Forged Performance/ OS Giken LSD Review (pics)
 

Ok.... The reason I listed Forged Performance first in my thread is because after much thought they deserve more props than my LSD does at the moment. I went to FP yesterday to have my OS Giken LSD installed. Well in so many words everything wasn't smooth as we wanted it to be. It was nothing on FP side. There was just some issues with the OSG itself and the new axle stubs. It mostly seem to came down to some tight tolerances on the LSD and the new axle stub thereseves which had to have some machine work for them to fit properly. Mostly around where the snap rings go in place. That's about as much as I know to explain. FP might shine in if they wish. But there's really no need. That's the basic of it.

But the reason I'v stated the above is to give you a brief idea of what happen. Because this ended up taking most of the day. And while there where some unexpected series of events which cost FP much time and more money to get this done, They really came through and HOOKED ME UP!! None of the additional time or cost was applied to myself. In which it easily could of been. Talk about first class customer service. They even stay after hours to get me out the door.:tup: I don't see why anyone local or far away wouldn't want to do business there. I've never hung around there shop as long as I did yesterday and I saw first hand of how much of the business side was ran. They where all happy to talk on the phone to customers, answer question. I saw them triple check all work. They test drove all cars finished more than thoroughly. You could argue that's how it's post to be. But seeing it first hand really does something you never forget and that's why I feel I should take the time to type all this. I've done business with FP for several years now and the shop is ran better than ever. For they have the best workers there from every aspect to work on specific projects coming together as a team. I invite you to at least stop by there if anything to check out there operation. Money spent there is well deserved, for most don't see behind the scenes. Some shops bend over backwards to get things done and alot of this goes unseen. So big thanks to everyone at Forged Performace and there hard work.


I gotta start off saying that I am very impressed w/ the performance change of my car from this one modification. Whether it was the OS Giken LSD, going to a clutch-type LSD or just having something that grabbed and getting power down coming out of the corners is mind-blowing now. So much was being left on the table by not being able to make good use of all the power the Z has on tap that I’m having to relearn the limits of the car since they are now beyond where I would’ve expected them to be before this mod. Prior to this LSD the only other LSD equipped car I've driven was my G37 with the VLSD. Night and day is all I can state. Simply put; OUTSTANDING! A true LSD is what this car needs more than anything else. The open diff is essentially a joke, and after this mod it gives you an understanding of what this car needs, but having this LSD made me realize that there is so much potential in this car.

I took it for it’s maiden drive today. I was fully expecting some wheel hop when pulling out of the driveway and turning onto the street. Nothing. Surely the inside wheel will skip a little or it’ll make some kinda noise as I head around the corner... there was nothing. No inside wheel skipping, no humming or detectable differential noise during cruising at any speed. I then went to a place I knew of that had two sweeping corners that really allowed the throttle to be held flat where as in the past it would have need modulation. When the back end would step out, it did it quicker than before but it was never unpredictable and it regained composure just as quickly. At the end of that there was a hard braking zone coming out of a corner. On another occasions I recalled getting a hint of rear end squirm for a split second just prior to downshifting, but the car never felt out of control. At this point for me I was smiling. IMO OS Giken put together a truly quality product here. I read good reviews from the BMW forums prior to deciding on it over other available LSDs for the Z and now I know I made a great choice. Hopefully I'll be able to give more reviews when I get some decent seat time. I still have alot more to fell out. It's hard to rely everything for there's so much going on.

So this is my quick review of my OSG threw my eyes. I put alot of thought and heart into this all day. So I hope it's helpfull. For normally I can never find the right words to express what I'm thinking. Damn ADD. So grammer police stay away.:icon17:

http://i1109.photobucket.com/albums/.../Parts/009.jpghttp://i1109.photobucket.com/albums/.../Parts/010.jpg
http://i1109.photobucket.com/albums/.../Parts/011.jpghttp://i1109.photobucket.com/albums/.../Parts/015.jpg

Open Diff
http://i1109.photobucket.com/albums/.../Parts/019.jpghttp://i1109.photobucket.com/albums/.../Parts/020.jpg

OS Giken
http://i1109.photobucket.com/albums/.../Parts/016.jpghttp://i1109.photobucket.com/albums/.../Parts/017.jpg

One of two axle stub
http://i1109.photobucket.com/albums/.../Parts/018.jpg

Glad you like it. The install issues have me a bit worried though.

There's no worries to be had. That's why I took it to Forged. They handled it like it was a walk in the park. That's what happens in the after market world. Nothing is perfect. That's why were all blessed to have great shops available across the states. I trust them with anything. If it wasn't good to go my car would still be there. Sharif has worked on every type of LSD on all type of different models. He's seen it all and knows what to do in every situation. Things happen all the time in this business.

umm...so without all that extra work..this will not fit?

Yeah, but I would be doing the install myself. I don't want to deal with a PITA like that.

Not on mine it wouldn't. Sharif had done another with no issues. They had to contact OS Giken and Nissan to figure out some things. Even OSG didn't understand. Guys, don't take this to heart. It really ended up being simple in the long run. Just takes time to make the right decisions. This is the modified world. No different from boring a motor perfect.

It could happen with any product. Maybe Forged will shine in. This could be a learning experience for all.

I'm not real good with lsd or transmissions with our cars. If my recollection is right, 370's with the sport package have a lsd?? where base models do not??? So you didnt have the sport package with lsd so you bought an aftermarket one? Lemme know if im getting this all right lol cause I'm a lil confused.

Yeah, sport package has a viscous LSD, which is pretty awful for serious use.

So if i got this I would notice a big difference?

In hard driving, probably. The lockup on the VLSD is pretty inconsistent.

How do we know whether the z have lsd on it?

I just realize that few z does not come with oem lsd...

The sport package includes a viscous LSD. The base model without sport package has just an open diff. Sport package also includes 14" brakes, 19" wheels (vs 18" non-sport), synchro-rev matching, it should be pretty easy to tell.

370z_2910 - not sure if all of those rule apply since you are overseas

Liking the review, I will definitely consider this if my Z ever goes down the track route.

Very good and detailed review.

You can't go wrong with OS Giken products.

Yea I have a base model Z so I didn't have a VLSD in my car. Even if I did, I still would of purchased this. It really is worth it by leaps and bounds if you plan to push or defiantly track you car.


Thanks. It's defiantly worth it. I wouldn't pass this mod up if you didn't have to.

Very nice, I bet it feels like a dream come true.

Oh it does. As I told Spencer earlier next best mod to a TT. Lol.

Yes, i do have all the following sport package, the one that you have mentioned including vdc...

For safety issue, maybe changing the lsd is advisable.....?

Just to clarify with respect to the installation issues. We're very familiar with Nissan's habit of using different length and shaped stub axles in the various trims of 350Z. With the 370Z, the base model includes traction control but still an open differential. In the process they also elected to use a revised set of stub axles as well. So with 6 different stub axle choices even OS Giken wasn't entirely sure what ones to use. We ordered one short and one long axle in preparation for the installation. Upon inspection of the OEM parts we discovered that we need two SHORT stub axles NON TAPER with snap ring grooves/snap rings. Instead of sending Chris home and ordering a second short stub axle we machined and modified his existing axle to precisely the same measurements and tolerances of the OEM part which including machining a new snap ring groove. This is a substantial amount of extra time, but we didn't charge the customer of any of this and our objective was to complete the job as promised and get him on the road safely. Under normal circumstances no modifications are needed during install. Mission accomplished. :tiphat:

Shifting gears to the performance aspects, the OS Giken is the highest performing and smoothest engaging clutch-style LSD we've used in every car we've put them in. Prior to using them on the 350Z/370Z, we had used them on the GT-R, Subaru, and Porsche GT3. It's the best kept secret in performance handling and laptime reduction, bar none.

The OS Giken is a 1.5 way clutch style LSD, with a perfectly machined outer case and ring gear shelf. No shims have ever been needed in our installs and that says a lot about their machining processes. The LSD locks 100% under acceleration, and 50% under deceleration and has an undetectable ramp that is seamless in it's engagement.

The best way to test and describe an LSD's action is on track, but the benefits as Chris alluded to are also immediately apparent during street use as well. A full locking differential allows the driver to roll into full throttle much sooner in the corner, without causing speed robbing wheel spin. On the OEM diff this is very noticeable on tight and slow mountain roads such as those that have visited the Tail of the Dragon. In contrast, with a "locked" arrangement you are providing equal thrust to both engines back there (your tires). Although it seems contradictory, you do not want an overload of power to the tire that is gripping, as it quickly causes you to light up BOTH tires and you cannot control the back of the car with the throttle as readily as a locking diff.

Hope that adds some additional color, to an already awesome product. Now lets talk about the OSG Twin Plate Clutches....haha...ok next time. Thanks for reading.

Thanks for clarifying all this Sharif. This is truly a great performance piece. I'm having so much fun in this car now. It's amazing the traction this baby gives. I actually finally experience the lock under declaration leaving you shop Monday. I wasn't really expecting it but that was amazing also. It almost seemed to oversteer some but very controllable and predictable just waiting for you to accelerate out of turn. I was smiling all the home.

Very nice review! :) The OS Giken differential's really do make a huge difference. We couldn't believe the difference it made on track when we tested them at Road Atlanta. For you track guys this really is a MUST. Enjoy the new diff!

Sounds pretty awesome.

Can I get a PM with a install quote for this? I'll be heading up to Georgia to go to AMP in the fall.

sent you a PM :)

Sharif--

So the issue was just getting the wrong stub axles, which presumably won't happen now that they know which ones to send?

That's correct.

Where can I buy this LSD? After oil cooler, pads, and fluid this is to be my next mod so she can be track ready.

You can purchase from Forged Performance themselves. Call for best pricing.

Excellent. Thanks for clearing that up.

We can take care of all of your track needs. :) I just sent you a PM! :tiphat:

So if I have a base model, I can order 2 short stub shafts from OS Giken and they will fit without modification?

You have to order them from Nissan.

The stub axles are a Nissan oem part. You can order them from Ryan or myself and we will make sure you have what you need. It goes without saying you also need two new side bearings.

Did you replace the side bearings? If so, do you have the part number?
Thanks

We were planning on it. But being my car had only 2000 miles on it they were in great shape. But with some milage on them it's best to go ahead and replace along with the seals. I'd also look into the Nismo differential cover with the cooling fins. I should of picked one up before I had this installed.

Here's a link for the part number. Which can be had at any dealer. Just confirm with Nissan this is the right part though.

BEARING-DIFFERENTIAL SIDE - 370Z (Z34) 2009+ :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com

Chris is mistaken. We replaced the side bearings as it's not possible to remove them from the old diff without likely damage. We did NOT replace the side seals because they looked perfectly new and had very low miles on them. No reason to change them out. :)

Guess I had it backwards then.:shakes head:

Thanks guys! Definitely the part I thought it was. I also heard they were pretty tough to get on there.

Also keep in mind with the OS LSD you will need 2 of the Right Side stub axles, NOT 1 L and 1 R. Oh and yes, they can sometimes be a huge pain to get in there :)

Right. I'm actually putting a Quaife into my base open diff and it shouldn't require any axle stubs.