I was watching this video http://www.youtube.com/watch?v=Yf9FPs40VUM (I know, it's a video about Hummers) and the narrator mentions something called "brake throttle modulation", which is the technique of applying a light amount of brake and throttle at the same time. As seen in the video, the technique allows the Hummer to get through some pretty aggressive terrain.
The video got me thinking. I grew up around farm tractors and it's quite common to use brakes to help with traction. As farm tractors usually have independent brake pedals, it's possible to apply a slight amount of brake to the wheel that is spinning. This [hopefully] allows the wheel with greater traction to help get you unstuck.
Trucks obviously have only a single brake pedal, but it just occurred to me that if I applied a slight amount of brake while stuck, that the antilock brake system would apply brakes to any slipping wheel, while preventing brakes from being applied to the wheels that are stopped.
Is there anything magical about the Hummer or can we use a similar technique with our trucks?
This would be great news to me because I like the idea of a locking differential, but issues with the G80 that Chevy has been putting in their trucks has left me a little concerned about buying one (especially considering that this is my daily driver). If I can gain traction by applying a slight amount of brake, I'll probably stick with the LSD since it's a nice happy medium for my needs.
Any information on this would be greatly appreciated.
wow that video makes me want a hummer really bad. i think what he is talking about is by appliying the brake you are forcing the limited slip to engage full traction to a wheel i dont see y it wouldnt work on our trucks.
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2002 f150
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I've heard about this a long time ago. There was a lively discussion here a while back.
Some said it worked, some said it didn't, a few said "sometimes". Something about fooling the diff into thinking that there really was traction on that spinning wheel. I've never been in a situation to try it myself.
Doesn't the H1 and H2 have lockers? I know the one H2 I've driven had stock front and rear e-lockers.
I've heard about this a long time ago. There was a lively discussion here a while back.
Some said it worked, some said it didn't, a few said "sometimes". Something about fooling the diff into thinking that there really was traction on that spinning wheel. I've never been in a situation to try it myself.
Doesn't the H1 and H2 have lockers? I know the one H2 I've driven had stock front and rear e-lockers.
I don't really think it's so much that you're tricking the differential as much as coming up with an unexpected, but advantageous use of your antilock brakes. Essentially, if it works, you would hopefully slow down the spinning wheel enough to prevent the clutch plates inside of the LSD from slipping.
I got my truck stuck in the mud once and I was disappointed in the performance of the LSD because I had only two wheels slipping. This is what made me consider buying a locker. Had I thought about this at the time, I would have given it a try.
That video is such a load of bull. The Hummvee and Hummer are not even in the same class. And the ONLY thing that makes them similar is the look. What a joke.
But on the brake subject if you have a LS and one of the wheels happens to lose traction then you can apply light brake pedal to get them to apply equal torque again.
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Fabtech 6" Lift with Skyjacker Rear Springs, Bilstein Shocks, ATI Procharger and much more.
They use Torsen diffs in front and rear. Torsens are a form of limited slip, TORque-SENsing limited slip. The parking brake trick only works on a clutch based LS like ours (I could be wrong but I can't think of it working in any other scenario), or in the Hummers case the actual brake would engage the front and rear brakes and the trick works on both sides since they are front and rear.
Some torsens are made with preload clutches (like the H1) and will apply more torque to the wheel with less resistance. The idea is when the parking brake is applied, it will multiply the torque distributed to the wheel in the air, and offset the torque bias proportion. This ratio in which the LS will start to give or 'slip' is something like 2:1 or 3:1. It's fairly simple but I'm no teacher either, hope it helps.
"When a Torsen differential is employed, the slower-moving wheel always receives more torque than the faster-moving wheel. The Torsen T-2R RaceMaster is the only Torsen to have a preload clutch. So even if a wheel is airborne torque is applied to the other side. If one wheel were raised in the air, the regular Torsens would act like an open differential and no torque would be transferred to the other wheel. This is where the parking brake 'trick' can help out. If the parking brake is applied, assuming that the parking brake applies even resistance to each side, the drag to the airborne side is 'multiplied' through the differential and TBR times the drag torque is applied to the other side. So the ground side would see (TBR X drag torque) minus drag torque, and hopefully that can help restore progress either forward/backwards. In Hummer/HMMWV applications, there are both front and rear torsen differentials, so use of the main brakes will operate this 'trick' on both axles simultaneously."
"We mentioned using the parking brake. We'll explain. By holding back the spinning wheel, the overall torque load is increased. That increases the separating force on the differential side gears, which adds to the pressure on the multidisk clutches, and increases drawbar pull.
If you're stuck, despite having an antislip axle, apply the parking brake and try again. Apply it lightly at first, then harder and harder until the car is moving. Don't use the foot brake; that will hold back the front wheels."
So it looks like it should work for our LSD, too. There's a good chart in the article that shows actual pulling power (drawbar pull) for all wheels on ice, and one side on ice and one off, for LS and non-LS with parking brake and without.
handles like a sports car? I have driven a Alpha H-1 and it hardly fits in a regular lane on the road. Hardly nimble, but god I swear my manhood grew by a good 6" when I was driving that thing
handles like a sports car? I have driven a Alpha H-1 and it hardly fits in a regular lane on the road. Hardly nimble, but god I swear my manhood grew by a good 6" when I was driving that thing
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