why would a 240 get worse milage than a 300?

 

Usually (not necessarily always) with engines of equal bore size but different stroke, the longer stroke version will be a little more efficient. Torque is what is needed to maintain momentum and the stroked version offers more torque at approximately any given RPM. More torque on hand means less throttle input for the same amount of work. Its basically lever physics. We all learned about that in 7th grade, right? At least back in my days we did.

 

ok, i see that. but wouldnt more torque ( made by more displacement) use more fuel. also if the truck didnt need the extra torque, would it be a waste?
or am i just in need of a good physics lesson?

 

Here is an easy way to think about it. Lets say you are trying to tighten a nut. If you use a short wrench it takes more effort to tighten it then if you use a long wrench. The longer stroke will produce more torque with less throttle than a motor with a shorter stroke. If you are worried about wasted power. Use the smaller I-6 engine with fuel injection and add some sort of power adder to it. Super charger, turbo charger, etc. This way you are only using the extra power when you need it and still have the benefit of the smaller motor with good fuel economy.

 

thats what i was thinking about doing. mild 240 with (**MAYBE**) a small turbo. try to stay out of the boost most of the time. but the physics lesson was really good, but left me with one question.

is there a simple way to find out how much power is needed to efficiently move weight?

 

yeah, I would like to know that, too.

and does anyone know how much horespower is needed to move a half-ton truck (79 F100) down the road?

just because my dad is a truck driver I know how many horses it takes to keep a loaded 18-wheeler going down the road at 60. the answer is 267; horsepower not horses.

 

Install a 3.9L Cummins with NV 4500 Trans and 3.25 Rear for about 30 MPG

 

There are many equations to figure this out. There is a book called "auto math". It has tons of formulas to figure out anything from shift points, center of gravity to volumetric efficiency and piston speed. Check it out. It will help you figure out when your engine is running at it's peak effiency for the best fuel economy.

 

cool, ill look that up.

 

After reading this whole thread, I am left asking myself the question........If he only drives 7 miles back and forth to work........how much would be saved anyway???

I have a similar commute to work and for the cost of the conversion, I think the 351W with the 650cfm 4bbl is doing just fine.

 

It was just a wacky idea that entered my mind. You never know what could happen unless you look into it or talk it over. Crap like that goes through my mind at night when I try to go to sleep.

 

Back to Ranger engines. If you look for a 3.0L V6 from a Ranger. I think all the newer ones are Flex fuel. So you could run E-85 in it. Not sure what, if anything, you would need to do for the fuel tank and fuel lines if they need to have a special coating like the engines do. But the 3.0 L has ok power (heck of alot more then the I-4) and gets a few MPGs better then the 4.0 L. Plus you could run E-85 in it, that is if it's avalible in your area.

 

G/f has a 4.0 aerostar and the motor isnt that bad. gets good MPG and seems tough as nails at this point. i like it. maybe when she gets her Chebby back she'll give it to me.

 

Ditto. A 4b (or 4bt) Cummins will give great mileage. Yes, diesel costs a little more nows day (maybe a lot more). However 30 mpg would like be possible.

 

What did they use the 3.9 Cummins in, those Iveco / Isuzu box trucks or something? That would'nt be a bad idea, and maybe mix up some of that converted cooking oil diesel.