scirocco14

iTrader: (5)

I run a front ball diff on my USVTA car. I've found that a light sway bar is OK to help reduce body roll, but thicker bars will increase the inside front wheelspin under power because larger sway bars will lift the inside wheel as the car rolls.

Heavier springs than the stock blue ones also help keep the body lean to a minimum and keep the inside front wheel planted.

Lower roll centers help keep the inside front wheel planted as well.

Increase the front droop to keep from picking up the inside front wheel off the track as the body rolls.

You'll still get beaten off the corners by the cars with gear diffs and spools, but the ball diff can carry more speed into the corners and turns better in the center of the corner. It's a trade-off.

Good luck!!

Mark

bertrandsv87

iTrader: (2)

Stiffer rear springs also helps with front tire lift... Ball diff with ofna diff lock lube(#10230) stays tight enough to pull the car well on corner exit...

Stanford55

iTrader: (36)

@gooba: thx for the feedback--seems like finer adjustments can be made with the 64p...luckily there's an actual hobby shop on the island where I can get some quickly.

RotorTruck

iTrader: (2)

Thanks Mark. Say.. how tight do you tighten that front ball diff? Couldn't that help a lot with inside wheel wheelspin?

scirocco14

iTrader: (5)

I set the ball diff according to the Team Associated TC4 instructions. Just barely tighten the thrust bearing bolt to where the diff doesn't slip. Usually a 1/4 turn CCW from where the bolt feels "tight".

IMHO, as a mechanical engineer, I believe that "tightening" a ball diff past the point where it stops slipping does not increase its limited slip capabilities, it simply destroys the diff balls, the diff rings, the thrust washers and balls.

Mark

Robbob

iTrader: (8)

Any thoughts/possibility on a thinner chassis or adjustable battery mount system for shorty packs? (something adjustable front to back similar to ExoTech on their other chassis's)

YoDog

iTrader: (28)

Adding more mounting points for the battery stays are easy for accommodating shorty packs. figuring out balance is another subject. As it is, the prototype is nearly perfectly balanced with the gear I have installed. Now...
A thinner chassis could be possible however, it's likely most will prefer a 2.25-2.5mm chassis plate with a 2.0mm top plate. We want to introduce some flex characteristics but too much flex will be influenced by drivetrain forces. This will make the car unpredictable. When I tested last on carpet, the car was quite stable and has tons of steering. This is with a 2.5mm chassis and top deck. I believe changing just the top deck to 2mm will yield the additional flex some setups will prefer. There are also anchor point options that can greatly influence flex as well.
Another possibility would be a 2mm Aluminum chassis as an option.

Thanks for the input.

Robbob

iTrader: (8)

I run a shorty Orca pack in my Diggity up against the stock front mounting holes and my Tekin RS behind it and I can tell you its too light left rear.

2.25 was more of what I was curious about but you got good point with the drivetrain.

You run any shims under your lower arms or just dropped on the chassis?

gooba

iTrader: (5)

I run a front ball diff if in my tc4 and built it per the manual then loosen it just slightly so the car rotates a little better in the front. However I do not get beat out of the corners by any belt drive car. I've had to have my car teched after a race(even one I didn't win) because I could out accelerate everyone

scirocco14

iTrader: (5)

Care to share your setup? I'm still fighting inside front wheelspin out of slow corners.



Mark

RotorTruck

iTrader: (2)

SWEET! How steerable is it thru a slow, tight 180* hairpin. I've had minimal steering thru those. I just loosened the rear ball diff 1/8 of a turn and will see if it turns better on Sunday's race (with the front a spool)... and if it pulls more to the left. At least now the rear tires turn in opposite directions when in the air and slowly turning one tire by hand. Before that 1/8 turn out both rear tires would rotate in same direction, and it would spin the driveshaft too.

JDM_DOHC_SiR

iTrader: (31)

Should have some interesting DC4 pic's to post up later tonight

gooba

iTrader: (5)

For 17.5 I run medium swaybars on both ends, lightweight diffs with ceramic balls in both ends, red front springs gold rears, x 2.0 rear toe block, and every carbon piece I could find. I run both diffs per the manual with the front slightly tighter. I've really focused on tuning with roll centers and squat and anti squat which has really helped me get my car to rotate. we only have one tight 180 corner on my local track which has kind of a funny line thru it to set up for the next corner but I seem to be able to hold closer to the inside than the guys running spools. I did have a problem with 3 wheeling visiting a different track and running mod a few weeks ago. I was lifting the inside front coming onto the straightaway but it didn't affect the handling any and wasn't prematurely wearing out that tire so I jsut tightened that diff a tad a drove it like a dirt car

scirocco14

iTrader: (5)

Thanks, Gooba!

What roll center heights are you running? I'm running -4mm on the front, and -3.5mm on the rear (USVTA tires).

Mark

hairy

iTrader: (1)

Can anyone tell me what the numbers represent on the shaft of the turnbuckle eyelet that fits on the shock?