Solid Motor Mounts or Poly
08-15-2010, 01:43 PM
#44
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I agree that they would have to be designed differently to raise the motor, which is what I proport they do.
I replaced a set of solids with a BRAND NEW set of poly mounts (which would sag much than stock mounts even when new) and the motor set SIGNIFICANTLY lower.
I'm not trying to bash, just trying to save someone trouble.
I replaced a set of solids with a BRAND NEW set of poly mounts (which would sag much than stock mounts even when new) and the motor set SIGNIFICANTLY lower.
I'm not trying to bash, just trying to save someone trouble.
08-15-2010, 11:24 PM
#47
Lightweight flywheels combined with a grabby clutch are a beyotch on the street too...
08-17-2010, 08:25 AM
#48
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It basically just doesn't develop enough momentum when it's spinning and it will bog easier when you launch. A heavier flywheel has more mass and therefore more momentum, so when you dump the clutch, the flywheel won't be stopped as quickly, essentially slipping the clutch in just a litte, resulting in less bogging.
Lightweight flywheels combined with a grabby clutch are a beyotch on the street too...
Lightweight flywheels combined with a grabby clutch are a beyotch on the street too...
08-17-2010, 04:05 PM
#49
It basically just doesn't develop enough momentum when it's spinning and it will bog easier when you launch. A heavier flywheel has more mass and therefore more momentum, so when you dump the clutch, the flywheel won't be stopped as quickly, essentially slipping the clutch in just a litte, resulting in less bogging.
Lightweight flywheels combined with a grabby clutch are a beyotch on the street too...
Lightweight flywheels combined with a grabby clutch are a beyotch on the street too...
So pretty much, the increased mass (and thus higher resistance to initial spin-up) causes a slower overall clutch/flywheel engagement.
08-18-2010, 01:36 AM
#50
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Lighter flywheels are ALWAYS BETTER for acceleration of any kind. If you think you need a heavier flywheel to launch harder increase revs... That mass is being rotated TWICE once to spin it and another time to move it forward with the vehicle. A heavier flywhell/clutch assumbly is easier to drive in stop and go traffic. You can learn to drive around the on/off nature of the lightweight assembly if you want the benefits.
08-18-2010, 01:39 AM
#51
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A heavy flywheel will also help "carry" the crank from one firing impulse to the next, smoothing idle and low speed operation. This is why BMW uses Dual Mass Flywheels/Flexplates. There are sliding weights that are near the edge of the flywheel at low speeds that move inward as revs increase. This decreases the effect the additional weight has on overall the rotating mass. In a vehicle that is more race oriented completely eliminating the weight is the best option.
All things being equal and optimized (i.e same parts/ideal launch RPM) the vehicle with the lighter flywheel/clutch assembly will result in quicker acceleration EVERYTIME.
08-18-2010, 09:12 AM
#53
I've always followed lighter mass = easier to spin up, ergo, less energy required to spin it up, ergo, more direct power transfer/less parasitic loss to the drive wheels. Same concept as a lightweight crank pulley, I guess; less to spin, more power to go to the wheels.
I can understand the engine bog argument, since the heavier flywheel has more rotating momentum once it's up to speed than a lighter flywheel (is that the energy transfer you're talking about, since I guess the heavier flywheel has more potential energy via spinning weight inertia than the lighter flywheel?), but as soon as you get past the initial power transfer, you're still using more engine power to keep the heavier flywheel accelerating, which seems to bias everything but initial launch towards the lighter flywheel (even more so if you figure in easier rev-match downshifts during auto-cross and road racing.)
Just pondering, so if I'm way off, smack me.
08-28-2010, 09:42 AM
#54
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More energy transferred to spin the flywheel, or more energy overall? I'm confused on that part.
I've always followed lighter mass = easier to spin up, ergo, less energy required to spin it up, ergo, more direct power transfer/less parasitic loss to the drive wheels. Same concept as a lightweight crank pulley, I guess; less to spin, more power to go to the wheels.
I can understand the engine bog argument, since the heavier flywheel has more rotating momentum once it's up to speed than a lighter flywheel (is that the energy transfer you're talking about, since I guess the heavier flywheel has more potential energy via spinning weight inertia than the lighter flywheel?), but as soon as you get past the initial power transfer, you're still using more engine power to keep the heavier flywheel accelerating, which seems to bias everything but initial launch towards the lighter flywheel (even more so if you figure in easier rev-match downshifts during auto-cross and road racing.)
Just pondering, so if I'm way off, smack me.
I've always followed lighter mass = easier to spin up, ergo, less energy required to spin it up, ergo, more direct power transfer/less parasitic loss to the drive wheels. Same concept as a lightweight crank pulley, I guess; less to spin, more power to go to the wheels.
I can understand the engine bog argument, since the heavier flywheel has more rotating momentum once it's up to speed than a lighter flywheel (is that the energy transfer you're talking about, since I guess the heavier flywheel has more potential energy via spinning weight inertia than the lighter flywheel?), but as soon as you get past the initial power transfer, you're still using more engine power to keep the heavier flywheel accelerating, which seems to bias everything but initial launch towards the lighter flywheel (even more so if you figure in easier rev-match downshifts during auto-cross and road racing.)
Just pondering, so if I'm way off, smack me.
Lol, no smacking required you are correct. I marked a section of you're quote in BOLD so that others looking at this thread pay attention.
A heavier rotating assembly can only benefit you at launch in a drag race application. After that it's dead weight and detrimental to acceleration.
IF you need to hit your tires harder don't get a heavier flywheel! Rev higher,get deeper gears,or make more torque. You can ,and probably should, do a combination of the above.
Also: lighter/smaller diameter crankshafts,smaller diameter/lighter driveshafts,smaller diameter clutch assemblies etc. help as well.
Example: A smaller diameter "heavier" steel shaft could accelerate/decelerate as well as or better than a larger diameter lighter weight AL shaft.
Ideal solution for this would be a Carbon shaft with a small diameter.
You want LOW weight and you want it near the center of the axis.
