Power Splitting

[God666]

I have read somewhere that on the TT, there is a 62% to 38% power divide between the front and the rear wheels. Not sure in which order ie. 62% to the rear?

Anyone know how this is achieved?

[Paradoxx]

Through gearing in the transfer case... it would be higher percentage to the front, and some 4wds are set up to have 50/50, its rare that it will be predominantly rear wheel drive. I'm surprised it's 62/38... I would have thought it would be closer to 50/50

[351]

wouldnt it be more likely to have a rear bias cos I thought most performance setups were rear biased to achieve as close to rear wheel drive without sacrificing grip, or like gtr skylines which is basically rear wheeel drive until the front axels slip, not that the territory will be like that I dont think

[Paradoxx]

Those are performance cars, but I think you will find that vehicles designed as SUVs and off road AWDs will be predimenantly front wheel drive.

[God666]

Through gearing in the transfer case... it would be higher percentage to the front, and some 4wds are set up to have 50/50, its rare that it will be predominantly rear wheel drive. I'm surprised it's 62/38... I would have thought it would be closer to 50/50

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Now you have me totally confused. How can you do that with gearing? Different gearing means different ratios and the front wheels are going at the same speed as the rear wheels!...... or have I totally missed the point?

[bcl]

"38:62 to the front:rear axles"

[mickey_gee]

now im confused. If I have 100% of the power from the back of the gearbox, how do you split it so it can be 38:62? Is there a slippery bit somewhere that uses up power or something?

MG

Edited 20/07/06 01:09 PM by mickey_gee

[Ralph Wiggum]

I'd bet it done using a varible fluid coupling. Changing the gearing wont change how much power the front or wheels get it will change the SPEED they turn at in relation to the engine speed. that would cause a blow up. The coupling is probably a fluid set up the bleeds oil pressure off to decrease drive to one of the axles. Imagine a torque converto with a drive shaft connected to the body and one connnected to the impeller inside the converto. The outer body of the convertor is driven be the engine. This means that the axle thats connectted to the body always gets 100% torque by varying th pressure in the converto you can vary the amount of torque thats transmitted to the drive shaft that connectted to the impeller inside the casing....does that make any sence???

[God666]

Yep, that makes sense.

[Raptor]

It makes more sense to talk of torque splitting rather than power.

The 62:38 split is correct and the bias is to the rear.

It is achieved by purely mechanical means by having the f & r take their drive from different points of a planetary gear set. As these are at different distances from the centreline it is simply the length of the 'lever arm' that is distributing the torque in a predetermined split.

Unfortunatley I couldn't find an image to make this easier to understand.

Thus the Territory is fulltime AWD, there are no fluid couplings (variable or otherwise) to be found (after the normal torque convertor).

From; http://autoweb.drive.com.au/cms/A_101280/newsarticle.html

How does it work?

The AWD Territory will employ a single-speed, full-time transfer case in conjunction with four-wheel traction control system using brake and engine intervention to control wheel slip.

Available engine torque will be distributed 62 per cent to the rear axle and 38 per cent to the front axle, giving Territory the rear-drive bias favoured by the extensive customer research that went into the new vehicle.

The four-speed electronic automatic transmission is similar to the critically acclaimed Sequential Sports Shift auto that made its debut in the BA Falcon.

A stiffer main case, 10-bolt rear connection and high contact ratio gear set contribute to improved drivetrain stiffness and noise reduction.

The new NV125 transfer case is mated to the transmission via a short, cast aluminium adaptor plate.

The transfer case is a single-speed, full-time open differential unit with torque splitting achieved via an internal planetary gear set.

Chosen for its robustness, light weight and packaging efficiency, the NV125 transfer case was selected by Territory engineers after extensive research and investigation of numerous AWD systems.

By utilising the stability control and traction control systems to direct torque at each wheel, expensive and complex torque-transfer and slip-limiting devices, such as clutch packs and viscous couplings, have been eliminated from the transfer case.

This ensures the Territory system is robust, durable and contributes to the vehicle's low running costs. The NV125 requires no regular maintenance.

Edited 21/07/06 06:38 AM by Adam