Thursday, 1 September 2011

Schumacher Cat SX3 . . . The Build (Part 2)

So onto the suspension.
Most of these parts come straight from the SX2, thats a good thing. The drive shafts look like they are from a Scania truck, well up to the rigours of off road racing and no pesky drive pins and grub screws to keep on top of.

The turbuckles are slightly changed. They appear to be made of the same material, steel not titanium (boo), but the adjuster looks slightly different. The manual is specific regarding the length of each making initial set up that bit easier.

I got myself slightly out of sequence here as unfortunately my kit was missing a small part. No big deal a quick call to the great customer service team at Schumacher and the errant part was swiftly replaced.

This meant that I was now fitting the steering assembly.
A popular upgrade to the SX2 was the alloy steering arms, this may not be necessary on the SX3 as these parts have now been beefed up and look like being more resilient. Schumacher have again noted a weak area and acted to rectify it. Well done guys, but maybe you shouldn't have downgraded this area from the original SX?

I opted for a Sanwa ERG-VRX digital servo, mainly because I had one in my pit box! This is a good bit of kit though with 8kg of torque and a 0.06 sec transit time.
It should be a good choice but time will tell.

The shocks are also carried over from the SX2. They are big bore beasts so make sure you are well stocked on shock oil!
The only difference here is that the 2.5lb rated rear springs have a different coil arrangement to the older 2.5lb versions. It will be interesting to see if there is a difference on track.

The shocks come with a set of low friction (blue) orings as standard. If you are a racer that rebuilds your shocks for every meeting they are great but I am not that disciplined and tend to leave it a little longer. This means they lose a little too much oil for my liking. I went searching for an alternative and came across the 'Nortech Whities' from Atomic Carbon. (See the pic above). I have heard good things about these so thought I'd give them a go.

Tip: Coat the threads of the shock shafts with a little 'green slime' on assembly to avoid damaging the orings.

All that remained was to bolt on these bad boys to complete this tasty looking chassis.

Tip:  Do not overtighten the shocks, this will cause the suspension to bind. Ensure the shock tops are able to move on the olive.

So here it is.
Good eh?

The electrics are alway a challenge. I opted for a 5.5t motor hooked up to a HW V2.1 120a speedo running 119mod software. Identical to my SX2 so I can compare them back to back on track.
My cells of choice are Intellect 5400mh 60c and are a perfect fit.
I went for all black wiring, cos it's cool!
RX duties are taken care of by a Spektrum micro reciever. It is possible to use a standard size rx but it would need to be sited next to the pinion/spur, my choice is neater.

In the pic below you can see the SX2 and the SX3 side by side. I think the SX2 makes the SX3 look a bit chubby, what do you think? Schumacher claim better weight distribution for the new model.

All that remained was to paint up the bodyshell.
This is what I decided on.
It is an homage to the Schumacher logo and original SX3 paint job and I think looks pretty good.

You can't see it in the pics but the white has a gold metalflake in it which looks great in the sun.

So there you have it.
I really enjoyed building this car, everything fitted together nicely and appears to be good quality. Experienced builders will enjoy it and, thanks to the excellent (even if it looks like a bootleg photocopy) manual, newbies will have no problem coping.

I am really looking forward to getting it on track. I will take it along to the TORCH club meeting this weekend and try to give it a few shakedown laps. I will report back with my findings.

I hope this build report has been useful for any contemplating an SX3.
Do it, it's only money!
If you have any questions or comments don't hesitate to use the comment button below or email me HERE.


  1. This is a great blog! It's convinced me to build an SX3

  2. Great blog. I just put my sx3 together but haven't gotten the chance to run it yet, how has yours been running over the past year? What parts if any should I stock up on?