Hello Gents!

I teach 7th grade math, and I have run this lesson before in smaller scale. We are working on Unit rate and proportional relationships. I'm looking for more resources for transmissions and gearing. Ultimately, I want my kids to be able to make gearing choices for a drag car.

Kids will be checking out my car raceprepped, and manipulating a transmission with the case off in the classroom

I need
-videos comparing final drive ratios or tire sizes at the track
-pictures of relevant gear stuff
-Real life accounts of how a gearing or tire change effected E.t. or trap speed.
-Thoughts on extensions or ways to break this stuff down
-an 'Expert' in Maryland(who could pass a background check, lol) that could donate a day to talk about gearing and racing with 13 year olds

Here's where I'm at in my thinking. This will be roughly a week of lessons.
1. Notice and wonder car
-Race wheels, no seats, idle, rev, put in gear

2. engine lesson. Gas/air/fire->Engine->clutch->trans->axles->wheels and tires

3. RPM’s
-How many times will the engine spin if it idles for 2 minutes. 800rpm
-5000(why? Dyno graph) How many times will the engine spin if I hold my revs at 5000rpm for 30sec before I launch the car?
-7200(limiter)If I was on the limiter for .5 seconds before I could shift, how many rotations would the engine do before I got to shift?

4. Tires 22x8x13
-22 is the tire diameter
Pi times D = C
How can we figure out how far the car went if the wheels rotate 40 times?
circumference of tire x rotations = Total distance

5. Transmission
-input shaft and pinion shaft
-Differential(FWD, RWD, AWD)
-Gears 1-5 and R
-Final drive/Ring and pinion

Divide teeth on one gear by teeth on the other gear to get the Constant of proportionality, or gear ratio.

What is larger?
½ or ¼? If a denominator is larger, the value is smaller. If the denominator is smaller, the value is larger.

Predict:
If we go faster in 5th gear than in 1st gear, will the constant of proportionality(gear ratio) of pinion shaft rpm to Engine rpm for 5th gear be smaller or larger than that of 1st gear?

@7200rpm in 3rd gear how fast will the car be going?
@7200rpm in 4th gear how fast will the car be going?

How can we figure out how many times the wheels rotated to go 1320 feet?
Total distance/circumference = Rotations



Any help or thoughts on how to break this stuff down would be amazing.

Thanks,
Tim

 

Not sure this will be of much use to you but I use it all the time.

http://www.zealautowerks.com/transcalc.php

 

Good thought. I've used the Mfactory one, and I'll definitely be using a gear calculator toward the end of the set of lessons. I'm hoping they'll be able to graph on their own before that.

 

This is total awesome. The MFactory one is good. How soon would you need something?

 

Message me your email I can send you my Excel gear calculator. Has a few more things than the others. I'll re-read this once I'm off of work and see what photos I may be able to provide.

As for being an "expert", I don't necessarily feel I am, but if you do this next year I would possibly be able to take a day off to help! Haha. I'm out of vacation this year due to my honeymoon, and if I am able to get another day off, it'll be to attend my wife's 2nd grade classroom.

 

Sounds great!

I am convinced this is what we need if we want to reach the next generation . . . have to get them involved as the competition for free time becomes exponentially harder the older they get.

I've got a bunch of ratios on my dragster . . . If the supercharger pulley is 33 teeth and the engine pulley is 36 teeth, how fast is the supercharger spinning at 7000 Engine RPM?

Fuel pump A is rated at flowing 6.5 gallons per minute at 4000RPM and is driven off the camshaft at 1/2 the speed of the engine. At a constant 7000 Engine RPM, what is the total flow in gallons of the fuel pump for a 7 second pass?

Or I could just let you borrow my mechanical fuel injection book!

 

That's a big pump. -1 or 700?

A P-560 nozzle flows 56.0 lb/hr at 30 psi. How much does it flow at 75 psi?

 

this sounds like a great idea! good luck!

 

Hilborn PG-150B

I've got 8 nozzles on that setup Enderle bugcatcher . . .