This has got to be wrong, there is no way you can get 18mpg out of a 460 f250 with 4.10 gears

 

Vary true, but an interesting thing is that for example in the 300 cylinder #1 is at TDC when cylinder #6 is as well, but of course cylinder #6 is at the top of the exhaust stroke. You cant really compare a multi cylinder 4 stroke to a single cylinder. A single cylinder 4 stroke is a rough engine, because it takes an entire revolution before the next cylinder fires.

Found this cool video, notice that there is no distinct power stroke.

******** width="425" height="344">


<embed src="http://www.youtube.com/v/NNqmNqaZlKA&hl=en_US&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" height="344" width="425">*********>

 

^^^ but you are correct, i made a mistake saying it turns the crank 60 degrees, when it really turns it 120 degrees.

And i also said in my previous post that there is no power stroke, but i really mean that there is always a cylinder firing, its not like a 1 cylinder 4 stroke where the piston has to rotate 2 rotations before another power stroke because there are 5 other pistons firing before that same cylinder fires again. Including 1 that fires when the 1st returns to tdc of the exhaust stroke.

Boy, i need to write these posts when i can think clearly and it all makes sense.

 

And why must this be wrong? I did the same trip several times with the quad for a couple months... went from having to switch tanks to doing the trip on about 2/3rds of rear tank. 2nd last trip out it only got 13mpg.... cleaned the K&N and the last trip it got 18 again. 240km and 37.8liters. Just got a Nissan Frontier 4x4 to replace it..... getting 19 with it... same trip, same quad, 36 liters of gas but worked the Nissan a lot harder to do the trip. I have a slide ruler thingie that does the mileage calculations for me.... just line up how far you go and how much gas you used. Please keep in mind the part where I got roughly 10mpg when I got the truck... I wasn't driving it long like that so I threw in the K&N and cut the box.... threw a little timing in as well, that took it from 17-18. I figured the cut air box was worth 5 of the 8mpg improvement. The K&N and removal of the tube from grille to airbox was 2mpg, the cut box was 5, and the timing was 1.

 

Removing the tube from the grill to the airbox will not net you mileage gains, I am very certain that, if anything, that will hurt mileage by pulling in the warmer air. Same thing with cutting holes in the air box. Even if you completely removed all of the intake tubing and let air run straight in the throttle body, you would not see the numbers you claim.

 

Even though the air is warmer, there is so much more of it available that it in fact improves mileage.... that 460 is pretty choked off with the stock intake system. I don't get brownie points on here for making false claims.... just stating what I get. Intown mileage isn't so hot, but once you get it on the open road, it works pretty good. Trying to help some guys out with some simple mods, not looking for money or anything, not selling anything, if you're happy with what you get for economy then party on but I wasn't about to put up with the 10 I got so I did something about it. Motor makes peak torque at highway speed so it really doesn't work hard at speed.

If the original poster is getting 8 with a 6, then obviously something is wrong, and even if it was 100% and factory new, there is usually something you can do to improve the original mileage. My truck gets less mileage with the OD off, (never calculated but noticeably lower), but the difference would be enough to convince me to swap gears out if I had to in order to make the difference.... it likes 2200 rpm on highway, and if you get it over 2500 in town, you will notice a big drop in mileage.

 

You running stock size tires in that 97?

 

I don't see how thats possible to get that kind of mileage with that setup. Most trucks with 302s don't get that.

 

My point is that in every 4-stroke engine, the crankshaft turns 180º during the power stroke (and 180º during each of the other 3 strokes). How much of that stroke is actually applying power depends on the amount of fuel-air charge in the cylinder and the timing of the spark. At idle, it could be 20º, and at max throttle, it could be 150º (the engineers at Ford would know better...). And that's true no matter how many cylinders are in the 4-stroke engine. What IS 120º in an I-6 is the amount the crankshaft rotates between 2 spark plugs firing in their power strokes, and that number would be 90º in a V-8. That's assuming, of course, that the engines' timings are balanced.

Jason

 

235-85R16 10ply Toyo M-55s... stock size.

It started with me and buddy having a mileage competition between my truck and his jacked up ranger which is currently running a 4.0L 5 speed, 4.56 gears and 37s. He kept commenting that my crappy mileage is why he drove smaller trucks, I wasn't down with that so we took a look at mine and questioned the intake tube and stuff right off the bat. When I got close to his economy he switched his exhaust to a Flopro and 2.5"? pipes and grabbed a couple mpg on me.

One thing I didn't mention out about my truck is it has custom exhaust.... Y to 3", full length single pipe, no cat with a Flowmaster in front of the rear axle, and shiny tip behind rear tire. That was on there when I got the truck and I'm sure it's part of the reason the intake mods work so well.... I don't think the exhaust alone helped my mileage much and if it did I'd be scared to drive it stock.

 

well I pulled out my chiltons book and found the bore/storke of the two. I guess they are the same bore with the 300 having a longer stroke. But I still belive that the larger displacement of each cylinder would make it less efficient. Maybe my readings on my odometer are off. I am running 31-10.50-15's. There also may be issues with the truck, but it runs great as it is and always starts right up and doesnt burn any oil.

 

yea im gettin around 11mpg. could it be because there are a few holes in my exhaust, bad o2 sensors and maybe a bad cat?

 

If the timing is set correctly it has very little affect. Timing only adjusts when the ignition occurs to compensate for slow burning air/fuel mixture in relation to engine speed. This way the most energetic part of combustion occurs at the most opportune time and creates the most power, regardless of engine speed. Just becasue timing is advanced 150 degrees doesn't mean that it changes when the combustion occurs in relation to the cylinders position.

But the point is still that the 6 cylinder has a longer combustion period, and less overlap allowing to use fuel more efficiently. There is still 120 degrees of rotation that allows more time for the combustion to push the piston down, before the next piston fires, not necessarily the spark plug. For example, a 1 or 2 cylinder engine would be most efficient, because there is no overlap. The expanding gas in the cylinder pushes the piston down until it bottoms out and the exhaust valve opens. Any more then 2 cylinders and you get combustion that overlaps the previous cylinders combustion which is inefficient.

I feel like were saying the same thing, we just aren't understanding each other .

 

on the gasoline.... your ecu is programmed to spray so much fuel with the air ratio... so if you buy 93... as opposed to 87 your just spraying in more expensive fuel with a low compression motor. and will take longer to burn yes but your RPM still idles the same.. and your still spraying the same amount of gas.

 

I changed my tires to 33's and noticed a 10% decrease in speedometer setting using a GPS. The odometer will have the same change (10% - less) due to the large size of tires because it is calibrated to the stock setting. You can check the odometer using the mile markers on the highway.
On mileage, if you have 350 4X4 I understand the transfer case is engaged full time but the hubs are not therefore increase the mechanical drag - ie loss of gas mileage. There are some articles about a kit to put in the trans/tranfer case connection to change to the from full time to only when you need/want 4X4.
I do not know about the 300, but on the EFI for the 302/350 unless you have a mass flow you are injecting gas by banks (1-4 and 5-8), so half the time the gas is injected on the intake stroke and the other on the exaust. Can not get great gas mileage when half is wasted.
If you want to get the best gas mileage for what you have put a vacuum gauge on the motor and only drive at highest vacuum.