Sakura D4: Dialing in the Setup

I was able to spend a day running the D4 at the local track, and do some tuning.  I posted a video a few days ago, and some people were interested in the setup.  I didn't start with exactly the settings in the manual, based on my experience with tuning for our local track.  The Surface is epoxy, and is fairly smooth.  It compares favorably with polished concrete.  We have found that this surface requires a very balanced setup overall.  Here is what I started with:

First up, corner weights.  This chassis balances very well and comes out nearly perfect L/R balance with only 2 grams difference.  With a 5300 battery mounted in the middle of the chassis (standard) the rear weight is almost 57 percent.  This had me a little nervous at first because our track has favored 50 percent rear weight setups so far.  Keep in mind that these weights are with the body on.

Next up, Alignment:

For the rear, I started with 1 degree toe in, and -1.5 degrees of camber.

Up front, I went with 1 degree of toe out, and -7.5 degrees camber.  Castor is at 10 degrees.

I really like the design of the D4 overall, but one area that I think that they missed the mark a little was in how much steering lock you get out of the box.  There are a couple of things that influence it on this chassis.  The lower control arms are larger in diameter than they really need to be, and the wheels hitting them is what limits the lock.  The stock knuckles are a super low scrub radius design, which is nice in some aspects, but they do contribute to the wheel coming in contact with the lower control arm sooner.  Not only does this limit the lock but it sets up the scenario where the gyro will drive the wheel into the control arm at larger angles.  This often leads to a locked wheel that will cause a snap spin.  Some adjustable steering stoppers would be a big help as well.  As a temporary fix, I added 3mm to each hex to push my 5mm offset wheels out and provide for some additional lock.  7mm hexes were used along with 1mm spacers.

Having the wider front track doesn't hurt at all.  We have been making our front tracks wider than the back as a way of tuning for a little while now.  It also seems to be the trend in 1:1 drifting, and is part of what helps them get such big steering angle.

Rather than list out all the other details, below is a complete setup sheet specific to the D4 chassis (click to enlarge).  These are the settings I ended up with after a day of tuning.  The setup isn't perfected, but is pretty balanced and only requires adding or subtracting weight on the diffuser for fine tuning.

More to come as I spend more time working with this chassis.