lighter pulleys
06-10-2014, 11:08 AM
#2
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https://www.rx8club.com/rx-8-discuss...rx-8-a-233937/
Don't bother with pulleys unless you like flushing money. They have the same 'benefit' of rotational weight reduction of a lightweight flywheel, but you are saving ounces, not pounds, and you are saving it near the center of mass, where it doesn't have as much effect.
Additionally, you do NOT want to underdrive your water pump, since it exposes you to easier overheating. And underdriving your alternator is effectively pointless. The power draw of the alternator is a fixed number, controlled by the ECU. If you spin it slower, the ECU will just increase the load on it to achieve the same voltage. If you were to manage to make it actually produce lower voltage, then you will have all sorts of other electronics problems, and if you were to produce higher, you would start frying expensive equipment. You can underdrive your AC pulley, reducing it's effectiveness, but if you don't want the AC, just remove it entirely for an even better improvement and significant weight reduction as well.
Lightweight flywheels are common, though opinions vary considerably. I prefer them, others don't. It's a matter of preference. There is undeniable performance gains, however there are also drawbacks that many don't want to live with. You will have to make up your own mind there.
Don't bother with pulleys unless you like flushing money. They have the same 'benefit' of rotational weight reduction of a lightweight flywheel, but you are saving ounces, not pounds, and you are saving it near the center of mass, where it doesn't have as much effect.
Additionally, you do NOT want to underdrive your water pump, since it exposes you to easier overheating. And underdriving your alternator is effectively pointless. The power draw of the alternator is a fixed number, controlled by the ECU. If you spin it slower, the ECU will just increase the load on it to achieve the same voltage. If you were to manage to make it actually produce lower voltage, then you will have all sorts of other electronics problems, and if you were to produce higher, you would start frying expensive equipment. You can underdrive your AC pulley, reducing it's effectiveness, but if you don't want the AC, just remove it entirely for an even better improvement and significant weight reduction as well.
Lightweight flywheels are common, though opinions vary considerably. I prefer them, others don't. It's a matter of preference. There is undeniable performance gains, however there are also drawbacks that many don't want to live with. You will have to make up your own mind there.
06-10-2014, 02:07 PM
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The "Benefit" and the "drawback" of the lightweight flywheel is all really the same thing: Less mass.
Less mass means that it can change it's speed much quicker because there is less mass that has to be accelerated, or decelerated, and since it is attached directly to the e-shaft, the engine's ability to change speed is affected too.
So the engine increases, and decreases, in rev speed much more easily. This is a benefit for neutral reving (like heel-toe shifting), vehicle acceleration, etc... But, like your example, being easier to slow the engine down is a detriment when starting from stopped, even more so for a rotary that already can be troublesome. Any other point that you can think of in which you want the engine to maintain it's speed despite something else trying to decrease it (friction, gravity, air resistance, etc..., a lightweight flywheel will make it harder to maintain that speed.
I don't know that i would have liked a lightweight flywheel on the 8, and I never installed one as a result. OThers love it.
Less mass means that it can change it's speed much quicker because there is less mass that has to be accelerated, or decelerated, and since it is attached directly to the e-shaft, the engine's ability to change speed is affected too.
So the engine increases, and decreases, in rev speed much more easily. This is a benefit for neutral reving (like heel-toe shifting), vehicle acceleration, etc... But, like your example, being easier to slow the engine down is a detriment when starting from stopped, even more so for a rotary that already can be troublesome. Any other point that you can think of in which you want the engine to maintain it's speed despite something else trying to decrease it (friction, gravity, air resistance, etc..., a lightweight flywheel will make it harder to maintain that speed.
I don't know that i would have liked a lightweight flywheel on the 8, and I never installed one as a result. OThers love it.
06-10-2014, 04:55 PM
#5
My flywheel is the best performance mod I have made. On track, car feels several hundred pounds lighter. If you look at factory wheel, you can see the difference. Factory has a huge band around the outside. Most mass is at rim.
A little bit of noise occasionally, but only with radio off. Took a day to get used to it.
What they said about pullys. Not enough mass overall. Light flywheel pulls a good 10 pounds out, and all of it at the outer edge.
A little bit of noise occasionally, but only with radio off. Took a day to get used to it.
What they said about pullys. Not enough mass overall. Light flywheel pulls a good 10 pounds out, and all of it at the outer edge.
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