Hello everyone,I am thinking about changing the gear ratio in my ranger for better MPG.Right now I have a 4.10 ratio and I here that a 3.73 or 3.55 might be better for mpg,I know that I will have to change it in the front to so I know that it will cost $$.


my ranger 4x4 xlt 4.0 v6 sohc.

 

no. leave it alone. 3.73 will give you lower rpm on the highway but the truck will struggle more to get to speed and around town. try driving a little slower on the highway. you could also disconnect and plug your egr line because it is vacuum actuated. plug the line to stop the egr from filling the cylinder with "dead" exhaust gas and it should help with fuel economy. theoretically

 

^ You are wrong about the EGR.

To the OP, you will probably see better mileage depending on tire size with 3.73 gearing but the cost to swap gears won't really justify it. Just enjoy the setup you have.

 

how am i wrong?

 

EGR gasses are inert gasses that are allowed into the combustion chamber at cruising speed. these inert gasses will not burn and are there to take up space, reducing the amount of air/fuel allowed in, creating better MPG

 

to change the gear ratio would be alot of money,but I'l still will do it if I could save 2,3 mpg.As for the tire size stock 245 75 16 with the 4.10s I just get a little over 13 in winter I don't think it will improve in summer much.

 

you will be below your power band with that size of tire and a 3.55 or 3.73 gear...almost certainty that you will get less gas mileage

 

ok thanks alot I did not know that.

 

egr is to recirculate exhaust gases into the cylinder and it increases cylinder temperatures. combined with 10% ethanol in gas now which increases temperatures by 50 degrees, engine temperatures are even hotter which kills fuel economy. plug off your egr vacuum lines and it will stop actuating and puting hot exhaust gas into the combustion cylinder. NGK sparkplugs put on a workshop here last week to deal with all the issues people are having with 5.4 sparkplugs stripping and breaking because they are no longer warrantying some because if improper install/ removal. the guy doing the workshop also suggested to decrease the sparkplug gap by 0.010" to combat the ethanol in the fuel. they say decreasing the gap will slow the combustion process to create a more complete burn which will help with fuel economy and power.

 

Unless you are running at WOT all day long you will only see a decrease in mpg. Egr flow actually creates more power at part throttle due in the fact that ignition timing is advanced for the egr flow. I have experienced this first hand through tuning. The theory you state about reducing spark plug gap goes against all "performance" Ignition theories. I highly doubt that by slowing the burn you will create more power especially with no way of advancing ignition timing to compensate. I would also imagine that you would lose quite a bit of high rpm power.

 

you get a more complete burn when it is slower. the point of it is not for performance but increased efficiency

 

You got me there. EGR also slows the burn to an extent but you still need a way to increase timing to take real advantage of it. I do not think a stock engine computer will compensate for an under-gapped spark plug and on these 4.0 engines missing is still a problem.

 

my point is all this info i got came straight from a major sparkplug manufacturer. i would believe them and my trade school training

 

If you are referring to reducing the gap in a 3v 5.4 plug, you cannot. it has a U shaped electrode that is fixed

 

stock size tires and 3.73 will give you better millage. With stock tires, 3.73s i was getting 23ish on the highway. 07 4x4 4.0L 5speed. Personally i think the 4.10s with stock tires is horrible for highway driving. Youll also barely notice the difference in the swap.

 

Thats what I think,after all the ranger is a small truck so I dont see why the 3.73 gears wont work, I dont need alot of power anyway I'm looking into saving fuel then HP.The tires I have 245 75 16 and they weigh about 26lb so 4.10 are really not needed.