Doubled-up Wiring?

edited May 2012 in IET Formula Goblin
I'm due to help a primary school in Sussex build their Go Goblin car again this year ready for a race in the summer. I assisted last year (first time the school had taken part) and we came 2nd out of around 8 schools on the race day which was fantastic.

However, after finishing the day I realised that the winning team (who were always quite a bit quicker than all the other teams) had doubled-up their main battery to motor wiring by using a second spare kit that they had.

To me that seems like they've broken the rules, but what do you all think? Seems unfair on all the other schools who used only the items in the kit. All the cars were checked for safety prior to the race day starting by some adjudicators but I believe they were linked to this team!

I expect them to be entering again this year, do you think I should say something if the same thing occurs again? Otherwise it seems impossible to have a chance of winning as the double-wired version will always offer lower resistance/more current to the motors!

Comments

  • If it really was faster, check gearing (pulley teeth) and tyres (rolling circumfrence) - tyre type & inflation pressure, specifically of the driven wheel, those things would make a difference. Wiring resistance is really not significant ;^)
  • At Greenpower organised and regulated Goblin events, modification of any component is not permitted. We are not sure where you saw this occuring, but would suggest you speak to the organisers (whether Greenpower or otherwise) to warn them that a non-standard car was competing last year.

    Admin

  • Thanks for your help. BobC - the wiring is fairly thin as standard so with the 2 x 12V batteries and large 12V motor it may well make a difference. I'd made sure that our car was set up as well as possible including tyre pressures, etc. The pulley, gearing, etc is all 'fixed' on the kit so not easy to change.

    I do have to say that it probably wasn't a Greenpower organised event but one run locally for some smaller schools in Sussex. I will make sure I speak to the organiser this year if I spot the same 'fix' again (the team were next to us in the Pits.

    Thanks
  • Pete
    The team had their knuckles wrapped and have not run with twin wiring this season. Last year they purchased a new car and decided to use the wiring from the old car as well. BTW they are still very quick this year even with one set of wiring.
    I scrutineered their car at a recent event and there was nothing obviously not to regulations but everything was set up perfectly. Wheels ran free and true, steering was as light as a feather and it was whisper quiet on the track all signs of a well setup Goblin.
  • We experienced last year that another team had used their own wiring for their kart, if I remember correctly all their wires where green. When questioned, they answered with "our wires broke so we replaced them with what we had". This team then went on and won. Can someone confirm that you can do this, as we purchased a new wiring kit for one broken wire, however replacing it with our own, slightly thicker wire with less resistance would have made a performace difference?
  • Knowing absolutely nothing about Goblins and the rules pertaining to them, I would think it highly unlikely that using heavier gauge wire would make any measurable difference to performance. You are correct that heavier gauge wire has a bit less resistance but I would suspect this would be nothing to contribute to the overall performance to the car. More likely contributory factors could be running gear, brake disc rotor rubbing, tyres (are you allowed to change the spec on these?) and motor cooling perhaps?

    CC (Foremarke - F24))
  • From my understanding, you cannot change the tyres, and they have to remain as they where.

    I think this is me looking for the ways at which the other Goblins where faster than our own. Ours managed around 6mph, where as the winning team where more 8.5mph, a massive difference is these small karts.

    I'll have to do more investigating as to how we can improve.
  • edited May 2015
    A quick check with a voltmeter should show you how many volts you are dropping across the wire from the battery to the motor. If you know how much current the motor consumes during a race (if not - if you can touch the motor after a run without hurting your hand, its probably less than 25A) you can work out how much power is being wasted across that wire.

    At a guess, its going to be less than a couple of Watts. Doubling up on the wire cannot therefore save you more than a couple of Watts, but its going to take a whole lot more than that to gain 2.5 mph in pure motor power alone.

    Brakes, tyre pressures, motor alignment, bearing quality and even aerodynamics will be having a greater affect on your performance.
  • As Admin posted at the beginning of this thread at all Greenpower run events Goblins are not allowed to change anything from the standard kit, with of course the exception of bodywork. This IS enforced, I distinctly remember counting pulley teeth at the end of the Gathering of the Goblins last year.

    as Ruds and Foremarke have suggested how the car is set up will make a significant difference to performance as will size and weight of the driver, weight and aerodynamics of the bodywork.
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