With these kind of basher rigs, upgrading occurs continuously. It's always a work in progress.
Adding a more powerful motor, one which could turn bigger pinions, was a step towards finding higher top speeds.
On 19/52 gearing, the XTR hit 69mph on a 6S Graphene pack, which is very good!
The Rocket 1780kv 4292 motor generally keeps it's cool, but these runs pushed it to the max. Running it hotter risks failure.
I created a very accurate gearing and rollout spreadsheet that I plan on turning into an app. It works out theoretical top speeds very accurately. On my Sworkz and Baja, it worked out speeds to within 0.3mph of real world results, so I'm satisfied the spreadsheet works well. However, on the XTR, I got larger differences - more than 3mph.
The conclusion I came to was that the centre driveline works at such extreme angles, losses were occurring that my spreadsheet was not compensating for.
So, I wondered how much better the XTR might run with a more efficient driveline. To achieve this, the XTR would need an after market chassis.
Unfortunately, there isn't one. So long story short, the XTR went through another stage of modification with a chassis of my own design, which I'll briefly show here.
The 3mm 7075 chassis is comparatively light. But whilst I'm never likely to bend it - people that send it to the moon have.
5mm Woven carbon fibre has been selected to upgrade the chassis, with a much stiffer, lighter material.
Straight off the bat - 46g saved, despite being 40% thicker and 10% wider.
The steering plate required mounting at a revised angle, to compensate the new 0° kick-up angle.
DIY milling with a Dremel isn't pretty, but it went as well as I could have hoped for!
Removing the mass of plastic, typical with RTR's and rollers, reaps lighter, stiffer and stronger results. This Scorched Parts steering servo mount makes for a much stronger, zero flex option. It's based on the Kraton mount, but it really doesn't matter for a custom build.
Titanium shock stand-offs were supplied by Scorched. I'm not sure if he gave them to me by accident, but I really like them either way. Thank you Dave!
The chassis has been configured to bring the driveline into the centre, bring the weight forward and increase available mounting space.
And so the XTR Wide Boy 'H' is born.
This rig is light. The new design eliminated most of the bracing - it's simply unnecessary with a chassis this stiff. The rear braces are retained, primarily because that's what the body mounts to!
Watch this space for incoming speed runs and 0-60mph times.
M2C front and rear carbon shock towers are on the way!
What a rig this has been so far - the gift that keeps giving.