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Normally I do all that I can to avoid running the same car as everyone else… even when it is a proven winner like the B4. But the situation with parts for the Yokomo B-MAX4 is so bad in the UK at the time of writing that I had to get something else, and the B4 has brilliant parts support trackside (PS Since I first drafted this post a new shipment of Yokomo parts appears to have arrived in UK - just as I sold my B-MAX4! But on past experience I’m not holding out much hope that the supply issues will have been solved).

This is only the second Associated car I’ve owned, I had an RC10GT many years ago which went pretty well except for the fact it had a nitro engine (always a hassle) and the assembly worker hadn’t trimmed the flash from some parts, binding them up. Generally I prefer metric cars because it is easier to get tools and hardware for them.

Since the car has been out for a few years I’m not going to waste anyone’s time by going into great detail about the build, but I will mention a couple of things about my “black box” FT kit, which has a few changes from the manual.

The build

Generally the design and parts quality is top notch, with very good fit and strong materials. The diff is very smooth when built, and the detail in the front suspension geometry is fantastic, the designer really thought about all the possible settings and included spacers to adjust them independently. However the amount of flashing on the suspension parts in particular is excessive, and requires a lot of prep with a Dremel (sanding drum and 7/64″ drill bit for hinge pins), a craft knife, and a small flat file. You have to get the suspension to drop under it’s own weight otherwise your suspension settings will be useless.

It’s also worth noting that the “black box” (Made in China) kits now come with the plastic chassis and top plate rather than the carbon. I couldn’t see much difference in colour between the chassis and carbon towers at first, but after assembling the car and double-checking with Associated themselves, I can confirm that the chassis is definitely the darker, more flexible composite – but it is still very stiff. The contrast with the bendy Yokomo B-MAX4 is immense. Another notable difference is that the car only has #1 pistons (probably a cost cutting measure), not the suggested #2′s for the front. I’ve ordered the full set of pistons as a spare (#6465). Another (tiny) change is that the car came with four blue anodised body pins for the body and wing – in fact it should only have three blue ones and one of the thinner plain ones, because the fat blue ones don’t fit through the “screw-with-hole” mounts. I’ve actually switched all the small clips to black Tamiya ones which are a lot more discreet.

The build was pretty fast in the end. I got the car on Wednesday and after a couple of evenings work and a couple of extra hours in the afternoon I had it built and ready for racing on Friday night. I did make a couple of boo-boos: I tapped a hole for the rear camber link with a 5-40 screw by mistake (this came loose when racing and messed up the handling), and I didn’t compress the diff spring enough at first time of building, my initial setting was way too loose. Tightened it down fully in the car and backed it off 1/8th at the track, this seemed to be a good setting, combined with 3.5 turns on the slipper nut.

One thing that does help the build go quickly is a decent set of tools. The allen keys and plastic spanners included in the kit are not up to much – you’ll need 0.050″, 1/16″, 5/64″ (2mm) and 3/32″ hex drivers, 3/16″, 1/4″ and 11/32″ nut drivers, and ideally a 1/8″ turnbuckle wrench (AE do a couple, #1110 and #1111). For the 3/16″ nut driver I have been using the 5mm socket on a Yokomo box wrench but this is not perfect, it’s worn out a little already.

Some quick pics now of the build…

Race report – Caldicot 12th June 2009

Well, I learnt almost nothing about the car setup during my first race, partly because of the aforementioned loose camber link, and partly because after I came home I realised I had not set the camber or ride height correctly! Camber was wrong because I misinterpreted how to use the Rayspeed camber gauge (I was setting the camber to 0deg instead of 1, the etched number is on the side that is angled), and ride height is firmly recommended to be arms-level in front and bones-level in the rear, when I was running it Yokomo-style at 24mm front (too low) and 25mm rear (too high). To add insult to injury, I forgot to reset the rear ride height after changing springs, which made the car nose flip off the small jumps!

What I did learn was that the car is very durable, and even the kit dirt-track setting is surprisingly well-balanced on a mixed carpet/slippy indoor track. A bit edgy at the limit perhaps, but far from undriveable.

I now have a load of parts for the car on their way from the US (at greater expense than I expected due to postage and customs – should probably have bought most of it in the UK instead), so lots of things to try! I also dowloaded AE’s Complete Tuning Guide for the B4 (#9656) for reference.

One final note about the battery pack. My EP4200s were a shade too wide to fit easily in the tray when assembled with the stepped Much-More battery bars. I’ve rebuilt the packs with the Trickbits Economy Battery Bars (#TB2001) which are flat, and now they slide in without scratching the tape/stickers around the tray. This should prevent any embarrassing battery shorting and let the chassis flex naturally.