aluminum drive shaft - anyone?

[Poodles]

Originally Posted by nikitopo

I also have an electrical engineering background and what I've seen is that car physics is very different and many times counterintuitive. Removing weight from rotational mass is more important, than removing the same weight from other areas. Our engines don't generate much torque(*), so we have to rely on RPMs to get power. This means that we have a lot of RPM changes and the moment of inertia of the rotational mass plays an important role. Some people say that the weight of the car negates such small variations, but they ignore the fact that this weight sits on wheels.

By the way, the weight of the driveshaft seems to be one factor. Another important factor seems to be its rigidity. STi developed a driveshaft kit that has same weight, but it is stiffer. They are saying that it twists less and the power delivery on the wheels is much better and the car feels more linear. A few people tried it and said that it makes a real difference even on daily driven situations. I believe it is another example of how small changes can make a noticeable difference. Additionally, it looks that we have to take care about weight reduction because we might lose in other important areas like the stiffness of the part. So, we need a good balance between both.


(*) The maximum engine torque of 205 Nm is a joke and can be generated even with hands using a wrench.

The STI "driveshafts" are actually what we consider axles. Moot point.

Moment of inertia means jack squat when it's such a tiny tube.

And you need to learn why your comment on torque is laughable. Go ahead and try to stop your wheel from spinning with a wrench, I'll wait

[churchx]

Many "noticeable differences" are noticed only because one subconsciously expects change after buying/installing some part. Or because installing part can come with other, easier to notice, sideffects, for example - with changes to NVH.