How's your MPG?

Discussion in 'Fuel Economy & Emissions' started by Stormin' Norman, Aug 12, 2008.

  1. Moparman

    Moparman New Member

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    That sounds not too bad for a carb; it's only a little over-carbed with that AVS.

    I'm trying to remember how my 318 distributor was set up. IIRC I had maybe 10º BTDC initial, and 24º mechanical advance. 15 initial seems like a lot - is it hard to start when hot?
     
  2. Secret Chimp

    Secret Chimp New Member

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    Nope. It is a bit harder to start than my old setup but that seems to be mostly from this aluminum manifold getting hot so much more readily than the old iron one (it usually likes to catch at a very low RPM and pull up to normal idle instead of just going RUMM). Not at all a crank-n-curse situation by any means though. But it starts right up from days-long dead cold with a few squirts from the pedal, just like on the old setup.
    Once it's warmed up it really just squats and goes. I have 2.93s so I'm not laying rubber even with these cheapie 215s, but it's a huge difference from the way I bought it.

    I have a couple of vids on YouTube of right after I got it running:
    http://www.youtube.com/watch?v=xJMXl09IAEs
    http://www.youtube.com/watch?v=irn7H085aWY

    It pulls nicer up top with the extra advance I have now - the cam's rated to power for 5000 rpm but it feels like it could just keep going; I don't for the sake of the old heads, though I did change out the valve springs.

    I'm running unported vacuum off of the carb for the advance, too. Don at FBO modifies the vacuum pot so it behaves nice at idle RPM. Very smooth and quiet and another 5+ inches at idle over ported and the car drives exactly the same as if I was using ported vacuum. Some guys with bigger cams or different pots can't run it that way as-stock, but it works for me.
     
  3. Moparman

    Moparman New Member

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    Sounds like you've got it well sorted it, with a good understanding to boot. Other than your heavy foot enjoying the extra power, I can't think where else to look for poor mileage. What's a typical vacuum reading and RPM on the highway?
     
  4. Secret Chimp

    Secret Chimp New Member

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    I wrote it all down once and I've lost the piece of paper - I'm at around 2100 rpm at 60 and about 15 inches of vacuum or more last time I checked. I don't have to crack the throttle much to maintain speed just by foot-feel.

    I'm about to go on vacation and spend all kinds of money... when I get back I'm going to convert this carb to the smallest original AVS specs I've found with Edelbrock parts, 0.089/0.092 jets and rods 0.068/0.057" (#1436), and fiddle from there. This setup was recommended for someone with a 340, so I'm sure I'll be fine on my 318.

    Right now I have .066/.058 rods and I don't actually know what size main jets I have (they aren't marked - the secondaries are, so I suspect someone messed with this sometime in the past). That'll make me 7.5 percent leaner based on area than I am now assuming I have .089 jets.
     
  5. eugene vik

    eugene vik New Member

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    mieage 1960 buick wagon

    usually pulls 18 mpg on trips has chev 350 350 found the notebook on the car and it has 2.41 gears kind a high speed??? i have tweaked on carb and distrib it runs HEI with at least 065 gap that big gap keeps the fire burning when you lean them down
    had a 600 edelbrock one step lean from factory set up
    drove it 4,000 miles round trip last year to CA and left with $2,000 and made it home, would not want to try that this year!!!:biglaugh:
     
  6. 1964countrysedan

    1964countrysedan Well-Known Member

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    I do not know if this counts but I got 26 MPG in my Toyota pickup on the way to my mom's.

    What i thought some of you might find interesting though, is that I only paid $3.52 a gallon.
     
  7. MikeT1961

    MikeT1961 Well-Known Member

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    Thank God for summer gas again! Add that to the summer Sumitomos instead of snows, and I did 825 kms on 84 litres of gas. That works out to just a tidge shy of 28 miles to the Imperial gallon. Most of that was what passes for highway driving here, so some stop and go, plus some in town driving, PLUS some idling for warmth at work over night. Not bad for a 351M, 2bbl carb, and 3 speed FMX in a 2 tonne tank thank is overdue for a tune up.
     
  8. 1964countrysedan

    1964countrysedan Well-Known Member

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    14.6 mpg on one tank, last trip, A/C on high entire time
    not quite as good on the next two
     
  9. santos4racing

    santos4racing New Member

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    My 92 Caprice , box stock. w/ 235 x 75 15" tires does 18-19 around town & 22-24 on the road. Curious to see how they do towing? Any info appreciated!
     
  10. knighttemplar

    knighttemplar New Member

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    The 90' VW Fox averaged 32-33...
    Just bought a 2001 Volvo V-40 Turbo Wagon- she averages 30-31 on the road and about 27 around town.
     
  11. Vista

    Vista Well-Known Member

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    I've been working on wagon of late to improve the performance and mileage. I've leaned out the jetting in the carb. The vacuum advance has been disconnected and I'm running 14 degrees initial advance. I haven't had a chance to put any highway miles on yet, but I've gotten 15.9 MPG around town (17 corrected for tire size). That's a substantial improvement over the 10 MPG I was getting. I need to run more than a partial tank though it to be sure.

    Update: Ran some more miles. Looks like the corrected gas mileage is about 14.8 MPG. Still a big improvement over 9-10 MPG. I've also dialed the initial timing back to 12 degrees to make hot starts easier and prevent knock.
     
    Last edited: Jan 19, 2013
  12. SRT8 Magnum

    SRT8 Magnum New Member

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    The computer shows a average of 11 mpg with all city driving. On the open highway at 75 mph it will get 24 mpg.
     
  13. 101Volts

    101Volts Well-Known Member

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    First tank: 18.68
    Second tank (Mostly highway) 22.4
    Third: 18.2 (And that's with at least half an hour of idling for a radiator fluid change.)

    I noticed the engine was a lot peppier after the radiator flush.
     
  14. ModelT1

    ModelT1 Still Lost in the 50's

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    They probably used high test antifreeze!:rofl2:

    By the way I thought you just put in a new radiator, thermostat and antifreeze!
     
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  15. Fat Tedy

    Fat Tedy Island Red Neck

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    I'm sure I read on the forum that if you used dual radiators you would get 35-40mpg up hill both ways, or was that dual muffler bearings:hmmm::huh:


    :rofl2:
     
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