Speed Limiter/Govenor
Laughing Gas
Joined: Jul 2011
Posts: 810
Likes: 494
It apparently can be done via Forscan (somehow). There's a couple threads on it over on Tremor Forum and a couple guys confirm they've done it, but not been real specific about which settings they changed to make it happen. I've done a little looking and testing but not found a setting that works on my truck yet. This thread also has some information in it that may be applicable (?) https://www.fordtransitusaforum.com/threads/factory-set-or-factory-option-speed-limiter.81785/page-2
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Hotshot
Joined: Mar 2017
Posts: 10,161
Likes: 1,372
From: Chaz
My f350 dually is the same as my srw’s at 96.
I have seen the f250-350 tires in different factory sizes and brands advertised at 106mph and 112mph max speed ratings.
The 450 pickup is 87mph max on the factory tire, I believe, but check before you try.
2nd Gear
Joined: Aug 2023
Posts: 2
Likes: 0
It apparently can be done via Forscan (somehow). There's a couple threads on it over on Tremor Forum and a couple guys confirm they've done it, but not been real specific about which settings they changed to make it happen. I've done a little looking and testing but not found a setting that works on my truck yet. This thread also has some information in it that may be applicable (?) https://www.fordtransitusaforum.com/threads/factory-set-or-factory-option-speed-limiter.81785/page-2
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Last edited by Kljm; Oct 30, 2023 at 12:28 PM.
Lead Driver
Joined: Jun 2006
Posts: 5,663
Likes: 985
From: Near Yosemite CA
My '22 F550 CC/4x is limited to 76 and it sucks when you want to get around some cidiot on the 99 or the 5, or want to go up a hill faster than 50mph with a load 🙄 I called Banks and supposedly the derringer will be available for the 22 F450/550's around the first of the year, looking forward to that!
I have programmed/chipped all my newer trucks I've had and have been happy with them all, no, not a waste of $$
I have programmed/chipped all my newer trucks I've had and have been happy with them all, no, not a waste of $$
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Fleet Mechanic
Joined: Aug 2022
Posts: 1,584
Likes: 1,117
I could see a 76mph limit for the C&C trucks being a problem but 96mph is fine for me with my dually. I didn't like the idea of my Jaguar being artificially limited to 300km/h (186 mph) either but it turns out I never hit the limit anyhow! LOL
I can see the tire ratings being the reason for the limits; I don't buy the driveshaft/rpm thing.
Dave
I can see the tire ratings being the reason for the limits; I don't buy the driveshaft/rpm thing.
Dave
Cargo Master
Joined: Apr 2003
Posts: 2,058
Likes: 424
From: Too close to Houston
It's a real thing. Google "What is driveshaft critical speed" and you'll read things like this:
What is critical speed & why is it important?
Most important is the Critical Speed. Essentially, any rotating shaft will reach a point where it will become dynamically unstable. This leads to a “whipping” or “jump-rope” effect that causes violent vibration and ultimately leads to driveshaft failure. Critical Speed is a function of the shaft’s length, material stiffness and tubing diameter.
Most important is the Critical Speed. Essentially, any rotating shaft will reach a point where it will become dynamically unstable. This leads to a “whipping” or “jump-rope” effect that causes violent vibration and ultimately leads to driveshaft failure. Critical Speed is a function of the shaft’s length, material stiffness and tubing diameter.
And driveshaft critical speed calculators like this one:
Spicer Driveshaft Critical Speed
Spicer has this to say: "In short, you never want the 1/2 criticalspeed of the driveshaft to occur within the 50 to 70 MPH range of the vehicle. WARNINGS. An unbalanced driveshaft can experience a criticalspeed failure..."
All that said, I will freely admit I have no idea what the critical driveshaft speed is for any Ford Super Duty. It may not occur within the speed range our engines are capable of. But maybe it does?
Mountain Pass
Joined: Jan 2024
Posts: 143
Likes: 46
[QUOTE=DPelletier;21020882]I could see a 76mph limit for the C&C trucks being a problem but 96mph is fine for me with my dually. I didn't like the idea of my Jaguar being artificially limited to 300km/h (186 mph) either but it turns out I never hit the limit anyhow! LOL
I can see the tire ratings being the reason for the limits; I don't buy the driveshaft/rpm thing.
Critical speed is a real thing, when I was working overhauling big steam or gas turbines, bringing them up to speed was a dicey process. You'd bring it up to 10% below the first critical speed, then push it though to 10% above and let it run a while, then bring it to 10% below it's second critical speed, then push it though usually to final running speed. The shaking going though the criticals was exciting. the main shafts were 12 inches solid steel, the vibration monitors would indicate a "U" shape at the first and a "W" at the second.
The first few times it can be a bit unnerving, but you learn not to let them run withing 10% of critical speed. They have the same issues coming down in speed, the same as going up in speed. All that said, I have no idea what the critical speed on a super duty truck driveshaft might be.......
I can see the tire ratings being the reason for the limits; I don't buy the driveshaft/rpm thing.
Critical speed is a real thing, when I was working overhauling big steam or gas turbines, bringing them up to speed was a dicey process. You'd bring it up to 10% below the first critical speed, then push it though to 10% above and let it run a while, then bring it to 10% below it's second critical speed, then push it though usually to final running speed. The shaking going though the criticals was exciting. the main shafts were 12 inches solid steel, the vibration monitors would indicate a "U" shape at the first and a "W" at the second.
The first few times it can be a bit unnerving, but you learn not to let them run withing 10% of critical speed. They have the same issues coming down in speed, the same as going up in speed. All that said, I have no idea what the critical speed on a super duty truck driveshaft might be.......
Laughing Gas
Joined: Nov 2010
Posts: 793
Likes: 255
A 2013 6.2L F250 with factory LT275/65/20 tires will definitely exceed 120mph and it pulls pretty hard up to that point.
I would imagine the newer trucks are capable of going 130+ no problem, all safety concerns aside.
I would imagine the newer trucks are capable of going 130+ no problem, all safety concerns aside.