So, after 5 years of ownership (most of them spent in the garage), I’m moving on from my Associated B4. Times have changed dramatically in 2wd buggy racing and it is time to try something more up to date (remains to be seen whether my new whip will be any faster though).
I’ve really enjoyed racing this car. It is a brilliant piece of engineering, everything on it is exceptionally well designed, and it has proven to be almost indestructible (nothing broken despite some good attempts on my part). It drives well too, but you have to wonder how much it is losing out to the mid motor cars due to the reduced weight over the front axle.
I’ve raced the car again a few times this year, and the biggest change for me has been the Schumacher Low Profile Cut Stagger tyre. This is an awesome tyre! It has made getting a good balance in the car so much easier, and you don’t need to get the side cutters out to modify the spikes. The only other change this year has been fitting the JConcepts serrated wheel nuts (which are expensive, but don’t come loose), and the RPM gear cover (which doesn’t lose the slipper plug as easily).
I’ve posted a couple of pictures of the car and a setup sheet. My setup is a little bit unconventional, but it is what I have ended up working towards after running the car very stiff indeed in the NiMH days. With the lighter LiPo’s, I’ve been able to drop a spring grade (at least). Green springs on the rear arm outer hole is about the same as silver springs on the inner hole.
The B4 isn’t going anywhere though, it will go back to its home in the garage, ready for the next generation of racer to have a go… just like my TOP Scythe, it isn’t worth enough to be worth selling.
Just a brief look at my B4 before it loses its NiMHs for good… and probably the brushed stuff as well, although I don’t have any brushless electrics for this one yet!
A couple of things have impressed me about the B4 over a few months of owning and racing it.
First is how incredibly durable it is. I am effectively learning 2wd from scratch, racing on a pretty unforgiving multisurface indoor track, and I haven’t broken a single thing. The only part I have had to replace is the rear bulkhead, which was my fault for mistakenly threading a 5-40 screw into it (instead of a 4-40).
Second is how astonishingly well sorted the car is out of the box. After trying almost every alternative part Associated do, and trying various ballast arrangements, I keep coming back to an unballasted car, with springs, 30 degree caster blocks and black steering rack ballstuds being the only parts that are not in the box. Considering the B4 was released 6 years ago and developed on clay tracks, that is just amazing.
Still running the simple white body on my car. Easy to see, easy to paint. Tamiya PS1 cans if you were wondering. I’m running the JConcepts 7″ V-wing (#0109) which is brilliant. Super durable and looks a lot better than the tiny little kit wing – which cracked at the first race meeting. This JConcepts wing is still rock solid. Does it make the car faster and better handling? No idea.
Under the shell at present is the following…
Futaba S9451 servo – this will stay.
Futaba R133F reciever – also staying – I see no need to go to 2.4GHz when 40MHz works so well and there are fewer crystal clashes nowadays!
Keyence Rapida Pro ESC – such a good speedo, no capacitors or diodes hanging off it, full on-board programming – perhaps one day the brushless speedos will be this good?
Orion V2 12×1 motor – I don’t like these at all – no power and a nuisance to work on. Only put it in because my 19×1 needed new brushes.
East Power 4200 NiMH cells – I’m amazed that these survived 2 years of infrequent use and misuse. During that time at least two cells dropped to zero in storage but came back to life. They are totally shot now though.
Not that it is particularly relevant now since so few people use NiMH, but to get the pack to fit neatly in the B4 tray (which was designed around earlier, smaller cells), I had to rebuild it using the Trickbits economy battery bars, which are flat and thin (#TB2001). Stepped bars make the pack too wide.
You may just be able to make out in this photo that I have drilled out the top of the Associated ballcup. I have also replaced the ballstuds on the car (at great expense!) with Associated’s socket-head versions from the GT2 and B44. This allows me to undo the ballstuds without unpopping the ball ends. Frankly this wasn’t worth doing. If you want to copy me, use a 2.4mm (3/32″) drill bit to clear the 2mm (5/64″) hex wrench.
What is worth doing is replacing the silver ballstuds that are standard on the steering rack, with the black ones (#3981). These are 30thou lower than the silver ones, and remove the bumpsteer that you get if you use the 30deg caster blocks (an essential in my book – #9593). On the topic of caster blocks, have a 2.8mm (7/64″) reamer or drill bit handy to open out the hinge pin hole – the moulding on these has got incredibly tight since Thunder Tiger took over. My Dremel saw a lot of service during the build!
The only other change I have made to the car is a few parts from Nortech Racing. These axle pins are very simple but well worth having in my opinion. The standard B4 axle pin is a rough roll-pin that isn’t as big as the slot in the wheel. Stripped wheels seem likely – thankfully it did not happen to me. These Nortech pins are slightly longer for a better fit in the wheels, and are smooth and solid too which should make them stronger. I was hoping that the longer pins would stop the wheel nuts from working loose, however that has not really been the case. They need checking after each run. It’s a shame Associated don’t supply flanged or serrated nuts like the Japanese cars have.
The other Nortech part is the 4-40 nyloc nuts to hold the camber link ballstuds in place. The plain nuts in the kit can work loose, I lost one myself. I suppose a little threadlock would help but that doesn’t help assembly and disassembly. Nyloc is the way to go. Associated also make a few different kinds of nyloc nut if you prefer.
So, that is the car, all that remains is the setup. As I said earlier, I have tried most things, but kept coming back to the same settings. A few observations…
The 30 degree caster blocks get the balance of the car spot on.
Moving the camber links in one hole at the wheel tightened the car up nicely and stopped its tendency to roll deep into the corner.
Since I run on a mostly carpet track, I found that the stiffer I went on the rear springs, the better the car got. More precision and greater corner speed. Generally I’m running silvers or greys in the outside hole on the wishbone (truck blues are a step too far and make the rear lose grip).
Front springing is in balance with the rear (generally blues or silvers in the outside hole). I also prefer #1 pistons as the #2’s seemed to make the front end a little unpredictable.
Anti-roll bar has never been better than running a slightly stiffer spring rate. It upsets the balance between roll and pitch stiffness
I could barely tell the difference between wheelbase settings
I tried putting more ballast on the front bulkhead to keep the nose down in fast corners. It failed to do that and just made the car feel a little more sluggish on the steering. Stiffer rear springs and shorter links did more to keep the nose down than.
This is the setup I have more or less settled on while running at Caldicot recently, I’ve tried most things now and this is what I keep coming back to.
One important thing to note is that this setup uses an old-school 19×1 brushed motor. Now this is just about enough power for a 2wd car indoors – BUT these motors have a really strong drag brake which has a big effect on handling – bigger than on any 4wd car I have run.
I realised this this evening when I fitted a 12×1 V-brush motor into the car – the difference in the handling was incredible! I had to drop down a grade of spring on the front and run 50% drag brake to get the car to steer.
So, take this setup with a pinch of salt if you are not running a lot of drag brake. If you are, and your track has a lot of carpet on it, it might just work for you.
After much fine tuning (ahem) during the NE indoor regional series this is the setup I settled on for the B-MAX4. Takes the edge off the steering and adds some positivity to the traction while retaining the great ride quality.
I won’t try and sell it to you with race results as they are poor by most people’s standards but good by mine!