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just a little more power

noonenosthis1
Explorer
Explorer
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
49 REPLIES 49

valhalla360
Nomad III
Nomad III
time2roll wrote:
valhalla360 wrote:
parker.rowe wrote:
The main benefit is not that it puts you at a different rpm closer to the torque peak...it is that you increase the torque multiplication in every gear.
So assuming you aren't regularly in 1st gear and struggling, explain what benefit that provides over simply dropping down one gear.

Is it somehow unmanly to downshift?

The benefit really is keeping the engine up in the peak torque range with higher RPM because HP = Torque * RPM and HP determines how fast you can climb a hill.
Sometimes to split the gears just seems better. Yes if changing the final drive was basically the same as a downshift it would be mostly pointless.

Six speeds sounds great but often it is a choice of 3rd or 4th going up a hill and the user may want gear 3.5


Problem with this theory is the deeper rear-end is just as susceptible to this issue. Even with 4.3 it won't hold top gear when climbing a decent grade and as you say a half gear down would be better with older 3/4 speed transmissions in many cases.

The 6 speed is pretty good about this and the newer 8/10 speed transmissions really make the rear-end irrelevant except when towing at max GCVW.
Tammy & Mike
Ford F250 V10
2021 Gray Wolf
Gemini Catamaran 34'
Full Time spliting time between boat and RV

dodge_guy
Explorer II
Explorer II
time2roll wrote:
valhalla360 wrote:
parker.rowe wrote:
The main benefit is not that it puts you at a different rpm closer to the torque peak...it is that you increase the torque multiplication in every gear.
So assuming you aren't regularly in 1st gear and struggling, explain what benefit that provides over simply dropping down one gear.

Is it somehow unmanly to downshift?

The benefit really is keeping the engine up in the peak torque range with higher RPM because HP = Torque * RPM and HP determines how fast you can climb a hill.
Sometimes to split the gears just seems better. Yes if changing the final drive was basically the same as a downshift it would be mostly pointless.

Six speeds sounds great but often it is a choice of 3rd or 4th going up a hill and the user may want gear 3.5


exactly. what is good for one person or combo may not be good for the next. a final drive swap tailors the vehicle to the person and load.
Wife Kim
Son Brandon 17yrs
Daughter Marissa 16yrs
Dog Bailey

12 Forest River Georgetown 350TS Hellwig sway bars, BlueOx TrueCenter stabilizer

13 Ford Explorer Roadmaster Stowmaster 5000, VIP Tow>
A bad day camping is
better than a good day at work!

dodge_guy
Explorer II
Explorer II
valhalla360 wrote:
parker.rowe wrote:
The main benefit is not that it puts you at a different rpm closer to the torque peak...it is that you increase the torque multiplication in every gear.


So assuming you aren't regularly in 1st gear and struggling, explain what benefit that provides over simply dropping down one gear.

Is it somehow unmanly to downshift?

The benefit really is keeping the engine up in the peak torque range with higher RPM because HP = Torque * RPM and HP determines how fast you can climb a hill.


Unfortunately it doesnt work as simply as dropping down a gear. maybe with the new 8 and 10 speeds that may work, but with the 4 and 6 speeds dropping a gear can change where the rpm is. on my V-10 4 speed combo running in 3rd at a comfortable cruising rpm put me at 73mph. after going to 4.30 I could either cruise in 3rd at 67 at the same rpm or use OD and drop some more RPM.
It is far more than "just dropping a gear".
Wife Kim
Son Brandon 17yrs
Daughter Marissa 16yrs
Dog Bailey

12 Forest River Georgetown 350TS Hellwig sway bars, BlueOx TrueCenter stabilizer

13 Ford Explorer Roadmaster Stowmaster 5000, VIP Tow>
A bad day camping is
better than a good day at work!

time2roll
Nomad
Nomad
valhalla360 wrote:
parker.rowe wrote:
The main benefit is not that it puts you at a different rpm closer to the torque peak...it is that you increase the torque multiplication in every gear.
So assuming you aren't regularly in 1st gear and struggling, explain what benefit that provides over simply dropping down one gear.

Is it somehow unmanly to downshift?

The benefit really is keeping the engine up in the peak torque range with higher RPM because HP = Torque * RPM and HP determines how fast you can climb a hill.
Sometimes to split the gears just seems better. Yes if changing the final drive was basically the same as a downshift it would be mostly pointless.

Six speeds sounds great but often it is a choice of 3rd or 4th going up a hill and the user may want gear 3.5

blt2ski
Moderator
Moderator
parker.rowe wrote:
mkirsch wrote:


Not anymore. Most HD pickup trucks only have one gear option these days.


Not for gas trucks. Dodge offers 2 options, Ford offers 3. Gm is the only one that does not have an option. They haven't for a while iirc.

There are only 3 major manufactures of consumer HD trucks, and 2 of those offer different gear options, with increased tow ratings for deeper gears, for the gas trucks.


Issue with the RA deeper us better, it helps MOST in first gear assuming everything else is the same.

BUT, with my GM 6.5TD, on a freeway grade of 3-5%, with the nv4500 I had, the 3.73 would have been the better RA ratio. As the grade got steeper, I dropped a gear, I could go to redline in next lower gear, same speed as 1800 in higher gear.....reality, I would assume a high percentage majority of us do not drive at WOT in the gear below. We do as I did in that truck, reduce rpm to 2700 to 2800, drive whatever that speed is. With the 3.73, I would have been going faster bt 5mph or so.

Same thing occurs in my Navistar, having 7 forward gears, reasonably space apart, I've pulled hills better that higher up/torque motors with fewer gears. Both of these in first gear, due to lower overall ratio times torque, out pulled a basically double HP/torque Dmax. 6.5 by an additional%grade before stalling at 20k lbs. The IHC with lowest power, 30% at 30k lbs due to an overall low around 45-1 vs effective ratio of 17-1.

Iff you want to talk 4% freeway grade speed, the Dmax at 320 HP more than left the 175/185hp of the IHC/GM behind.

Reality, a lower ra may or may not help in actual towing experience. Depends upon the situation, what you want that truck to do or behave.

Marty
92 Navistar dump truck, 7.3L 7 sp, 4.33 gears with a Detroit no spin
2014 Chevy 1500 Dual cab 4x4
92 Red-e-haul 12K equipment trailer

parker_rowe
Explorer
Explorer
mkirsch wrote:


Not anymore. Most HD pickup trucks only have one gear option these days.


Not for gas trucks. Dodge offers 2 options, Ford offers 3. Gm is the only one that does not have an option. They haven't for a while iirc.

There are only 3 major manufactures of consumer HD trucks, and 2 of those offer different gear options, with increased tow ratings for deeper gears, for the gas trucks.
2015 Starcraft TravelStar 239TBS 6500 GVWR
1997 GMC Suburban K2500 7.4 Vortec/4.10
1977 Kawasaki KZ1000

mkirsch
Nomad II
Nomad II
dodge guy wrote:
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.


It most certainly will! It will let the truck pull in a different gear. On a gasser as little as 300rpm makes a difference to n towing at the top of one gear or the bottom of the next. It does indeed make a difference. That’s why different axle ratios are offered by the manuf.


Not anymore. Most HD pickup trucks only have one gear option these days.

Putting 10-ply tires on half ton trucks since aught-four.

valhalla360
Nomad III
Nomad III
parker.rowe wrote:
The main benefit is not that it puts you at a different rpm closer to the torque peak...it is that you increase the torque multiplication in every gear.


So assuming you aren't regularly in 1st gear and struggling, explain what benefit that provides over simply dropping down one gear.

Is it somehow unmanly to downshift?

The benefit really is keeping the engine up in the peak torque range with higher RPM because HP = Torque * RPM and HP determines how fast you can climb a hill.
Tammy & Mike
Ford F250 V10
2021 Gray Wolf
Gemini Catamaran 34'
Full Time spliting time between boat and RV

Cummins12V98
Explorer III
Explorer III
MFL wrote:
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.


We are lucky in NW WA to have Cenex Farm supply that has Red Diesel and all three grades of non ethanol.
2015 RAM LongHorn 3500 Dually CrewCab 4X4 CUMMINS/AISIN RearAir 385HP/865TQ 4:10's
37,800# GCVWR "Towing Beast"

"HeavyWeight" B&W RVK3600

2016 MobileSuites 39TKSB3 highly "Elited" In the stable

2007.5 Mobile Suites 36 SB3 29,000# Combined SOLD

dodge_guy
Explorer II
Explorer II
parker.rowe wrote:
mkirsch wrote:
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.


You still have torque multiplication happening.

For easy math, lets say you have an engine with a nice flat torque curve.

100ft lbs at both 2000 and 2300rpm.

Running in direct (1:1), also to make the math easier.

100ft lbs x 1 x 3.73 = 373 ft lbs

100 ft lbs x 1 x 4.30 = 430 ft lbs

The main benefit is not that it puts you at a different rpm closer to the torque peak...it is that you increase the torque multiplication in every gear.


Yes! A lot of people don’t understand that. They just think it makes it scream and use more gas, when it’s just not true.
On my V-10 Excursion I went from 3.73 to 4.30 and gained .5 mpg. Why? Because I was now able to use OD which it couldn’t before. It also made each gear more efficient.
Wife Kim
Son Brandon 17yrs
Daughter Marissa 16yrs
Dog Bailey

12 Forest River Georgetown 350TS Hellwig sway bars, BlueOx TrueCenter stabilizer

13 Ford Explorer Roadmaster Stowmaster 5000, VIP Tow>
A bad day camping is
better than a good day at work!

dodge_guy
Explorer II
Explorer II
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.


It most certainly will! It will let the truck pull in a different gear. On a gasser as little as 300rpm makes a difference to n towing at the top of one gear or the bottom of the next. It does indeed make a difference. That’s why different axle ratios are offered by the manuf.
Wife Kim
Son Brandon 17yrs
Daughter Marissa 16yrs
Dog Bailey

12 Forest River Georgetown 350TS Hellwig sway bars, BlueOx TrueCenter stabilizer

13 Ford Explorer Roadmaster Stowmaster 5000, VIP Tow>
A bad day camping is
better than a good day at work!

Turtle_n_Peeps
Explorer
Explorer
OP you have very limited options if you don't (can't) run a tuner. You will only gain a few HP out of a tuner anyway.

Unlike the popular belief on RV.net, gears don't make power. If you don't like to rev your engine to peak HP it does not make any difference how many gears you have. If you want peak power, you have to rev your engine to peak RPM. It's that simple.

If you want power at a lower RPM you only have a few choices. Buy a diesel (which you say you don't want to do) or buy some sort of a supercharger. Whether that be a turbo or belt drive.

Another option you can also use is if you want more power is E85. I think your Ford can use it? If so, you should be able to gain on the order of 25 to 30HP buy switching to E85. Be aware if you switch to E85 you will go through fuel at an alarming rate but you will make some more horse power.

My suggestion is just let the engine rev and do what it needs to do.
~ Too many freaks & not enough circuses ~


"Life is not tried ~ it is merely survived ~ if you're standing
outside the fire"

"The best way to get a bad law repealed is to enforce it strictly."- Abraham Lincoln

parker_rowe
Explorer
Explorer
mkirsch wrote:
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.


You still have torque multiplication happening.

For easy math, lets say you have an engine with a nice flat torque curve.

100ft lbs at both 2000 and 2300rpm.

Running in direct (1:1), also to make the math easier.

100ft lbs x 1 x 3.73 = 373 ft lbs

100 ft lbs x 1 x 4.30 = 430 ft lbs

The main benefit is not that it puts you at a different rpm closer to the torque peak...it is that you increase the torque multiplication in every gear.
2015 Starcraft TravelStar 239TBS 6500 GVWR
1997 GMC Suburban K2500 7.4 Vortec/4.10
1977 Kawasaki KZ1000

time2roll
Nomad
Nomad
lenr wrote:
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.
30% vs 15% would be an easy choice if the truck seemed to be hunting for that middle gear.