gas milage

[1978Blazerk5]

is it true that a more powerful engine gets you better gas milage?and do narrower tires get you better gas milage?


Thanks

 

[southernspeed]

A more efficient engine gets you better mileage. So a modern 2 litre engine producing 180 hp will be better on gas than an old skool Pinto 2 litre producing 120 hp because it's more efficient per cc. A 600 hp 502cube motor won't be more economical than a smaller engine....but much more fun!
And yes, skinny tires are better. Less rolling resistance.

 

[sled_dog]

narrower tires have less rolling resistance with the road and less wind drag.

More powerful engine? Yes and no. If you had a lot of power, you could stay in overdrive more, and keep the RPMs lower, which will give you better fuel mileage. However, you will be very tempted to use that power all the time, which will KILL your mileage. Bigger more powerful engines require more fuel to make that more power. So yes, and no.

A 6.2L or 6.5L swap is about the best bang for the buck fuel mileage swap in a K5.

Otherwise, give up and buy a Honda dude. You will never make a brick on wheels into a big fuel mileage machine. If fuel mileage is killing your wallet, you may well just have to lose the K5. A sad fact of the modern world. Buying a 4 banger commuter vehicle pays off in the end. And if you can afford it, you could always buy a nicer newer car to be comfortable, get good mileage, and keep the K5 for playing.

 

[1978Blazerk5]

well i got a 78 k5 350(crate motor) th350 33s 4.56 gears

would it help my gas mileage to build up my 350 alitle bit.

according to GM with the engine on a dyno the numbers are 260hp
300 ft.-lbs of torque. with 8.5:1 compression (crate motor)

 

[sled_dog]

in that situation, no I really don't believe it would help you much.

A commuter car is your best bang for the buck I'd say.

 

[4xcrazy]

I'd say 3.73's or even an overdirve transmission would help out alittle.

with that drivetrain combo,,,33's and 4.56's an no overdirve? kinda winding up that motor alittle on the highway maybe??

just athought

 

[ntsqd]

Any infernal combustion engine gets it's best economy at peak torque. That is where the "Brake Specific Fuel Consumption" (i.e. most power from least fuel) happens. Gear it & drive it at or a little under what ever RPM that happens to be at. Running the engine significantly slower than peak torque will actually get worse mpg.
With my '91 Sub (350tbi/700/3.73/285-75's) running in direct at under 65 gets better mileage than in OD at those speeds.