Vorza S Buggy at ROSSA 2022 Round 2!

Mon, 12th September 2022

At the first ROSSA event of 2022 held in June at the Llabender Airport in Wales, UK, Nick Sperduto ran a Maverick Quantum Flux R which became a member of the 100mph club and ran to 101mph and believe it to be the world’s fastest Maverick RC.
You can check out the achievement here!

rossa_1.jpgGreat turn out and car lineup!

Now for ROSSA round 2, Nick was stepping up the mark with the HPI Vorza S to run in the 1/8 open wheel 6s class.
90 Cars entered the event from 33 drivers with over 300 successful runs made across the 3-day event.
Nick was kind enough to send over his report of the event and let us know how the Vorza got on!

After receiving the Vorza and only a short time to prepare before the Rossa event approx. 2 weeks I got to work. The first thing to address was the suspension as it's an off-road car it's too soft to run as a speed car as the rear will squat and cause the chassis to touch the floor and potentially flip the car at speed. I fit tube to the shock shafts to act like a bump stop and used thicker shock oil and springs. I then added droop screws so I could effectively adjust the ride height, the stock car has holes for them but doesn't come with them.

Then onto the front, I couldn't use droop screw because once wound down they slip off the lip of the chassis so won't allow you to adjust the car low enough. I made the decision to remove the shocks completely and use some turnbuckles instead.

rossa_3.jpgStock Vorza on the left and the initial modifications on the right

Next thing to setup was the transmission, the stock ratio is too high for a speed car at 4.3 so I opted to change this to the HPI Trophy crown and pinion to reduce it 3.3, I thickened up the oil too. After this I realised the output on the pinion is 8mm and 6mm stock so I had to use Trophy centre diff output cups also.

Transmission sorted, now onto the power. To be able to achieve speed I wanted the stock ESC wouldn't cope with the amp draw and also, I wanted data logging so I went for the Castle MMX8.

rossa_2.jpgNicks initial setup ready for the journey to wales.

I thought I was ready to go but after a last-minute decision I decided to go with the higher amp rated ESC the Castle XLX2. Due to lack of space I had to remove the fan and make an ESC plate for it to mount on the centre spool housing. The stock motor has been kept and used throughout the build and testing.

Last on the agenda was batteries. I'd used Onyx Power Solutions batteries in my other cars so I wanted to use them in this, I went for 2 x 3s 8000mah 2P packs. Due to the small battery tray I had to cut this and redrill the chassis holes and used another battery tray to protect the side of the battery. The shell also required cutting for the batteries to fit.

Wheels and tyres were changed to Arrma Hoons 42/100.
rossa_4.jpgNicks changes to the chassis to add the huge XLX2!

Once at the ROSSA event in Llanbeder Aerodrome Wales I went out for a test run, the car felt twitchy on the Arrma Hoons so I changed them out for Contact RC Foams instead. This is what all my other cars were running too. I had a range issue so had to change to a twin antenna receiver which I thought I would have.

First base run getting it through the traps ran 116mph which I was happy with. Then 118mph on the next.
I geared up 2 teeth on the pinion and ran a 120mph pass which was good and a few around that mark.

I had cut the back of the wing to allow for better airflow but it made it too flexible and could see it moving about a lot, so I drilled a carbon wing I had spare and mounted this and was ready to run again.

I went out again and hit 122mph then 124mph. The heat was approx. 35C and 50C on the ground which was taking its toll on the cars and making it for challenging running conditions.

I geared up again and ran another 124mph and realised it was 82% throttle on the transmitter. I ran again and got 126.38mph which was the fastest I achieved on the day, and I felt that the stock motor was nearly maxed at that on 6s. It may have been over geared slightly and could have pushed just over 130mph but not much more. I believe this is the UK fastest Vorza on 6s currently which I'm happy with.

Next time I'm going for the 144mph record.

All in all, it was a great event which I enjoyed a lot and learnt more each day. A big thanks to ROSSA UK for organising the amazing event for us UK speed runners to go to. Please check them out on fb and the website. I would like to thank HPI Racing, Modelsport UK, for the car and parts and Onyx Power Solutions, RC Mann, Big Beard RC for the help and advice.


Check out the full kit web page here:

#160179 Vorza S Buggy Flux 

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