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4x4 or 2wd for a superchargerd performance Truck

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Old 10-20-2019, 07:12 PM
  #21  
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4wd all the way. And they are far from fragile.

There's dudes in the UAE running 9's with reg cab short bed trucks with 100% stock drive lines in them.

And man when you make big power like said above the 4wd keeps you out of trouble

Also like arthursc2 said, and made an excellent point, the 4wd is far stronger because the power is split between the front and rear drive line. Simplistic way is try to break a 2x4, now stack 2 of them and try to break them. It's essentially the same thing.. Whether you double the strength of something or put half the load on it, either way it now can handle double the hit.
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Old 10-21-2019, 10:09 AM
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AWD All day..
All my vehicles are AWD, except the racecar.

Ive been running my supercharged setup for about 4 months, and did her first event this past weekend and man does she move.
I have come to the conclusion that the AWD driveline does handle more abuse due to the 60/40 split.

Im running stock trans, stock axles, stock driveshafts and ***** going strong. Only thing i have is a slightly higher torque converter off a CTSV

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Old 10-21-2019, 10:41 AM
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Originally Posted by kaze_v8
AWD All day..
All my vehicles are AWD, except the racecar.

Ive been running my supercharged setup for about 4 months, and did her first event this past weekend and man does she move.
I have come to the conclusion that the 4WD driveline does handle more abuse due to the 60/40 split.

Im running stock trans, stock axles, stock driveshafts and ***** going strong. Only thing i have is a slightly higher torque converter off a CTSV
true 4wd is a 50/50 split at the t-case
Old 10-21-2019, 01:46 PM
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I'm not even sure there is anything but 50/50 is there? Do these trucks have biasing front to rear diffs? Not diffs in the axles, but in the T case?
Old 10-21-2019, 02:28 PM
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the viscous AWD ones will bias to the axle with the least traction. Not sure how the brake based systems will bias
Old 10-21-2019, 03:16 PM
  #26  
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How the 60/40 split works on the AWD SSS.
The NNBS AWD system works off the ABS system i believe, being able to put more power than 60% to the rear wheels if need be.


NVG 149 Transfer Case Description and Operation









The RPO NP3 is a single speed, single mode transfer case. The mode is full-time all wheel drive. It has a planetary differential gear set that splits the torque, normally 38 percent to the front wheels and 62 percent to the rear wheels.



The NVG 149 utilizes magnesium housings. Proper fasteners, brackets, and fill/drain plugs must be used to prevent galvanic corrosion. The planetary differential uses the carrier (6) as the input. The annulus gear (4) connects to the rear output shaft (5) and rear wheels. The sun gear (3) connects to the front output shaft (7) and front wheels through the chain (8) and sprockets. The viscous coupling (2) consists of a sealed housing filled with a high viscosity silicone fluid and thin steel plates alternately splined to the inner and outer drum. The inner drum is connected to the input shaft (1), and the outer drum to the sun gear (3). Whenever there is a speed difference between the front and rear wheels, the inner and outer plates of the viscous coupling spin relative to each other and the silicone fluid provides resistance. The resistance was tuned to be high enough to bias power quickly to the wheels with traction, and low enough to prevent binding in a tight turn on dry surfaces. This is the most common way the viscous coupling is activated, the shear mode. If the speed difference is high, the coupling can lock or hump. This "hump" occurs when the heat generated, expands the fluid inside the housing, changing the fluid dynamics between the plates. This results in pressure between the plates, forcing them into contact with each other, similar to a clutch pack. In the hump mode, the coupling can bias torque 100 percent to one axle, if required. Situations requiring this are extreme such as backing up a steep gravel grade or climbing over off-road obstacles. The viscous coupling is not serviceable; it must be replaced if defective. This is because each viscous coupling is calibrated for optimum vehicle performance for both the shear and hump modes. If the viscous coupling is in the "hump" mode too long, severe damage will occur. To prevent damage to the viscous coupling, DO NOT:



Tow with only two wheels down

Drive without one propshaft

Drive with a "donut" spare tire for an extended period of time



Power Flow - No Wheels Slip







During normal operation, 100 percent torque is delivered to the input shaft (1) from the transmission. The torque is split to 62 percent to the rear output shaft (2) and 38 percent to the front output shaft (3), by the planetary differential. Because there is not a loss in traction or slip in the front or rear wheels, the viscous coupling is locked in place and there is no "shear" mode or "hump" mode involved.



Power Flow - Front Wheels Slip







When traction is lost at the front wheels, the viscous coupling works in conjunction with the differential to bias the torque more to the rear wheels. The rear torque goes higher than the 62 percent, and up to 100 percent torque to the rear output shaft (2). The torque at the front output shaft (3) is lowered from the 38 percent, to as low as 0 percent torque.

Power Flow - Rear Wheels Slip







When traction is lost at the rear wheels, the torque is biased to the front wheels. The torque to the front output shaft (3) goes higher from the 38 percent, up to 100 percent torque. The torque at the rear output shaft (2) is lowered from the 62 percent, to as low as 0 percent torque.



Customers may have concern that the transfer case is not operating properly because one set of tires spun for a brief period. It is normal for one set of tires to spin until the viscous coupling engages.



Turning off the traction control switch, if equipped, enhances the function of the viscous coupling. The viscous coupling, as described above, engages by heat. Allowing one set of tires to spin or slip for a brief period will generate heat in the viscous coupling. The engine speed should be kept at a constant speed during the brief spin of the tires. Pulsating the engine speed or hard acceleration will not allow the viscous coupling to operate properly.



© Copyright General Motors Corporation. All Rights Reserved.



Document ID # 873908

2003 Chevrolet/Geo Chevy K Silverado - 4WD





******************



Transfer Case Viscous Coupling Test

Tools Required

J 45382 Transfer Case Tester











To determine if the viscous coupling is operating correctly, use the following test procedure. Testing the viscous coupling operation by removing a propeller shaft and driving the vehicle will cause the viscous coupling to fail. The test will determine if the viscous coupling is faulty from a totally locked up failure, or if the viscous coupling fluid has leaked out from being severely humped.





Important

The Viscous Coupling Test is very sensitive to the temperature of the transfer case. If the transfer case is very hot, the time to turn will be faster. If the transfer case is cold, the time to turn will be slower.





1. Operate the vehicle for 24 km (15 mi), or until normal operating temperatures are reached.

2. Set the parking brakes for the rear wheels.

3. Position the transmission in NEUTRAL.

4. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.

5. Remove the front propeller shaft. Refer to Propeller Shaft Replacement - Front in Propeller Shaft.

6. Install the J 45382 into the transfer case front output shaft.

7. Using a torque wrench at 11 N·m (100 lb in) on the J 45382 , turn the front output shaft 90 degrees.

8. Note the length of time it takes to turn the front output shaft the 90 degrees.

* If the front output shaft turns slow, and takes at least 10 seconds, the viscous coupling is operating correctly.

* If the front output shaft will not turn, the viscous coupling or the planetary carrier assembly could be locked-up.

* If the front output shaft turns easily, and the 11 N·m (100 lb in) cannot be obtained, the viscous coupling is faulty.





© Copyright General Motors Corporation. All Rights Reserved.

Old 10-21-2019, 04:46 PM
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Very cool. I didn't even know they used a viscous style coupler in them. That's pretty sweet!

Disclaimer: I don't know **** about the 4wd systems used over the years. Going to youtube it up

Last edited by 00pooterSS; 10-21-2019 at 04:57 PM.
Old 10-21-2019, 04:58 PM
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Ok thats all well and good, for the most part. But you said 4WD was a 40/60 split, not AWD

Not to mention that the viscous coupling can bias to whichever axle has the least traction, especially if the coupling is worn
Old 10-21-2019, 06:39 PM
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I've often wish I had AWD instead. I don't even have auto trac. My 07 did and I freaking loved it. I do understand that it's not cool to bust the rears loose all the time and let it lock down with auto trac. I used to enjoy the hell out of it though. I also know it's not good to go from 4wd to 2wd while racing but I've always done that too. But of course I'm not high power so that's probably how I've gotten by with it. Always some damn drawback. But if you play you gotta pay sooner or later.
Old 10-21-2019, 07:10 PM
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I use my auto trac but only in the rain and from a roll, at the track or from a dig I lock it in 4x4 high. I can definitely feel the transfer case apply more power to the front diff in a launch, it torque steers like its a fwd, after a couple hundred feet it apples power to the rear and she's out. On the road if I get it out of shape like I did the other day, I can feel the front brakes apply while in power production so I know the stabilitrack is trying to control a loss of traction, it feel wierd but I think that's why I'm still typing... Lol.


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