PR Racing 4wd Testing – Day 4

You can use 47 different combinations of batteries and locations, and motor locations. I chose this one. I like it. Max built his differently, so we will see which is better. He has the new conventional motor left rear, battery right rear. I don't believe in that.

After the great first day, I sort of hit a wall, then 2 and a half frustrating days, and then today right at the end, I found something, and everything was great again. 10th scale is a good change of pace, and gives you as a designer a fresh look on things and new ideas to try for 1:8th. The 10th scale is so sensitive to setup and with a short lap, and setup changes making a couple of tenths differences here, another couple tenths there, it is both rewarding and frustrating to test things.

I have found that the 4wd buggy is really really good when things go a bit wrong. Hitting curbs, pipes, bumps, it just keeps going. It has a ton of up-travel, and that is probably the main reason for this. After figuring out the basic setup for the links, it is a pretty neutral car to drive, it doesn’t do anything strange. I’m running the motor in the front, which gives a 48% front, 52% rear weight bias, which is very much weight forward for 4wd cars. The rear felt a bit skatey, but I got it good now.

Extra link hole drilled below stock holes

Extra link hole drilled below stock holes

The front link, I run middle on tower, 2mm under outer ballstud. The knuckle I run with the 2mm shim up top. On the rear I drill an extra low hole on the tower below the lowest hole, and then drill a long hole on the hub, 3mm longer than stock. I did this after analysing the car in CAD. It is interesting to see that the UK drivers had reached the same conclusion from testing and had drilled an extra low hole. Theory and practice meet again! I lengthened the link in order to make the rear end more stable, as the link is really short on the hub as stock.

Drilled longer link hole

Drilled longer link hole

Best pistons so far, 2×1.7mm front, 350 oil, 3×1.7mm rear, 300 oil. The softest PR springs, Yellow, were ok, but I had better luck with AE white front, green rear. I actually wanted to try softer but I didn’t have any! I have asked PR for softer springs, and they are making some. I have the shocks stood up all the way on the tower, and inside on arms. I’m running 2 anti squat shims under the C-plate, instead of the 1 stock.

The car felt really good now, on a super loose track. Oh, no swaybars either, none. The car feels balanced and comfortable to drive fast now. I am assuming we have traction in Spain, so it will be interesting if the only changes I need to do are diff/shock oils, swaybars, shock springs. I hope so! If I have to go over everything again to make it work, it will be tough!

I attached the front shocks like this because the angle looking from the side is a lot better. I still have to try back to back to be sure of the difference.

I attached the front shocks like this because the angle looking from the side is a lot better. I still have to try back to back to be sure of the difference.

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