Driveability Issues with Lightweight Flywheels
03-29-2011, 08:01 AM
#11
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a lighter flywheel, especially in a high-compression car like this, will greatly increase the amount of engine braking off-throttle. this is pretty cool most of the time (look no brakes!) however, this has the effect of lightening the rear end. if you are a less-experienced driver, be certain not to chop the throttle mid-turn when driving aggressively.
03-30-2011, 09:11 AM
#13
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3-4 pound is significant imo - thats like 20% lighter on a scale, and more when you look at the rotational inertia (think a 4x multiplier in weight, generally speaking). When you go to a lighter flywheel the engine is more responsive for good and bad to external inputs from the gas and transmission. You can drive a light flywheel daily no issues but you will have to adapt. With a stock flywheel you have grown accustomed to letting the rotational inertia take up some of the damping that you will now need to control via your foot. Cars typically come with heavier flywheels because they stabilize or dampen the throttle response - aka they protect the car from the driver.
Imo many people like the idea of a lighter flywheel because when they sit still and race the engine, they like how immediate the response is. Some people don't prefer that when driving as you can bog the engine or slip the clutch more easily. Its about personalizing the car to suit you - if you can drive a light flywheel car, that would be the best way to get a feel for it.
Changing the flywheel is about changing a character trait of the car when its in neutral and decelerating mainly, not its performance - acceleration is tied to how quickly the engine and gearing can move the car. I've jumped from my stock AP2 into a modified AP1 with a lightweight flywheel and I couldn't smoothly drive the thing for about an hour.
Going from a stock AP1, the difference will not be as great, but its noticeable. Some people seem to think that FWs must always be lighter, but that's not always the case. Small engines (like the S2000's) typically use heavier flywheels to support them in retaining energy, masking variability in the engine, and damping harshness, but if you can compensate in your driving and don't mind the side effects, it wouldn't be an issue. Fwiw, I plan on going to an AP1 FW from AP2 when I redo my clutch system, but thats from 22 to 14 lbs.
Imo many people like the idea of a lighter flywheel because when they sit still and race the engine, they like how immediate the response is. Some people don't prefer that when driving as you can bog the engine or slip the clutch more easily. Its about personalizing the car to suit you - if you can drive a light flywheel car, that would be the best way to get a feel for it.
Changing the flywheel is about changing a character trait of the car when its in neutral and decelerating mainly, not its performance - acceleration is tied to how quickly the engine and gearing can move the car. I've jumped from my stock AP2 into a modified AP1 with a lightweight flywheel and I couldn't smoothly drive the thing for about an hour.
Going from a stock AP1, the difference will not be as great, but its noticeable. Some people seem to think that FWs must always be lighter, but that's not always the case. Small engines (like the S2000's) typically use heavier flywheels to support them in retaining energy, masking variability in the engine, and damping harshness, but if you can compensate in your driving and don't mind the side effects, it wouldn't be an issue. Fwiw, I plan on going to an AP1 FW from AP2 when I redo my clutch system, but thats from 22 to 14 lbs.
03-30-2011, 10:17 AM
#14
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i got the ACT 9lb and ACT HDSS clutch. not much changed. i think what they mean by drivability issues is that the revs will drop down faster because theres less weight which means you have to be a little faster with the clutch or it will stall. i personally like the revs going down cause when you have rev hang it sounds like you dont know how to drive
03-30-2011, 10:28 AM
#15
I have no issues with the Centerfoce clutch and the 8.6lbs ACT flywheel.
If you're going to spend your whole life in traffic, I'd suggest a 10 lbs flywheel so you can have the best of both worlds.
If you're going to spend your whole life in traffic, I'd suggest a 10 lbs flywheel so you can have the best of both worlds.
03-30-2011, 11:37 AM
#16
A lighter FW will not cause any drivability issues with an AP1 or AP2 - the car will only benefit from it. You have to remember the PP typically weighs as much or more than the FW - and cutting 4-5 lbs will not greatly effect the total mass of the system - so as to effect the drivability of an S2000.
I currently have the Comptech FW (~9.8 lbs I believe), ACT PP and OEM disc. My previous combo was Toda FW, Mugen PP and OEM - that combo slipped, so I returned the setup and went with my current setup. If you go with the ACT PP (or any high clamping force PP) - make sure you consider using the clutch interlock bypass mod to reduce the wear on the thrust washers at start-up.
https://www.s2ki.com/s2000/topic/619...switch-bypass/
The advantage to the Comptech FW is it can be resurfaced, and starts off with a moderate drop in mass. The Toda is lighter, but is at the service limit out of the box, and subsequently cannot be resurfaced. I would NOT use any aluminum FW - this includes the Fidanza multi-piece FW (I know the contact surface is steel - that doesn't negate the issues associated with aluminum - to include warping, cracking, and corrosion issues). Chromoly is much stronger and much more rigid than anything that uses aluminum. Comptech, Toda and ACT are all chromoly steel. The only disadvantage that I can think of with regard to the Comptech FW is the starter ring gear is a separate piece (spot welded) - although I have never heard of one failing. I don't have any experience with the ACT FW - although I have not heard anything negative about it.
I currently have the Comptech FW (~9.8 lbs I believe), ACT PP and OEM disc. My previous combo was Toda FW, Mugen PP and OEM - that combo slipped, so I returned the setup and went with my current setup. If you go with the ACT PP (or any high clamping force PP) - make sure you consider using the clutch interlock bypass mod to reduce the wear on the thrust washers at start-up.
https://www.s2ki.com/s2000/topic/619...switch-bypass/
The advantage to the Comptech FW is it can be resurfaced, and starts off with a moderate drop in mass. The Toda is lighter, but is at the service limit out of the box, and subsequently cannot be resurfaced. I would NOT use any aluminum FW - this includes the Fidanza multi-piece FW (I know the contact surface is steel - that doesn't negate the issues associated with aluminum - to include warping, cracking, and corrosion issues). Chromoly is much stronger and much more rigid than anything that uses aluminum. Comptech, Toda and ACT are all chromoly steel. The only disadvantage that I can think of with regard to the Comptech FW is the starter ring gear is a separate piece (spot welded) - although I have never heard of one failing. I don't have any experience with the ACT FW - although I have not heard anything negative about it.
03-30-2011, 12:44 PM
#18
A lighter FW will not cause any drivability issues with an AP1 or AP2 - the car will only benefit from it. You have to remember the PP typically weighs as much or more than the FW - and cutting 4-5 lbs will not greatly effect the total mass of the system - so as to effect the drivability of an S2000.
I currently have the Comptech FW (~9.8 lbs I believe), ACT PP and OEM disc. My previous combo was Toda FW, Mugen PP and OEM - that combo slipped, so I returned the setup and went with my current setup. If you go with the ACT PP (or any high clamping force PP) - make sure you consider using the clutch interlock bypass mod to reduce the wear on the thrust washers at start-up.
https://www.s2ki.com/s2000/topic/619...switch-bypass/
The advantage to the Comptech FW is it can be resurfaced, and starts off with a moderate drop in mass. The Toda is lighter, but is at the service limit out of the box, and subsequently cannot be resurfaced. I would NOT use any aluminum FW - this includes the Fidanza multi-piece FW (I know the contact surface is steel - that doesn't negate the issues associated with aluminum - to include warping, cracking, and corrosion issues). Chromoly is much stronger and much more rigid than anything that uses aluminum. Comptech, Toda and ACT are all chromoly steel. The only disadvantage that I can think of with regard to the Comptech FW is the starter ring gear is a separate piece (spot welded) - although I have never heard of one failing. I don't have any experience with the ACT FW - although I have not heard anything negative about it.
I currently have the Comptech FW (~9.8 lbs I believe), ACT PP and OEM disc. My previous combo was Toda FW, Mugen PP and OEM - that combo slipped, so I returned the setup and went with my current setup. If you go with the ACT PP (or any high clamping force PP) - make sure you consider using the clutch interlock bypass mod to reduce the wear on the thrust washers at start-up.
https://www.s2ki.com/s2000/topic/619...switch-bypass/
The advantage to the Comptech FW is it can be resurfaced, and starts off with a moderate drop in mass. The Toda is lighter, but is at the service limit out of the box, and subsequently cannot be resurfaced. I would NOT use any aluminum FW - this includes the Fidanza multi-piece FW (I know the contact surface is steel - that doesn't negate the issues associated with aluminum - to include warping, cracking, and corrosion issues). Chromoly is much stronger and much more rigid than anything that uses aluminum. Comptech, Toda and ACT are all chromoly steel. The only disadvantage that I can think of with regard to the Comptech FW is the starter ring gear is a separate piece (spot welded) - although I have never heard of one failing. I don't have any experience with the ACT FW - although I have not heard anything negative about it.
03-30-2011, 02:41 PM
#19
Registered User
I second avoiding aluminum. I can only imagine the carnage when it scatters and comes screaming through the transmission tunnel into my legs. The ACT is steel and pretty light.