Why you need a LSD if you like cornering!

[7thgear]

sorry I'm missing something


how are you accelerating at the same rate at half throttle as you are at full throttle?


your first instance is the outside rear doing a small spinup as you've almost completely let off the gas (note that the TPS won't read below 20% for some reason) Maybe this was a surface issue?


and the second instance is on the inside wheel, but you did stab the gas so I'm not too sure this is out of the ordinary?


.. hmmmmmmmmm

I don't know what to say :o

[puma]

first one is the inside wheel, it is turning right, look at where the cursor is, blue line is right rear


the other one does spin under acceleration but it is still spinning...


Have you taken data out of you car? It never read below 20%, i would guess this is because there is no iacv on this car and it controls the engine idle by keeping the throttle always above 20%. This is the TPS, not the throttle pedal.

[puma]

here is the difference between TPS and pedal position. This is an untuned car. Also, it is an extremely bumpy track so the uneven throttle is because modulation is very hard when the car is jumping a lot, being steady is impossible.


edit: just realised i didn't take the same lap as the previous printscreen but you can see it still does it in this lap (a little bit less though) and the rear swaybar was disconnected in this lap.

[puma]

Originally Posted by Captain Snooze

Hey Puma, which track is that? Looks interesting.

Icar in Québec Canada

[puma]

here is the previous lap where throttle is at 0 for longer. You can clearly see the difference between actual TPS and throttle position. Even at 38% pedal, tps is at 50. Sorry for those who aren't too much into data, i'll stop now

[7thgear]

my bad, I read the track map in the wrong direction.

and yes, I also have a solo DL and it annoys me that the TPS doesn't go below 20%, which to me sounds like a little too much for mere idle.. as the car idles with the throttle plate closed through a bypass valve/tube/hose/hole

and if you plot your throttle application vs TPS you'll see a bit of delay.. also a bummer






but again, we see a wheel spin with minimal throttle application in the first instance, you say that the track is bumpy, this could very well be the reason.. if the rear unloads the torsen stops working and you get spin

[puma]

exactly, the lag is also something really annoying, look at the last portion of my last graph, you can see how the tps doesn't move with the pedal at all.


Also, it is true we get that a lot because of the bumpy track and the fact that my driver like to run on the curbs. I checked with an other track which is much smoother and we still had some inside wheel spin but not as much as this track.


I think in our case the mechanical LSD would help with the tracks we are running with but i can see how this is not a mod needed for everyone like some were trying to debate. One thing is for sure, when we install a diff during the winter i'll make some new logs when we go test again.


One thing that scared me when i looked at those data wasn't much about performance but about snapping axles with the violent drop in speed when the wheel touches the ground. I suppose the lsd should help with that and make the purchase of stronger axles unecessary.


what do you guys think?

[CSG Mike]

I'll give you guys something to think about

[7thgear]

5 G leteral load what the fuck?


also your accelerometer is set to record at a high frequency

[puma]

i must admit i really don't know what i should be seeing as i don't see anything out of the extraordinary


the high G lateral is only because the DL wasn't calibrated, it's 0 must be somewhere in between the highest and lowest value

[dradernh]

I'm looking at the steering (wheel?) angle and thinking...that looks like someone was having fun!

[CSG Mike]

[GT86_PRAGUE]

Originally Posted by CSG Mike

The major differences:

Engagement - Cusco RS is positive engagement, while OS Giken is negative engagement. In other words, the Cusco is trying to engage all the time, while the OSG is trying to disengage all the time. Cusco RS engagement is controlled by springs in the center gear, while the Cusco MZ engagement is controlled by cone springs on the ends. OSG engagement is controlled by cone springs on the ends, and disengagement is controlled by springs in the center gear. This sounds complicated, but we'll be more than happy to show you in person what is going on.

Maintenance - Clutch packs all eventually wear out. How quickly they wear out depends on your setup, how you drive, and if you're using the proper fluid for your application. **USE THE RIGHT FLUID** Typically speaking, the OSG clutch disks should last longer than the Cusco RS clutch disks.

Maintenance cost - OSG diff fluid is more expensive than Cusco diff fluid. Our blanket recommendation is to use the fluids by the respective manufacturers, but they may vary on a case-by-case basis. Clutch disk cost is approximately the same, but the Cusco will require more frequent clutch disk changes. That being said, you will NOT be replacing the clutch disks frequently. Most Cusco LSD owners have never replaced their clutches, and I've yet to run into a single OSG owner who has replaced their clutch disks.

Initial cost - OSG costs ~200 more than Cusco. Custom configuration of the OSG also costs more than custom configuration of the Cusco.

Break in - Cusco requires a 30 minute break-in. OSG requires no break-in.


Both LSDs come in a 1/1.5 and 1.5/2.0 configuration. Meaning, if you buy a 1.5 way LSD, you can reconfigure it into a 1.0 or 2.0 way LSD later on, if you choose to do so, depending on the version you buy.

Thanks! Is it possible to combine OSG with FD 4.88/5.1?

[Koa]

Originally Posted by stugray

So did you pull the fuse so that the VSC would not respond?



Ummm... SO slowing the spinning wheel would slow you down??
I thought that was the whole concept of a LSD.

Stu, your posts are almost always informative and Socratic, but Mike seems to have ya bested in the track department