few stupid questions

[Stratus_Power]

i just have a few stupid questions:

1) wat are the pros and cons of 18' wheels aand smaller wheels, let say 16-17'
2) wat are the pros and cons of rotary engine as compare to normal engine
3) is 20milespergallon consider good millage?
4) how exactly does LSD work?

thanx in advance

[persid]

1. They are heavier, easier to break/crack and larger tires cost more money, especially once you get over 17". Depending on the car, they might improve the handling, but only if you go with lower profile tires. They will also most likely decrease the acceleration of the car. The main thing is to stay smart, if your car is a sports compact, there's really little point in going with 18" rims. If it's a early 80s Golf, than there's no point in going with anything over 15". If it's a Z06, than 18" wouldn't hurt If you want wheels for looks, buy whatever. If you want them for preformance, do more research on your specific car and needs.

2. Rotary engines are much smoother than piston engines, can make great power for their small weight and are compact and thus can be placed lower in the engine bay which will improve the center of gravity. The non turbocharged ones are extremely reliable up to the point where the apex seals go, then you need a rebuild. That's usually 250-300k km for FB and FC RX7s. The two largest disadvantages are that they drink a lot of fuel and that the turbocharged ones can become fairly unreliable when pushed as they cannot stand bad tuning as much as piston engines can.

3. Do you consider it good mileage? If you can afford it, it's good. If not, than 100mpg is bad

4. This site will explain it much better than I would:
http://auto.howstuffworks.com/differential.htm

[red RX-7]

yah i only get about 325km on a tank in my 86 RX-7 and it cost about $38.00 a tank for regular.

so gas is not cheap! but its fun to drive...