No more r3vtard assist

[The Dark Side of Will]

REM polishing is worthless. Causes increase in tolerance and fractures from gear cutting root;

LoL.

[Wanganstyle]

Top speed by Wanganstyle; LSD Diff Puzzle thread; ask me to spill beans here!!!

...and the PRO3 cars that put the OS Giken diff in seem to lose most of a second a lap,
pretty predictably.

One data point,
t

That's fine; the GTS cars here gain about half a second to a second.

It's all in the setup; we don't have pro3 here in NorCal; what can be changed on the footwork to suit?


Sent from my iPhone using Tapatalk

[Wanganstyle]

deleted

[The Dark Side of Will]

There are just sooo maaaannnyyy holes in your apparently simple statement that my response was the most appropriate.

[Skarpa]

Sorry to break into the middle of your argument but if someone could enlighten me on these questions I'd be very thankful.

Digging up this thread for a couple of questions.

1. How would a diff with four discs (mild material), no preload and stock ramp angles perform?
2. What is the correct method of setting up non-springed lsd? How is the shimming done and what is the tolerance for free play in the stack? Will heat expansion cause the diff to lock more easily?

I'm pondering on a lsd setup for my car: Stock, 2 discs with added preload, 3 discs or four discs. I'm going on a budget so I think I'll try to avoid regrinding ramp angles. The diff is fora N/A street car with about 250 hp and 300 Nm. Mostly daily driver with possible occasional abuse. No track.

[TobyB]

what can be changed on the footwork to suit?

Hmm?

And to be more specific, the PRO3 cars that have gone from a
fully- functioning "fresh" stock LS to the OSG diff have gone faster,
by some large fraction of a second, without any other changes.

I haven't gotten around to trying the same experiment with a
welded diff yet...

t

[Wanganstyle]

deleted

[Wanganstyle]

deleted

[Wanganstyle]

deleted

[The Dark Side of Will]

I have a great example for you of a failed REM gear

One gear? meaningless. There are sooooooo many reasons that one part can fail that determining it to be REM polishing is impossible.

Did it have a crack before hand? Was the batch misprocessed? Did the operator have a bad day? Was it exposed to higher than typical loads the day it failed? Was it exposed to higher than typical loads some time before it failed which set the failure process in motion?

The reason humans have to be taught root cause failure analysis is that they're naturally lousy at it.

The factory street car Oem gearsets are chemically treated; the outer surface is harder than the inner. When you remove this the gears are not as durable anymore; it lost the nice surface and also material has been removed from the gear faces in polishing.

This is called case hardening. It typically goes a few .001's to a few .010's deep. REM affects the outer micron or so of the surface, which means the outer .00005" or so.

So tell me again how a .00005" REM polish eats away case hardening at least 100 times that thick.

If you have never heard of WPC I suggest you check it out; it doesn't remove material and is factory in many high end aftermarket applications.

I know what WPC is.
What we're discussing is the harebrained claim that REM causes gear failures.

Motorsports 210mm gears have been proven to be much more durable than polished old style REM.

That's nice. It's a claim and an anecdote. It is definitely *NOT* data.

[Wanganstyle]

Deleted.

[The Dark Side of Will]

What's to understand it's that you've made a wacky claim and offered *nothing* to back it up.

[Wanganstyle]

Deleted

[The Dark Side of Will]

Seeing a photo of a gear in which one looks polished, one doesn't, and thinking the one that looked polished had been polished because Dinan was mentioned was an erroneous, but perfectly reasonable assumption. Allowance for the error of that assumption is why I used the word "appears".

REM polishing is worthless. Causes increase in tolerance and fractures from gear cutting root;

This is nonsense.

I never claimed that REM makes gears stronger. I am stating that your claim that REM causes them to break is in error.

Run a cooler if you want less temps

Coolers (and pumps, since BMW's run independent) have weight. Fluid has weight. Fluid has viscous drag. Polishing has neither weight nor drag.

Is it racing or not? If it's not, run a cooler. If it is, save the weight and have the gears polished.

[Wanganstyle]

Deleted