MPG Increace

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1973dusterkid

1973dusterkid

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Ok so right not I am working at a Dodge dealership and love it but am having to drive 40 miles a day. Right now I cam getting 8mpg and need some advise to increase MPG's. I know some of you are going to say get another car for that but I don't want to I love my car being my Daily driv
er and cant stand not to drive it.

Right now I have a holley 750 carb 4160
I was think about getting a holley 670 vac sec manual choke square bore. Do you think that would increase MPG's

I also thought about putting duel electric fans for a little less drag on the engine. I would also run a oil cooler.

What other things do you guys think will help
 
If that is your set up in your sig, you are screwed for mileage.

Going from rear to front,

2.76 gears
Tall tires
2-1/2 exhaust max (IMO)
Get a stock 360 cam
600 CFM carb or a TQ w/small primaries
MSD or equal ignition

I was able to get 20 MPG's (at interstate road) with my '79 - 360 in a Dodge Magnum. It was the OE engine with these parts;

Trap door air cleaner w/a K&N filter
OE intake w/a 625 Carter
MSD and a cavuum advance distributor, plugs gapped @ ,055
Dual exhaust off of the exhaust manifolds w- a "H" pipe @ 2-1/4 inch pipe size and Thrish turbo mufflers. The law required cats. I used two before the "H" pipe.
2.76 gears and 235/60/15's.

Tune this well and lean on the cruise. You should at least get 18-19 on the Hwy. use of a taker tire than what I used (26 inches) should help a little bit.
When your meage seeking, every little bit helps the big picture. When you start to max out, the gains are hard to find and the changes found when dividing miles per tank into gallons used can become a fickle math problem.

Good luck!
 
What are your cam specs? If this thing is really lumpy, it will always be hard to get good fuel mileage.

Its a lot easier to get good fuel mileage when you have a carb with smaller primaries. Electric fans will help, especially if you don't have a clutch fan, but it's going to be a small incremental increase.

The most important things for fuel mileage are the timing and the cruise air/fuel ratio. Without having a wideband O2 sensor, it will be hard to get the air/fuel ratio right on.

With that being said, I have a 340 with a 750 Double Pumper Quick Fuel Annular carb and a 227/231 .530 lift cam and my car gets 12-13 mpg easily in the city if you keep your foot out of it (and have the ultra-progressive secondary link installed). Being hard on it, it gets 10.

Even with everything tuned in right, and quite a few tricks, its going to be hard to break 15 mpg. If I drove mine on the highway, it may just squeak into the 15's.
 
Should have been clearer I really don't want to swap gears of cams stuff that is easy to do.

Carb/Fan thats a hour job
 
goldduster318 said:
What are your cam specs? If this thing is really lumpy, it will always be hard to get good fuel mileage.

Its a lot easier to get good fuel mileage when you have a carb with smaller primaries. Electric fans will help, especially if you don't have a clutch fan, but it's going to be a small incremental increase.

The most important things for fuel mileage are the timing and the cruise air/fuel ratio. Without having a wideband O2 sensor, it will be hard to get the air/fuel ratio right on.

With that being said, I have a 340 with a 750 Double Pumper Quick Fuel Annular carb and a 227/231 .530 lift cam and my car gets 12-13 mpg easily in the city if you keep your foot out of it (and have the ultra-progressive secondary link installed). Being hard on it, it gets 10.

Even with everything tuned in right, and quite a few tricks, its going to be hard to break 15 mpg. If I drove mine on the highway, it may just squeak into the 15's.
Click to expand...

Cams not to crazy but a good lope to it. I was going to try to get 12 so I could say I broke the double digits.
 
Not to be a stickler, but not having a hood is not helping you at all, for a lot of reasons.

If you aren't willing to change the engine, have you thought about swapping to an overdrive of some kind?

It takes a little patience and setup, but once it's done, you can see a vast improvement in MPG just by having another gear to put it into, especially on a 20 mile commute.

The A833 O/D might hate you on the 3.09 first gear, but another inexpensive option that requires a little modding in the trans tunnel as well, is an A500 automatic. Those can be used with or without full lockup and aren't as big as the A518. They bolt right up and you can set up electronic overdrive engage to happen progressively and have a bypass switch for manual control, as well as separate or combined manual control over the lockup converter, which can help immensely.

Another option would be to look into a Dynamic converter. They have better stator and impeller pitch ratios that allow performance stalls without a lot of slipping under cruise. They also make performance stall ratios for lockups, if you decide to go with an overdrive.

Rob is right, a fan and small tinkering is not going to get you any more improvement on fuel economy than monitoring your throttle position/ foot/ behavior, without your will to start changing significant parts.

The truth is, you can have a high performance car and get good fuel economy, but unless you start opening up the idea to an overdrive or fuel injection (both, ideally), you won't come near good fuel economy and keep your HP/TQ where it is (or better).

One thing you can do that is practically free is to monitor your driving. There have been several universities that have recorded mood/ circumstance on driving MPG and they have found that the driver has more of an impact on MPG than anything you can do to a car. Top Gear (UK) did a test on a BMW M3 against a Toyota Prius, around their track on MPG/ fuel consumption, while still attempting a reasonable and relative E.T. The Beamer SPANKED the Prius, and I'm not surprised, considering how hard they were driving the Prius.

Get a vacuum gauge and keep as much vacuum as you can, with your right foot. It's dirty, cheap, easy and will save you more gas than anything else, outside of some other mods that I think would help your HP and fuel economy (overdrive and injection).
 
park the car and get something different for DD, that way when you come back to the car in the evenings and weekends the drive is that much more special and its not costing you $30+ a day to travel

people who drive trucks as a car, or drive RWD cars that get under 20MPG as a daily driver for long distances baffles me; unless you need it for work thats just stupid
 
I guess I am just going to have to work more hours because I like the car so much like it is a cant really bring myself to change it
 
1973dusterkid said:
I guess I am just going to have to work more hours because I like the car so much like it is a cant really bring myself to change it
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Or buy a cheap slant 6 daily driver in the same body style. Maybe even paint them the same....
 
66plyValiant said:
park the car and get something different for DD, that way when you come back to the car in the evenings and weekends the drive is that much more special and its not costing you $30+ a day to travel

people who drive trucks as a car, or drive RWD cars that get under 20MPG as a daily driver for long distances baffles me; unless you need it for work thats just stupid
Click to expand...

This is also what I do. I just filled up my 2012 Chevy Cruze this morning and it got its worst MPG ever...30.1

On your commute ($3.55/gal):
30 mpg = $4.83 round trip
20 mpg = $7.10 round trip
15 mpg = $9.47 round trip
10 mpg = $14.20 round trip
8 mpg = $17.75 round trip.

If you had a car that got 30 mpg, you could drive almost 4x as far for the same money.

Also... 8 mpg = 4437.50 for one year of driving to work (5 days a week/50 wks a year). The same distance at 30 mpg is $1207.50. That's enough to probably buy another car and insure it.
 
goldduster318 said:
This is also what I do. I just filled up my 2012 Chevy Cruze this morning and it got its worst MPG ever...30.1

On your commute ($3.55/gal):
30 mpg = $4.83 round trip
20 mpg = $7.10 round trip
15 mpg = $9.47 round trip
10 mpg = $14.20 round trip
8 mpg = $17.75 round trip.

If you had a car that got 30 mpg, you could drive almost 4x as far for the same money.

Also... 8 mpg = 4437.50 for one year of driving to work (5 days a week/50 wks a year). The same distance at 30 mpg is $1207.50. That's enough to probably buy another car and insure it.
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Dam you paying a lot for gas haha
I know another car is best but it just one of those things I just want to drive the car miss driving it if I don't even drive it for a day.
 
My suggestion.

That cam is only ~220 at .050 so it's relatively small on duration/overlap.

Get an A/F meter and see what the cruise ratio is running. I bet it's really rich on cruise and needs some dialing in. If it's running in the 12's and you get it into the low-mid 14's it will help the mileage.

Tune up has a huge effect on mileage. Unfortunately, people that think they are positively spot on for a tune up are not close. Cars will run with all sorts of off base tune up.
 
Get an AFR-gauge and a vacuum-gauge and start tuning the low and mid-range.
Put higher tires on the rear wheels.

Why do you think installing an oilcooler will improve mileage?


edit: crackedback treed me with similar thoughts :)
 
I had a 360 with 2.02 J heads, bored .030 over, .284 duration cam, 3.91 gears (28 inch tall tire) with a 904 auto. Carb was a 750 Holley dp. I got 16 mpg at 55 mph. It was in a 74 Dart Sport. The car got into the 12.90's at 104. I think you are down from where you could be.
Here is my suggestions. First, pull a spark plug. Should be cardboard brown. If it is black, then you are too rich and going down on your primary jets instantly helps gas mileage. You may end up going down, per say, from 73 to 70 jets on the primary and may instantly get 2-3 mpg. My 2nd suggestion is be sure your timing is set right. The best measuring stick for this is a drag way E.T slip. My 360 ran the best at 38 degrees BTC. Ironically, this gave it the best gas mileage too. 3rd suggestion is watch your driving habbits. Is it fun to feel a little "G" force taking off??? You WILL pay heavily for that. Drive it like a State Trooper is following you everywhere and he is having a bad day and he is annoyed at your car.... ! 4th suggestion is if your running 20w-50 oil, go to 10w-30. Less drag for the whole system. Good luck!
 
BigBlockMopar said:
Get an AFR-gauge and a vacuum-gauge and start tuning the low and mid-range.
Put higher tires on the rear wheels.

Why do you think installing an oilcooler will improve mileage?


edit: crackedback treed me with similar thoughts :)
Click to expand...


I have a vac guage need to get my hands on a AF guage.
As far as the oil cooler I was going to run it if I did electric fans just to make sure temps stayed doen.
 
I would check your dist advance /vacuum advance and fuel ratio those numbers are out of line whats your rpm at cruising speed?
 
You never mentioned what tires you are running, tall skinny radials will help out with your gear ratio, and rolling resistance.
 
Get rid of all the extra seats, radio, spare anything with weight, then pump the tires way up. Get it into high gear as quick as possible. Try to never use the brakes.
 
He is just going to be stubron and screw himself.

On to the next post where someone might actually do something smart and listen to the been there and done that guy.

As for myself, I drive 50 miles to work one way in my '03 quad can Dakota that will be up for sale shortly. I have to give up a ride I wanted for so long now. But it is a dollor and sense issue. The Dakota gets 20 mpg if I grandma drive it. LOL! That never happens! 60mph isn't a reality. I average 16-17 MPG's. I'll be looking for a 40mpg car by whom ever has a great deal on one.

I still have my hot rod and classic cruiser at home. A penny pincher is what I need 5-7 days a week.
 
Slicks = even more contact patch on the road/ more parasitic drag that comes with the traction.

Road bikes have skinny tires for efficiency.

What you have on your hands is a street/ strip car that is suited for the occasional cruising, the way it is.

Even if you set up a vacuum gauge and minded your driving habits, like anticipate traffic, don't drive aggressive and anything else you can do to leave the gas and brake pedal use to an absolute minimum, without a hood, without tuning with an O2 sensor in the header on idle, cruise and WOT positions, you are looking at a gain of about 1mpg by monitoring, alone, given that you have done your homework, don't brake often, don't accelerate hard, etc.

I ride a train to work every day. I just got a cherokee that I'll be doing some mods to get me into higher mpg range and guess what I'll be doing? Riding the train to work every day. It costs me $68 even, every single month, like clockwork. I don't care what kind of transportation there is on the road, nothing will come close to that. Not even a scooter @100mpg+, after insurance that will cover accident/ hospital cost reasonably. Forget winter driving. It murders everything by a long shot at that price.

I know that not everyone can do that, but my point is, unless you are willing to get something else, or make some reasonable sacrifices with your current setup, in order to keep performance and get MPG, you won't see it. You are going to have to get out of old school tech/ mind frame with your entire drivetrain.

I think you need gears, more than anything. Overdrive or at least a good converter and a good, wide band o2 sensor, weld a bung into your exhaust as close to the runners as you can, check AFR on a reader, log your idle, cruise (high vacuum) and wide open throttle, as well as the transition. You will need a friend monitoring and recording while you drive.

This will tell you what kind of metering your carb will need with everything, including accelerator pump shot.

Reading plugs can't really be done, once you're close, anymore, because of the increased amount of ethanol used in fuels, today. If you are close, but not on, it won't look warm. It will look lean, but too lean is also bad, so you really need to look on ebay, summit, amazon, etc. and find an O2 AFR reader kit with a wide band o2 that is used only when tuning and capped, to get the job done right, that suits your budget and needs.
 
20% overdrive unit
light slow take offs practice with open glass of water
drive under 70 MPH and do 55 MPH if you can stand it.
 
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