200 built for maximum gas mileage
- Thread starter xpsnake
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grocery getter
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what addo said 
also, if your looking at freeway only then try 2.79's and skinny tires. if you don't want to mess with the gears, go with the tallest and skinniest tire you can. it will hurt your city mileage though.
what trans do you have now?
also, if your looking at freeway only then try 2.79's and skinny tires. if you don't want to mess with the gears, go with the tallest and skinniest tire you can. it will hurt your city mileage though.
what trans do you have now?
8) you want to build the engine to make good power in the rpm range you are planning to run the engine in. you need to select parts that compliment each other in that rpm range. you also need tight control over your air/fuel misture as well. to that end i would run a megasquirt efi system along with a cam that works in the off idle to 4000 rpm range. i would also run the trans and rear gear combination that addo suggested.
My set-up is designed for exactly your goal. With the exception of a T5, I think I've done everything I possibly can. The T5 is a huge mpg improvement if you're willing to do the swap. I don't think it's possible to rise above 25mpg without it. My best is 24, but on average, watching my gas foot and nothing over 70-75, is 22mpg. Driving all out I get as low as 17.
All of the above, plus a K&N air filter and Cruise Control. Headers with a low restriction muffler and 2 1/4" exhaust pipes. Synthetic oil in rear axle. Keep tires inflated a couple of PSI above normal pres. 5W-20 Synthetic or Synthetic Blend oil. Thermostatically controlled fan (electric or viscuous). 185* thermostat or close. Empty the trunk. Remove rear seat.
Do you know what rearend gears you have now? My 81' came with 2.79's with a 6.75 ring. It gave great hiway milage about 18-19, but on the backroads with alot of hills and in the city I got about 14-16 mpgs. I swapped in a 7.5 with 3.45's, a 2bbl, Mallory Hifire cd with an Ecoil, and a set of headers and my hiway is right a 21-22 mpgs but my city and backroads mpg's are around 19-20.
mysavioreigns
Famous Member
I have 3.25s currently and get great mileage. I'm going down to 2.79s on the new 8" though.
It's pretty simple in theory. In order to get the best fuel mileage, you want to convert as much of the chemical engery present in gasoline into mechanical energy moving your car forward.
At a fundamental level, that means that you want to set up the engine to be as efficient as possible. Since an engine is a dynamic thing, it is going to be more efficient at some rpm's and loads than others.
So, you want to pick your parts (carb, ignition, exhaust, etc) to be as efficient as possible (Completely burn the gasoline) and you want to pick your drivetrain (tranny, gears, etc) to run the engine at it's most efficient rpm and load.
Putting this oh so simple theory into practice can be challenging. YMMV
At a fundamental level, that means that you want to set up the engine to be as efficient as possible. Since an engine is a dynamic thing, it is going to be more efficient at some rpm's and loads than others.
So, you want to pick your parts (carb, ignition, exhaust, etc) to be as efficient as possible (Completely burn the gasoline) and you want to pick your drivetrain (tranny, gears, etc) to run the engine at it's most efficient rpm and load.
Putting this oh so simple theory into practice can be challenging. YMMV
LaGrasta":arayp20a said:No? Honestly, I don't even know what that is.Bort62":arayp20a said:LaGrasta":arayp20a said:
Have you tuned your cruise AFR w/ a wideband ?
Using a wideband 02 sensor to measure what your air/fuel ratio is at cruise, and then tuning appropriately so it comes in somewhere around 15 or 16 to 1.
EFI makes that part SO much easier as you won't suffer any negative effects in around town driving or acceleration. With a carb, it's a balancing act.
Patrick66
Famous Member
check out the turbo/supercharger/EFI tech section.
http://fordsix.com/forum/viewtopic.php?t=38349
TBI is your only option unless you want to modify your log head or buy an aluminum one.
http://fordsix.com/forum/viewtopic.php?t=38349
TBI is your only option unless you want to modify your log head or buy an aluminum one.
A
Anonymous
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mysavioreigns":1f706wwb said:
I had a rear end shop put a 2:41 gear ratio in my car with a 200 I6 running 13" tires as thin as I could buy them which was some where around 3 1/2 inches wide. My car would not spin the tires in the mud without really getting on it in first gear but on the highway (which is most of my driving) I could run 70 mph and the tack would show I was doing 1700 rpm after I got up to speed which took some doing if I was feathering the throttle . Sometimes it seemed like it would take me forever to get to the last gear but I sure had fun. Great mileage on the highway (29 to 32) but in town driving I never come out of 2nd gear and the gas wasn't that great but not real bad either around (18 to 23). I agree with rbohm you should do your setup in the power range you plan on running your engine for all around driving. You have to meet some where in the middle of your power range because if you don't you will lose mileage on one end or the other which will gain you nothing in the long run.
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