Average Mileage for Clutch Replacement?

Originally Posted by beingdevious

and whoever says there is loss of torque.. its all lies. yes, there is less spinning mass/momentum in the wheel.. but you still have the SAME power output of the engine. you are able to get to the higher torque producing RPMs quicker, and thus get the torque/hp quicker. its a steeper curve on the dyno chart.

dont think anyone said anything about loosing torque.

A light weight flywheel will spin up quicker and spin downer quicker upon clutch engagement. It's all to do with momentum. The light weight flywheel is only advantageous when you are constantly on the gas to compensate for loss of momentum when the load is on. Flywheel momentum is part of the torque, in addition to toque coming from the engine. I have no trouble contending light flywheels loses torque. The end product is poorer overall fuel economy compared to standard flywheel.

I've heard some people throw out numbers concerning the cost of clutch kits and/or flywheels, and have looked around some on vendor sites, but I have yet to confirm the lowest price or best place to buy from. It looks like I'll probably just be doing the Sachs OEM clutch, as the UUC option is over $1k. Where's the best place to find it? I've looked on BavAuto and AutohausAZ, for example, an am considering either. Any better options I don't know about, or cheaper LW clutch kits?

Originally Posted by GoingNuts

A light weight flywheel will spin up quicker and spin downer quicker upon clutch engagement. It's all to do with momentum. The light weight flywheel is only advantageous when you are constantly on the gas to compensate for loss of momentum when the load is on. Flywheel momentum is part of the torque, in addition to toque coming from the engine. I have no trouble contending light flywheels loses torque. The end product is poorer overall fuel economy compared to standard flywheel.

More mass = better fuel mileage? Completely ridiculous, I observed similar mileage and better acceleration. Only drawback is its easier to stall --which is rare. Maybe it depends on ones driving style?

i have noticed no difference in gas mileage. and since then ive had it, ive gone through 3 tanks of gas.

I am at 165K. Still driving like a jackass and everything holds awesome.
I am totally amazed.

Originally Posted by GoingNuts

A light weight flywheel will spin up quicker and spin downer quicker upon clutch engagement. It's all to do with momentum. The light weight flywheel is only advantageous when you are constantly on the gas to compensate for loss of momentum when the load is on. Flywheel momentum is part of the torque, in addition to toque coming from the engine. I have no trouble contending light flywheels loses torque. The end product is poorer overall fuel economy compared to standard flywheel.

wow. what a huge load of BS.

The loss of momentum is called "false torque." It seems useful during part-engagement of the clutch, such as right of the line, but once the clutch and flywheel lock together, the higher mass of a stock flywheel immediately becomes a burden. check the dyno graphs on UUC.

as for the fuel economy part, i hope you had fun making up your load of shit for the day. seriously, all you ever do is come on this site and rant bullshit. you've quickly become the laughingstock of those of us who actually knows what they're talking about on this site.

ignore list:
1) bmwbun
2) goingnuts

Originally Posted by jeffro3000

wow. what a huge load of BS.

The loss of momentum is called "false torque." It seems useful during part-engagement of the clutch, such as right of the line, but once the clutch and flywheel lock together, the higher mass of a stock flywheel immediately becomes a burden. check the dyno graphs on UUC.

as for the fuel economy part, i hope you had fun making up your load of shit for the day. seriously, all you ever do is come on this site and rant bullshit. you've quickly become the laughingstock of those of us who actually knows what they're talking about on this site.

ignore list:
1) bmwbun
2) goingnuts

Originally Posted by Sevenscars

More mass = better fuel mileage? Completely ridiculous, I observed similar mileage and better acceleration. Only drawback is its easier to stall --which is rare. Maybe it depends on ones driving style?

More mass means greater momentum. That's an undeniable fact. Guess what greater momentum means ? It means the car can maintain its speed with minimal force input. When momentum is reduced, more force is required, and this translates to greater energy input.

Now, defend your position reduced momentum does not require increased force input to retain the same speed.

Originally Posted by jeffro3000

wow. what a huge load of BS.

The loss of momentum is called "false torque." It seems useful during part-engagement of the clutch, such as right of the line, but once the clutch and flywheel lock together, the higher mass of a stock flywheel immediately becomes a burden. check the dyno graphs on UUC.

as for the fuel economy part, i hope you had fun making up your load of shit for the day. seriously, all you ever do is come on this site and rant bullshit. you've quickly become the laughingstock of those of us who actually knows what they're talking about on this site.

ignore list:
1) bmwbun
2) goingnuts

Never heard of false torque before. But as usual, you just parrot things you don't understand. I find it curious you trust what you were told/read more than your own eyes. It's no loss to me to be on you ignore list. I'd have nothing to gain discussing with you about anything when I can just talk to people who told you the stuff that you believe. Easier for me to cut out the middleman.

My clutch died around 70k. Dunno how hard the driver was before me or whether he/she just didn't know how to drive clutch properly. Also important to note my cdv was removed before I purchased the car. I hear this decreases the life of the clutch. Hopefully I can manage 100k+ off my new one. I'm at 103k now.

165k and original clutch

CDV in use will decrease the life of the clutch. its designed to be a smooth engagement. therefor...slipping...heating up.

As soon as my clutch goes out i'll likely get the same setup as beingdevious. hopefully my engine's torque output will remain at 206lb-ft

I was worried about losing the false torque and drivablilty of the heavier flywheel but jetskier, beingdevious, e46abuser, and a couple others i've heard from all seem to have nothing but good things to say about the aluminum flywheel setup.

To anyone else reading along: just ignore goingnuts. you'll have alot less ignorant posts to sort through when looking for information.

There's no such thing as false torque. People should disregard this nonsense.

i replaced my clutch at 109k a month after i got my car, it was time for a new clutch because it fell apart (the springs broke)

the engines output absolutely WILL NOT be affected by a lightweight flywheel. it is impossible. the flywheel is a transfer device from the engine to the transmission.

if you have 200ft lbs before, you will have 200ft lbs after. you will just be able to get there quicker (due to a quicker rev)
i don't see whats so complicated about this.

Originally Posted by GoingNuts

More mass means greater momentum. That's an undeniable fact. Guess what greater momentum means ? It means the car can maintain its speed with minimal force input. When momentum is reduced, more force is required, and this translates to greater energy input.

Now, defend your position reduced momentum does not require increased force input to retain the same speed.

It takes MORE energy to move an heavy object as opposed to light one. No Sh&% once in movement its gonna have more momentum -which required more energy/fuel to get moving in the first place - a point I was making.

If Im wrong ... .I will go with EXTRA heavyweight flywheel next time. Who sells those by the way?

I'm at 179K on the original clutch. It's shuddering a little, but doesn't slip.
I've heard varying opinions about whether the flywheel can be turned or must be replaced. If it's not glazed (overheated from slipping a lot) then you should be able to reuse as-is.

Originally Posted by beingdevious

the engines output absolutely WILL NOT be affected by a lightweight flywheel. it is impossible. the flywheel is a transfer device from the engine to the transmission.

if you have 200ft lbs before, you will have 200ft lbs after. you will just be able to get there quicker (due to a quicker rev)
i don't see whats so complicated about this.

exactly. From UUC:

Is there any torque loss with a lightweight flywheel?

When you install a lightweight flywheel, there is no torque loss from the engine. End of story.

A flywheel, by it's very nature, is an energy storage device. It's purpose is to either absorb excess energy from the engine, or average out the energy being put into the transmission, when an imperfect rpm vs. gear/wheelspeed clutch engagement happens.

The energy is stored in it's mass. When you rev your engine, energy is used to move that heavy flywheel... energy that is not put to the wheels. The mass of the flywheel stores that energy by it's motion.

Thus, a lighter flywheel requires less energy to be moved, allowing more of the net total force produced by the engine to go to the wheels, making the car quicker. The mathematics of this are covered on our website here:
http://www.uucmotorwerks.com/flywhe...wheel_works.htm

But the important question is then, how does this jibe with "real world" experience?

Those who say their car feels quicker with a heavy flywheel are revving the motor above the correct gear/wheelspeed amount, and "dumping" the clutch. The heavy flywheel stored energy, and then transferred it to the transmission/wheels. Technically, during this engagement, the stored energy plus the engine input energy is more than the engine makes alone. The critical thing to realize is that this only holds true during the period of clutch engagement and is a "false torque" sensation.

That "false torque" sensation tricks human perception into thinking the car has more power, when the torque measurement of such an engagement style shows that the "false torque" jump up is immediately followed by a sub-normal torque dip as the heavy flywheel requires more energy input to re-accelerate than the lightweight alternative.

An example of this is quite clear in a dyno graph. This section shows a torque curve, specifically the initial clutch engagement at 2000rpm and up to 3500rpm.