ford v10 gearing suggestions

[marty]

after struggling to get through I-80 last weekend i have decided to do a gear change on my truck. my goal is to get over 75mph on the highways or at least get the truck into 5th gear. currently i could get up to 80+ but i would be revving it to 4k rpm in 4th gear. i know the truck can take it, but i would like to preserve some fuel economy, even if it is 7mpg compared to 5mpg.

the truck is a 2001 f250 v10, manual 5sp, 3.73 gearing, stock tire size (265) with 112k miles. i was thinking 4.10 but don't know if it is enough or 4.30 but don't know if it will be too low to get around town. currently the truck is used for towing a 5-6000lb trailer and as a back up vehicle for the race van or a snow vehicle.

any thoughts?

any other mods that would make a significant difference other than buying a diesel?

[benfoxmra95]

Marty if you go from 3.73 to 4.1 ratio.

It will increase your rpms by 332

If you go to a 4.3 ratio your rpms increase by 495

4.56 = 706 increase

4.69 = 812 increase

I just got a ford van with a v-10 and it has 4.69 rear end gears and I just drove it home from denver and it pulled 75 mph all the way.

This van is on the e-450 chassis so it's quite heavy, it had adequate power.

Not sure what the gas mileage is yet but was told it will get 9-13 mpg on the highway.



On the Ford PCM (eec-V), injector pulsewidth is directly linked to the amount of airflow going into the motor measured by the mass air flow sensor.

Therefore more air across the sensor = more fuel being sprayed. There are some other variables with o2 sensors that go into this equation, but that can be a lengthy explanation, so i'll keep it in a nutshell

Right now your driving down the road, and you have to give it alot of pedal (air) to keep the truck moving at a constant 75 mphs.

So here's where you might get better gas mileage you might not.

You increase the engine rpms with (numerically higher rear end ratio) so you are now into an area of the torque curve that produces higher torque and so you'll need less pedal (air) to maintain speed. therefore theoretically less fuel being used.

But your penalty is the higher rpms will consume more gas because the engine is going through more cycles (more times it sprays fuel) so your fuel consumption may not get better it may get worse if you go with too high a rear end ratio becuase the motor will be spinning faster going through more intake fuel spraying cycles.

it's a balancing act and finding the right gear ratio is the key.

This is the biggest engineering struggle manufactures have with cars and MPG's Finding the best scenraio for each car is hard. that's why if you ever start looking closely at all cars the rear end gear ratios are all over the place. there's vehicles with 2.73 rear end gears, that in theory if they had enough power could pull 250 mph.... and others as high as 5.38.

[snay]

If you are going to keep the truck for a while gear it low and put in a bender/splitter it will give you the best of both worlds i can get you some prices from my sponsor in slc if you would like.

[marty]

thanks for that info ben, that was the stuff i was looking for. i think the 4.3 would give me the extra grunt i need. now 5th gear at 80mph i am at 2500 rpm and that motor likes to be wound above 3k to get out of its on way.

snay, what programmer does your sponsor use? i was going to try to find something that had the ability to have two maps, a towing map and a more fuel efficient map for putting around town. we have ATS here in denver and i think they use superchips

ben or snay, any opinions on after market maps and engine life? help or hurt?

thanks
marty

[marty]

fwiw, i have also heard the early v10s don't enrich the mixture at full throttle, they just push it back into the tank. the new ones will give you a bit more gas when you have it floored

[benfoxmra95]

snay is talking about a rear axle ratio splitter, mechanical..


Your talking about a handheld flash device for tuning. i.e. diablo or SCT

personally I prefer the SCT. but they both accomplish the same thing. the sct has nicer software.


But know this!.....you will not get any better fuel mileage from either of these units.....!!!

The ecm is always.... looking for 14.7 afr off the o2 sensors and constantly adjusting the fuel to acheive 14.7 which is where the best fuel effiency lies.

with these programmers You can tell the ecm to hunt for 15.7 (leaner) but you be stepping into the pedal more to try and keep the vehicle moving beacuse power is less at this leaner afr

with these programmers You can tell the ecm to hunt for 13.7 (richer) but your fuel economy will suffer, power will stay the same as 14.7.

So these programmers really are not useful for economy, they will tell you they are but it's marketing hype, trust me. I have personal dealings with SCT and diablo and used both their programmers tuning cars and trucks on a superflow dyno.

The stock factory calibration is about the best you can get for fuel economy. now when your trying for bigger power, then the factory calibration is no good and that's when you go to town with the programmer.

[benfoxmra95]

fwiw, i have also heard the early v10s don't enrich the mixture at full throttle, they just push it back into the tank. the new ones will give you a bit more gas when you have it floored

You would need a Wide band o2 sensor to verify what AFR the motor is running in OPEN Loop enrichment. most manufactures aim for 12.5 for WOT running on a motor.

optimum AFR for a NA motor like that is 12.8 for best power and 11.6 for cooler running under higher loads but just a little less power because its richer.

at cruise on the highway you are in what's called closed loop so the ecm is doing it's best to maintain 14.7 (stoich)

In open loop this is an enrichment state that's for power at WOT and the ecm is set to maintain a richer fuel afr like 12.5


The parameters that need met to go into open loop fuel enrichement on that PCM are more than 75% throttle, and load higher than "1.0"(map pressure)

at 75 mph your not cruising with the pedal more than halfway to the floor, this is not a wot enrichment state, so the computer is in a closed loop state trying to acheive a afr of 14.7 for best fuel economy under any part throttle light cruise mode.

[marty]

snay is talking about a rear axle ratio splitter, mechanical..



:oops: doh

those are pretty damn trick, in an ideal world that is exactly what i need, but $3-3500 for the gear splitter and almost $2000 for the gears installed may be a bit steep for a truck with 112k miles. on a newer truck though...

http://www.gearvendors.com/index.html

[benfoxmra95]

$2000 for rear end gears? is it a 4wd?

if just a 2wd, it shouldn't cost that much at all.

the gears themselves should cost around $300-$400, and a bearing kit should be about a $100 and labor shouldn't be more than $200-$300.


BTW....if it is a 4wd, you really don't need to do both front and rear axles at the same time. if you use 4wd in the winter then yes you need to do them both.

but if your trying to do it on the cheap, just do the rear now and then do the front later on.....just don't put it in 4wd...bad things will happen to the t-case.

[marty]

$2000 for rear end gears? is it a 4wd?

if just a 2wd, it shouldn't cost that much at all.

the gears themselves should cost around $300-$400, and a bearing kit should be about a $100 and labor shouldn't be more than $200-$300.


BTW....if it is a 4wd, you really don't need to do both front and rear axles at the same time. if you use 4wd in the winter then yes you need to do them both.

but if your trying to do it on the cheap, just do the rear now and then do the front later on.....just don't put it in 4wd...bad things will happen to the t-case.

yep, 4wd. when i first started to research giving the truck more umph i had thought about trying to find a 2wd diesel if the price of upgrades was more that the price of a beater diesel. its nice now to only have to go 50 miles to the track but after i rode miller, i may have to do some traveling next year for usgpru races :D

[PremiumBlend]

If you decide to have gears installed, and you are pulling your axles yourself my cousins own Front Range Driveline off of Federal and Union. (About 5 blocks south of Hampden) They are some of the best guys around and will do it right, they probably install more than 50% of the drivelines on the race cars up at Bandimere. I had them do my Chevelle... cigar pattern on the 1st shot! :)

If you don't plan on taking your axles out, call Chuck Solladay at High Country 4x4. He has done some great work for me and my brother-in-law many times.

Just a couple places to start for prices at least.... hope this helps.

[snay]

Marty call Matt Moon at GILLETE DIESEL he has hands on experience with the v10 his dads truck i talked to him this morning and let him know you would call him 801 571 7780

[snay]

Marty call Matt Moon at GILLETE DIESEL he has hands on experience with the v10 his dads truck i talked to him this morning and let him know you would call him 801 571 7780New gears installed would be around 2,500.00 front and rear

[mbohn]

Sounds like you are ready for a diesel.

[marty]

Sounds like you are ready for a diesel.
yeah, no kidding. thing is this truck is SO close to being paid off and i am pretty tired of truck payments. i think the gearing will be the ticket

[Mark Schellinger]

Damn Marty I feel your pain.
Bottom line though... even if you warm up a shit sandwich, it
is still just a shit sandwich.
We have been towing for-ever. Started back when diesel trucks
were only ugly work trucks, so we had badass big block gas trucks.
They worked pretty good, but when we started using diesels, trailer life
got way better. I don't get why people don't buy diesels. They are more money I guess.

Anyway I enjoyed reading this thread.
It was cool to see Ben knows about something :lol:

[marty]

Damn Marty I feel your pain.
Bottom line though... even if you warm up a shit sandwich, it
is still just a shit sandwich.
:lol:

:lol: :lol: yep, hopefully a little mustard will help it not taste so shitty

[PremiumBlend]

Damn Marty I feel your pain.
Bottom line though... even if you warm up a shit sandwich, it
is still just a shit sandwich.
:lol:

:lol: :lol: yep, hopefully a little mustard will help it not taste so shitty

Screw it... 100 shot of NOS will do the trick on those hills! :)

[benfoxmra95]

Anyway I enjoyed reading this thread.
It was cool to see Ben knows about something :lol:

lol...

Effer.