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

[FishOnOne]

noonenosthis1 wrote:
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

If you don't have 4.30 gears this is where I would start. Having said that it will require you to change out gears both rear and front differentials since you have 4x4.

[MitchF150]

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...

If you want low rpms AND power, then diesel, or some other sort of major modification to the induction system will be needed... (ie, blower or turbo setup)

Also, if you are trying to take the grades at 70 mph, then you might need to adjust your expectations as well...

Good luck with whatever you decide!

Mitch

[Lwiddis]

I agree…downshift. 4000 RMP won’t hurt the engine.

[valhalla360]

Grit dog wrote:

valhalla360 wrote:


Smaller diameter wheels will help in the sense that they effectively change the gear ratio slightly in your favor (assuming they still have sufficient payload rating)

The difference between 74 and 67 pounds on an 8000lb truck pulling a 12000lb trailer is not going to make any difference.

He was saying 2 different tires the same size weigh close to +/- 70lbs each. Idk what a little 245-75-17 or whatever weighs, but rough guess, little 17" tire/rim combo vs big set of wheels and tires is an easy 20lbs of rotating mass per corner, based on changing many of both.
I good approximation of the effect of rotating mass is about 7:1. Every lb of rotating mass sucks as much power as moving 7lbs of static mass.
Combine gearing efficiency of smaller diameter and effectively 500lbs ish of static mass reduction will help noticeably.
That said, I'd rather have the stability and capacity of larger rims/tires, but certainly not a deal breaker to downsize if searching for a little more snort.

Even if there was a 7-1 ratio, 7lb x 4 tires x 7 = 196 lb on a rig that weighs in at around 20,000lb total.

[time2roll]

Your truck already has the more power. Enjoy the ride.

[MFL]

Ford towing specs 3K difference, say 12K to 15K, between the 3.73, and 4.30 gearing, so that is a big difference. I agree, with 4x4, it is cost prohibitive. Does the OP have 4x4???

Available tire sizes range from 245/75/17 up to 275/70/18. At 3,500 rpm, my 6.2 pulls very strong up 7-8 percent grades, even towing double. Having had a 5.4 V8, I think my 6.2 is reasonably quiet and happy, up to 4K rpm.

Jerry

[blt2ski]

Grit,
Not sure it's a 7-1 ratio. It might be. BenK has used a ratio on bikes, a human notices 1 to 2 oz reduction on a moving part, vs needing 2 lbs on a non moving part.
When I put 285s on my truck, about 10-15 lbs extra per corner, mpg went down 3 mpg about the same as when I've had 1500 lbs in the bed with stock 265 rubber.
That's more in line with Ben's 16 or 32 to 1 ratio.
At the end of the day, you and I and may be jimlin are on the same page, that wt reduction via tire or rim reduction, does net you more HP to the ground vs drivetrain loss.
OP I have not seen come back with where they are HP low. If elevation, not sure lighter tires/rims will help, since one is losing 2 to 3% of HP per 1000' elevation gain. So assuming 6000 to 8000 ft elevation, that potential 20-25% power loss. Nothing short of a forced induction add on will help in this situation.

Marty

[lenr]

The 2015 Super Duty 6.2 came with either a 3.73 or 4.30 rear end. If the OP’s is 3.73 the Ford tow rating for the 3.73 is 12,100. With the family and the trailer loaded up the OP is likely close. The rear end ratio was important back in the 3 or 4 speed transmission days because the gear ratios were far apart. The 6 speed in a 2015 has much closer ratios—just let it shift. Valhalla360 has the right idea. Acceleration and mountain pulling are all about HP because HP has RPM in the equation. The exact equation is HP = Torque x RPM / 5252. The 6.2 is an overhead cam engine that will spin up to 5000 RPM although you might not want to listen to the noise. If you want to go faster push the accelerator. Also, changing the rear end ratio involves two gear changes because of the 4x4—not worth the cost. My son has the same truck in a 2012. He pulls upwards of 10,000 lbs of livestock or 12,000 lbs of hay. It never runs in 6th pulling a trailer on level ground. As stated above gas engines just don’t put out much torque at low RPMs. Using the formula: less torque = less HP at any given RPM. The best gas engine (without turbo) for low end torque is the Ford 7.3 available in 2020 or later.

[JIMNLIN]

The difference between 74 and 67 pounds on an 8000lb truck pulling a 12000lb trailer is not going to make any difference.

Agree.
Those numbers were to represent how heavy certain LT E tire types can be in certain 17" and 18" sizes vs say a all season OEM LT285/80-17 E at 40-43 lbs (depending on brands).

Speculating anywayz on the OPs tire sizes/brand/tire types.

Now if the OP had a new gen diesel with 800-1000 lb torque then tire/wheel weights aren't that big of a deal.

[Grit_dog]

valhalla360 wrote:


Smaller diameter wheels will help in the sense that they effectively change the gear ratio slightly in your favor (assuming they still have sufficient payload rating)

The difference between 74 and 67 pounds on an 8000lb truck pulling a 12000lb trailer is not going to make any difference.

He was saying 2 different tires the same size weigh close to +/- 70lbs each. Idk what a little 245-75-17 or whatever weighs, but rough guess, little 17" tire/rim combo vs big set of wheels and tires is an easy 20lbs of rotating mass per corner, based on changing many of both.
I good approximation of the effect of rotating mass is about 7:1. Every lb of rotating mass sucks as much power as moving 7lbs of static mass.
Combine gearing efficiency of smaller diameter and effectively 500lbs ish of static mass reduction will help noticeably.
That said, I'd rather have the stability and capacity of larger rims/tires, but certainly not a deal breaker to downsize if searching for a little more snort.

[valhalla360]

JIMNLIN wrote:
We quite often see 250/350 owners who bit into towing 14k-15k lbs with the small block 6.2 engine. Many swapped for the same 250/350 with the diesel.

Just to add to MFL on point comment on tire/wheel diameters.
Also I've found with gas small blocks, and big blocks, tire and wheel weight can drag down their towing performance.
Example of a tires weight;..... a BFG Mud Terrain KM3 LT295/70-18" that weighs 74 lbs. Now add the wheel and the little V8 has over 400+ lbs of tires and wheels to keep the load moving.
Even the same brand BFG same tire type in a 17" weighs 67 lbs.

Yeah.... I know we have lighter weight tires out here but this is just a example of parasitic drag on the small engine.

Smaller diameter wheels will help in the sense that they effectively change the gear ratio slightly in your favor (assuming they still have sufficient payload rating)

The difference between 74 and 67 pounds on an 8000lb truck pulling a 12000lb trailer is not going to make any difference.

[Grit_dog]

mkirsch wrote:
Tuners only affect gas engines at WOT. Unless you run around with the gas pedal mashed to the floor, they won't help.

Gearing, smaller tires, do not add power. They allow the engine to spin faster at a given speed, with the caveat that you're stuck with it ALL THE TIME, even not towing.

The most cost effective solution is, if the truck is doing the job now, and you don't want to trade it, to learn to be happy with what you have.

One is only “stuck” with the look and reduced load capacity of smaller (17” wheels are the only viable option for significantly smaller tire diameter in this case) wheels.
Truck has enough rpm’s and gears to run bobtail highway speeds on small tires at sane rpm’s no problem. Even if they already have 4.30s.
Plus OE 17” steelies takeoffs are dirt cheap, with tires. Good option to throw on for towing if it suits the OP. It fits the bill of “a little more power” for the least amount of money and issues.

[mkirsch]

Tuners only affect gas engines at WOT. Unless you run around with the gas pedal mashed to the floor, they won't help.

Gearing, smaller tires, do not add power. They allow the engine to spin faster at a given speed, with the caveat that you're stuck with it ALL THE TIME, even not towing.

The most cost effective solution is, if the truck is doing the job now, and you don't want to trade it, to learn to be happy with what you have.

[blt2ski]

For elevation power issues, ONLY way to truly counter that is putting some kind of forced induction on the motor. Ie a super or turbocharger.
As Jim also pointed out, if you have heavier tires, that uses up HP too.
Gearing may help, probably not enough to make it worth while as pointed out.
At the end, a mild to moderate boost supercharger is best if you don't want to change trucks, or a turbo diesel new truck.

Marty

[JIMNLIN]

We quite often see 250/350 owners who bit into towing 14k-15k lbs with the small block 6.2 engine. Many swapped for the same 250/350 with the diesel.

Just to add to MFL on point comment on tire/wheel diameters.
Also I've found with gas small blocks, and big blocks, tire and wheel weight can drag down their towing performance.
Example of a tires weight;..... a BFG Mud Terrain KM3 LT295/70-18" that weighs 74 lbs. Now add the wheel and the little V8 has over 400+ lbs of tires and wheels to keep the load moving.
Even the same brand BFG same tire type in a 17" weighs 67 lbs.

Yeah.... I know we have lighter weight tires out here but this is just a example of parasitic drag on the small engine.