Standing Start
- Thread starter bman
- Start date
Judesdad17
Member
May Sound crazy but most karters I have seen starting from a standing start also bounce up and down from the seat rapidly until up to some speed to take weight off the kart and allow it to accelerate better. Also if you are road racing or oval track racing will depend on which for a set up that works better. Like Family man said a higher stall clutch but if road racing you don't want too high of a stall. What ever clutch type you are running it would be best to call that company and explain to their tech person what you are doing. You will need to know peak engine torque RPM .
I am oval dirt racing on a 1/10th mile track. I am currently using a stinger shoe clutch and I am running a size 11 driver which is the smallest driver I could find for it. The peak rpm of the motor is just over 5k but the power band is around 4800. The clutch company is telling me to drop to the weakest spring and set the idle about 300 rpm below the engagement point. Any ideas are greatly appreciated.
Thanks
Thanks
alvin l nunley
Site Supporter
If the clutch is holding the engine at peak torque, that torque is transferred to the rear axle through the chain. Horsepower equals; torque x rpm/5252.1 so you can see that the more torque at the axle, the more horsepower at the axle. Understand that horsepower is a calculation,
Put a bathroom scale between the front of your kart and a strong wall. Warm the engine up and floor it. The clutch setting with the highest reading on the scale will be the one you want to race with. I'm sure you understand that the clutch setting with the highest Reading will be the clutch setting that gives you the fastest dead stop start.
From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory. (Al Nunley)
Put a bathroom scale between the front of your kart and a strong wall. Warm the engine up and floor it. The clutch setting with the highest reading on the scale will be the one you want to race with. I'm sure you understand that the clutch setting with the highest Reading will be the clutch setting that gives you the fastest dead stop start.
From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory. (Al Nunley)
alvin l nunley
Site Supporter
driver in the car. You shouldn't have any wheel spin, but if you do, you can go to bigger driver on the engine. The number of teeth on the clutch doesn't matter. As long as the clutch is slipping it peak torque, the gearing doesn't matter.
From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory. (Al Nunley)
I have access to a dyno also. Should this tell me the same thing as the scale?
alvin l nunley
Site Supporter
a dyno is good, if you have a good operator and good data acquisition. Do the dyno test and the scale test and see if they agree.
From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory. (Al Nunley)
Circa 4000 RPM is what I recall being the sweet spot for an LO206 senior package. If you can get it on a dyno that could give you some clues. Many will say engage at peak torque, I say engage at peak HP. With the dyno curve on hand you can try both.
With kart tires it can be hard to break traction off the line with 50HP, you'll be OK with the 206
With kart tires it can be hard to break traction off the line with 50HP, you'll be OK with the 206
alvin l nunley
Site Supporter
what most don't understand is horsepower is a calculation. It's torque times rpm divided by 5252.1. What is going to give you maximum acceleration is horsepower at the axle. Maximum torque at the axle gives you maximum horsepower at the axle.
From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory. (Al Nunley)
alvin l nunley
Site Supporter
to the contrary, torque is measured. I don't know where you get the idea that it is calculated.
And you're right about the standing start, until the axle moves, you cannot calculate the horsepower. The moment it does move, no matter how much or how little, you can then do the calculation.
I know you're just trying to make fun of me, but I'm afraid you've accomplished just the opposite.
From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory. (Al Nunley)
Jamie Webb
New member
This advice from your clutch company is sound advice. From what I've seen, the 206 likes a low engagement point, especially in standing starts.
alvin l nunley
Site Supporter
the inventiveness of that proposal shows how creative Karter's are. I have no doubt that if it works, they'll make a rule against it.
From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory. (Al Nunley)
Freezeman
Site Supporter
Alvin, If it works? Get out the bathroom scale and measure your arm strength, most people have some. I tested that inventiveness years ago in many Grind prix starts that where used in street races. It should be ruled against especially when in most cases now a days the standing start is mainly used in young beginner classes so they learn some about racing with out the dangers that are present from learning how to do rolling starts. Heck around here you can be black flagged for bouncing in your kart.
Thought you knew me better than that Al. In my view, whether you are using inertia, or hydraulics on a dyno, you are calculating the torque value by way of pressure (which you are in fact measuring), or calculating it based on acceleration of a fixed mass. That's about as far down the rabbit hole as I'm willing to go