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gas mileage??

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Wrenchero

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hello all.i know most guys are looking for more power but i am looking for better mileage.i have a 68 satellite convertible that i take trips with.it has a stock 318 2 barrel with stock cam,stock exhaust manifolds,dual 2 inch exhaust,8.75 rear with 2.76 gears and 904 trans.it gets 16-17mpg on the highway.should i be happy with that or should i try to do better.i have 2 thermoquads i was thinking of trying. a 9185 318 truck carb and 9801 mopar universal thermoquad with electric choke, and edelbrock performer intake.i dont mind messing with it because i can always go back to how it was.thanks for any input.
 
IF I’m any example I’m getting about 6 mpg with my stroked 440....
 
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If you get 2 mpg more how much do you spend get it is the question. Return on investment.
 
My 71 340 Cuda got 17 in town with 3.55 gears. It had a TQ on it.....
 
i dont have any experience with tq's. any good comments out there
 
I think that you are probably getting the best mileage you can expect. A ThermoQuad will be a slight improvement if you never open the secondaries....
 
My Road Runner is consistent at 13.x MPG all city driving. I'm actually pretty happy with that, but my old Coronet with a 440 and TQ could squeak 14MPG around town with very careful driving.
 
You will likely get the best mileage in 55-65 degree weather. Colder than that and the fuel/air mix doesn't atomize as well, hotter than that and air loses some density. Tall skinny tires reduce rolling resistance. A leaner fuel mixture, hotter spark plugs, low restriction exhaust, EGR....
Anything that makes air noise means it is causing drag. Open grille, tires that are inboard too far, mirrors, door handles, vent windows, hood scoops, etc. This stuff becomes an impossible goal though. Look at the Bonneville salt flats cars: They are designed for straight line top end testing. They are as smooth as an airplane in terms of air flow. A street car needs certain things to be legal to drive so chasing 2 mpg at the expense of mirrors, door handles, attractive body moldings and stylish rims may be pointless.
 
Wrenchero said:
is that a manual trans cranky?
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727. I always shied away from TQ's but the car came with it stock and it ran pretty good when I got it so, I left it on. Would assume it had a kit put in it before I got it but it ran great for several years before it got where it needed one which was WAY longer than any Holley I ever had. The TQ had a lengthy learning curve but it was mostly due to my mistakes. Learned a good deal from that carb but got it tuned and running good again after about a week or so. Had a 72 Challenger in 74 and only tinkered with it's TQ but never rebuilt one until the Cuda in the early 90's.
 
Not much help here....we are metric in New Zealand. I rate my driving economy by "Smiles per Tank"....I get more than my fair share. :lol:
 
Completed a 4,600 mile road trip in a similar car this fall ('72 Satellite Sebring Plus, 318 CID, 904, 2.71 8 1/4 rear end) Gas mileage was 15, 16, 17, 18 with an overall average of 17.3 MPG. I don't believe mechanically you can increase that much more. Cruising at about 70 MPH (non-stop) seems to net the best mileage. But I am also always looking for ideas to increase gas mileage so my eyes and ears are wide open (my road trips are extensive).

As a comparison, my parents new/factory stock 1971 Road Runner 383 auto with 3.23 averaged about 12.5 MPG.

DSC01151.JPG
 
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I had a '76 Dodge panel van, empty w/318 2bbl, 3.21 gear. Typical mileage 12-13 on highway. Built a 360, LD4B intake, Carter AFB (same as current Edelbrock?), headers. 15-16 MPG on highway, 14-15 pulling 4500# trailer on highway. I tried & had no luck with the T Quads or Holley spread bores, but they were pretty used & didn't respond much to rebuilds.
 
ALL of the Holley spread bore carbs were nothing but junk even when they were new....at least in my experience but TQ's responded pretty well. Just gotta learn the what to do with them. A warped main body or even the throttle plate would usually kill them along with the wrong float settings etc.
 
Fran Blacker said:
If you get 2 mpg more how much do you spend get it is the question. Return on investment.
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Sounds like he'd only be out an intake gasket set and modifying the kickdown (or getting a cable kit from Bouchillon) to try?
I'd put a crossover in the exhaust (X pref, or an H) for a bit more torque right where you need it-highway speeds, also.
That being said, check out this archived link from Mparts:http://board.moparts.org/ubbthreads...mpg-273-318-experiment-numbers.html#Post47507
 
66Satellite47 said:
I had a '76 Dodge panel van, empty w/318 2bbl, 3.21 gear. Typical mileage 12-13 on highway. Built a 360, LD4B intake, Carter AFB (same as current Edelbrock?), headers. 15-16 MPG on highway, 14-15 pulling 4500# trailer on highway. I tried & had no luck with the T Quads or Holley spread bores, but they were pretty used & didn't respond much to rebuilds.
Click to expand...

This makes sense. That 318 was probably working harder just to keep the van in motion.
This is the instance where a small engine in a heavy vehicle is a bad combination. You'd think that a 273 in a Satellite would get better mileage but if that engine is straining to maintain freeway speeds, the throttle opening is larger and the engine is working too hard to be efficient. A 360 could be used and even though the engine has more cubic inches to feed, the engine is barely working to move the vehicle.
 
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