed smog with flying colors and the best I ever saw was 27@70 mph, 24 miles one way, 98% freeway. although the sales brochures claimed up to 37 highway. that claim was back in the 55 mph days and I think they had a 1bbl carb as an option.
I have a bone stock 50,000 mile '69 roadrunner. I've never measured it but guessing it gets 14-15 MPG highway with my foot out of it. Drove it a total of 1,500 miles the last 3 years.
Also have a Pro Street A990 Clone '65 that gets 4-5 MPG and drove it a total of 150 miles last year. Don't care how bad of mileage they get, statistically, they produce far less emissions then my daily car which gets 40,000 miles a year.
Also have a Pro Street A990 Clone '65 that gets 4-5 MPG and drove it a total of 150 miles last year. Don't care how bad of mileage they get, statistically, they produce far less emissions then my daily car which gets 40,000 miles a year.
I think just a 2 barrell
fratzog lover
Well-Known Member
A very fun 5 MPG.
Certainly your prerogative.
That car and carb are long gone. I told him to get a new carb and guess Ford made a mistake and sold him an export only carb. 1971 German 1.6, lasted forever, still running great when he sold it.
ramenth
Gratis persona
Mileage also has a lot to do with how you drive a car.
That 100 mpg carb is impossible only scooters can get that mileage.
It takes a certain amount of hp (fuel) to move a car of a certain weight and aerodynamics.
The biggest factor that changed mileage for newer cars on Highway is overdrive.
Intown I feel there's little improvement
My 5.9 jeep gets about the same as my 400 bronco 12-13 mpg, my cab crown vic is the same as my 5th Ave 15- 16 mpg.
Fuel injection has a slight increase its main advantage is winter time.
It takes a certain amount of hp (fuel) to move a car of a certain weight and aerodynamics.
The biggest factor that changed mileage for newer cars on Highway is overdrive.
Intown I feel there's little improvement
My 5.9 jeep gets about the same as my 400 bronco 12-13 mpg, my cab crown vic is the same as my 5th Ave 15- 16 mpg.
Fuel injection has a slight increase its main advantage is winter time.
Hersbird
Well-Known Member
My 71 Sebring with a rebuilt stock 318/factory 2 bbl, 904 and 2.7ish:1 rear grears got 22mpg when moved from Seattle to San Fran down I5 keeping with the flow of traffic. The overdrive is the #1 improvement. Either run stupid 2 something gears, or get good acceleration and have an overdrive.
Aerodynamics have improved even if sometimes they don't look it.
Fuel injection is nice for varied conditions, but a well tuned carb and a warmed up car can do just as well.
EGR believe it or not helps economy.
The power they get from limited displacement is amazing as well, the simple non-turbo 2.0 Ford makes 160 hp in Ford's cheapest cars. A 6.4 would need to make 512 hp to equal that output per liter. The SRT only makes 485, the old 426 even less. That 2.0 is direct injected which is really a big step forward. Then they can eliminate the throttle body restriction as well and control it more like a diesel.
Aerodynamics have improved even if sometimes they don't look it.
Fuel injection is nice for varied conditions, but a well tuned carb and a warmed up car can do just as well.
EGR believe it or not helps economy.
The power they get from limited displacement is amazing as well, the simple non-turbo 2.0 Ford makes 160 hp in Ford's cheapest cars. A 6.4 would need to make 512 hp to equal that output per liter. The SRT only makes 485, the old 426 even less. That 2.0 is direct injected which is really a big step forward. Then they can eliminate the throttle body restriction as well and control it more like a diesel.
I think you've hit the big ones here. Fuel control, timing control, variable cams, cylinder deactivation, not to mention much more efficient transmissions...newer tech (that grew from our classics) really has created some incredible efficiency and power.
Fuel control is the big one. It allows some amazing applications of high compression or boost, each of which allow us to get a lot more energy out of our gasoline, specifically sending less of that energy into the air as heat and using more of it to propel the car...which directly means better MPG.
Take a look at the Mazda Skyactiv engines. The 2.0L in the new Miata has 12:1 compression! At one time, this was reserved for very special cars and race applications.
Amazing stuff!!
you changed your avatar..... lol. I just realized I look at avatar pictures to know who is saying what, and when you change it, I'm all confused.
really, my take are a few things. fuel injection burns so clean. Always changing to maintain A/F ratio. As stated, cars run a much lower rpm now because of more gears. More gears keep the car in its' best torque operating range for better mileage by using less pedal. Aerodynamics, wind resistant matters, especially at speeds above 50 mph. Tires are players in this too. Rolling resistance is less with todays "all rim and no tire" approach. Todays cars can have a flat and still look like it's ready to drive. Suspension actually helps. Suspension can rob performance and a little gas mileage in city driving.
as stated, all the safety features and electronic conveniences have added weight, which has taken back a little of the gas mileage. EPA regulations actually defeats their own purpose by making cars less fuel efficient, and that takes back a little of the gained mpg.
as stated, all the safety features and electronic conveniences have added weight, which has taken back a little of the gas mileage. EPA regulations actually defeats their own purpose by making cars less fuel efficient, and that takes back a little of the gained mpg.
itate
Where is that wrench I just had in my hand?
One thing I haven't seen in this thread is how much more aerodynamic newer cars are. A good part of newer cars have a drag coefficient around .3 and some as low as .25, our older cars would be lucky to be under .5 cd.
That being said my old 85 Plymouth Horizon 2.2 5 speed got 41 mpg highway and around 30 in town which is a hair better than my 98 Neon dohc 5 speed.
That being said my old 85 Plymouth Horizon 2.2 5 speed got 41 mpg highway and around 30 in town which is a hair better than my 98 Neon dohc 5 speed.
Probably fuel injection and electronics are biggest improvement....
MopaR&D
Nerd Member
I drove a 2016 Charger R/T (5.7 Hemi) that we somehow got as a rental when visiting my grandparents. I agree for the most part that a lot of this newer technology isn't very necessary but DAMN that 8-speed transmission is a thing of beauty (I want one for my Duster!!! LOL). Driving around rural southeastern PA (mostly back country roads and 50 mph highways with lots of hills) I was able to average 18-20 MPG while hauling around my mom and 2 teenage brothers with the A/C on. And it was pretty darn fast as well, WAYYY more fun to drive than any other full-size sedan you can rent. I could even do small burnouts if I turned off traction control heh heh...
This is why I love new engine/trans swaps in old cars though, just removing the emissions equipment and 'tune' from the ECU gives back about 5% of power, then putting it in a vehicle that ways 1000+ lbs less than what it's used to pushing around... the performance AND fuel economy is phenomenal. I don't think it's possible to build an old LA small block that would make the same kind of power AND fuel economy/emissions as a new 5.7L Hemi for instance. That's why it's always a trade-off, you see people having to build our "classic" V8s for either good economy (low-end torque) and mediocre power or lots of power and sh** fuel economy; it's really a balancing act on these older engines to manage both. That's where the technology from better materials/reduced friction, better combustion efficiency, precise fuel metering (EFI), ports and manifolds designed with modern computer-aided flow modeling etc. etc. comes into play.
mopowers
Well-Known Member
Can anyone explain how the wide big rig tires for the Smart Way program have less rolling resistance than two smaller "dually-style" tires? It seems like there'd be more resistance due to the larger contact patch. Any truckers on this site?
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