Tuesday, April 19, 2011

Drivetrain, transmission, differential information

Before i say anything, i must apologize for it being well over a week since the last post...i have been taking note of your questions and comments, but i just havent had more then an hour to make a nice post, and even injured myself a little between all of it.
i havent left, be assured.

Some questions, answered:

How does a differential play in all of this?
i plan on answering that with this post, drivetrain got alot of votes, and a differential is part of it, so i should explain.

Alot of people had a comment, or knew about the video i showed in the last post. As a racer in that game, and that being where i gather a fair amount of knowledge, i feel like i owe a little promoting to it.
The game is called Live for Speed, and it is created by three people. Scawen, the main programmer, Eric, the person in charge of the graphics ect, and Victor, the one in charge of everything online.
The goal of it is to be the most realistic racing simulator, and for it to be online based. In my eyes it is the most realistic, leaping far over gran turismo, or forza.
you can customize every adjustment of a vehicle i mention, and experiment with the game's amazing physics.
The game is still in alpha stage, so there is still stuff being added, and updates to come. To top it all off, it es even very cheap compared to most other games.
Please check it out, you dont need a wheel, or a powerful computer: LFS.net

Drag bikes?
bikes with gearing set to top out just as you reach the end of the quarter mile, to optimize acceleration, and with a long wheel base so the front doesnt pull up on you. some things are also done to the body and chassis to lighten up, and provide good aerodynamics. a wheelie bar is often added.

used car recomendations?
honestly, id say go to your local used car dealership. the salesmen are there for a reason, and if you are actually looking for a car, they can be very helpful. Be assertive with them, and you wont be pressured into anything.
Still think im a better choice? tell me what you are looking for, and a price range, and id be more then happy to help!

civic going through tires fast cause camber.
If your suspension is soft, and you have negative camber, as the suspension compresses, it will just add more negative camber, to the already negative camber. (that makes sense, right?)
so stiffer coil-overs will both provide a more stable ride, possibly help with camber, and could help it corner better.
other then that, rotate tires frequently, to opposite ends of the car (left front to right rear, right rear to left rear, left rear to right front, right front to left front). this will keep the tires wearing a little more evenly.

use your blog in my own blog?
absolutely, i just ask for a link to my blog in the end, or something of equal value.

"one thing i dont understand: why do your tires have to be hard on snow? softer tires = more grip?"

under conditions where you have a hard, predictable surface you are 100% correct. (well 90%, too little pressure can just do harm)
think of it like this, in the snow, in order for you to go anywhere, you first have to compact the snow in front of the tire, or else you will spin against the wall of snow. if your tire is inflated more, it is slightly less wide, and has more pressure coming from each part of the wheel (weight is less spread out). so being less wide, you have to compact less snow in front of the tire before you can move forward.
this isnt the most important thing in snow driving, just helps. you should have a very light foot, and a knowledge of traction control, and differentials to be set (tires can help)

setups for a 1998 spec miata?
let me start by saying, the miata is known (as a hairdresser's car) for being very lightweight, and very nimble, and well balanced. It is said, that it is very hard to improve this car other then with more horsepower, or a complete overhaul.
That being said, i would focus on a few cheap engine modifications, remember stick to more air, cleaner air, colder air, more fuel, or a new ecu. (stuff like that)
other then engine stuff, i would try to decrease weight, experiment with wider tires, MAYBE try to lower it a little bit.
try this for size. go for a little thrashing in your miata, go crazy, do some tire-spinning, take corners hard, brake hard, and just get your tires hot. feel your tires all around, if they feel colder on the inner part, then the outer part, consider more negative camber, if they feel about the same all the way around you cant do much.

thats ALOT of question answering...
*copies what he has so far incase something happens*

What did i plan on doing again? OH YEAH! drivetrains...

SOOOOO....as the pistons rotate the (forgets what its called) [might be crankshaft?], it spins until the ends of the engine block. at the end closer to the front of the vehicle, there is an alternator, where the engine spins it and recharges the battery with it. At the end facing the back of the car, you spin the flywheel. What this is, is a little disk that when pressed against the clutch, will spin the transmission, and in turn the driveshaft(s), and in turn the differential, and in turn the wheels.
Whoa, hold on! i thought the clutch is released half of the time? It is. If the engine was constantly connected to all of this, then whenever you stop, your engine does too.

So when you have the clutch completely pressed against the flywheel, that spins the transmission (transmissions are like mazes...all you need to know is there are different size gears that control the resistance on the engine)
After the transmission is all done with what it needs to do, it passes the power onto the driveshaft, this just carries the torque to where it needs to go. The differential.

One might think that both wheels spin at the same speed no matter what, right? couldnt be more wrong. as you take a corner, the inside wheel takes a shorter distance, thus needing to spin less. to compensate, you need a differential.
this video is by FAR the easiest way to explain, so please just watch.

if you diddnt view that, dont bother reading on, not gonna lie..

so with that, if one wheel can spin easier then the other, it will get all of the power, often resulting in one wheel spinning, and the other stopped. (this will often mean you are stuck)

To solve this, one might get a locked differential. this is having both wheels spin at the same speed no matter what. this gets all the power to the ground, and wears tires fast. often used for drifting and drag racing, or just very high speed races where a little bit of slip wont matter too much.

If you are looking for something more practical, you might want resistance between the two so if one spins freely, it drags the other to spin also.

there are different methods of positive traction differentials (possi's), but before this becomes way too long to read, i will end it. next post will continue on the types of differential's.

Please ask questions, thats what keeps me motivated, because thats how i know people actually pay attention.