Weight Transfer

Steve · #1 03-06-2006, 08:05 PM

Using a modified (mid engine mount) ZZ, I put a battery tray on the back using a slotted piece of lexan. The tray can lock in place anywhere along the slot. The idea was to see if mounting the batteries further to the back would improve traction off the line.

I started with the tray mounted all the way to the back. On launch, the front end would come up just barely, which is what I was shooting for. I should also mention that the drive gear was slotted for a little extra punch.

5 run average ETA: .6925 / best run .686

I then moved the tray all the way forward, so it just cleared the rear tires.

5 run average ETA: .6912 / best run .685

NOT what I had expected at all! I was positive that moving the batteries back would increase traction, and certainly result in a lower ETA.

Did moving the batteries back decrease traction, even though the nose came up a little?

Perhaps it DID increase traction to the point that the motor bogged down?

Tomorrow I'll test with the tray in the middle of the slot, any bets on what we'll see?

*** As a side note, I ran 5 runs with the slotted drive gear in the "non-play" position: Average ETA: .792

Racer9 · #2 03-07-2006, 03:07 PM

interesting findings. I imagine that it is raising the front end and wasting a little bit of time doing that instead of just taking off. But the slotted gear thing is pretty crazy. If it really saves that much time from such a simple mod that's pretty insane.

as a side note: Ever thought of lightly damping the clutch action with soft springs or something? maybe they'll help absorb the impact and help get a good start. idk though

Steve · #3 03-07-2006, 07:31 PM

Testing with the battery tray in the middle of the slot resulted in:

5 run Average ETA: .6915 / best run .685

I would appear, for this chassis setup, that putting the batteries directly behind the rear wheels provides the best hole shot. I have not video taped it yet to see if there is any wheel spin, though I suspect there is still some, though it might not be a bad thing, as it keeps the rpm's up.

Next up, comparison to a stock ZZ chassis. Does moving the battery to the rear actually make a difference?