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Circuit Owner
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Hello,

We are in the process of setting up a new slot car club in Wales and we are going to be running a standard Scalextric digital setup albeit on routed tracks.

There will be several classes - some with club cars and some open classes.

Because of the power limitations of SSD and the power handling of the chips we want to make the open classes a free-for-all EXCEPT for the motor which we want to limit to the standard Scalextric 18k mabuchi.

The idea being with club cars is that they are identical and the racing is down to the driver and with the open classes it is down to how well you can construct and/or tune a car and drive it without resorting to a mega bustard motor!

My question?

Scrutineering is likely to be down to me and one other and I don't know how best to test that a car presented with a "standard" mabuchi is actually what it seems.

Do I need a rev counter for example? Or can I put a multimeter in line on full throttle to see what power it draws?

Any advice gratefully received.
 

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Visual inspection is a good start.
Have a close look at the endbell retaining lugs - if they have been tampered with the endbell has been taken off.
Banning removal of endbells eliminates a whole bunch of tuning options.
(With these sort of motors it is unusual to take off the endbell for any other reason, although of course this would be done as part of routine maintenance on higher end motors.)

A problem that doesn't solve is better spec motors that came out of the same factory in China.
Perhaps some guys out there can list some quicker motors that look exactly the same as the standard Scalex motor???

Measuring revs at a fixed voltage is a quiet useful way of comparing motors, although you can expect some production tolerance in standard motors.

In my experience, measuring free running current isn't that much good as a scrutineering check.
Measuring stall current is better, but needs to be done at quite a low voltage to avoid motor damage.
 

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The Revell 25K motor looks very similar to the Scalextric 18K motor, though the 25K motor would only give an advantage if you're running magnets OR have long straights, on a twisty track without magnets the 18K motor is better.

Perhaps you should only use motors supplied by the club initially?
 

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Circuit Owner
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Thanks gents.

300SLR:

Stall current at say 5V could be good - I have plenty of 5V wall warts and could easily rig up a tester.

Would 5V be OK?

I realise manufacturing tolerances, on what is essentially a toy, will be high and there will be "hot" motors that are genuinely standard. We will have to live with that to some extent but I guess the "current draw" test would show up any glaring differences.

Julian_Boolean:

Thanks for the heads up on the Revell motor. Club supplied motors is an option - I guess with my signature on them or something so I know they have actually been used!

They are cheap enough on ebay - about £3.50 each if you buy 10 or more.
 

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Ian
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Fact - There will always be some production tolerance in standard motors.

I know people who buy several of the same motor in order to use the best one they can and this is legal in anyones books. There will always be an unusually good motor, a well run in motor, the manufacturers tolerances change over the years, so an older or newer motor of the same type can be totally different, without breaking the rules. It's going to come down to selfrespect...

I can't help thinking that you can delve too deeply into the rules, the rules should be set out for all to see and follow! Really the rest should be left for the individual members, anyone who doesn't follow the rules is only cheating themselves… The fact you would or could actually check each motor should be a deterrent for most, but really slotcars are meant to be fun you would not want to get that engrossed in rules that they detract from what you are meant to be doing in the first palce…Enjoying yourselves!
 

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Circuit Owner
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Discussion Starter · #6 ·
I agree wholeheartedly with you Bleep.

I would not want to do any scrutineering on a regular basis but if we get somebody with an overwhelming desire to win regardless of whether it is fair or not - I want the option of offering them the opportunity to play fair or I will start to scrutineer more frequently.

I would rather believe that everybody has that self-respect but I know from what has happened at other clubs in the past, that some people who want to win at all costs can seriously annoy those who play fair and just want to enjoy themselves.

Would you like to be beaten every week by a guy you KNOW has an unfair advantage but the club doesn't seem to care? Not many people want to get drawn into spending battles with £200 sunk into a single car where you can have as much fun with £30-£40.

I want the specs on open classes to be pretty loose and I think (I could be wrong which is why I am asking for help) that levelling the available power and giving free choice on pretty much everything else is the way forward.

Do you think I should just say standard unmodified Scalextric chips only (that's easy enough to spot) - and let people take the risk their more powerful motor will fry the chip and cost them £12?

I may need to do the APB power upgrade but that's easy enough.

We are trying to attract new members into our hobby so I don't want to scare them off by having to spend stupid money just to get a competitive car.
 

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Premium Member
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Hi all,
this is an old problem that all clubs have at some time in their history. There is always someone who is prepared to go that extra step and push the boundaries of the rules (and sometimes beyond). If you have enough money to throw at motors then you can pick the best out of the ones you buy. If you are clever enough you can modify them to look right but go better too!

There will always be suspicions and conflicts with those people, and if someone comes along with a car that just happens to have a very quick motor unfortunately people can become suspicious of them too.

At our club we have now said that you can put what motor and gears you like in certain cars. The plastic chassis can only take so much power anyway, and if your car isn't quick enough then buying a faster motor is cheaper than buying 3 or 4 more standard motors (or even cars) to try and find a quicker one.

We also have club classes where the cars are provided by the club and each car is driven by each driver on the same lane. This is the only proper drivers class, as everyone is using equal equipment.
In addition we have classes where you can tune/modify the cars to improve their performance, as well as scratch build classes, so hopefully cater for everyone's different strengths or likes.

This is just the way we have developed the classes and there are many other ways to run a club, but with a weekly grid of 12 to 16 drivers we must, hopefully, be doing something right.
Whatever you do good luck with it and enjoy the racing!
 

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Circuit Owner
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Discussion Starter · #8 ·
Thanks 911TT,

There will be a few sets of club cars so that will level the playing field nicely.

Maybe I shouldn't worry too much about the rest.
 

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its easy to do if everyone is willing.
a tamiya 1/32 speed checker will test your top speed. assuming all motors,gears and tires are similar.


or if you just want to test motors, you can get a cheap LCD Digital Mini-Tachometer
 

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Rich Dumas
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3,596 Posts
As has already been pointed out there can be a considerable difference in performance between different examples of the same motor. The RPM rating of a motor does not tell the whole story, especially if you are comparing different motors. For a start you might look here: http://slotcarnews.blogspot.com/2007/02/sl...motor-list.html
For most of the motors actual test results at 12 volts are listed. The power rating is calculated from the RPM and torque measurments and is actually the best way of comparing different motors. If you have several examples of the same motor you only need to determine the RPMs to compare them, the torque values will normally be proportional. If you look at the data for Carrera and standard Scalextric "black stripe" motors you will see that a good example of the Scalextric motor can be more powerful than a Carrera motor. We run several classes that use Scalextric motors only and I will only use ones that turn at least 21K RPM. If you measure RPMs at the rear wheel you will have to figure in the gear ratio.
 

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Circuit Owner
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Discussion Starter · #11 ·
Thanks for the advice.

Can I assume that current draw is a function of rpm and torque?

If that is the case then maybe the current draw at low voltage with the wheels held stationary would be a good indication of the force the motor is capable of exerting.

If I set up a tester that has my multimeter in line with a 5v feed to the braids and hold the driven wheels stationary whilst I apply power for 2 seconds - would the current draw be a reasonable indication? At the end of the day it is current draw that will overload the APB or deprive other racers of power and that is my main concern - that everybody gets their fair share!
 

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Greg Gaub
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IMHO, spec motor, random (or scheduled) scrutineering, and stock chips (Scaley or slot.it) is the way to go. There's still a LOT of tuning that can be done outside of the motor, and if the motor is spec, then a stock chip should be fine. No upgraded chips, because that can give them an extra volt to race with, not to mention the security of running any motor mods they want. It sounds like your open class would allow an NSR car with the simple replacement of the motor. Such a car would perform really well, right out of the box. As such, you'll probably have a lot of slot.it and NSR cars in that class, at least until the tuners come in with their well tuned SCX or other cars. I've seen proxy winners running Scaley chassis/body cars with nothing but body float to give their car the edge (though all the other parts were changed, just like everyone else's car)

Cheaters cheat, but even more so when they know they won't be caught, or worse, that they won't be punished WHEN they are caught. The club I ran with got so bad about that that when anyone pointed out that certain people were breaking the rules, those people were made to feel unwelcome. I'm amazed that there are so many people that would rather lose to cheaters than bother with enforcing rules, but there appear to be. :\

But, as mentioned, when it comes down to it, only IROC racing is really about the drivers. Even with a spec motor, the tuners will be able to make their cars very smooth handling with so much traction that it's hard to crash in a corner without doing it on purpose. But, without limits, it becomes as much or more about money than even tuning skill.
 

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Circuit Owner
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Discussion Starter · #13 ·
Thanks Greg - good advice.

We have yet to decide as a club what exactly we will do - our first ever meeting is tomorrow evening.

I wanted to offer up some options and some preliminary discussions confirm that quite a few people want close racing without having to faff around getting too technical or too deep into the wallet.

If NSRs are too good then perhaps we might have a separate class for them - it's all fluid until we find a formula that works for us.

There's plenty to discuss tomorrow that's for sure!
 

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QUOTE (Mr Modifier @ 8 May 2012, 15:30) <{POST_SNAPBACK}>Thanks for the advice.

Can I assume that current draw is a function of rpm and torque?

If that is the case then maybe the current draw at low voltage with the wheels held stationary would be a good indication of the force the motor is capable of exerting.

If I set up a tester that has my multimeter in line with a 5v feed to the braids and hold the driven wheels stationary whilst I apply power for 2 seconds - would the current draw be a reasonable indication? At the end of the day it is current draw that will overload the APB or deprive other racers of power and that is my main concern - that everybody gets their fair share!
That test is a reasonable way of finding out if what look like identical unopened motors will perform to a fairly similar way.
Although testing at 5v is unlikely to do any harm, I think I would do the test at a lower voltage to avoid any claims the test was hurting the motor. A few pence worth of diodes will lower the voltage of your existing supply.

How current RPM and torque are related is altogether more complicated, but for simple scrutineering purposes that's probably detail you don't need.
 

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Good luck with the club.

I must admit to not being the best driver at our club by a long chalk.

As a relative newbie to slot cars i have no idea how to pep up a motor and do not have the budget to buy loads of motors.

What i do enjoy is the opportunity to tune the cars within the club rules which i think i have generally got the hang off. You may well find that some of your members may enjoy that as well.

Keeping the motor capabilities within the standard SSD chip is a fine idea as is not having too many different classes.

If it was me i would approach the club with an opinion that people are not going to cheat but have the rules ready to cope if you think they are.

Testing all the motors for everyone's cars may take you quite a while each week and may put people's back up straight up. A random check with names in a hat would be less controversial.

Once again good luck

DrH
 

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Circuit Owner
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Discussion Starter · #16 ·
Hi DrH,

I agree completely.

I may NEVER have to scrutineer. What I want is the option to start doing it if we get problems and be able to point back at the rules and say it is something I should have been doing. That way any suspects can not claim they are being victimised without immediately confirming my suspicions!

I hope I never have to wheel out my device to measure motors but I will have it available as a deterrent.

I will, of course - get somebody else to test mine!!!
 

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Circuit Owner
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Yep.

Funnily enough I was talking to another SlotForum member on the phone the other day and he had exactly the same problem at one of his clubs.

I will play it straight and more importantly I will be seen to be playing it straight or it all goes pear shaped.
 

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I see this as a philosophical problem not technical.

I see the problem as differing expectations between people and the fact that "stock" classes never really are.

Take Karting as an example but the similarities are there. When I raced in UK the silhouette of the engine had to be stock and for very little money what the owner did inside the motor was "free". Then go to North America the class was stock with a book of rules metaphorically like a phone book. It cost more to prepare a quick stock motor than it did in the UK where it was "free".

Now personal expectation. If a guy wants to race once a week and goes to the drawer takes out his car and goes to the track and gets beaten he will ask why can this be all the cars are supposed to be the same. Well the cars will never be because his opponents will be fettling away every night trying to find an edge.

Motors. As has been said they are rated at 18,000 but some pull 22,000 plus nearly 23,000 ( I have two like that but have lost the file with the results;-). How do you penalize a guy for having a good one. He as has also been said may have bought 10 and used the best one. (Also happened in NA Kart racing) Why because he wants to. Just because the other guys don't, doesn't mean he is wrong.

So how to solve? Set up the rules then:

A buy out rule? Popular in some 1:1 lower end racing activities. Have a meeting and set a price. Either for the motor or the whole car. Bear in mind the price needs to include postage etc not simply the replacement cost. The time fettling is lost. The seller has to get another car and start again.
Buyer has to place a deposit. Then the motor is tested. If OK buyer losses deposit, if not OK buyer pays the agreed price.
The Nett result is "Put your money where your mouth is" don't simply whine.

A success weight penalty like WTCC. The points leaders have to carry extra weight. The amount can be arrived at by trial and error.

Bracket racing. If the club has a timing system racers are grouped by times set in practice or based on the their previous week's times. If they "break out" ie their time is significantly better than last week their result is nullified and they move to the next group.

If there are enough guys with enough time and inclination to strive for and achieve better, put them in a class or their own. Something for others to aim for or not.

Side note even one of the club cars will be faster than the others! Oh and funny that the guy asking the question is called Mr. Modifier


Edit: Another side note. later Scelextric NASCAR seem to be slightly better quality or say consistent than other models so a NASCAR class would be one to consider. Same applies To V8 Supercars.
 

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Greg Gaub
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Yeah, NASCAR or Aussie V8.

I like the idea of bracket racing, but you might not have enough people to do that right off the bat.
The buy back rule is also interesting. I'd heard of it, but never raced in a club with that rule in place.

Yeah, even club cars can vary, that's why for IROC racing, all racers run through all cars. The best racers will bubble to the top no matter what.
 
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