That's what I was thinking, 825 would be a burnout champ if you wanted it to. Then again I've haven't hammered down on my truck yet, do these things spin the tires very much?

 

Of course it does.

HP = [Torque x RPM] / 5252.

At any RPM that you change the torque, the horsepower MUST change. But the point being made here is that the torque at the RPM where the engine makes peak HP is not changed, so peak HP does not change.

 

Exactly. They must have cut hp and torque in the lower RPMS....my guess is they changed the air/fuel maps so that the torque curve is less flat and much steeper in gears 1-3 of SRWs . If you do this, peak hp can remain, but all values leading up to it on the power curve look like the upward side of a steep hill. I imagine that also increases drivability in less than optimal conditions, e.g., so you don't just spin tires using 1/4 throttle on a wet road.

 

No, he isn't. Troverman said it only affects torque, not horsepower. Oklarado said he didn't think that was possible. He is correct because any change in torque at a given rpm will change the horsepower at that rpm. There was no mention of peak horsepower in their discussion.

 

Mark basically said what I was thinking, so I didn't comment further. "Horsepower" and "Torque" ratings are both at a set RPM. Ford doesn't specify exactly how much torque the engine is making at any RPM other than 1800, nor does it specify exactly how much horsepower the engine is making except at 2800RPM. So my point was that in 1st gear at 2800RPM, a SRW truck is still making 440HP. At 1800RPM, it may well be making less horsepower than it would in gear 4.

Regarding the gas EcoBoost example, yes, those engines have variable valve timing. I'm guessing the torque de-rate could simply be a function of boost - on both this example and the diesel. By reducing the max boost that can be generated at an RPM, torque can be reduced.

There is no way to remove the torque limitation by any button in the truck or any factory approved method. "Sport" mode is F-150 only, although there is a "sport" traction control setting which probably reduces stability control interference. I'm sure some tuner could remove the torque limit, but this would be unwise for longevity.

Ford claims the de-rate is to protect the rear tires, but in all likelihood it is probably designed to protect the rear axle / differential and possibly the transmission.

The 6R140 is designed to handle 1400lb-ft. However, the torque converter can essentially double the torque from the engine to that which the transmission "feels." So, 925x2 is obviously over the limit. However, the torque converter is locking in other gears (Mark can correct me if I'm wrong) so at that point the transmission is safe. Since the DRW trucks only limit in 1st, it seems the SRW trucks need to protect both the transmission in 1st, and the axle in 2nd and 3rd? Perhaps torque-induced wheel-spin combined with the brake-based traction control, and or sudden finding of traction can "shock" the axle into breaking a half-shaft? The dually trucks have a stronger axle and extra wheels and weight which apparently reduces the likelihood of wheelspin that could cause harm.

 

I just wish there was a way to turn it off. My 2017 kinda feels like a slug compared to my 2011. More HP and torque on paper, but you can't even use and enjoy it in the first 3 gears. If you're going to put an engine with this much power and torque in a vehicle, build the drivetrain to handle all the power all the time.

 

I was looking at 6.7 dyno charts yesterday and got to thinking maybe it has the cab chassis tune in it for the first three gears?

 

Don't forget the turbocharger is different on the '17 vs. the '11. I made the same transition and while I am happy with the acceleration of my new truck, I think the acceleration characteristics are mostly attributed to the turbo spool time.

 

That is correct.

 

I'd love to be able to turn this off so my wife quits complaining the truck sucks compared to our traded in detuned 6 speed manual Cummins that only was rated at 350 hp and 660 ft/lbs. I still like the new truck and I'm hoping it pulls as good as the two '11 6.7s I had in the past. I generally get along with machines and adapt to how they work, she wants everything to be instant when she hits the pedal.


Ford has to do things to make these trucks driveable for the masses I guess but for a lot of people it's ridiculous. I've never had abnormal treadwear on tires, even on heavily tuned trucks I've had in the past, all in how you use that power I guess.

 

Torque limiters have been a thing for years. My '05 V6-powered Mustang had a torque limiter in first gear, and I'm certain my F150s did as well. In many cases it's more about driveability than it is tire life.

When you gotta get out of someone's way, you plant the accelerator and expect the truck to GO. Not sit there and spin the tires. Maximum traction occurs when the tires are hooked up, not spinning.

 

I'm ok with traction control limiting if it does break lose but not the computer stopping me from getting the most out of it until they break lose. My wife would agree after the truck falling on its face with a semi that wasn't even close to her suddenly ending up on top of her entering the interstate...this was the week we picked it up and we almost gave it back, it has since gotten better but that's a little unnerving. My ecoboost would sit and fry the tires off first with less than half the torque and yes I know it's lighter than the super duty but has no issues getting the heck out of the way when it needs to. My first 2011 6.7L would bark the tires in 2nd gear bone stock if you gave it the throttle, this truck would sit and laugh at me if I wanted it to do that.


Nobody take this the wrong way I love the new truck to death, but I personally would tweak the heck out of this part of it...and in time I probably will.

 

you think these are bad then you should drive a ram with the Cummins. Dead pedal is really bad on those. A few times it about got me in a wreck.

 

My ecoboost was quick too. It just felt too car-like (especially with the console mounted shifter) and I didn't like that I didn't feel as solid and planted as I do when I'm in a Super Duty. Maybe I'm spoiled by the performance and sound of the ecoboost, and maybe I don't have a clear memory of the 2011, but I remember really being able to feel the torque in the 2011. Maybe I had a ringer and this time got a dud. This one feels gutless and takes forever to spool up. I can floor it and the lag is ridiculous. Maybe I should plan better, like floor it 5 seconds before the anticipated need for power?? Too bad that is hardly ever possible in driving situations unless you're just playing around. You go to pass someone, floor it and nothing happens for what seems like an eternity. I think this is dangerous. There are certain times when it's amazing but overall it's pretty much a slug. If they would only put an ecoboost (preferably a twin turbo V8 or maybe the raptor tuned V-6 version) in the Super Duty I would go that route never look back. Don't even care how poor the fuel economy would be.

 

Ram has it as well. Torque Management is what they call it....and it really blows!

Why crank out 900+ft-lbs of torque when you're just going to limit it anyways