Posi?
- Thread starter bolsen
- Start date
SpartaPerformance
Molon Lahve
Dangerous?? How?
SC Cheesehead
'God Speed Blues Brother'
That's what I'm wondering.
I've always preferred posi over an open rear end.
I'll tell you how it's "dangerous". If you are on a crowned road, like most are, and you hit 2nd or 3rd gear at WOT and it's cold and/or wet the car gets sideways. With an open rear end only the one tire spins and the car doesn't get sideways. So yes with someone who is inexperienced/not prepared it can be dangerous. Still I prefer having a traction enhancing diff and most of my vehicles are so equipped. But I prefer my vehicles to have "4 wheel steering".
SC Cheesehead
'God Speed Blues Brother'
Sounds like hitting WOT on cold and/or wet roads may be a little dangerous in and of itself...
Sounds like hitting WOT on cold and/or wet roads may be a little dangerous in and of itself...
Yea but it's fun.
RF Overlord
73 is the best number.
That's more of an example of "driver stupidity". (not referring to you, EMAS)
Not necessarily stupidity, more likely inexperience and/or lack of knowledge of the specific vehicle and it's attributes.
Ok lets get some terms cleared up and a 101 class on differentials.
The term "Posi" came from shortening posi-traction the GM brand name for their clutch type limited slip traction enhancing differential. However it has become the common generic term many people use for any sort of Traction Enhancing Diff.
There are many different types of TEDs and a full or mini "spool"
A spool or what many off-roaders do a "lincoln-locker" (welding the spider gears to the side gears) locks both axle shafts together permanently. This is really only suitable for drag racing and off-road use because at least one tire needs to slip to be able to do anything other than go in a straight line.
A true "Locker". Some of the common ones are the ARB, ECTED and Gov-lock. The ARB and ECTED are manually engaged either by air or electrically and lock the two shafts together like a spool when engaged. The Gov-lock is automatically engaged when the difference in speed of the two shafts is too large.
Also referred to as lockers are the Lock-right and the Detroit locker. These use "teeth" to engage the axle shafts and will allow different shaft speeds, usually accompanied by a "ratcheting" sound, if you can hear it over the stereo or exhaust.
Here is a link to show how and explain how the ARB, Detriot, and Lock-right work. http://www.fourwheeler.com/techarticles/128_9702_locking_differentials/index.html
The most common type of TED, including what is used in our Marauders, is a clutch type limited slip. There are dozens of brand names for these so I won't attempt to list them all. Ford's name is Traction-lok. Here clutches or friction plates are used to limit the side gear motion relative to the case. When the difference in torque on each shaft is large enough they will allow differential action because of the clutches slipping. IF the proper fluid or additive isn't used you can sometimes hear that ratcheting sound. These can be set up to have different thresholds of when they will allow slip. IE put more plates or use a stronger spring and it will take more torque for differential action to occur. These will all eventually wear out with use. Here is a link showing some cross sections of a clutch type unit and how a open diff works. http://auto.howstuffworks.com/differential.htm
A special type of clutch style TED is Dana's Power-Lock. By the use of "ramps" on the side gear shafts the higher the input torque the greater the torque difference at the axle shafts will be required to induce differential action. This one can be "dangerous" if you aren't aware because it can "lock" when accelerating in a corner.
An unusual TED is the Torsen or Torque sensing unit. It uses a system of worm gears to apply torque to the axle shaft that is providing the most resistance so it will shift the torque away from the tire that doesn't have traction. The problem with these is they actually provide a multiple of the wheel with low traction to the wheel that has more traction. So with one wheel on ice or off the ground in the case of a 4x4 it will not provide any torque to the wheel that does have traction. A light application of the brake will provide torque to the wheel with traction.
The most unique TED is Warn's short lived Positrac (note no hyphen to avoid copyright issues with GM's Posi-trac) it used a system of overrunning roller clutches to allow the outside wheel to spin faster than the inside wheel.
Billions of vehicles have been factory equipped with one or another type of TED for decades and are still available in some vehicles to this day. If they were that dangerous they wouldn't still be available factory installed. Ralph Nader would have got them off the OEM market long ago like he did the Corvair.
The term "Posi" came from shortening posi-traction the GM brand name for their clutch type limited slip traction enhancing differential. However it has become the common generic term many people use for any sort of Traction Enhancing Diff.
There are many different types of TEDs and a full or mini "spool"
A spool or what many off-roaders do a "lincoln-locker" (welding the spider gears to the side gears) locks both axle shafts together permanently. This is really only suitable for drag racing and off-road use because at least one tire needs to slip to be able to do anything other than go in a straight line.
A true "Locker". Some of the common ones are the ARB, ECTED and Gov-lock. The ARB and ECTED are manually engaged either by air or electrically and lock the two shafts together like a spool when engaged. The Gov-lock is automatically engaged when the difference in speed of the two shafts is too large.
Also referred to as lockers are the Lock-right and the Detroit locker. These use "teeth" to engage the axle shafts and will allow different shaft speeds, usually accompanied by a "ratcheting" sound, if you can hear it over the stereo or exhaust.
Here is a link to show how and explain how the ARB, Detriot, and Lock-right work. http://www.fourwheeler.com/techarticles/128_9702_locking_differentials/index.html
The most common type of TED, including what is used in our Marauders, is a clutch type limited slip. There are dozens of brand names for these so I won't attempt to list them all. Ford's name is Traction-lok. Here clutches or friction plates are used to limit the side gear motion relative to the case. When the difference in torque on each shaft is large enough they will allow differential action because of the clutches slipping. IF the proper fluid or additive isn't used you can sometimes hear that ratcheting sound. These can be set up to have different thresholds of when they will allow slip. IE put more plates or use a stronger spring and it will take more torque for differential action to occur. These will all eventually wear out with use. Here is a link showing some cross sections of a clutch type unit and how a open diff works. http://auto.howstuffworks.com/differential.htm
A special type of clutch style TED is Dana's Power-Lock. By the use of "ramps" on the side gear shafts the higher the input torque the greater the torque difference at the axle shafts will be required to induce differential action. This one can be "dangerous" if you aren't aware because it can "lock" when accelerating in a corner.
An unusual TED is the Torsen or Torque sensing unit. It uses a system of worm gears to apply torque to the axle shaft that is providing the most resistance so it will shift the torque away from the tire that doesn't have traction. The problem with these is they actually provide a multiple of the wheel with low traction to the wheel that has more traction. So with one wheel on ice or off the ground in the case of a 4x4 it will not provide any torque to the wheel that does have traction. A light application of the brake will provide torque to the wheel with traction.
The most unique TED is Warn's short lived Positrac (note no hyphen to avoid copyright issues with GM's Posi-trac) it used a system of overrunning roller clutches to allow the outside wheel to spin faster than the inside wheel.
Billions of vehicles have been factory equipped with one or another type of TED for decades and are still available in some vehicles to this day. If they were that dangerous they wouldn't still be available factory installed. Ralph Nader would have got them off the OEM market long ago like he did the Corvair.
ctrlraven
BiRDMAN
Limited Slip yes, posi no.
SC Cheesehead
'God Speed Blues Brother'
Yea but it's fun.
True, that!
I had a '65 GTO back in the day that used to be subjected to that exercise on a routine basis... Good point. I was thinking of limited slip in the context of the "posi-traction" brand name. Agreed on the issues with true "posi," not really street-friendly.
yjmud
New member
RF Overlord
73 is the best number.
Agreed, but this is America...we are incapable of doing anything for ourselves and need gov't supervision to accomplish the simplest tasks, so smarter drivers will never happen.
SC Cheesehead
'God Speed Blues Brother'
Ooooooh, do not get me started....:mad2:
DOOM
HEMI HUNTER
Who would go "WOT" on a CROWDED WET ROAD??? :loco:
CROWNED not crowded.
Vortech347
I shouldn't have sold mine.
Who in the hell would be happy with an open dif?!
If you can't skid control just about any situation at full throttle you shouldn't put the pedal down period.