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gas mileage??

All the od in the world will do no good if your engine is not built to run at lower rpms unless you incress mph to get the engine into proper operating range gas mileage will suffer.
My Charger RT with 4.10 gears, auto and nonstock 383 for instance wil get about 13mpg at 65 mph.
A switch to 3.23 and it will hardly run at 65 mph and gas milage suffers untill the engine is brought back to its magic 3200 rpm range and then goes back to 13 mpg. Mph you will have to figure. If I lived in Montana or Texas the 3.23 gears would be a load of fun.
 
mopar 3 B said:
All the od in the world will do no good if your engine is not built to run at lower rpms unless you incress mph to get the engine into proper operating range gas mileage will suffer.
My Charger RT with 4.10 gears, auto and nonstock 383 for instance wil get about 13mpg at 65 mph.
A switch to 3.23 and it will hardly run at 65 mph and gas milage suffers untill the engine is brought back to its magic 3200 rpm range and then goes back to 13 mpg. Mph you will have to figure. If I lived in Montana or Texas the 3.23 gears would be a load of fun.
Click to expand...
That's 100% right. I got 20mpg with 4:30s but when I switched to 3:55s it dropped to 18mpg so I used 5th and was right back where I was or at least very close. Like mentioned my motor was built to run these rpm's and is happy doing it where a 600hp motor would see very little benefit. My particular issue is the Viper gearing, it's a .5 6th. In the future I plan a 5th 6th gear swap to make it more friendly to these old motors.
 
Some of you guys are making me believe I can increase my MPG by downshifting from "drive" to "second" on the freeway and keeping it there!
 
Dibbons said:
Some of you guys are making me believe I can increase my MPG by downshifting from "drive" to "second" on the freeway and keeping it there!
Click to expand...
Lmao, no, no, no.... There is a point at which a motor becomes inefficient, it's no different than pulling a steep hill at 35 mph in 4th gear and not downshifting. Because of technology where a computer can have so much control over timing, fuel, etc it's nothing for newer cars to be able to pull off low rpm cruising but for most of us guys it's likely 2,000 rpm and above. In my case the 4:30s were spot on for cruising putting it around that 2,000 rpm range but made the car no fun to drive (had to shift every 50ft), 3:55s are awesome except now 6th is of little used unless you like cruising 90mph.
 
My little 1970 Porsche 914 had a 1.7 liter VW four cylinder motor (fuel-injected) and a 5-speed where both fourth and fifth were overdrives. I could only use 5th if I could maintain a steady speed of at least 70 mph, otherwise did not have enough torque at lower speed/rpm. I was always trying to reach the 30 MPG mark, but never got past 29 MPG.

914.jpg
 
How long has it been since some of you guys have owned a 318 powered car?

Let me remind you that they do NOT struggle to maintain freeway speeds in a B body car.

My unmolested 60,000 mile 73 318-2 with 2.76 8 1/4 (only mod is dual 2 1/4 exhaust) can cruise at 80 all day and has legs and power to do 100 easy.

Average MPG is 14 right now, but I'm pretty sure it can do better.
I am still working on the tune, the vapor vent system and it has a fixed fan with no shroud.
This is also intermittently using the A/C.

I had a 67 unmolested 9.2:1 2 barrel 75,000 miles 67 Coronet with what ever standard gear came in that year's 7 1/4, and it got a ridiculous 16-18 average and 22-23 or more highway.
I'm sure that car was somewhat of an anomaly, but I've heard (and because of it believe) similar stories.

For reference, my family has owned a LOT of Dakota trucks.
I've found that these modern, EFI, computer controlled, roller cam, overdrive and lockup equipped LA family engines installed in roughly 4200 pound vehicles tend to get the following-

3.9 / UNK factory axle average 18 MPG
5.2 / 3.55 axle average 16 MPG
5.9 / 3.92 axle average 13 MPG

All with regular A/C use.
 
...and I can also tell you that my 5.9 R/T gets 23 MPG at 50 MPH in O/D (effective 2.7x final drive) and it worsens quickly to 17 at 55 and 15 at 65.

NO WAY could it get better MPG near it's torque peak of 345 at IIRC 5000-ish RPM.
 
YY1 said:
How long has it been since some of you guys have owned a 318 powered car?

All with regular A/C use.
Click to expand...

Agreed. Mine will cruise at 75 and if you just give her a little more you can feel the torque start pulling hard. It won't pin you back in the seat but there is no confusion there is much more to be had. If you floor it and down shift (2.94 gears so will hit the sweet spot when it downshifts) it she will quickly head toward 100....
 
i have to agree with yy1 and jim kueneman.the stock 318 has great torque and as said it doesnt pin you in the seat ,but it goes when you want it to.i drove it yesterday and it will get to 80 very easily and cruise with plenty left.i dont want to race it and i dont want to change the way it runs dramatically.just wondering if i could get better mpg.most of my driving is highway
 
A working heat riser and a clear exhaust crossover. A choke that takes too long to come off consumes a lot of fuel. Make sure the choke pull-off is adjusted properly. When warmed up if the crossover isn't at it's design temp you're not vapourizing the fuel properly and you are sending unburnt, but paid for, fuel out the exhaust. Make sure you're vacuum advance is working properly and the correct one for that application. Bump your initial timing as far ahead as you can safely run. Advance until it pings under your usual heaviest drivng, then back it off just enough to stop the pinging.

Watch your driving habits. Every time you lift your foot then set it down again you activate the accelerator pump. Lots of fuel there. Put a raw egg under the accelerator pedal.

Try to travel downhill and with the wind as much as possible, both directions ideally :).
Steve
 
That year 318 is the best you will get. A 1973 318, with 2.71 gears in a Charger. I was getting about 22 on the highway back in 1982, sometimes up to 24 mpg on a 120 mile trip, never over 65mph, about 17 in town, that was with leaded gas 91 octane min needed.
 
why do you think you got that kind of mileage.did the gas back then have something to do with it
 
Back in '73, the price of gas DOUBLED. Making 2 bucks an hour, man, it was hard to get by!!
My 318, 904, 2.76 '68 Charger got a solid 25 mpg, highway. Had a stock Carter 2v, single exhaust. Stock cam, too.
Here's a few things I did - bump timing until part throttle knock, than back off a degree. Accel pump backed off a notch. Choke backed off a notch. "Zip tube", made out of a piece of flexible 2" exhaust pipe used to get cooler air from the battery area to the single, stock snorkel. Added a hot coil to the ignition. Rear springs were a little saggy, so I lowered the front even more, ala 'nascar look. Toe was 1/8 in. Reading the plugs showed "textbook tan" color on all cylinders.

Interesting thread!
 
Best average mileage with a 360 was 20. 600 cfm Carter on a OE iron 4bbl., recurves distributor with as much initial timing I could get. MSD 6A triggered. Off the exhaust manifolds, dual exhaust w/H pipe. ‘73 trap door air cleaner. K&N filter. 276 cogs w/235/60/15’s on all 4 corners.

There was a little more in it but lost the car before I could further the experiment.
 
A few other things I did. Backed off the drum brakes for no drag. Had Ansen wheels - lighter that steel. Built a front spoiler, like Petty's 73-4 Charger ran. Don't know if it helped or hindered, but it looked cool.
 
mopar73dge said:
That year 318 is the best you will get. A 1973 318, with 2.71 gears in a Charger. I was getting about 22 on the highway back in 1982, sometimes up to 24 mpg on a 120 mile trip, never over 65mph, about 17 in town, that was with leaded gas 91 octane min needed.
Click to expand...

In 1975, I went to the Indy 500. Speed limit was 55 and I didn't want an out of state ticket! So, 6 hours at a steady 55 got me 27.2 mpg.
No tricks, just didn't move my foot.
 
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