Originally posted by deane
1. Can i run the car w/o an exaust?
or at least with one that i have made myself?
YES you can run without exhaust.
But you & your family & your neighbours will hate you for it, it'll be very loud. Expect the cops to be called.
Loss of back pressure will not stop your engine. A good engine with good compression will create enough vacumm in its crankcase+carb to draw enough fuel in to keep running. But because now the fuel is less, it'll run very LEAN... = HOTTER. This lean running will overheat & kill your engine.
However also the "exhaust" in a 2-stroke engine is part of a "Tuned Pipe System", which is designed to increase the power of the engine by making through-breathing more efficient. Remove it and if the system was any good, there'll be huge loss of power.
2-strokes respond to Tuned Pipes much better than 4-stroke engines. That's why 1:1 cars don't bother with it (don't fool yourselves, riceboys!).
Nothing against designing your own Tuned Pipe, many ppl do. If you want to its best to talk to some of the offroad 1:1 bikies who race 2-strokes, they'll know everything about Tuned Pipes.
2. Use any other sort of motor in the car? ie airplane engine? I ask this because the aircraft engines seem to be HEAPS cheaper. making a mount might be tricky.
Again, nothing stopping you. Your car, your money.
Unless you're racing, then there'll be
rules as to what max size engine you can run, in which class.
In both cars and planes, there are cheap and there are expensive engines. The big-name-brands usually aren't cheap.
Don't forget though:-
1) aircraft engines are designed to run consistantly & steadily at every possible posible throttle opening, not just idle/max like a car engine...
2) think big propellor pulling air, flying fast thru the air... then think about the
cooling requirements when you stick the same engine under a plastic shell doing a quarter of the speed.
Remember too that expensive RC car race engines are optimised for their specific usage. A plane engine say "60" with twice the capacity isn't likely to give even the same power as a top 3.5cc "21" engine.
Bigger plane engines also have thicker crankshafts, so you'll have to engineer your own fixtures and clutch etc etc.
That said... if you're not into racing, do have a look at airplane
FOUR-stroke engines. I think they're real cool, they run at a lower pitch than 2-stroke screamers and they give out lots of torque. And you don't even need a fancy exhaust system to optimise their output (see above!), just any old metal tubing will do.
So far I think only Kyosho has a 4-stroke SuperTen car, using a OS 46 engine.