Proposed Slot.It Challenge Rules Change

[chapracer65]

Hey Guys

Boy, I find the new website more confusing to navigate; it's awfully busy.  I wasn't sure where to post this idea.  I went to 2010 Slot It Challenge Rules and I had to scroll down and down to the bottom of a long list of posts to find where to reply.

Anyway, considering the variations in motors, I thought I would float this idea for the next round of Slot It.  What if we pay an additional $15, or whatever the motors cost, and draw 2 motors?  You could then pick the better motor to race.  You would then have to use only that motor in succeeding races.  At the mid-series motor swap you would put both motors back in the bag and draw 2 new ones.  I would be willing to pay the extra cost for a better chance at getting a decent motor.

Russell

[tele52]

Russell,

I like your idea since I seem to have a propensity to be stuck with motors in the lower performance category. It's not fun to be lapped 5 times a heat. I have even considered making this Slot.It challenge my last one. It's a great class, but I'm not competitive with my motor draws.

Jim J.

[porsche917]

I don't know if it's as much about the motor as it is about selecting the proper gearing.  I fully understand what you guys are talking about but have found I just need to focus more on what crown and pinioin to use.  Don't misunderstand me, I would never turn down a 20K motor but if I have a 17K one I will do my best gearing work to end up with a rear wheel RPM of 7.3K.  Its not the best but it will keep you compeitive. 

Being on the 3rd place bubble I can say that the racing has become much closer than it was in January.  This is all part of everyone learning how to match the gearing to the motor RPM. 

Marty

[chapracer65]

Marty

I understand about gettting the proper gearing to get the proper wheel speed.  But, comparing Motor A, with lower RPM, and the necessity to go to a taller (numerically lower) gear setup, such as 2.4::1, and Motor B, with a higher RPM, and a gear setup of, say, 2.7::1, would not Motor B have more torque at the wheel and the ability to accelerate faster?  All this being dependent upon controllability, of course.

Russell

[Autorama]

I understand that some of the motors perform a lot better than others at 10 Volts. The last motor I drew was running at 17.6K after break-in, I was still able to get it going with a 23X9 gearing (2.55 ratio).  Some may say that I could have tried a different gear ratio (ie 25X10, 2.5 ratio), but not really.

I think that by now, all of you heard of me saying never to use a 10 tooth pinion; the reason is simple: All slot.it gears are 48 pitch but the pinions are not. The 8 tooth pinion is 46.18 pitch; the 9 tooth pinion is 50.80 pitch; the 10 tooth pinion is 55.42 pitch; the 11 tooth pinion is 60.04 pitch. The difference in pitch is due to the fact that slot.it needed to fit all sizes of pinions inside the channel that stops the gear from moving away from them — this is a HUGE design flaw.

Back to subject; to get the better gear mesh you need to disconsider 10 and 11 tooth pinions, making the gear selection very limited.

With the current track voltage set at 10  and motors as slow as 17K, using the smallest “usable” gear ratio (9×23), the maximum RPM at the wheel is 6.6K (17000 RPM / 2.55 ) — The sweet spot for out track is around 7K for an inline configuration without ballast.

Now, if we increased the voltage of the track to say 10.5 or 11 volts, whoever picks a slower motor has greater chances. The problem here is that the person with the fastest motor could still extract better times using ballasts, so those would become illegal. Without ballast the car is still limited to the lower 7K range at the wheel or it becomes unraceable (I make up words as I go).

—- Basically my suggestion is:

• 8 or 9 tooth pinions allowed
• No ballasts
• Track voltage at 10.5 or 11 volts

Let me know if this makes sense. We can always give it a test run on a Thursday night.

Ary.

[turboman93]

I would like to also like to exclude the use of the F series of tires.  These provide to far of a performance gap for those they have the tire truers and have the time to make them work.  I for one don’t have 4-5 hours truing and rounding a set of tires.

One of the reasons we did a spec motor was to prevent people having to spend time and money to find that one gold motor that worked.  We’ve replaced that issue with tires.  The F series tires are inconsistent at best just like the BRM tires.  I would be open to limiting the tires to P6 in 19×10.

Just my $.02.

[chapracer65]

I would not necessarily be opposed to banning F series tires, but I did the test runs last Saturday at 10.5V. and 11V. using F30’s.  I found the car OK to drive with these tires but I do not know how it would have driven with P6’s.  I would like to test with P6’s at these voltages if we will have to use them.  This could affect my decision on what voltage to run.

Russell

[Autorama]

At this point I think we don’t need to change any of the rules, just go with higher voltage so everybody will get decent performance from the motors.

The pinion issue can be used as a guideline; if someone wants to use a 10 or 11 tooth pinion is their choice.

[porsche917]

I am in favor of keeping the rules as they stand allowing any Slot It tire to be used except silicones.  I don’t know that there is any perfect compound or perfect set up.  I think we are all getting better at setting up our cars on the club track and all running closer as a result.  The change in voltage will have a huge impact on car set up and gearing.  The change in voltage may also allow participants to start using lead to balance their cars.  When we were running at 10v it was more a case of who could build the lightest car and run the smallest crown. 

I believe we should leave the tires alone and see what the change in voltage has on the cars performance.

Marty

[Bellator]

The race voltage change (11v) has been approved by vote and I have updated the official rules document found here.

[Author]

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