just a little more power

[noonenosthis1]

Hi all,
We have an 2015, F350, 6.2,srw, crew cab, 4x4. We tow a Flagstaff 2020 529RLKS, uvw 9631 lbs. We live in California, so just about anywhere you go, you go over a hill, mountain. I would like just a little more power going over the hills. Any ideas? Not getting a different truck, hubby likes this one. He has it set up for pheasant hunting. We live in California so I believe some of the tuners are not an option.

thanks

[lenr]

The only transmission offered in an F-350 from 2011 to 2019 was the 6R140 6 speed transmission. Shifts down from the top 3 gears down into the next lower gear are all close to 30%. The change from 3.73 to 4.30 is a 15% change. So, about on average the 4.30 axle would save an additional downshift when one is already below 6th about 50% of the time. The 4.30 would definitely reduce downshifts from 6th at highway speeds. Only the OP may decide what is worth what to them. However, if the truck only tows a small percentage of the time, it wouldn't be worth an axle change to most folks.

[mkirsch]

parker.rowe wrote:
I'm not sure why people think the rear gear ratio only changes rpm/mph.

It increases torque multiplication to the rear wheels. It will tow more easily in all gears. It may allow towing one gear higher than usual

If the truck is in fact a 3.73 truck, it will make a difference going to 4.30's. Ford didn't offer that option for fun.

Yes, it will increase cruise RPM in 6th by 2-300 rpm. Might loose 1mpg unloaded. But as Fish stated you may gain mpg towing.

You know WHY it "tow more easily in all gears?"

Because the engine is running at a higher RPM at all speeds!

The engine produces more HP at higher RPMs, up to the peak of the power curve.

People think "gear ratio only changes rpm/mph" because that is precisely what it does.

If you were doing 60MPH at 2000RPM with stock 3.73 gears, you will need to rev the engine to 2305RPM to maintain 60MPH with 4.30 gears, or you will only be doing 52MPH at 2000RPM.

[time2roll]

Yes KLEANAIRIFORNIA pretty much all has ethanol. Much better than MTBE that was being used.

[MFL]

Cummins12V98 wrote:
Jerry Said: "I use non ethanol premium fuel"

UH Jerry the OP is in KOMMIFORNIA and Non Ethanol is a non spoken word.

Oops...maybe not in Ka? Even in my area, pure premium is usually only available at top tier stations. I might add, that pure regular (non-ethanol) is even harder to find.

[valhalla360]

parker.rowe wrote:
I'm not sure why people think the rear gear ratio only changes rpm/mph.

It increases torque multiplication to the rear wheels. It will tow more easily in all gears. It may allow towing one gear higher than usual

If the truck is in fact a 3.73 truck, it will make a difference going to 4.30's. Ford didn't offer that option for fun.

Yes, it will increase cruise RPM in 6th by 2-300 rpm. Might loose 1mpg unloaded. But as Fish stated you may gain mpg towing.

With all else equal, you are correct...but else isn't equal.

Who cares if you are towing one gear higher than usual if the engine is running at the same RPM/MPH? (assuming you don't exceed the ratings) The engine doesn't know if the torque multiplication is happening in the transmission or in the rear end.

Back in the old day's of 3 speed transmissions, there was so much difference between gear ratios, it was common when dropping down a gear to overshoot the ideal RPM/MPH for the engine and load. This left the engine racing while lightly loaded (not ideal for efficiency or power generation). A different rear end ratio could sometimes help align the RPM/MPH desired with the engine's ideal RPM.

With modern transmissions that have lots of gears to pick from, if you need torque multiplication, it can just drop down a gear (assuming you aren't already in 1st gear and struggling) and since the gear ratios are relatively close, it should be able to find a gear that keeps the engine in it's happy RPM range.

Ford offers the 4.30 for when you are pushing the truck so hard, it does struggle to get beyond 1st gear (or for old timers who automatically think you need a 4.X rear end if you tow?). That doesn't seem to be the OP's concerns.

[parker_rowe]

I'm not sure why people think the rear gear ratio only changes rpm/mph.

It increases torque multiplication to the rear wheels. It will tow more easily in all gears. It may allow towing one gear higher than usual

If the truck is in fact a 3.73 truck, it will make a difference going to 4.30's. Ford didn't offer that option for fun.

Yes, it will increase cruise RPM in 6th by 2-300 rpm. Might loose 1mpg unloaded. But as Fish stated you may gain mpg towing.

[time2roll]

That engine should be running about 4000 rpm to slug it up a hill.
OK to set the cruise at 4000 rpm and hold the gear to prevent upshift before the summit.

[Cummins12V98]

Jerry Said: "I use non ethanol premium fuel"

UH Jerry the OP is in KOMMIFORNIA and Non Ethanol is a non spoken word.

[valhalla360]

mkirsch wrote:

valhalla360 wrote:
A deeper rear end won't do anything to help this.

At least not enough to justify the cost and inconvenience of roaring around like an old Army Jeep the rest of the time.

OP indicated the real issue was running at high RPM is uncomfortable (not harmful...uncomfortable)

So by that I assume, it's not an issue of being stuck all the time in 1st gear struggling at 15-20mph climbing hills and they can't get the engine up into the RPM range to put out lots of HP.

As long as there is room to drop down more gears, the rear end isn't the limiting factor, so unlikely it would do anything to allow better hill climbing.

OP indicated a 2015, so I'm guessing a 6 speed transmission...If it was a 1980'something with a 3 speed, I might give a different answer based on more specifics.

[FlatBroke]

I put the Edge programmer on my “03” GMC Duramax shortly after I bought it. I never run it above level 2 and that gives my just the little bit of horsepower I was looking for.

[mkirsch]

valhalla360 wrote:
A deeper rear end won't do anything to help this.

At least not enough to justify the cost and inconvenience of roaring around like an old Army Jeep the rest of the time.

[valhalla360]

noonenosthis1 wrote:

MitchF150 wrote:
I suspect the OP just does not like the higher rpms that are required to get the peak power numbers for the already pretty healthy motor...

Just gotta let the engine rev on those grades.. That's like 3500+ rpms and yes, it's loud, but it's gonna be good for up to 5500 rpms if needed too...
!
Mitch

Bingo! But no we are not going 70 mph.

Then the answer is no, you can't fix it short of major engine redesign (such as adding a turbo).

A deeper rear end won't do anything to help this.

[dodge_guy]

You will want to regear the truck. This alone will change it from OK to excellent. You may even pick up a little bit of mileage when towing!

[MitchF150]

Well, that's gonna be part of the game with a gas powered vehicle.. They can make tons of power on their own... They just make it at the higher rpms..

My little 3.5 liter V6 has some 365 hp and 420 torque... The peak HP comes in around 5500, but the peak torque is right around 2500 rpms... That's what you need to get up those long grades.

The "rub" here is that it's got a twin turbo setup on it.. 🙂

There is a 'cost' to this however... It creates a TON of heat in a short period of time, so you just can't keep giving it the 'beans' without monitoring the coolant temps..

Once you get ver 10 psi boost, the temps spike pretty fast. 230* is about as much as I can take, and then I back off.

Yes, I slow down and that's fine with me.

Okay, so you don't go 70, but if you are going 50 up the grades, that's okay too.. At least for me.. 🙂

Anyway, if there was a magic device to just bolt on, meet California Emissions, then it would be a widely known and down process.. 🙂

Good luck!

Mitch

[noonenosthis1]

MitchF150 wrote:
I suspect the OP just does not like the higher rpms that are required to get the peak power numbers for the already pretty healthy motor...

Just gotta let the engine rev on those grades.. That's like 3500+ rpms and yes, it's loud, but it's gonna be good for up to 5500 rpms if needed too...
!
Mitch

Bingo! But no we are not going 70 mph.