Increasing MPG

[dutchmeister]

I was told by George Asche that increasing my HP can increase MPG.

Is this true?

I know about milling the head, replacing the cam, dual exhaust and dual carbs.

All of these will increase my HP.

He states more power means less fuel wasted (like going up hill.) The question is does that translate into better MPG. Right now I have an estimate of current MPG at around 7 I have a B1D with a 230 c.i. That kind of bites, especially on road trips.

What other suggestions for at least some improvement?

What are you getting for MPG?

Thanks y'all.

Edited June 22, 2012 by dutchmeister

[Dave72dt]

Reductions in parasitic drag, like low tire pressure, brakes dragging, steering alignment, heavy gear oil. Driving style is a big one, finding the engine's cruising RPM and not going over it, good engine tune, cruising in the cooler times of the day instead of the heat. Same things that can be applied to the newer daily drivers.

And PLEASE don't start a debate on what gear oil to use.

[wallytoo]

i hope you get better than 7 mpg. that's what i get with my 1.5-ton. i've even managed to squeak out 9 mpg for one tank. my tires are 55 psi rear (duals)/60 front.

[Jeff Balazs]

Dutchmeister;

Many years ago I had a car that I built extensively. Once I was done tweaking and tuning my highway cruising gas mileage increased by a whopping 75%. This was accomplished without changing gearing or tire size. I had replaced the stock 1 bbl intake with a pair of DCOE Webbers, did a big valve conversion on the head and installed headers and a free flow exhaust system. In other words I got it to breath properly. By doing this I more than doubled the HP which was great.....but it was the mileage improvement that I really came to love.

This was a different engine design and I rather doubt it would be as easy to get that sort of improvement out of our flatheads. I am certain with the correct mods one could probably get a gain of say 10% to 20% without sacrificing reliability. My gut feel about these trucks is that there is probably more fuel economy to be gained from changes to the gearing,etc than there is from tuning. I know I will be looking very closely at all this I get my truck roadworthy.

Jeff

[John-T-53]

With the 5-speed overdrive, I've achieved up to 20 mpg on the hwy when the conditions are right (rare). Average is still 13 mpg around town. This is a 1/2 ton with a stock 218.

Adding dual carbs and dual exhaust will help. HEI ignition might also help.

I'm not sure about what a cam will do for mileage...George sells a "380 cam" with a bigger lift and longer duration (I've been told 375 is stock lift).

Cams are all about compromise - give up one end for gains on the other.

Maybe some of the guys here who've installed different cams can chime in...

Edited June 23, 2012 by John-T-53

[pflaming]

Change the differential ratio. I put in a 97 Wrangler but haven't driven it yet so the jury is still out.

[MBF]

I'd think I'd do a compression check, and then check for tight valves. You may also want to check your timing and that the springs inside the distributor and flyweights are working properly. The 7 mph sounds low. I'm getting 13+ in my 1 ton w dual wheels. Mike

[dutchmeister]

Thank you guys for all the help!

Quick question, what should my manifold pressure be?

I have a Carter B&B with stock intake.

[1941Rick]

218 cu in, twin BB carbs, Reds headers and overdrive gives me 22 mpg imperial. do not drive over 60 mph. If you are running stock setup with low gears at highway speeds you will not get good mileage.

[Rusty O'Toole]

There are certain changes that improve efficiency, this can translate into more mileage or more power or both.

Higher compression, free breathing exhaust, reduced friction, lighter flywheel for less inertia, are just a few examples.

[dave5711]

Im amazed at how bad the mileage can be in these old flathead motors.

I would have thought there relatively small displacement, and lack of power would have yielded much better economy.

[Plymouthy Adams]

worn out engine...poor state of tune...bad carburator..low tire pressure, dragging brakes..leaving the e-brake on...driving with foot on brake..accelerate fast..stop quicker..in conjunction with the bad gearing these vehicles have compared to todays machines and road conditions..yeah..I agree..I knew of a station wagon...13 MPG driving for ecnonomy...13 MPG at 116 sustained cruise..

[ggdad1951]

I'm getting about 8-9mpg on FEF right now by dead reckoning. He slows down pretty good by himself in nuetral, so I know I'm fighting drag in the brakes/rear end gears ...

[HanksB3B]

Mine gets 17mpg which is about the same as some guy with a new 354 hemi Ram Truck told me while fueling up.

But don't forget...we use Regular,

Hank

[greg g]

46 bizzy coupe, stock 218 engine 16/17 mpg all day any day any way.

same car with 56 230 dual carbs, low restriction exhaust. milled .050, lightened flywheel,18 to 20 mpg.

more power, more fun more mpg.