# Laser Tach



## joeslotcar (Mar 12, 2003)

Is this crazy $ or do I need to educate myself on these? Some please explain.

http://cgi.ebay.com/HO-LASER-TACHOM...3&clkid=6442556153913129384QQautorefreshZtrue


-Joe


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## eastside johnny (May 13, 2008)

You can buy one direct from him for $190 plus $12 shipping........

[email protected]

I was watching that one. Interesting bid history.
If I was selling for $190 I think that I would have a starting bid a bit higher than $1. ??
BUT...I don't do ebay sales & just bought on ebay one time so I'm not familiar with all of the ins & outs of ebay.

I have a VRP Dyno that uses a slave motor and it gives me good numbers to work from. These are relative to the Dyno which is fine to track changes etc. I don't mind the resistance of the slave motor since when you're using your slot cars they have to overcome the resistance of moving the car as opposed to "free wheeling". Paul states that his uses a laser for RPMs of "the roller" with no resistance on the roller. This is true, but still relative to the machine since it's the RPMs of the roller & NOT RPMs of the slot car. The memory feature is a nice touch......
I guess that it all comes down to the level of competition that you are up against in your race program. The closer and tougher the competition is, the more and harder you have to work to get the "edge" (that's why I've owned a magnet zapper & Gauss meter since back in the 90's) The cost is also relative to your race program. Not uncommon to see a racer with a tackle box FULL of nothing but axle set ups. Silicone/sponge rears in increments of 1-2 thousands, various compounds ( soft, med, hard, etc.) and lots of gear ratio choices. The cost of all that would make these tools seem somewhat inexpensive.............."How fast can you afford to go?" Just the same as 1:1 racing.

Nice to see that there are guys putting out quality products of all sorts in this hobby no matter if it's tools, tires, armatures, bodies, etc. We all have our levels of involvement and preferences......racing, collecting, modeling, magnet cars, nonmagnet cars, inline arms, pancake arms, etc.


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## SwamperGene (Dec 1, 2003)

eastside johnny said:


> I have a VRP Dyno that uses a slave motor and it gives me good numbers to work from. These are relative to the Dyno which is fine to track changes etc. I don't mind the resistance of the slave motor since when you're using your slot cars they have to overcome the resistance of moving the car as opposed to "free wheeling". Paul states that his uses a laser for RPMs of "the roller" with no resistance on the roller.


A slave motor dyno can be _better_ as it will give you an idea of performance under load. In fact if I remember correctly the Micro-Dyno made by Gerry Cullen had adjustable resistance so you could vary the load.

Unless you start talking straights of 10' or more, most cars will never see anything even close to their "maximum RPM" anyway...as a good example this is precisely why many people don't notice a difference when they advance the timing in a Super G+. :freak:


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## SwamperGene (Dec 1, 2003)

I wonder how hard it would be to re-house one of these (or just use as is):

http://www.harborfreight.com/digital-photo-sensor-tachometer-66632.html


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## noddaz (Aug 6, 1999)

*Why re-house it?*



SwamperGene said:


> I wonder how hard it would be to re-house one of these (or just use as is):
> 
> http://www.harborfreight.com/digital-photo-sensor-tachometer-66632.html


While the chassis is on your regular dyno point that lazer tach at it...


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## neorules (Oct 20, 2006)

If reflective paint on the arm would do the trick it could work. Otherwise tape the rear tire and do the gear ratio calculation to get motor rpm.


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## Montoya1 (May 14, 2004)

SwamperGene said:


> A slave motor dyno can be _better_ as it will give you an idea of performance under load. In fact if I remember correctly the Micro-Dyno made by Gerry Cullen had adjustable resistance so you could vary the load.
> 
> Unless you start talking straights of 10' or more, most cars will never see anything even close to their "maximum RPM" anyway...as a good example this is precisely why many people don't notice a difference when they advance the timing in a Super G+. :freak:


There was a bit of a kerfuffle after last year's Derby 24hr race over illegal advancing of arms in turbo cans, given what you say the speed increase on that straight would considerable.

With cars not reaching maximum RPM is again brings up the debate are US tracks too tiny or HO cars too fast...


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## eastside johnny (May 13, 2008)

Montoya, I was there for the 24 hours in '96 with the first team USA and for sure that would be a HUGE advantage on that long straight! Nick & I exchanged news letters for several years but then tapered off so I didn't hear anything about the arms last year. Just curious.....if someone was sneaking arms in OR advancing the ones that you got in the "kit"? I remember that it was suspected that "special magnets" may have been brought in a year or two later. Small stuff is easy to bring in in your pockets. Too bad that someone (a loser) would have to do that to try and get a win.


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## Montoya1 (May 14, 2004)

Always a pleasure to talk to a fellow member of Team USA (the way I look at all past members and anyone who supplied a body that was used can use that moniker for life).

I don't want to get into it too much, chinese whispers and all that, but more often than not the 24hr is blighted with some kind of cheating scandal. This really hurts me as I am passionate about the event and always say running on that Bowman track is one of the ultimate HO bucket list items.

The scuttlebutt seems to be somebody found a way to play around with the guts of a can motor without opening it. The Derby AGM minutes do say that some motors had been found to have been advanced.

Would a device such as the one in this thread be able to 'tell' if somebody had done that, if the value of a motor that had not been advanced was known?

The special magnets I suspect was just the home team shimming the magnet with the piece of lexan provided to make outer wheel flanges from, and most of the years they did it (the rules have been changed Orwell-style to make it OK for all to do) Team USA still won.


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## partspig (Mar 12, 2003)

Montoya1 said:


> Always a pleasure to talk to a fellow member of Team USA (the way I look at all past members and anyone who supplied a body that was used can use that moniker for life).
> 
> I don't want to get into it too much, chinese whispers and all that, but more often than not the 24hr is blighted with some kind of cheating scandal. This really hurts me as I am passionate about the event and always say running on that Bowman track is one of the ultimate HO bucket list items.
> 
> ...


OK, so what does all this blather have to do with a tach?? Highjack! Highjack!!


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## Montoya1 (May 14, 2004)

Only that the device being discussed here could prevent such cheating.

Seeing as you are very hot on proper forum etiquette, please remember that you should not quote from a post directly above your own. I don't care about such things, but you clearly do...


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## partspig (Mar 12, 2003)

OK MR. Proper etiquette, seeing that you know more than me, on everything, ....... just how will a device that measures RPM, like a tachometer, be able to detect whether or not an armature's timing has been tampered with??


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## Montoya1 (May 14, 2004)

I don't know, just asking. notice I said _could_, not that it can or will.

Post content and posting etiquette are not the same thing by the way. Or are you implying that it is proper etiquette to only post stuff that is 100% factual and proven? Whilst that _would_ make forums much more 'efficient' places to visit they would also be very dull, not to mention a hell of a lot emptier!

What is with the hostility anyway?


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## partspig (Mar 12, 2003)

What does a tach have to do with the cheating that goes on at the 24HR race? And how can a tach determine if the armature has been tampered with?? Come on we want an answer. You brought the topic up, you must have some inkling of how it would work in tech to catch those nasty bad boy cheaters. You still have not answered either question! Just side stepped the questions. You really have no idea do you. Just useless blather to waste time and bandwidth on. And shame on you for reading hostility into my post. That's not proper etiquette either, is it? I was following this post with some interest, but it has become hijacked into something other than what it started out as. So, I guess the big question is, ............. if it COULD be used as such. How would you apply it to tech? Inquiring minds want to know.


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## SwamperGene (Dec 1, 2003)

Fer cryin' out loud the guy did not infer knowledge of anything...he asked the same question himself!



Montoya1 said:


> Would a device such as the one in this thread be able to 'tell' if somebody had done that, if the value of a motor that had not been advanced was known?


The answer Deane is no, you couldn't reliably use RPM's to test for advanced timing as even identically wound arms can exhibit slightly different characteristics. 

You _can_ visibly spot twisted/moved comm's and could likely make a simple cardstock jig to verify 0 timing. All you need to do is verify the relationship of the commutator plates to the armature poles.


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## NTxSlotCars (May 27, 2008)

Can this be rigged as a lap counter? Is there similar tech available?


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