Very ON-TOPIC, Let's talk fuel milage

Gas milage has been on my mind as of late. I've been daily driving my '57 again and this week I'm on pace to woof down $80 of premium...and I'm not even driving that much. With the cost of gas nowadays, it's a topic we're all reminded of every time we pass the signs advertising the rising costs. Now I'm not complaining or bitching. I've said it before, "It costs to be the boss in a badass hot rod", and this is one of the major prices that we pay, and I pay willingly. I think the thread on Alternative power plants missed the point.

What I'm trying to accomplish with this thread: I want to hear your engine/drivetrain combos, and what kind of MPG you are observing. Do you guys have any tricks for improving MPG? Cam timing? A certain profile? What carbs are you using? Any specific tricks for squeezing a few extra MPG out of your Holley or Strombergs? Multi carb set-us? What about rear end gears? Obviously a high gear is going to lower RPMs, but is there a point where the motor isn't revving enough? Obviously OD helps, but I'll guess most of us don't have it.

What I DON'T want to hear: Talk of diesels, hybrids or EFI. That's not what this board is about. Nor do I want to hear about E85. Remember that scene in "Apollo 13" where the engineers are like, "We need to make this do that, using nothing but this stuff." It's kinda like that. How can we make the most MPG using nothing but old ass engines, carbs, and mostly traditional parts?

 

well my daily is about 4000lbs, has a 461 olds in it with 10.7:1 compression and a pretty healthy cam with a quadrajet on top of it. backed by a built th350 with a 2000 stall converter and a 2.41 rear (soon to be 3.23) and i get about 14mpg around town and close to 20 on the freeway. my around town might go up a touch with the 3.23 but down a hair on the freeway.

 

Cool man, thanks for the response.

My 57 is about 4000 lbs, 383 Chrysler (10.2:1, stock cam, weiand dual plane with 600 cfm Holley w/ vac secondaries), torqueflight and 3.50 rear. I have 205s on it, and highway cruising speeds are around 3000 rpm. My fuel milage is around 15 highway, and 9-10 around town. Really awful.

Anybody think I can improve milage by stepping up the carb size?

 

I know a guy who's also here on the HAMB who bought a mid nineties Toyota pick up for around $800, has driven it over 80,000 miles at about thirty miles to the gallon and never looked back. It seems like a responsible decision to me. Why drive your hobby every day anyway? How long would it take to make back $800 in thirteen mile a gallon gas?

 

Up sizing to get better milage? Okay, maybe a spreadbore might work, but for the money you would spend, It might take some time to break even. Perhaps a better thing to do is to seriously figure a way to lighten the car. Also how tight is the engine? If it's blowing by here and there, that isn't helping. Of course downsizing the displacement might help too. But in a car like that, do you really want to go that route? Maybe you should pick up a cheap rice burner to do the daily thing with, and keep that one for pleasure.
My old daily driver was a warmed over 350/350 combo in a full sized truck, with 340 gears. When I pulled the original 305, I got considerably better milage. Plus I could go from zero to 60 in about 4 seconds without frying the tires. Around town it probably got 10 or 12 mpg, and about 16 or 18 on the highway.

 

See this:

Joe, you know my setup. For those who don't: 3700lbs car, '67 289, really mild cam, 9.5ish:1, Edlebrock 600 vac sec, Torker II Single Plane, GM style HEI w/ 12* inital advance, vac advance with medium weights, C4, 3.73 open rear. I believe to be around 20 on the highway and 14? city. The car seems to run the best at 3000, which equates to about 60-65. Anything more and I'm suckin down gas, anything less and it seems to do the same. The HEI helped as well as the different advance curve IMO.

 

stock 53 flathead withwhat p.o. calls mild cam headers . otherwise like henry made it in a i geuss roughly 4000 pd truck again of 53 vintage with a 3.92 rear gear and the factory three speed . it sucks it up best to date has been 10 mpg . wouldnt trade it for any new car though . ill just keep bleedin' . oh and yes it is the driver .

 

Getting your foot into it plays a huge role in mileage. It's hard to restrain you self sometimes. I've always been interested in the IMCA roundy round engines restricted to 500 CFM two barrel carbs making big power. An engine built with a gameplan of efficiency in mind using a careful selection of parts may be the ticket. Then again, restraint isn't always the mantra of hot rodding.

 

Lean Mixture, Low RPM, & High Manifold Pressure...
That's the key to economy with any engine...

With my daily I'm getting 15-16 MPG on avg. using regular unleaded/10% Ethanol...
17-18 MPG if I use non-oxygenated regular...

'39 85HP Flathead. All stock except Red's Headers/Dual Exhaust to the back bumper...

I'd like to try using the adjustable carb jets next...

 

I do have a modern daily driver, a 98 Mustang GT. 4.6 V8/5 speed, gets 23-25 on the highway...I love it, but...

The idea of this thread was to maybe help some people here who don't have modern daily drivers and would like to save a few bucks. Not to mention that even with a modern daily, I think the vast majority of people on this board drive their cars more miles than your typical classic car owners. Pinching pennies at the pump adds up fast.

The idea of upsizing the carb to improve milage is based on this idea. The 600 cfm carb is just big enough for the engine. If I went with a bigger carb, maybe I would pull on the secondaries less if I could drive longer on the primaries. This could be totally wack. I'd really like to hear from the guys running 3 twos on a progressive linkage.

My original motor, 272 y block with a motorcraft 2 bbl, 3 speed non-od and a 3.55 rear got almost 25 MPG highway.

 

I think you're trying to find a way to kill a bear with a pellet gun. The very nature of a "hot rodded" engine makes it immune to fuel conservation. You may improve it a little from what you have now, but not by much and still be enjoyable for you. It's going to be very hard to come up with a pumped up V8 that is hot rodded and gets the mileage of a Honda Civic and if you did, it would probably be expensive. Not meaning to sound like the voice of doom, but if ya wanta play, you will have to pay.

Though you didn't want to hear it, a cheap beater would be the solution for daily errands, such as going to and from work. As astounding as it may seem, lots of people do it. The solution isn't to change the engine, it's to change or modify how often you use it. In these times of high fuel cost, it's going to cost money to be cool all the time. You could tint the windows and wear a disguise if you're ashamed to be in a beater.

 

350/200r, two edelbrock 500cfms, headers, 3:73, 1800rpm at 65mph, 3450lb 48 Chevy pickup, 15mpg hwy, 10-11mpg in town, without air. At 55mph I can get 16-16.5 hwy.
I drive a 4cyl Nissan pickup as daily driver, 25-26mpg hwy.
2000 Corvette coupe, automatic, 30mpg hwy.

 

I should become a teacher.

 

actually, the velocity created by those smaller primaries in the carb you have will give you better economy. the main things that will get you the good mileage AND power are timing curve properly setup and a lean primary with a rich secondary fuel mix. mucho easier on a apreadbore though

 

How about aero stuff?
I've got a '62 Suburban...I just swapped in a 4spd manual OD trans with .72:1 overdrive. That'll help a ton. I need to get the trans rebuilt because I don't have Second, so I'm going from first to Third (1:1). I know that's killing me.
I also don't have the right speedo gear in it, so my MPH is off--meaning, I can't accurately figure out my MPG at this point.

But some things I'm going to do are the following:
I'm going to fab a filler panel between the front bumper and the cross member that hangs way down. This should clean up the air going under the truck a little bit. I'm also going to install a metal chin spoiler on this filler, behind the bumper, where it will mostly be out of sight. It'll be black, so it won't jump out. Nothing new in the tech here--a spoiler is going to deflect air from all the things that hang down under a vehicle and create drag.
Then, on the grill mounting panel, there's a HUGE opening behind the grill, most of which dead ends into the core support. I'm going to close all that off, just leaving an opening wide enough for the radiator. The air will go through the radiator, but on the sides it was just stacking up against the core support.
Finally, on the nose of '62-'66 Chevy hoods, there are two openings between the marker lights. These also grab air and let it stack up under the hood. One of them needs to be there for the hood latch (I don't want to re-engineer that whole thing). I'm going to create "pockets" or "caves" behind these openings that will keep the opening in the hood, and the original look and styling, but will be closed off so it doesn't allow all that air into the hood, where it just stacks up in the engine bay.

Like wizzing in the lake to raise it's level? Maybe. But it's one of those projects I'll have to do to find out if it really helps. But it's a fact that if you can keep air from stacking up in front of a vehicle or under the hood, and if you can move the air from under the vehicles, you'll go faster and/or get better fuel economy.

I'm not looking for 35mph, but I drive the thing upwards of 20,000 miles per year, so even if I can get on more mpg, over a couple years, that's gonna ad up. Hell, just on the 5,000 mile Bonneville round trip, that comes out to two free tanks of gas.

-Brad

 

If you have to ask that question you just really don't get it... and probably never will..

Not always true, you are improving the efficiency of the engine in many ways which can improve fuel economy as well... the problem then is keeping your foot out of the smile pedal....



I miss my '59 pickup, after the 4 speed and rear end change I got mid teens in town and 20-21 on the highway with the 235... My '06 Dakota gets no better... I think I finally found someone to actually follow through on painting my International and will be doing the same tranny, rear end, deal with it... though most likely a five speed if I can find one to put on the stock six...

 

On the carb size thing I feel that you will not get the desired result.

Just went from a 600 edelbrock to a 750 edelbrock. Reason? 600 was toast and I happened to have the 750 on the shelf.

56 3100 PU 350/350 combo 2.73 gears with 29" tall tyres, not sure of the weight.

Mileage went from 23 on a run and 15 around town to 19 on a run and 12 around town.

Looking at getting a 500cfm carb to see what effect that will have.

On the plus side with the 750 the truck now pulls HARD!

Not a good thing when petrol is $9 a gallon.....

P.

 

my experience shows some things....

A smaller car helps mileage overall.

A lighter car helps mileage overall.

A smaller engine helps mileage overall.

A mild rear gear helps mileage overall.

Overdrive helps mileage whenever you're in overdrive.

Carb selection is not as important as you might think, although it will affect driveability, and if you have a progressive carb setup (4bbl or multiple carbs) it helps to run on only the primary side as much as possible when cruising.

Cam selection is not as important as you might think, although it will affect driveability with the gearing that gets you good mileage.

My advice to Joe is to try out different rearend gears. Since you have a stock cam, you could get away with 2.75s and still have the car be pretty driveable, but you will lose a lot of off-the-line punch. It's a trade off...but if you play around with rearend gears, you should be able to find a ratio that gives you a reasonable compromise. I have run everything from 2.75 to 3.70 gears in my 55, and settled on 3.25s for now. It gets better mileage than the 3.70s, not as good as the 2.75s, but it performs noticeably better than the 2.75s.

 

I have a two wheel drive blazer that has been my work truck close to 20 years 787,000 miles never got over 10 MPG. my new truck 54 GMC has a 331 Cad with 3 two barrels, I have had several 331 cads over the years and without trying in 5200 lb plus early cads alway got over 17 mpg. and one in a 48 plymouth got over 22mpg highway with air blowing cold.
the GMC has the stock Granny geared 4 speed and 3.0 gears in the ass end. never had a stick behind a cad and am looking forward to a gain there. I took many inches out of the frontal area (chop, channel, section and lowered) the hood is down 12 1/2 inches and roof is 18 inches lower than stock, that has to help punching a smaller hole thru the air. I'm going up in weight but will deal with that at different levels.
I think that giving up bigger cubic inch motors is the wrong way for Rodders it's always worked better with smaller lighter and lower cars. I think that formula still offer the most options for driving fun.

kind of like the old gun guys slogan
"you can have my Hot Rod when you pry my cold dead fingers off the steering wheel"..........Jim

 

Sounds like it's six pack and A833 overdrive time. Mopar Performance has made the manifolds available again, and the OD is a Craig's List bellhousing, flywheel, and clutch away. With a tight or freshened up motor, cam that sucker right and there's no reason why high teens to twenties around town and mid to high twenties on the highway is out of the relm of possibility, provided you educate your right foot.

 

Take pity on us over here on the other side of the pond, our local Gas station is selling ordinary unleaded at £1.08 per litre.
1 US Gallon = 3.78 litres = £4.08 a gallon.
With the current exchange rate thats $8.52 per gallon!

(Jeez, I hope my maths is wrong!!!)

 

Think Torque.
That would be a good starting place.
r

 

From one Jersey guy to another, I'll share my secret with you. My daily driver is not known for great mileage, and since it is not a vehicle that is "of this board" I will refrain from mentioning it even though it is proudly made in America. I commute 52-miles one way to work. My vehicle was getting no better than 18 MPG and it was taking a toll on the finances.

So I drove my mileage up by dropping my speed down. Instead of cruising at 75 MPH, I run between 68 and 70 instead. My mileage is now usually just a tick over 20 MPG.

2 MPG improvement and it didn't cost a dime.

 

hi joe in the chevy i run a new crate 350 sbc 300 hp with 8.5 to 1 comp m-22 4speed 337 rear gets about 16 in city and 20-22 0n road my ford with y-block pertronix ingnition fordmatic and 310 rear gets 15 city and 20 on road pick up about 2 mpg with pertronix also put in 65 caddy pertronx help mpg in that too. in the chevy when i had the 402 sbc with a cam m-22 4 speed and 4.11 rear ithad 11to 1 comp it was faster but if a got a true 11 mpg i was lucky

 

Hey, Brad..I think you are correct with an OD stick in the suburban. I've had a 63 suburban for 12 years and I miss using it as a daily. I tried 2.76 gears and it did not help with the 400sbc/Th350. I DON'T WANT TO DRIVE A 5-10 yr old car! ...I most likely will try a 700r4 w/3.70 gears OR one of those OD 5 speed sticks.

 

Know where the power circuit kicks in in your carb. Install a vacumn gauge and try to keep the vac. above that. I think I'm the only one that drives the suggest speed limit coming in to work. Guess everyone really likes their job, they seem to be in such a great rush to get there.

 

Thanks for the responses guys. This is where I was hoping this thread would go.

The problem for me as a Mopar guy is that O/D is wicked expensive. Seems easier to swallow the $50 at the pump than the $2500 for the GearVendors unit. Keisler is making adapters for the TKO600 to the B/RB, and just started making adapters for the B/RB to a 4L60E...pretty cool, just big money. Unfortunately, even a stock big block Mopar will make short work of a standard T-5.

I'm thinking maybe I'll swap rear end gears and see how it goes.

Squirrel, thanks for the unbiased input.

 

my daily driver is a 53 f100 ,1982 305 cui. 9.1 comp.ported heads,350hpcam ,holley 600,headers,hei. 1972 turbo 400 .open 10 bolt with 273 gears truck is 3,280 lbs.highway average 22mpg ,town 17, i burn reg. unleaded,and use syntechic oil,

 

Passon Performance lists rebuilt 23 spline 833OD transmissions at $795 on their website, and 18-spline ODs at $1795.

Check out their site and give them a call...It'll still basically be a 3spd with OD, but $795 seems to be a pretty decent alternative. You're running a big block, so the base model trans might not be strong enough, but even at $1795, that's gotta be a whole lot cheaper than the adapters and TKO or 4L60E.
-Brad

 

I got this is one of those chain emails. It may be a bunch of crap, but it is related to saving gas money. Take it for what it's worth.


<TT>> Only buy or fill up your car or truck in the early morning when the </TT></PRE>
<TT>> ground temperature is still cold.</TT></PRE>
<TT>> Remember that all service stations have their storage tanks buried </TT></PRE>
<TT>> below ground. The colder the ground the more dense the gasoline, when </TT></PRE>
<TT>> it gets warmer gasoline expands, so buying in the afternoon or in the </TT></PRE>
<TT>> evening...your gallon is not exactly a gallon. In the petroleum </TT></PRE>
<TT>> business, the specific gravity and the temperature of the gasoline, </TT></PRE>
<TT>> diesel and jet fuel, ethanol and other petroleum products plays an </TT></PRE>
<TT>> important role. A 1-degree rise in temperature is a big deal for this </TT></PRE>
<TT>> business. But the service stations do not have temperature </TT></PRE>
<TT>> compensation at the pumps.</TT></PRE>
<TT>> </TT></PRE>
<TT>> When you're filling up do not squeeze the trigger of the nozzle to a </TT></PRE>
<TT>> fast mode. If you look you will see that the trigger has three (3) </TT></PRE>
<TT>> stages: low, middle, and high. In slow mode you should be pumping on </TT></PRE>
<TT>> low speed, thereby minimizing the vapors that are created while you </TT></PRE>
<TT>> are pumping. All hoses at the pump have a vapor return. If you are </TT></PRE>
<TT>> pumping on the fast rate, some of the liquid that goes to your tank </TT></PRE>
<TT>> becomes vapor.</TT></PRE>
<TT>> Those vapors are being sucked up and back into the underground storage </TT></PRE>
<TT>> tank so you're getting less worth for your money.</TT></PRE>
<TT>> </TT></PRE>
<TT>> One of the most important tips is to fill up when your gas tank is </TT></PRE>
<TT>> HALF FULL or HALF EMPTY. The reason for this is, the more gas you have </TT></PRE>
<TT>> in your tank the less air occupying its empty space. Gasoline </TT></PRE>
<TT>> evaporates faster than you can imagine. Gasoline storage tanks have an </TT></PRE>
<TT>> internal floating roof This roof serves as zero clearance between the </TT></PRE>
<TT>> gas and the atmosphere, so it minimizes the evaporation. Unlike </TT></PRE>
<TT>> service stations, here where I work, every truck that we load is </TT></PRE>
<TT>> temperature compensated so that every gallon is actually the exact </TT></PRE>
<TT>> amount.</TT></PRE>
<TT>> </TT></PRE>
<TT>> Another reminder. If there is a gasoline truck pumping into the </TT></PRE>
<TT>> storage tanks when you stop to buy gas, DO NOT fill up--most likely </TT></PRE>
<TT>> the gasoline is being stirred up as the gas is being delivered, and </TT></PRE>
<TT>> you might pick up some of the dirt that normally settles on the </TT></PRE>
<TT>> bottom.</TT></PRE>
<TT>> </TT></PRE>
<TT>> Hope this will help you get the most value for your money.</TT></PRE>