To reduce the weight of our car

[shanchan]

To reduce the weight of our car,i wanted to change the material of the half shaft.
The previous material that we used was EN24(4340).
I need suggestions for a better and lighter material.

[Pat Clarke]

You have two choices...
1. Unobtanium,
2. Unavailabillium

Pat

[Timmey]

Or go for wireless torque transfer

[MCoach]

Here is what our solution for weight reduction the past several years has been:

We threw out all of the carbon fibers, all of the titanium, all of the fiberglass, and anything that didn't consist mostly of steel or aluminum. Then we threw out all of the things that we felt weren't that necessary, so out went the driver seat, and the shifter shaft, and all the little bits that didn't meet our goal for a light, simple, effective vehicle. Then whatever was left, we just used far less of it. Solid design is all about shape factors.

Frame? chopped the main roll hoop by 12". dropped 20lbs there. Unsprung weight? Got rid of all the "twiddly bits" that were just weight. 25lbs there. The driver? suck it up and don't skip legs day. Drop 10lbs there. Sprung weight? not sure yet but should be dropping another 15lbs there.

Specifically for your halfshafts:

Think about the function of the shaft. What is its job? To transfer torque from one side of it to the other. Apply the concept of shape factors to it and the best theoretical shape is a tube. So bore all that unused material out of the inside. An example here is the typical Formula 1 driveshaft. It's almost identical to the version our team uses.

[Big Bird]

That is really nicely put, MCoach - thank you.