Originally posted by dresden_k
1.) What exactly are the numbers in a compression ratio representing? I know that lower, like around 9:1 is good for turbos, but I don't know why. Is there a difference in fuel mileage the higher one's compression ratio goes? Is it directly related to horsepower?
The ratio by which air is compressed in the engine. With a 10:1 compression ratio, your engine would compress (random, easy numbers) 10 cubic feet of air into 1 cubic foot of air.
Lower is good for turbos because you're forcing hot, precompressed (by the turbo) air into the cylinder. A low CR gives more leeway in tuning than high. You can easily crank up the boost to increase cylinder pressures. Decreasing is another matter.
Originally posted by dresden_k
2.) What is offset all about on a wheel? What do Hondas usually set their offset too and what are the effects of changing the offset with a different set of wheels?
Offset determines how far the centerline of the wheel is from back side of the hub. Stolen illustration:
The page it came from has a more thorough description as well.
http://www.tirerack.com/wheels/tech/offset.htm
Typical numbers for Hondas vary depending on wheel and tire size (smaller has more leeway). Civic platform cars are usually around +38mm to +45mm.
Originally posted by dresden_k
3.) Why are most aftermarket pistons aluminum? To reduce reciprocating mass?
I think primarily because aluminum alloys are so versatile.
Originally posted by dresden_k
4.) I know that turbos use exhaust gasses and superchargers use engine driven belts, but what are the other differences? Is it true that superchargers have a narrower operable RPM range?
This is rather hard to define simply because there are many forms of supercharger, each with its own qualities. For example, a centrifugal supercharger like Vortech's operates almost exactly the same as a turbocharger. (Except crappier)
In addition, there are so many sizes and types of turbochargers available that you can achieve almost any result with the right setup.
Originally posted by dresden_k
5.) What would be involved putting a Prelude steering rack w/ speed sensitve steering in a 4th gen Accord?
Not entirely sure, but I have a feeling it would be a huge PITA.
Originally posted by dresden_k
6.) Why do race calipers have more pistons?
Allows use of a larger pad, which distributes pressure over a larger area of rotor.
Originally posted by dresden_k
7.) If I put a stiffer rear sway bar in my car, I understand that I will reduce understeer. Am I doing this by increasing the tendancy of my car to oversteer?
Yes.
Originally posted by dresden_k
8.) Is it possible to build up a H22 to take a decent turbo and still have the engine last for 5+ years?
Easily. It just costs a bit more money. In my experience, most turbo related problems on cars which were not OEM turboed are caused because the car's owner cheaped out on fuel management and/or tuning.