Lifting the transmission to lower the c/g?

[Jay Dub]

To be completely honest, these sort concepts are just the tip of the iceburgh when it comes to chassis dynamics. There are many good texts available that can vastly increase one's understanding of racecars, chassis dynamics, and overall design. The XXX main book is a good basic tool to start with and will provide most up and comers with a good tuning basis. I do however feel that there are certain aspects (in that book) that are inadequite or one sided, and need to be addresses or further explained in a more personal forum (like here).

I have a few basic concepts, and these will help everyone become a better tuner. I might expand on these later, but to start here are a few:

1. You learn as much from a setup change that doesn't to what you thought it would as one that does.

2. Write everything down, whether you think it means anything or not. Most of the time it will make sense later.

3. Every adjustment on your car affects every other adjustment on your car. You can never change just one thing.

4. Every adjustment on your car works on a "bell curve" of sorts. This is a very important one. It is important to realize that there is one, specific, point in any given adjustment that will provide your car with maximum/optimum (insert word here). Any deviation from this will reduce (insert word here).

5. Relating to #3. It is very important to understand what any specific change made is, and how it affects other peramiters on your car. E.G. Moving your rear hubs forward, will affect: wheelbase, ackerman, weight distribution, dynamic antisquat (driveshaft angle), camber, etc, etc, etc.

-Jeff

[THEYTOOKMYTHUMB]

Damn! Thanks for the input! I've just learned how to set up cars thru experience. Now I feel like I need to read up and find out what I've actually been doing. I mean that in a good way. I think it would be interesting to read into it. It would probably really improve even the most experienced racer's skills to have a deeper understanding of all these terms and the physics behind it all.

[Jay Dub]

Everyone can benefit from more knowledge. It can however be frustrating, because you begin to realize that there are many more options for tuning than you previosly thought possible. This makes your decisions more critical, as you need to decide which options are the best ones in a given situation. This often will lead to better observations of what a car is doing and where, and ultimately give you enough information to make a more educated tuning change.

For example, You may here someone say " My car is pushing". This is an exapmle of an uneducated observation. "My car pushes in the begining 1/3 of the corner, over rotates @ the apex, then pushes coming out under throttle. It also is a little twitchy off center" This is an observation you can work with.
In the first observation, "pushing" can be anything, not enough tire, weight bias front to rear, camber locations, spring, shock angle, and so on. Where as in the second observation, I would recognize that usually with the car being twitch "off center", I would stiffen the front oil slightly to calm it down. Then I would address the "pushing". From experience, I have found that too long a spring rate (in the front) can cause a situation where the car oversteers (over rotates) in the middle of the corner but not entering or exiting. So, I would change to a shorter spring to keep the weight transfer more predictable. Then (after running the car to see how it works), I would more than likely go down a spring rate to take away any residual push. If you dont have a shorter spring, you can always lay the front shocks down in the front to help with this. The problem with this option is that you are also affecting the damping as well (remember rule #3). So, you can see that good observations, will lead to more educated tuning. There are allot of other tunig options to try, but these would be the first to try.

This is of course providing you have the proper (read competative) tire combo on your car, or have no other option but to run a given tire. Which brings up a fun exersize BTW. Try going to the track, and only run one set of UN- competative tires, and see if you can tune the car to see how fast you can go. YOU will learn allot. -Jeff

[Mr. ED]

I admit; I only read the title, but the answer seems kind of obvious to me.
When you put anything higher up in your car , the total weight stays the same and ride hight stays the same (unless it was the shocktower you moved up ). Going on from that point, I'd say you'll raise the C/G by raising the transmission, not lower it.

[shane]

I noticed that my RC10 TrackMaster and JCAR trannies have the outdrives a bit higher than the stock tranny. But when the car is drastically lowered, the universals/dogbones are almost parallel. It's just a guess, but I bet there was some reasoning behind the design.

I just figured it was for gear/chassis clearance. My $.02

[Charlie don't surf]

It is for clearance, the DD type diff gear used has to have it- you should see the older CW DD cars-

[THEYTOOKMYTHUMB]

Well, I don't necessarily understand all of this, but I am going to raise my truck again to level the axles. On my track and in my particular situation having the axles pointing slightly north makes the truck spin out every once in a while for no obvious reason. There seemed to be little advantage in this instance. I'm sure with more technical set ups the outcome could be very different. Any suggestions to improve steering would be greatly appreciated though(I'm always looking for any secret advantage over the comp ). Yes, it's spec class Slash oval which I would have laughed at myself if I didn't race it every week. Fun, fast, competitive and best of all we consistently have an E Main and sometimes an F or G. They had 92 entries in the indoor off road CORR truck trophy race last weekend + 12 entries in the 4 hour endurance race(4 man teams). Lots of fun and abuse.

[JK Racing]

Thumbs, I'm jealous...I really miss dirt oval, nearest one to me is almost a 3 hour drive. But I have tons of offroad tracks all less than an hour away...