Track Tac

Cheating up the tach

After looking at my race studio2 its got more options then I can understand or use .
its entirely possible it could be manipulated.
 
Post #8 semi explained why I read their tach unless they don't have one then I use mine.
At the two tracks I tech on Friday and Saturday, none of the winning engines are above 5050 on engines that have a governor rule of 5500.
The range of rpm on winning engines at both tracks is 4850 to 5050.
One track is long sweeping oval and the other is two tight turns. Both rpm ranges have been seen at both tracks.
Why am I looking at their tachs and not putting them on a stand and only being concerned with 5500 you ask. Because of the above winning rpm range. If that 5050 begins growing I need to be aware of it because there would be three reasons I can think of. The first would be the possibility of a rough track causing the kart to launch this increasing rpm. The second would be a love tap at top end from the kart behind. I am aware of those two possibilities because I watch the event. The third reason is obvious. Things are happening that probably shouldn't be.
With the above rpm knowledge I am able to stay on top of any engine that is constantly winning with rpm above the norm. Without checking their rpm and just putting them on the stand for the 5500 check opens the door for them to play because, " tech only looks at Max rpm with his tach".
A good tech knows how the game is played.
For those of you who don't really follow the predator situation, the above info should give you an understanding of why it is necessary to pay attention to both check points.
 
In the interest of giving an opposing point of view, I'll play the devil's advocate.

As a recall tach seems to not be required in this class, any info taken from those with tachs is strictly voluntary.
To see the entire picture, you would need to view a replay of the entire race, from startup to shutdown at tech area, and be able to absolutely ascertain that the race you are viewing is, in fact, the race just run.
As not everyone is required to provide this info, the tech man should use known info for any tech decisions. That means (to me) info collected with the same instrument on all engines being teched.

Just my view, the governor has to be shutting the throttle blades before the engine reaches the target rpm. I would say that the 4850-5100 rpm range would fall into that zone. If you are only going to read my tach for that info, it opens it up for me to be above the max rpm on the stand.

I guess, any info volunteered can be for education purposes only. not dq/ no dq purposes. In my opinion.
 
I see using different gauges (tachs) similarly to using different no go gauges or different (pick a tool - scales, fuel tester, dial caliper, depth mic, mic, dial indicator, etc.) for different competitors.
That opens a lot of doors for variables -- of which a competitor (or tech man) shouldn't be very tolerant of.

But hey, if all the racers are cool with the way that you are doing it now, then move on. Nothing to see here.
 
DynoDon, I don't understand why someone would give up 450 RPM (5050 - 5500)? I don't understand why a rough track would have anything to do with peak RPM? I thought these engines were limited to 5500, on the track or on the stand? What does the power curve look like, is it falling off real fast at 5000 RPM? Don't be mad, I'm just trying to learn some stuff.
 
The engines can't turn 5500 and win a race because they fall off drastically after 5000. A rough track will cause the kart to bounce thus allowing the engine to increase a few rpm.
 
DynoDon said:
The engines can't turn 5500 and win a race because they fall off drastically after 5000. A rough track will cause the kart to bounce thus allowing the engine to increase a few rpm.
Click to expand...
It just seems to me that the governor would prevent the engine from going over 5500? I know what you said about your observations with RPM checking after the race, and I don't want you to think I'm doubting what you said, I'm just trying to figure out a reason for it.
I sure would like to see a dyno curve, with numbers, to see how steep that falloff is. I know what you said that
I'm wondering; why would it be of any concern if the engine did, because of a brief lack of contact with the track, go over 5500 RPM during a race?
I'm going to have to go back and look at Amazons listings and see if they sell some kind of a handheld MPH sensor.
 
alvin l nunley said:
It just seems to me that the governor would prevent the engine from going over 5500? I know what you said about your observations with RPM checking after the race, and I don't want you to think I'm doubting what you said, I'm just trying to figure out a reason for it.
I sure would like to see a dyno curve, with numbers, to see how steep that falloff is. I know what you said that
I'm wondering; why would it be of any concern if the engine did, because of a brief lack of contact with the track, go over 5500 RPM during a race?
I'm going to have to go back and look at Amazons listings and see if they sell some kind of a handheld MPH sensor.
Click to expand...
It's not a concern for a legal stock motor, the rule proves if someone can win turning more it's been tampered with.
 
This is what Amazon has, about $100. Just stand at the end of the straightaway, point it, write down the karts number and speed, get an average amongst all the karts, you need an average because people run different gear ratios, and anybody above the average needs some looking at. The importance of obeying the rule goes a long way in justifying the costs, and the work it will take. If you're going to have a re-stricter class, you need to manage, and enforce, the restriction rules and regulations.
MPH hand held.jpg
 
Good idea : it seems redundant though check the speed too decide if you need to check the rpm rule.
Simplify things and check just the rpm .
 
I already have that gun. Bought it years ago for my driver ed classes. No good for karting other than to give you a speed.
 
Predator classes are a little different . Then restrictor plate classes .
The object is go as fast as possible within the 5500 rpm max rule .
The rule is 5500 rpm not speed related at all .
Parity is a goal ( i think : im no restrictor or predator/ out of the box racer ) .
Problem is racers can not leave anything along . They also have a misconception of the rules IE : that dosent apply too me 😁. Or the rules did not say I couldn't .
 
alvin l nunley said:
It just seems to me that the governor would prevent the engine from going over 5500? I know what you said about your observations with RPM checking after the race, and I don't want you to think I'm doubting what you said, I'm just trying to figure out a reason for it.
I sure would like to see a dyno curve, with numbers, to see how steep that falloff is. I know what you said that
I'm wondering; why would it be of any concern if the engine did, because of a brief lack of contact with the track, go over 5500 RPM during a race?
I'm going to have to go back and look at Amazons listings and see if they sell some kind of a handheld MPH sensor.
Click to expand...
Understanding the rpm limit requires an understanding of the limiting device.

https://www.comsol.com/blogs/simulating-engine-governor-spring-loaded-centrifugal-governor/
Manipulating the weights and spring pressure changes the governor curve.

While I applaud DynoDon's efforts to control this class, the trail to a very bad place gets an overlay in this fashion.
 
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What's up with people? Do you want to win a race that bad. I have have heard of people changing the number on a sprocket. Lord help.
 
What Al said. The track has their own hand held tach and that's what you go by. Have the track check you rpm's before the race and adjust accordingly. Just like weighing your kart
I always weighed mine before the race to make sure I was good.
 
Rigging the tach can easily be done. At Providence Raceway we use our "House" tach to check the RPM. That way it takes this element out of the equation.
 
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