Make it faster

[Zippity]

Dumb question time.

I am in the process of rebuilding a Flexi chassis.

If it is currently geared at 9:39, how do I gear it to go faster (i.e., to have more speed on the straights)?

Do I increse the spur gear by one tooth increments or reduce the pinion? - What are the trade-offs?

I know it sounds dumb, but I can/have never been able to figure it out :(



Ron

[GaryH]

Originally posted by Zippity
Dumb question time.

I am in the process of rebuilding a Flexi chassis.

If it is currently geared at 9:39, how do I gear it to go faster (i.e., to have more speed on the straights)?

Do I increse the spur gear by one tooth increments or reduce the pinion? - What are the trade-offs?

I know it sounds dumb, but I can/have never been able to figure it out :(



Ron

To increase straight line speed one ususally decreases the tooth count of the spur gear and/or increases the tooth count of the pinion gear. If you are trying to decrease your lap times on a road course increasing straightaway speed could help, but if the new gearing slows you down in the curves you may not improve your lap times. I'd suggest dropping the spur gear by one or two teeth and seeing what happens. That is a change from a 4.33 gear ration to a 4.11. A change to a 10 tooth pinion, with a 39 tooth spur, would give you a 3.9 gear ratio.



Ok Geezer, it's time for your smart-a**ed remark. You never pass up the opportunity to make a fool of yourself.

GaryH

[pkripper]

well if u want more top end speed u can drop the spur gear or u could also raise the pinon but i would drop the spur to a 37 the smaller the spur the faster the bigger the pinon the fast ,and go to probobly a 10 it all depends on what track u r running on give more info on that and i will be able to help u a little more but i would just try what i told u

[GearBear]

Zip,

As GaryH stated you could either go to a smaller spur or larger pinion. I think I would start by going to a 9/37. Reason being is that if the gearing works out correctly you can then go to smaller tires by re-jigging your axle to the 37 tooth spur height. Thus lowering your overall CG.

[Zippity]

Actually, I am using an 11 tooth pinion and a 39 tooth spur gear.

I removed the S16D motor from my Champion Turbo chassis and placed it, along with the rear axle and gear onto a Parma Flexi 2 chassis.

Why did I do this?

Here is a photo of our track - completely flat with some tight 'esses'. I want a car that will handle :)

http://www.zippitynz.com/_images/Slot_Cars/kiwiblue2.jpg

[GearBear]

Zip,

I have had better luck getting the Champion Turbo to handle well than the Parma Flexi2. The most important thing to do is get the nose of the chassis down on the track. With the body off you should be able to press down on the "wings" and have almost no movement. I actually add some 10 thou bulletproofing to the end of the wings to make sure of this. If your car is too tight you might want to add some tape from the wings back to the pans.

Look at Alicia Gilbert's car below
http://www.oldweirdherald.com/pnwimca/pnwimca03-02/Mvc-048f.jpg

I also put a piece of strapping tape under the pan behind the cotter pin and at the front. If you do that with your car you will be set up the way I have mine set up for the Canadian White :)

BTW: Are your sweepers able to be done full tilt? It looks like they might be!

[Kiwi Racer]

OHHHHHHHHHHHHHHHHHHHHH
now i understand why your meeting never went ahead zip!!! none of you guys know how to gear your cars:D

[Zippity]

No one races a PF2 here in Wellington :)

I want to give one a try as it is heavier than the CTF and therefore should have a better/lower CoG and hopefully, it will handle better.

Just bring it on Kiddo :D:D

The 'Real Men' in the Capital have better things to do with their time in the summer. :):D:):D

[Kiwi Racer]

So are you so called adults gonna try and organize a meeting at a later date? i dont wanna see my hot 1/24 cars go to waste!
Get back to me about the F2?

[Mike Wyatt]

You can judge this several ways:

1. The car should peak out about 2/3 of the way down the longest straight.

2. After about a minute's running, it should run warm- but not so hot that you can't keep your finger (the one with the nerve endings still intact- not the one you hold lead wires with while soldering) on the can without screaming in pain.

If the car peaks too late, or runs hot, it's carrying too much gear (too low a drive ratio). Drive ratio (vs. gear ratio) is the effective ratio including the tire size.

Divide spur by pinion, then the result by the tire size in thousandths.

That track sure looks to me like a higher drive ratio setup would pay off. The higher ratio will let you maintain some power through the tight turns, and the car will be less "jumpy".

Try (first) dropping one tooth on the pinion, then a couple on the spur.

Example:

Now: 11:39, w/ .760 tires = 4.67
Try: 10:39, w/ .760 = 5.13
Or: 10: 37, w/ .760 = 4.86

Let us know how it works!!! I have a chart that does all this, if you want one- e-mail wyatt@apk.net


You may find that 4.86 is just right.

[circuitguy70]

2. After about a minute's running, it should run warm- but not so hot that you can't keep your finger (the one with the nerve endings still intact- not the one you hold lead wires with while soldering) on the can without screaming in pain.


ROFLOL :p :p

Good one

[brianl]

After about a minute's running, it should run warm- but not so hot that you can't keep your finger (the one with the nerve endings still intact- not the one you hold lead wires with while soldering) on the can without screaming in pain.

And here the other night I was asking everyone how I messed up the gearing on my car because it was NOT that hot.... Like I could even tough it and without first spraying it with compressor cooler.....