How Light is Your Flywheel+Clutch? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

MWS · 08-12-2018, 02:53 PM

Quote:

Originally Posted by maytag

Let's think like scientists for a moment, shall we?
We have hundreds of experiments, with as many variables. We have ONE failure (of the hundreds of tests). We blame ONE of the variables because it seems to make sense. We'd never get past peer review. Ever. If we published, we'd be laughed to shame.

I'm a big fan of the scientific method (as it relates to OTHER people, lol), but I'm just too darn risk adverse to experience failure after failure just to prove a hypothesis to myself. I previously mentioned the example of hitting myself with a hammer, once is enough...now Im picturing a room full of scientists whacking themselves in their heads with hammers to replicate results then moving to another peer review group poised with hammers in hand and heads on the tables. Lol.

Also, I'm not in the camp of trusting one person, as even an "expert" has to pass my mental review process. I guess what I'm asking is "what design seems better to you, at least from a common sense point of view?" Using that criteria, you'll always be right...or at least for a few minutes.

maytag · 08-12-2018, 03:57 PM

so now I'm looking at catalogs, and I'm forced to look at the cost:benefit as well. It looks like (just using Pelican as a source) I'm gonna spend most of $1000 MORE to do the LWFW and associated sprung-clutch, versus just replacing with stock-type components. (some of this is because of what looks to be a real bargain on a LUK clutch kit right now.)

is the increased performance, and the associated potential risk exposure, worth $1000 to me right now? (That's the question I'm posing to myself)

::sigh:: I hate it when I start to get pragmatic.

WillH · 08-12-2018, 04:32 PM

What is the difference in rotating mass?

maytag · 08-12-2018, 05:19 PM

Quote:

Originally Posted by WillH

What is the difference in rotating mass?

From post #1 in this thread:

Lightweight Flywheel only - 13.0 lbs.
Lightweight Flywheel + New Sachs Clutch Assembly - 25.4 lbs. *
Stock Dual Mass Flywheel only - 26.5 lbs.
Stock Dual Mass Flywheel only + New Sachs Clutch Assembly - 38.8 lbs.
Lightweight Flywheel + New Sachs 4 Spring Clutch Assembly - 18.0 lbs.

Lew · 08-12-2018, 05:37 PM

Quote:

Originally Posted by maytag

so now I'm looking at catalogs, and I'm forced to look at the cost:benefit as well. It looks like (just using Pelican as a source) I'm gonna spend most of $1000 MORE to do the LWFW and associated sprung-clutch, versus just replacing with stock-type components. (some of this is because of what looks to be a real bargain on a LUK clutch kit right now.)

is the increased performance, and the associated potential risk exposure, worth $1000 to me right now? (That's the question I'm posing to myself)

::sigh:: I hate it when I start to get pragmatic.

I just gotta laugh at this....The name Maytag fits you perfectly....Wishy Washey!

The Devil made me do it!

5 to 1 odds you don't do it! Anyone else think that?

maytag · 08-12-2018, 05:52 PM

Quote:

Originally Posted by Lew

I just gotta laugh at this....The name Maytag fits you perfectly....Wishy Washey!

The Devil made me do it!

5 to 1 odds you don't do it! Anyone else think that?

ahhh, say what you will, Lew.... but when I make the decision, it will be a decision I've made after I have considered ALL of the risks, benefits, costs, etc. Not because I have joined the rest of the sheep. Your silly taunting aside.

If cost is of no importance to you, congratulations. But cost (value) is ALWAYS a consideration for me. It WILL always be so. I'd enjoy you explaining to me why it shouldn't be thus, but I assume you would merely quote someone else again, since so far I haven't seen you present any of your own original thinking to the matter. Again, your silly taunting aside.

For the record: "Maytag" comes from being the guy who can fix or build ANYTHING track-side. I'd stack that name up against "lew" all day, and twice on Sundays. Since you asked.

WillH · 08-13-2018, 03:07 AM

18 lbs is a lot of rotating mass to lose. If you put a few back with the harmonic balancer for the crank pulley you still have a lot less mass to spin up. This will probably be my way to go when the clutch is due.

itsnotanova · 08-13-2018, 05:38 AM

I'd have to say that almost every track boxster, 996, 997 and 987 is using a LWFW. Most motors I hear of go out because of oiling issues, spun bearings or rods. There has been a few cranks breaking but not many. I totally respect Jake's opinion on the M96/M97 motor but I have to disagree about using a LWFW. Maybe it's like the ims bearing and track cars don't have as many issues as the street cars?

maytag · 08-13-2018, 09:49 AM

Quote:

Originally Posted by itsnotanova

I'd have to say that almost every track boxster, 996, 997 and 987 is using a LWFW. Most motors I hear of go out because of oiling issues, spun bearings or rods. There has been a few cranks breaking but not many. I totally respect Jake's opinion on the M96/M97 motor but I have to disagree about using a LWFW. Maybe it's like the ims bearing and track cars don't have as many issues as the street cars?

Thanks Woody.
That concurs with all of my own searching. I've read and read and read until my eyes glazed-over. I've spoken, to, visited, emailed and FBM'd with dozens of individuals representing (combined) hundreds of cars running LWFW on their 986 motors of every ilk, size, mileage, etc. I cannot find a single person who can offer me a solid "yes, I had a motor that had a crankshaft failure that I can attribute to a LWFW. Let me tell you about it". Except the one, single, lone example that everybody references. That guy is on renntech. His crank failed in his 996 motor with a LWFW and a SLEW OF OTHER modifications.

So I think I have proven beyond any reasonable doubt that the LWFW does NOT cause crankshafts to fail. I will state that unequivocally, based solely on the data. (I mean, as long as we're considering opinions to be facts, mine might as well be too, right?)

BYprodriver · 08-13-2018, 09:39 AM

Quote:

Originally Posted by maytag

so now I'm looking at catalogs, and I'm forced to look at the cost:benefit as well. It looks like (just using Pelican as a source) I'm gonna spend most of $1000 MORE to do the LWFW and associated sprung-clutch, versus just replacing with stock-type components. (some of this is because of what looks to be a real bargain on a LUK clutch kit right now.)

is the increased performance, and the associated potential risk exposure, worth $1000 to me right now? (That's the question I'm posing to myself)

::sigh:: I hate it when I start to get pragmatic.

Don't forget the cost to have the flywheel balanced, they are often way out of balance.

maytag · 08-13-2018, 09:50 AM

Quote:

Originally Posted by BYprodriver

Don't forget the cost to have the flywheel balanced, they are often way out of balance.

Yup. My machine shop is on standby. :-)

maytag · 08-13-2018, 05:06 PM

Did it. Parts are on the way. :dance:

Of course, I probably wont get to work on it for 3 weeks still..... sunnuva.....

maytag · 08-16-2018, 03:48 PM

dropped the flywheel and pressure-plate off to my machinist today. He'll balance and index them for me over the next couple of days.

I'm hopeful that tonight I can get to the garage before my wife or neighbors catch me, and I can get the IMS done, and the new halfshafts in, so I'm ready to install when the machinist finishes.

comin' back together!