PR Racing SB401 – 1st Test

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.

The Nr1 upgrade for 1:10th 4wd cars on dirt, a centre diff. So much better it stupid!

Not bad, I will post some build pictures, and all mods I have figured out need doing later this week. Next week we are going to the Euros, so this week is all about 1:10th scale.

The 4wd was a pleasant surprise. I tried J Smoker’s car at OCRC in January and it was really good, so I was pretty confident I would be able to get the 4wd car good. (and that’s truthfully the only thing I care about) BUT, I have to say I was surprised at how good it was already the first day. Out of the box it wasn’t really on point on a loose dirt track, so looks like I will be recommending some setup adjustments for the box setup for loose tracks :-). After a few changes it was pretty good, and then after installing the centre diff it was awesome. I’m happy with it already after just one day. It’s a shame we don’t have any high grip tracks to try it on. I wonder how the Euros track will be…

PR Racing 1:10th Day 2

Do you like my paint?

Apparently I got a carpet version of the car :-). Anyway I had all the parts needed for dirt it seems, the centre diff being one of them. Today I completely removed the upper decks. The car is quite stiff stock. Tomorrow I will still experiment with the side braces, I only removed some screws out of them today, but the car is still so stiff, that I think I will remove them altogether tomorrow and see how it goes.

I have been running 3 hole 1.6mm pistons, with 450/350 oils, but tomorrow I will try 2×1.6/2×1.7 pistons which a lot of people seem to be running in other cars.

Still, so far so good! I haven’t broken anything so far. I bent a rotor though, after hitting a curb and coming to a dead stop at the end of the straight. Crazy shit!

Tried trial and error geometry stuff at the track. Tomorrow morning the car will get the CAD theory treatment, and then I will go back and try whatever I come up with. Happy days!

Smooth Shocks PR Racing Day 3

I have found that the o-rings are quite sticky and tight, so I decided to only use one instead of two. I replaced the other one with one of those shims with a lip on it. This made the shocks nice and free. Apparently PR have/are working on some different o-rings for smoother action.

Today I also drew the car in CAD and figured out a setup to run. I will write more about that tomorrow. It’s late. We only left the track just before midnight.

PR Racing 4wd Testing – Day 4

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

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

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.

PR Racing 4wd Testing/Euros Prep – Day 5

953 laps. That’s how much I managed to do as my Euros prep. That’s about 6h of run time. That’s 953 laps more than last year though, so not too bad. The thing about driving 10th scale is it is easy to identify driver error. Somehow in 1:8th, there is so much going on, it’s harder to analyse purely the driving aspect and how it affects your lap time. After getting the car good, and then getting consistent, which probably took 600 laps, I focused on my driving, and what I found was that when I think I am concentrating and driving, I would do a 22.4, then when I really concentrated I would do a 22.0 or so. A few tenths by concentrating. Wheel spin affects the laptime. I arguably had too much power, with a LRP 6.5, but watching the big boys, like Cavalieri and Maifield, they always have tons of power, so I want tons of power too. The thing is that pulling the trigger and spinning the wheels was slower. Calming it down a bit, and just feeding enough power to the wheels on the short straights, and then smashing it on the back straight, resulted in about 0.3s faster lap times. No joke, going slower was faster once again. Going a bit slower into the corners and trying to maintain the speed around them resulted in the best laps every time. It’s a balancing act, and that’s what the best drivers are so good at. If you want to see someone who is great at driving a car within it’s limits and maintaining speed around the track watch Marc Rheinard drive. It almost looks slow at times but the lap time is super good.

The thing is, that to get that result posted above, it took me 900 laps. A talented driver will do that after maybe 40-50 laps? How the hell will I get to that point? It’s not easy, that’s all I know. At the Euros we don’t get 900 laps of practice.

My SB401 Staring Setup – After 5 Days

Above is the configuration I use.

Drilled longer link hole

Rear link drilled lower

30g behind the receiver. Nitro guy wiring.