H3 question.
#3
11-01-2010, 06:09 PM
Thanks for the response. But i think full time 4wd is different than AWD. This is what i heard. full time 4WD- 4wd is on all the time. AWD- powers come on to specific wheels when starting to lose traction. Maybe true or maybe not. i am not sure. maybe someone actually knows.
#4
11-01-2010, 09:16 PM
Yes, ALL HUMMERS are 4WD Full Time just depends on how much power is distributed to the front and rear diff. depending on transfercase selection and model.
AWD and 4wd are NOT the same thing. I have an entire 5 paragraph explination on this subject. But, it is late and I will try to find in tomorrow and post it.
AWD and 4wd are NOT the same thing. I have an entire 5 paragraph explination on this subject. But, it is late and I will try to find in tomorrow and post it.
Last edited by TAINTER; 11-02-2010 at 11:14 PM.
#6
11-02-2010, 11:13 PM
This is my understanding of the types of AWD and 4wd systems. There are "bastards" of both type of systems. Also it depends on what the vehicle manufacturer defines their own "system" as. There are so many variations but here are the basics.
4WD = Low range and High Range gearing
AWD = Only high range gearing
Part-time 4WD: No centre differential. Cannot be used on dry/wet, semi-slippery roads due to the lack of the centre differential. When activated, both front and rear axles are physically locked to each other and have to spin at the same rate. This becomes a problem when turning on sufficiently high friction surfaces.
Permanent 4WD:. No two wheel drive mode. System is equipped with a centre differential, and hence is safe to use on all surfaces. All four wheels are powered all of the time (50/50 front and rear axles). This is arguably the best system since the torque split ratio does not change and is the most predictable. All wheels "help out" all of the time and this stabilises the vehicle + improves handling. With the extra two drive wheels, the vehicle has twice the amount of traction all of the time (even in no-slip conditions) vs. a 2WD vehicle.
Full-time 4WD: Basically permanent 4WD but with a split mode in the transfer case. Depending on the vehicle 30-70 or 40-60 split. This was born out of customer demand for a better turning radius.
Permanent AWD: Basically permanent 4WD but without low range gearing.
Full-time AWD: System is active at all times, however in most cases, the one set of wheels (usually the rears) only receive 5-10% of the engine's power unless slippage occurs. At that point, power is progressively transfered to the opposite axle to help out. Some systems can transfer power to the rear upon acceleration to improve traction. However, they revert to 2WD mode when coasting.
4WD = Low range and High Range gearing
AWD = Only high range gearing
Part-time 4WD: No centre differential. Cannot be used on dry/wet, semi-slippery roads due to the lack of the centre differential. When activated, both front and rear axles are physically locked to each other and have to spin at the same rate. This becomes a problem when turning on sufficiently high friction surfaces.
Permanent 4WD:. No two wheel drive mode. System is equipped with a centre differential, and hence is safe to use on all surfaces. All four wheels are powered all of the time (50/50 front and rear axles). This is arguably the best system since the torque split ratio does not change and is the most predictable. All wheels "help out" all of the time and this stabilises the vehicle + improves handling. With the extra two drive wheels, the vehicle has twice the amount of traction all of the time (even in no-slip conditions) vs. a 2WD vehicle.
Full-time 4WD: Basically permanent 4WD but with a split mode in the transfer case. Depending on the vehicle 30-70 or 40-60 split. This was born out of customer demand for a better turning radius.
Permanent AWD: Basically permanent 4WD but without low range gearing.
Full-time AWD: System is active at all times, however in most cases, the one set of wheels (usually the rears) only receive 5-10% of the engine's power unless slippage occurs. At that point, power is progressively transfered to the opposite axle to help out. Some systems can transfer power to the rear upon acceleration to improve traction. However, they revert to 2WD mode when coasting.
#7
11-03-2010, 11:22 AM
fun reading,but?
it sounds like opinion,not engineering fact.
is the center diff locked or open?. 50/50,no torque split,sounds like locked? if locked is it safe on all surfaces?
"[/quote]Full-time AWD: System is active at all times, however in most cases, the one set of wheels (usually the rears) only receive 5-10% of the engine's power unless slippage occurs. At that point, power is progressively transfered to the opposite axle to help out. Some systems can transfer power to the rear upon acceleration to improve traction. However, they revert to 2WD mode when coasting"
[quote]
5% to the rear? what car would this be? what is the "system" thats active?
the main q?is what is a hummer?
Permanent 4WD:. No two wheel drive mode. System is equipped with a centre differential, and hence is safe to use on all surfaces. All four wheels are powered all of the time (50/50 front and rear axles). This is arguably the best system since the torque split ratio does not change and is the most predictable.
"[/quote]Full-time AWD: System is active at all times, however in most cases, the one set of wheels (usually the rears) only receive 5-10% of the engine's power unless slippage occurs. At that point, power is progressively transfered to the opposite axle to help out. Some systems can transfer power to the rear upon acceleration to improve traction. However, they revert to 2WD mode when coasting"
[quote]
5% to the rear? what car would this be? what is the "system" thats active?
the main q?is what is a hummer?
Last edited by drtom; 11-03-2010 at 11:43 AM.
