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Don't roast me, but....?

Discussion in 'The Hokey Ass Message Board' started by vintagetin88, Aug 6, 2012.

  1. vintagetin88
    Joined: Nov 26, 2010
    Posts: 63


    So I love old school stuff, but was never a big speed demon. The ol' Charger has seen the strip a few times, and has does a few dozen burnouts a year... The car is my primary source of transportation you see (I do have a '62 C-10 stepside with the 235 for parts and winter snow), so all the mods have been to make it more drive able (mild 360, electronic ignition, overdrive four speed trans with truck granny gear to make it pull, highway gears).

    I hope that you hot rod guys don't ream me too bad for this, but, in 1966 minimum wage was about $1.25...gas was $.32 a gallon. Today, minimum wage is $7.40 in Michigan, and gas is $4.15 a gallon...yeah.. Minimum wage doesn't get ya very far. I make way more than minimum wage..but I take my car to more than a Sunday cruise once a week. Or a drag. It's been on every date, every road trip, and every job interview with me in the last 3 1/2 years. Hell, I've seen most of the country behind it's windshield.

    So I have to ask. With leaving all it's old school bear with me... how can I build the most fuel efficient v-8? No I'm not looking for any unrealistic numbers. I achieve about 15-18 average. Interstate will do 19.5 consistently. I was thinking about dropping to a 318, but I'm afraid it's lack of low rpm torque would kill it in overdrive.

    Would adding roller internals help? A low lift cam and some soft valve springs as well? I know that would reduce friction. All I really use is the torque. The car doesn't see over 5,000 rpms.

    And a smaller car is out of the question, and so is a late model. I drive no such things. I like the girth of my behemoth Dodge. It's safe and comfy.
  2. EFI, overdrive, and the right roller cam
    will get you into the low 20's at 70mph.
  3. Deuces
    Joined: Nov 3, 2009
    Posts: 18,496

    from Michigan

    Must be nice making more that minimum wage... :(;)
  4. fxcomet
    Joined: Oct 5, 2009
    Posts: 75


    Realistically? You've probably done as much as you can do. Weight is your enemy here if you're looking for mpg. You could drop it in the front, maybe add an small front spoiler under the bumper, but it's not gonna get you much. Love the car, btw.

  5. Diavolo
    Joined: Apr 1, 2009
    Posts: 810


    The key to fuel economy is low rpm and torque. I would start by finding the steepest gears I could find and put them in the rear end. IMHO, you should be turning sub 2000 rpm at freeway speeds. An overdrive is the easiest way to get there, but a gear swap is probably a financially smaller impact. I don't know if it is compatible, but an old Borg Warner with the solenoid overdrive would get you there too.
  6. Diavolo
    Joined: Apr 1, 2009
    Posts: 810


    Oh, just to add... don't expect great take off. It will make your car a dog off the line. If that isn't important, and I don't think it is to you, don't worry about it.
  7. vintagetin88
    Joined: Nov 26, 2010
    Posts: 63


    Thanks man. It's not quite as raw a fenderless prewar solid front axle tin lizzy...that would have a lot more potential for go fast and saving me some money at the pumps. Yeah, 3,600 pounds isn't helping. It's probably got the best combo it's gonna get.
  8. vintagetin88
    Joined: Nov 26, 2010
    Posts: 63


    The car has an A-833 new process overdrive trans. It's a standard shift. I think the overdrive is something like .73:1? And it has the factory rear gears, which are probably in the 2.90's range. I haven't tried the could the driveshaft turns per 360 degree wheel turn thing yet. It runs very low rpms. The factory tach is a bit...crappy. I'm planning on taking it to Bonneville next year to see what she'll do. I'll need some shoulder belts first.
  9. We can fix that problem! ;)
  10. n847
    Joined: Apr 22, 2010
    Posts: 2,706


    Are you complaining about 18+ miles per gallon in a "1966" Charger? My 1999 Pontiac Bonneville is getting almost the same fuel economy back and forth to work. My 47 Plymouth with SBC/ford 9" combo...not so much! I say you continue to drive the crap out of it, and brag about occasionally getting 20+ mpg!
  11. Don's Hot Rods
    Joined: Oct 7, 2005
    Posts: 8,319

    Don's Hot Rods
    from florida

    Any time you do something like this you have to weigh the return on your the cost of getting a couple more miles per gallon going to be worth it in the end ? Obviously, if you drive a bunch of miles year picking up a little more gas milage might be worth it, but if you only drive like most of us do, to work and around town, you may never recoup the money you laid out for the parts to get you those extra MPG.

    Sometimes going to a smaller displacement motor in a big car doesn't get you the improvement you think it will, it has to work harder to move all that metal. Your car has a few things going against it, like the fact that Mopars are not exactly gas misers by their design, and your car not only weighs a lot, but it has a big front end that pushes a lot of air.

    Taller gears is one thing that can help, as well as having the motor really tuned up well and watching how you drive. My daily driver has an onboard gas milage indicator that tells me how much gas milage I am getting at any given time. If I am going down the road at 35 mph I can pull something like 28 mpg, but if I bump the speed up to 45 it drops down to 24 mpg, even though my overdrive kicks in at 41 mph.

  12. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,265

    Rusty O'Toole

    What ever happened to the Chrysler Lean Burn system. It had a special carb that would lean out to 18:1 on demand, and a special distributor that would advance the spark to 52 degrees. On highway cruise conditions you could get 25MPG with a full size V8 car.

    I think they had to abandon the idea when they tightened NOX standards. Wonder if you could build something similar with Megasquirt injection and ignition control.
  13. kscarguy
    Joined: Aug 22, 2007
    Posts: 1,572


    19.5 mpg from the 360 is far better than my 2002 Dakota. With the small 4.7 V8, I only get 16 matter what.
  14. Yep Don,
    Nothing an old fashioned math problem won't solve or remove the mystery.

    I'm guessing its 4,000 to monkey around and get 3-5 miles per gallon over the already good mileage. That's a lot of driving to make that up.

    1000 gallons @ 4.00
  15. Mr48chev
    Joined: Dec 28, 2007
    Posts: 27,327


    Driving habits have a hell or a lot to do with gas mileage as the guys said above.

    My 71 GMC looses about a mile to the gallon for every five mph over 55. and it doesn't get even close to decent mileage as it is so the percentage of loss is pretty high.

    Back in 1969 I got out of the army in Fort Hood Texas and one of my buddies and I headed to California (me to visit my aunts and grandmother and him to go home) when I drove the 69 Cutlass S I had I got 16 when he drove it he got 18. That was on alternate tanks the whole trip.

    State of tune is important including having an electronic distributor that is curved right. The car also needs to be geared out so that it is able to cruise at it's favorite rpm range on the highway. The wrong gearing either way and you are either lugging it or running at a higher rpm than you should be.
  16. i cant remember the last time i saw 18 mpg.
  17. I wonder if adding an air dam to keep air from going under the car would help, like the Maxton Mile cars did (and still do at the new place since Maxton closed). Wouldn't be that hard to make something that bolts on, maybe rig it so it installs with cotter pins so you can take it off easy for speed bumps or steep driveways or whatnot.
  18. 50dodge4x4
    Joined: Aug 7, 2004
    Posts: 3,535


    If you have an 833 OD trans and 2 something gears, you may benefit by going to a 3:23 gear set (or even 3:55 depending on your rear tire size). The 323s will get that 3600 lbs moving a bit easier then 2 somethings will. I also suspect your under your 360s power band at highway speeds. When you have to push harder on the throttle to get it moving or to maintain speed on hills, you will use more gas.

    All that said, getting a 360 past 20 mpg is a milestone few have passed. Might also mention that if you drive with the windows down, your fuel mileage won't be as high as possible. That large enclosed rear area is a big parachute slowing you down and burning gas. Gene
  19. Rattle Trap
    Joined: May 11, 2012
    Posts: 358

    Rattle Trap

    I once changed from a 180* thermostat to a 195* and gained 4 mpg. An old aircraft mechanic told me to try it and I was shocked it actually worked.
  20. Cutlassboy68
    Joined: Dec 3, 2011
    Posts: 593

    from Boone, Nc

    I have a 68 cutlass w-31 (go figure my name)... Anyways I drive it alot, baby seat and all installed... 4 speed. Was geared 3.27 and getting around 12 mpg normal driving. I was road racing and went to fast around a corner running with a newer vette and broke axle. No money to rebuil the rear end so stole the 12 bolt outta spare 442 and put it in. Geared 2.43 and now i get 20-24 mpg but alot less bottom end... Top end is there though...
  21. trollst
    Joined: Jan 27, 2012
    Posts: 1,758


    There's another matter the car...install a vaccum guage, drive by the highest possible reading, you'll get the best mileage possible out of your car, after two weeks you'll be frustrated enough to ignore it. However, it does work.
  22. vintagetin88
    Joined: Nov 26, 2010
    Posts: 63


    While driving from Detroit MI, to Navarre Florida, which I've made about 3 times in the Charger, the car was between 18-22 on every fill up. So I just averaged them together. I do it everytime I travel. And it's always beared the same results.

    The o/d trans in it now is from a truck, so the first gear is kind of granny gear. You don't even have to touch the gas to get her rollin. With the tall rear end gears she pulls good.

    The front of the car is plow, but the rest of the car is actually pretty efficient at higher speed. After all...the car was designed to reduce drag..or at least that's what I was told. The design also created a bit of...lift. Which is bad. I'll just put a superbird nose cone on it. haha. kidding.
  23. a bloke
    Joined: Jul 6, 2007
    Posts: 230

    a bloke

    +1 - I had one in an OT car (just to remind me how much it sucked) and you can really stretch the mileage with it. It was interesting to see what a difference it make when you're driving into, or with, a strong wind. With a tailwind you could ease off the gas and still make good speed.
    Trollst is right about ignoring it though, once you hear that V8 sing...

    Also, what exhaust are you running? Headers and a free breathing system might just nudge you over that 20mpg.
  24. Mart
    Joined: Mar 3, 2001
    Posts: 4,163


    Still running the mech fan?

    Take it off and put an electric one on a switch. just turn it on when stuck in traffic.

    Might help a bit.
  25. Well as much as I like chargers ( not) it is not oldschool.

    That said if you are running a .73:1 OD and a 2.9 gear I can help your mileage a ton, drop a lower gear in it so you are turning more than idle at highway speed. You ae going to be way below your usable torque curve with that 360 in OD with a 2.9 gear.
    Sorry to burst your bubble on both accounts, Old school and gearing.
  26. mrconcdid
    Joined: Aug 31, 2010
    Posts: 1,157

    from Florida

    I say keep the $5,000 you plan on building this imaginary engine and just buy more gas, if your getting 18 mpg and hoping for 22 it will take years to recoop your investment of a new engine. The new engine will be old and need replacing buy the time you break even on the build.

  27. Don's Hot Rods
    Joined: Oct 7, 2005
    Posts: 8,319

    Don's Hot Rods
    from florida

    On a related subject, boy, have gas prices taken a jump in the last few days !!!! :mad:

    Anyone remember the Mobilgas Economy Run that was held every year in the past ? It was a big deal back then, but was phased out in the 60's. If anyone is interested, here is some info on it:

  28. Shaggy
    Joined: Mar 6, 2003
    Posts: 5,208

    from Sultan, WA

    My old daily had a 283, L79 cam, 2500stall on a t400 and a 650dp holley and got 25 mpg on the hiway, but garbage in town.....
  29. Hey don
    Do you remember that V dub bug that was lightened to the max and running on what looked like bicycle tires from the '60s? Went cross country trying to break some sort of mileage record I think it got somewhere in the neighborhood of 100 MPG average from coast to coast.

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