tmacie

Ok, I know this can be dug up from piecing together searches but, I figure why not just put it in one spot.

In your opinion, what combination of upgrades will give top fuel milage? At what point will the upgrades make you loose economy?

This isnt specific to my truck, i want it to be general or if you want, a 12v list and a 24v list.

Thanks for your input, if this thread actually exists, I apologize but didn't find it in my searches.


Travis

John Faughn

I want to watch this for a 12v , but I think that leaving out how its drivin , the 1st thing is gear ratio, 3.54 on mine , then when I can aford a trans. from what I've read it puts the power to the pavement more effintly , then more fueling & timing , so now to watch for the list to help make it.

TxDiesel007

In my opinion all of these are factors

rear end
fuel plate
plate position
starwheel and position
tire size
driver control
pump timing
fuel additive
cleanliness of system

Anything else i left out i cannot think of, but a little bit of all of these can really help your mileage

Tx

John Faughn

I've read a lot of posts that were counter intuitive , bigger innjectors and bigger delevery valves and lets not leave out breathing , bigger air filter with heat deflector, upgraded intake and exhaust manifolds then bigger exhaust , the problum I see is all of these added together help but by the time your done recovering money spent vs. payback

tmacie

Thanks for your list Tx. John, as you said some of those things are counter intuitive. If anyone could explain how/why these things increase efficiency that would be great. Eg: Injectors, bigger up to a point will get you more efficiency, but past that point will hurt. An explaination to why this happens and at what point it happens would be excellent.


Travis

John Faughn

I'm not sure but it could be about emissions.

tmacie

Not quite sure what you are reffering to.....



Travis

John Faughn

If the eng. is getting less fuel than it burns cleaner, you go to the drags [ lots of mods ] they'll never pass any emissions , since the 70s the government tells the manufactors how to make the engs. run .

tmacie

Ahh I was jsut using the injectors as an example....just saying it would be cool if each thing on peoples list could be explained. I don't really want to get into the payoff of said upgrade, just what upgrades get you more MPG and why.


Travis

mr T

my answer is boring and you may not wanna hear it...but a properly tuned motor and controlling your right foot is the best way for mileage IMHO

and 12 valves benefit from timing advances

tmacie

Mr. T,
Thats exactly what I want to hear. Its really not for just me, but everyone!


Travis

cumminsdriver635

Mr.T is dead on... When i advanced my timing, it helped my fuel mileage, and driving easy makes a big difference. When i drive dads stock 98, he gets around 16mpg, when he drives it(shifts at about 1600rpm ), it gets 19-20mpg. If you can keep your foot out of it, and maybe advance the timing a little, you will see the biggest gains o think. Also, 3:55 gears help a lot, and if you are mainly on the highway/interstate the auto will do better. I got 22mpg coming back from indiana driving pretty easy, but running about 75mph.

Eric

WideOpenThrottl

cumminsdriver635, how will the auto benifit for better milage on the interstate?? does it have a higher top gear ratio than the 5spd.?
I was always under the notion that a manual driven nicely will always net better milage do to the fact that there is less power loss through the drivetrain.
tim.

tmacie

Anyone have any notes on physical upgrades that were not specifically put in for milage puroses but for power purposes, but had a side effect of gaining milage? Example: I put in bigger delivery valves and got 4 more mpg, i wanted more power so put in bigger ones than that and lost 2mpg.

Basically I'm looking to find out how much power can be added before milage gains drop off.

Thanks,
Travis

MnTom

Travis, a lot of the benefits of upgrades vs. mileage are vehicle dependent. What I mean is what works for one truck may not work the same for the next. That is due to the number of variables involved. Timing, injector condition, road conditions, pump conditions, tranny, axle/wheel bearings, well you get the idea. My understanding at least with injectors is the spray pattern (number of holes, spray angle, etc.) helps with the way fuel is burned. If you atomize fuel more (smaller droplets) you will get a better burn. Temperature of fuel also makes a differance. Colder fuel has a higher viscosity meaning it is thicker. When you force cold fuel through and injector the spray angle will be less and the droplet size will be larger. I have also increased my fuel mileage just by adjusting the valves. There are a lot more things involved for the fuel system but I am not anwhere even close to knowing a whole lot about it.
John, speaking from experience, a good auto tranny will help with getting power to the ground. I can get up to 55 mph without the tach going over 1600 rpm. and still get moving fairly quickly. I do not use as much 'pedal' to achieve the same results that I did with the stock tranny. Just look at my sig and you will see for the bombs on mine the power is somewhat higher than what would be expected. I attribute that to being able to put the power to the ground rather than loosing it in the tranny.
Tom