Re: Dual Mass Flywheel .vs. Lightweight Flywheel--What Performance Differences Do You
MIB said:
Hey Rob, I don't mean to burst your bubble, but saying that something has the IDENTICAL effect as an M3 will not win you favours here.
Actually, I mis-wrote. I did mean to write "similar", not "identical"... and "similar" in the way that there is a similar change in any car equipped with a lightweight flywheel. Whether it is the M5, a 3-series (the video car is a 330i), a Mustang, or a Honda... the effect of a lightweight flywheel can be generally demonstrated by that video.
You should look at the video - it's showing the difference in engine acceleration speed between the OE flywheel and a lightweight setup. It's quite interesting.
MIB said:
Reduce does not = Eliminate.
I believe I made that quite clear...
"significant rattle reduction (and complete elimination in some M5s)" in that post.
MIB said:
So why elimination in some M5's and not others? Is that Identical to the M3's as well? I haven't looked at the clips as yet, but were they filmed with one of the GOOD ones? Do you see my point.
Answering those in reverse order, the video shows nothing regarding rattle or not. It's a close-up shot of two tachometers showing rev speed, no audio whatsoever.
As to why in some M5s and not others, there are a number of factors that determine transmission rattle due to removal of the dual-mass flywheel's power pulse variation absorbing capabilities:
1) Build tolerance of each individual transmission - as much as we like to think BMWs are "minted" perfectly, the truth of the matter is that variations exist between components. In these transmissions, some are looser than others, more likely to rattle at idle with a lightweight flywheel.
2) Wear of the individual transmission - whether thorough mileage, contaminants, or hard use, the fact remains that each transmission wil change it's propensity to rattle as time passes, and each one in slightly different ways than every other one.
3) Condition or type of transmission fluid - thinner fluid has less damping effect than heavier fluid, that's a basic concept. The OE fill changes viscosity as it ages or is used (and more or less depending on usage style). Likewise, the use of alternate fluids will change the damping effect. Whether the M5 has OE, Swepco, Royal Purple, Redline, or Amsoil will change how much damping there is from viscosity and the effects of the additive packages.
MIB said:
Since you don't put a number on that, we can't quantify it.
The reason why I say my Pressure plate gives 4,200lbs + clamp is because I saw the guy measure it, and his gauge only read that high. So I am interested in you Quantifying your statement in comparison to "Whats out there."
We will be supplying data on the website shortly. Bear with me, I am not ducking your question but looking to answer it more completely in due course.
MIB said:
If that is true, then you haven't done a very good job, as the Stock pedal feels limp and like crap. Most guys would welcome a slightly firmer clutch pedal, one that has some feel to it.
Then I have the answer you will really like; our setup includes a different slave cylinder, matched to this clutch. The original slave cylinder can be retained, and the effect is a firmer pedal feel. Best of both worlds - the M5 owner can choose the pedal feel he prefers.
MIB said:
Rob, I'm sure your product will be welcomed, but overstating its abilities will not. Call it as it is. Everyone who knows anything about clutches and Pressure plates and flywheels, knows how difficult it is to produce something that can do everything.
Again, not to duck the question, but I ask a small amount of patience until we publish the details. I think you will see the capabilities of this setup have not been overstated.
MIB said:
Of course I expect it to be hugely better than stock, (Thats not hard, the bar was pretty low.)
Trust me, my disappointment in the original BMW design is substantial. The fact that the E39 M5's clutch is not significantly different than that of the 5-series from 20 years ago despite the big increases in power and chassis weight is simply astonishing.
MIB said:
But lets see if you deliver on the Noise factor.
While I would never guarantee an absolute absence of slight rattle (see the list of factors above), I can say that the net result is not like any other aftermarket lightweight flywheel, and is similar to a lightened OE flywheel.