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frank_ster 05-28-2013 10:22 PM

RWD /4 WD conversion for 5EAT
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So as the title says, i have converted my 5 eat from awd 55% rear 45% front bias to rear wheel drive with transfer clutches to engage the front wheels.
so the car is 100% rear wheel torque with a certain amount able to transfer to the front wheels. the exact amount is yet to be determined and can be modified to suit needs.

how .. well the trans mission intermediate shaft is welded and trued to the rear output shaft. The center diff planetary gears are removed, however the vtd ( variable torque distribution) clutches are re installed to provide variable torque to the front wheels that is actuated via hydraulic piston and pressure that is controlled by a electric 12volt solenoid in the trans mission control valve body.

the vtd is controlled from the tcu ( transmission control unit) on a active and pasive method. if there is a quick throttle demand the clutches are engaged, as well as high throttle angles. the speeds are monitored and if there is a large difference the tcu will also apply added pressure to make both axles to spin at the same speed. This function also works well with the conversion.
for instance on the lift with wheels in the air the rear wheels spin when put into drive. if the accelerator is pressed slowly the rear accelerates but the front are not driven. If there is a stab to the throttle the front wheels then engage. this would be the case of accelerating from a stop. the large amount of requested torque activates the front wheels to aid in pulling preventing the rear wheels from spinning.

modification of adding a 3 position switch to disable the tcm control of the vtd will allow rear wheel drive only for purposes of characteristics of a typical rear wheel drive car. another position to force the vtd to maximum engagement so provide as much torque to the front wheels as possible.
and the last position to allow automatic tcm control of the vtd.

what this means ? well rwd on demand if the fun of a rwd car is desired.
auto mode for snowy or slippery roads where subaru awd driving charatics are desired. and full 4wd mode for maximum transfer of torque like how a sti 6mt dccd fucntion witch would in most conditions initiate powerslide and oversteer.

The 4 eat ( execpt the 4 eat vtd on vdc cars ) actually functions in the same way but only reversed the front wheels are directly driven and the rear is engaged on a active and passive automatic manor.

photos: the two shafts are welded together on the lathe, then i machined the weld, and then i annealed and straitened the shaft ( took me hours to figure out how! ). The shaft is strait with in 0.001" over its length of about 30 inches.

test fit into the trans mission,

reassembly of the bearings on the output portion of the shaft as well as the vtd clutch hub and speed reluctor ring.

reassembly into the center differential carrier with the planets removed.

here is a video of the car doing a rear wheel burn out.

i will make some more videos of the car on wet grass or mud showing the front wheels engaging.

frank_ster 06-02-2013 09:10 PM

well its been a week and its not making any grinding noises:)

need to install the switch to disable the auto 4wd.

been getting the ass end out but the front wheels engage and bring it back!

idiot4hire 06-02-2013 10:07 PM

My head just exploded I'd be happy to have to just have rwd permanently but took it to a new level

Sideways the Seven 06-02-2013 10:25 PM

So much awesomeness here! Very nice work!

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mass-hole 06-07-2013 08:34 AM

Will this put more strain on the clutches since the gears are not longer there?

frank_ster 06-07-2013 09:29 AM

^ in normal driving no. if you decide to start tractor pulling on pavement for long distances then yes as the clutches are the only means of power to the front wheels. but if there are clutches added to the stack using thinner steel plates the strength of the front clutches would be as strong as the torque output of the engine.

i would eventually like to put it on a awd dyno just so see what kind of torque can be transmitted through the stock clutch pack. to the front wheels.

but don't forget this setup makes it exactly like a 4 eat

frank_ster 06-07-2013 09:38 AM

driving home yesturday in the rain with rwd only .. eeh! i remember now why i hated rwd cars ! .. damm at an intersection and it shifts hard into 2nd and teh car wanted to do the helicopter.

frank_ster 06-07-2013 05:42 PM

apparently the nissan gtr awd is done this way.

Sideways the Seven 06-09-2013 12:17 AM


Originally Posted by frank_ster (Post 4461649)
apparently the nissan gtr awd is done this way.

Yep. Isn't it a JATCO box too?

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fishbone 06-11-2013 12:19 PM

Sorry, one thing I am not clear on is what is involved in this mod. Are we talking extensive hardware (which for me would be at the point that you have to separate the tranny), or just electrical?

frank_ster 06-11-2013 01:06 PM

^ intermediate and out put shafts need to be welded together.
the job can be easily done with tranny under the car same as center diff bushings install.

then electrical if rwd only mode is desired.

frank_ster 06-12-2013 04:31 PM

still going:)

quick4dr 06-13-2013 07:16 AM

pure awesome!

fishbone 06-13-2013 11:30 AM


Originally Posted by frank_ster (Post 4465679)
need to be welded


:lol: j/k

1337Logic 06-13-2013 11:55 AM

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