[QUOTE=RandomHer0;8701931]What the...you have a race prepped Z with no full locking LSD?

Anyways, yes, I have the Cusco 2-way, 80% lock. Possibly the best mod on my car.[/QUOTE

{edit} thought the car had totally different shocks and springs then it does, my bad NM.

Oem VLSD doesn't belong on a car being pushed hard let along tracked, definately a weak link.

 

Understood, I was just reading what was in his sig.

"Full Race Prepped for NASA TTA/PTA"

 

I am on JIC FLT-Rs, Cusco A-Arms, SPL rear camber/toe kit, Hotchkis sways....among other things, its a race car, so I am not sure what you are getting at...?

 

I just looked at some rear wheel speed data logs for a World Challenge Viper running the OS Giken Super Lock and two other LSDs (one VLSD and one GLSD) and the OSG has by far the smoothest and most complete lockup. There's a nice, smooth hourglass shape to the wheel speeds as the diff comes to full lock on corner exit. And that's with the standard Type S setting. A little more work by Mr. Tomitaku and the traces looked even better with the car picking up .1 in lap time.

 

I wish i had access to that kind of data, but i do know i can apply more power with less slip coming out of corners with my OS unit. Low speed around town i can hear and feel it lock up, on the track/at speed, nothing but smooth.

 

Is Quaiffe (?sp) a good option?????
(I was going to upgrade my diff this winter)

 

The Quaife is a great option for a street can and can be a good option for a track car if you're willing to adjust the suspension and your driving style to work with the Quaife. They must have the rear wheels on the ground at all time. If your rear roll stiffness is such that an inside rear wheel gets light in a corner, the Quaife diff will go open and you'll spin the inside tire. Its just the nature of the beast. Sometimes you can band-aid it by increasing the preload with a wave washer swap but that starts to induce a little push on trialing throttle.

 

I went from a VLSD to an OS Giken LSD and the difference was like night and day. Considerably faster on an autoX course (possibly by as much as 2 seconds). For track days the results are not as apparent but still very good for a tight track (3rd gear on straights) w/ a good amount of corners I've dropped a second w/ this mod alone (1:13.3 vs 1:14.XX). I did not add the Nismo finned diff cover so by the 2nd track session of the day I notice that the oil is boiling over and coming our of the breather tube. The finned diff cover is a must for track use IMO.

Super smooth for the street, the only time I notice it is on wet roads when taking a slow-speed tight turn from a stop.

 

Ordering the OS Giken today as a xmas present to myself...thanks to the guys at Z1!

Those of you that have it, have you changed the settings much on it as far as ramp up rate and preload? I dont know much about them and a friend of mine who is sponsored by them didnt really explain it well. Any info is appreciated!

Joseph

 

I've kept mine at 100%, I think that there could be an improvement if the lock dropped down to 90% or 80% for really tight corners but it works great at 100% overall IMO. Keep in mind that it's not the type of clutch pack you can disassemble easily. Usually has to be done by a shop that has someone trained by OS Giken.

 

Bolted it in, kept it at the OS factory setting. Wouldnt really know how to adjust it or how i would want it adjusted for handling. Did i mention i now have corner exit traction!!!

 

They are shipping with what the OSG engineers call a Type S setup. That generally works very well for a street/track car. There is a small issue with a pure autocross car in that a slalom with frequent on-off throttle tends to pump the oil out from between the plates. This causes a slightly harder lockup when you're back on the gas and creates a small push.

Working with Sean at OSG and two of my customers we've come up with a solution. You can upgrade the disk stack to their TCD units. Its documented to small degree here on my shop's Facebook page:

http://www.facebook.com/pages/BetaMo...C/143989191670

Turner Motorsports also ran the TCD disks in their GrandAm BMWs for the last race of this season and saw an improvement in lap times and easier handling from the cars at corner exit.

 

What is the cost for the upgrade?

 

The reply from the folks at OSG:

The TCD disks can be installed but you have to make a very good case (National Championship winning kind of case) that I can sell to OSG.

 

Clutch type LSD's usually require a change in setup because of the preload and inherent drag in the diff.

In my racing I've found that running the least amount of pre-load possible will result in the best mid-corner speed, but if you start getting into big power you'll need the diff setup more aggressively, so for your car the standard OS setting or even less preload (if you wanted to really mess with things) would work fantastic. You could also de-activate some plates to help with on throttle oversteer even more.

So if you have adjustable bars you'll be running a bit stiffer in the rear, or throw a bit more rear spring at the thing.

Good luck!

We're sponsored by OS Giken in the Canadian Touring Car series, but those are in our Hyundai Genesis coupes.

Beta - that WC data sounds nice. It's nice to see some more people involved in some real racing here

 

My car is not a race-prepped Z, but I run the Quaife, autocross a lot, and have never lifted a rear wheel. I'm just running the suspension mods in my sig on aggressive street tires, but we used to have an APS TT beast of a Z on JIC's and 315 race tires that ran a lot and I never saw that one get a tire in the air either. (None of the other race-tired Z's at our track seemed to have exhibited this problem either.)

I'm sure the Z can do it, but it's not as prone to do so as some other cars and probably takes a rather extreme setup/situation to lift a rear wheel.

 

OSG is our new favorite LSD. No harsh lock ups, yet fully locks up. And doesn't eat the shims like the Carbon LSD's can do with time. We use it on the GT-R, Z's, and even our GT3.

Just to clarify a previous person's post. You are not going to see a 2.8 second laptime improvement with an LSD. As he alluded to, there were other factors at a play that contributed to his laptime improvement. The laptime improvement on an NA Z is about 3/4 second based on our testing and experience. YMMV because your improvement depends on the track layout, number of turns..etc..etc. On higher powered/traction limited cars, the laptime improvement could be much greater than that. But on a well setup RWD NA car, I'd be thrilled with 3/4 second improvement at something like a Road Atlanta.

 

Congrats on the purchase Joseph! Your car is a beast!

The OS Giken was installed on my car a couple of weeks ago and the change is very noticable. I didn't realize how significantly the upgrade would change the feel of the car. Like everyone has said regarding this LSD, it really makes a big difference (though I can only compare it to the stock VLSD).

So far I've done a track event and an autox and I'm having a lot of trouble getting used to it. There is a lot more traction when getting out of corners but I feel like I have no idea how early I can get on the throttle or at what point it will let go/break traction. And when it breaks loose I feel like its sudden. I don't know if 4.08 gears make it more difficult or if its just me needing to adjust my driving (smoothness has always been a problem for me).

I guess I was naive in thinking....ok, I will put this on the car and just be a second faster, no problem. But it really requires getting used to and I would even say it requires more smoothness when getting on throttle to really get the most out of it. But when I get to mid-corner w/o drama there's a lot more traction/acceleration there, once I learn how to use it, my times will surely drop.

I also agree that .5 sec to a 1 sec improvement would be awesome! I'll be running at a familiar track that I am consistent at next weekend so I'll be able to report back on the lap time difference.

Is my reaction to the LSD normal or am I just doing it wrong?

 

If you're using the throttle like an on/off switch then it can be more difficult to drive with a LSD that has more lockup. Squeeze the throttle down. One trick is to give it a 3 count when you decide to add throttle: As you start applying throttle, count "1 Mississippi, 2 Mississippi, 3 Mississippi" out load and at the last Mississippi you should be foot to the floor - but NOT before. As you get better at controlling your right foot you can give it a 2.5 count and then a 2 count.

 

Well, I have always been under the impression that the Quaife is more user friendly, which is why I'm strongly leaning in that direction. I'm just not sure I have the ability to get the most out of the OS Giken - I need something more idiot proof!!!!!!!!