OS Giken Super Lock
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OS Giken Super Lock
Vette magazine February 2011 issue features an OS Giken LSD install in a C6 Corvette. The article is ok, and does a good job of showing the differences between the stock and Giken differential, unfortunately any performance improvement as a result of the change is obscured by a change in tires at the same time. Hard to tell how much if at any the LSD contributes to the 1 sec + per lap improvement vs. the new Nito tires which replace old worn Michelin all season. Same with the 0-60 foot launch time.
Re: OS Giken Super Lock
Can you scanArthur Grant wrote:Vette magazine February 2011 issue features an OS Giken LSD install in a C6 Corvette. The article is ok, and does a good job of showing the differences between the stock and Giken differential, unfortunately any performance improvement as a result of the change is obscured by a change in tires at the same time. Hard to tell how much if at any the LSD contributes to the 1 sec + per lap improvement vs. the new Nito tires which replace old worn Michelin all season. Same with the 0-60 foot launch time.

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Re: OS Giken Super Lock
I have not tested my car back to back with the OSG vs my old ZF, so I can't give a time improvement. I can say that turn-in is much better with the OSG, it also puts down power on corner exit much better. Another thing that I like better about the OSG is the single piece that holds the spidergear vs the two piece design in the ZF and many other lsd's that tends to break.
http://www.elitetint.com" onclick="window.open(this.href);return false; http://www.osgiken.net" onclick="window.open(this.href);return false;
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Re: OS Giken Super Lock
Nope wouldn't want to infringe on their copywright especially since it's currently on the newstand. It's a quick read if you stop by your local bookstore.Jeff Wong wrote:Can you scanArthur Grant wrote:Vette magazine February 2011 issue features an OS Giken LSD install in a C6 Corvette. The article is ok, and does a good job of showing the differences between the stock and Giken differential, unfortunately any performance improvement as a result of the change is obscured by a change in tires at the same time. Hard to tell how much if at any the LSD contributes to the 1 sec + per lap improvement vs. the new Nito tires which replace old worn Michelin all season. Same with the 0-60 foot launch time.
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Re: OS Giken Super Lock
I have heard good things about it, but as I look at eventual upgrades to the car, not sure that the cost of the differential change buys as much as say a new set of R-comps on the clock. Now if like your car you have done both it makes sense. I guess I would have liked them to take a more scientific approach to what is a pricey upgrade. Clearly it is an upgrade.Toby Larsson wrote:I have not tested my car back to back with the OSG vs my old ZF, so I can't give a time improvement. I can say that turn-in is much better with the OSG, it also puts down power on corner exit much better. Another thing that I like better about the OSG is the single piece that holds the spidergear vs the two piece design in the ZF and many other lsd's that tends to break.
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Re: OS Giken Super Lock
Stock Corvette diffs are very very good, even for autocross. Not saying it doesn't warrant consideration at all, just that the potential gains for the car, and hence its place in a prioritized list of upgrades for any given class, put it much further towards the bottom than it would be for most other platforms.
Wouldn't be surprised if the diff actually made the car slower, leaving them to throw on some cheater tires to cover it up and give the impression of benefit.
*queue the pitchfork-carrying Giken supporters*
Wouldn't be surprised if the diff actually made the car slower, leaving them to throw on some cheater tires to cover it up and give the impression of benefit.
*queue the pitchfork-carrying Giken supporters*
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Re: OS Giken Super Lock
Might want to ask Junior Johnson (multiple Nat. Champ., multiple and current ASP Champ.) how good a stock 'Vette diff. is and what an OS Giken did for the car (C6 Z06).Jason Rhoades wrote:Stock Corvette diffs are very very good, even for autocross. ...
Just sayin, Jason....
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Re: OS Giken Super Lock
Heresy!Wouldn't be surprised if the diff actually made the car slower, leaving them to throw on some cheater tires to cover it up and give the impression of benefit.
http://www.youtube.com/watch?v=gldlyTjXk9A" onclick="window.open(this.href);return false;
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Re: OS Giken Super Lock
Hmm....might also be somewhat interesting to ask Junior just how much he actually paid for that spanky new diff, no?Bill Schenker wrote: Might want to ask Junior Johnson (multiple Nat. Champ., multiple and current ASP Champ.) how good a stock 'Vette diff. is and what an OS Giken did for the car (C6 Z06).
Just sayin, Jason....
Just sayin, Bill }:)
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Re: OS Giken Super Lock
Without before and after data, all the endorsements and adoption by guys with titles doesn't mean much. I have no doubt that the OS is better than stock, but is $3K or whatever they cost installed better? These magazines and top performers all have data loggers, so it's not like they couldn't generate the data for discussion. Interestingly a google seach doesn't turn up any hard data. In the case of Grass Roots, they put in the new dif, new tires, and new brakes and got just over 1 second on a road course (Gainsville Raceway). I think the switch from old all season Michelins to Nitto's should be worth 1 second per lap. Replacing 5 year old factory pads, wth Hawks, has to help as well.
My question is does Mr. Johnson have a OS Giken decal on the side of his car? Did he pay full list? If yes, or no, then recommendations are suspect.
My question is does Mr. Johnson have a OS Giken decal on the side of his car? Did he pay full list? If yes, or no, then recommendations are suspect.
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Re: OS Giken Super Lock
Of course he does ...


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Re: OS Giken Super Lock
Nice shot.
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Re: OS Giken Super Lock
Speaking of discounted diffs, Wavetrac is looking for somebody to use their unit in a 996.
Gary Thomason wrote:Hmm....might also be somewhat interesting to ask Junior just how much he actually paid for that spanky new diff, no?Bill Schenker wrote: Might want to ask Junior Johnson (multiple Nat. Champ., multiple and current ASP Champ.) how good a stock 'Vette diff. is and what an OS Giken did for the car (C6 Z06).
Just sayin, Jason....
Just sayin, Bill }:)
http://www.elitetint.com" onclick="window.open(this.href);return false; http://www.osgiken.net" onclick="window.open(this.href);return false;
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Re: OS Giken Super Lock
The problems with doing a proper test of one of these are cost and logistics: you would have to build two complete differentials for your car and then hot-swap them at the track. How many of us have that kind of money? You can bet no magazine will do it... don't want to runs the risk of making that new big advertiser look bad (that's not a ding at Giken... it's just how that world works.)Arthur Grant wrote:Without before and after data, all the endorsements and adoption by guys with titles doesn't mean much. I have no doubt that the OS is better than stock, but is $3K or whatever they cost installed better? These magazines and top performers all have data loggers, so it's not like they couldn't generate the data for discussion. Interestingly a google seach doesn't turn up any hard data. In the case of Grass Roots, they put in the new dif, new tires, and new brakes and got just over 1 second on a road course (Gainsville Raceway). I think the switch from old all season Michelins to Nitto's should be worth 1 second per lap. Replacing 5 year old factory pads, wth Hawks, has to help as well.
My question is does Mr. Johnson have a OS Giken decal on the side of his car? Did he pay full list? If yes, or no, then recommendations are suspect.
The other problem is finding someone that knows what they're doing when tuning/adjusting them: the ones I've driven have been wrong after the "approved expert" has installed it, requiring at least one more diff R&R (more $$$) to rectify. Once they're set up correctly, they work quite well.
Until you have everything else on your car dialed-in perfectly, don't spend the money. Spend the money on the driver.
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Re: OS Giken Super Lock
I hear you but since they were running this at a fixed track, they can balance the variables. Understand the advertiser issue, in a ear long ago I used to be in both the newspaper and radio business, as well as freelance writing. However you sort of expect some level of rigor from publications such as Grassroots, Hot Rod or the like, vs say Road & Track, Car & Driver. Just saying if your doing a performance build, it's the time slip and dyno that matter.Steve Lepper wrote:
The problems with doing a proper test of one of these are cost and logistics: you would have to build two complete differentials for your car and then hot-swap them at the track. How many of us have that kind of money? You can bet no magazine will do it... don't want to runs the risk of making that new big advertiser look bad (that's not a ding at Giken... it's just how that world works.)
The other problem is finding someone that knows what they're doing when tuning/adjusting them: the ones I've driven have been wrong after the "approved expert" has installed it, requiring at least one more diff R&R (more $$$) to rectify. Once they're set up correctly, they work quite well.
Until you have everything else on your car dialed-in perfectly, don't spend the money. Spend the money on the driver.
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Re: OS Giken Super Lock
Add link with correct spelling for 996 owners ;) http://www.wavetrac.net/news.htm" onclick="window.open(this.href);return false;
http://www.elitetint.com" onclick="window.open(this.href);return false; http://www.osgiken.net" onclick="window.open(this.href);return false;
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Re: OS Giken Super Lock
All Corvette diffs are not the same, the Dana 44 in the (manual trans) C4 is not the same animal that is in the C5 and C6. The C4 also lacks the power of the later cars, which likes to break diffs.Bill Schenker wrote:Might want to ask Junior Johnson (multiple Nat. Champ., multiple and current ASP Champ.) how good a stock 'Vette diff. is and what an OS Giken did for the car (C6 Z06).Jason Rhoades wrote:Stock Corvette diffs are very very good, even for autocross. ...
Just sayin, Jason....
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Re: OS Giken Super Lock
But it has been done... GRM did it back in 2009, with a proven driver, fixed track, same day.Steve Lepper wrote: The problems with doing a proper test of one of these are cost and logistics: you would have to build two complete differentials for your car and then hot-swap them at the track. How many of us have that kind of money? You can bet no magazine will do it... don't want to runs the risk of making that new big advertiser look bad (that's not a ding at Giken... it's just how that world works.)
The other problem is finding someone that knows what they're doing when tuning/adjusting them: the ones I've driven have been wrong after the "approved expert" has installed it, requiring at least one more diff R&R (more $$$) to rectify. Once they're set up correctly, they work quite well.
Until you have everything else on your car dialed-in perfectly, don't spend the money. Spend the money on the driver.
http://www.group2inc.com/pdf/grassroots ... sgiken.pdf" onclick="window.open(this.href);return false;
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Re: OS Giken Super Lock
Nice Jason!
I wonder how much better the OS Giken could have been with a tune by our local supplier/tuner. When Henry/Ken first had it installed in their MX5 they didn't like it. After they had the AX specific tune done that car did pretty well.
I wonder how much better the OS Giken could have been with a tune by our local supplier/tuner. When Henry/Ken first had it installed in their MX5 they didn't like it. After they had the AX specific tune done that car did pretty well.

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Re: OS Giken Super Lock
But why let facts/reality get in the way of known forum facts/misinformation/opinions?Jason Isley BS RX8 wrote:
But it has been done... GRM did it back in 2009, with a proven driver, fixed track, same day.
http://www.group2inc.com/pdf/grassroots ... sgiken.pdf" onclick="window.open(this.href);return false;

Last edited by Bill Schenker on Fri Dec 24, 2010 11:34 am, edited 2 times in total.
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Re: OS Giken Super Lock

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Re: OS Giken Super Lock
Edited my post to make it more clearerer for Mako.Mako Koiwai wrote:... what does this have to do with Jason's link? ... which is about as hard a facts as one is going to get on the net

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Re: OS Giken Super Lock
True the power is very different, although the torque is not. And when they installed the OS in the C6 they actually changed the case from the stock C6 to the Z06 case.Jason Isley BS RX8 wrote:[All Corvette diffs are not the same, the Dana 44 in the (manual trans) C4 is not the same animal that is in the C5 and C6. The C4 also lacks the power of the later cars, which likes to break diffs.
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Re: OS Giken Super Lock
I've had access to wheel speed data logs from a World Challenge GT Viper team that tested the OSG Super Lock against two other diffs. Per the suspension engineers involved the traces from the OSG were far smoother and showed more consistent and repeatable lockup and more neutral behavior (less push) on deceleration then the other two diffs involved in the test. I do not have those traces to publish because the team considered that information proprietary and a competitive advantage. But, even with that positive data the driver's had a more difficult time turning fast laps with the OSG Super Lock then with the other two diffs. I never heard the reasons why or if things got better with tuning. Unfortunately the team eventually folded like many other WC teams in this economy.
My conclusion from this bit of information was that the engineers were impressed with the OSG Super Lock, the drivers were not as impressed. Maybe it was because of the change in vehicle behavior after racing three years with the other two diffs? Maybe the Super Locks needed more tuning? Maybe the suspension needed some adjusting to work better with the Super Lock? I don't know.
My conclusion from this bit of information was that the engineers were impressed with the OSG Super Lock, the drivers were not as impressed. Maybe it was because of the change in vehicle behavior after racing three years with the other two diffs? Maybe the Super Locks needed more tuning? Maybe the suspension needed some adjusting to work better with the Super Lock? I don't know.
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Re: OS Giken Super Lock
Lots of drivers - in fast road racing cars - like a car that pushes on throttle, it feels stable. I think I was one of the few H Prod cars with a diff, most are still welding the spider gears. :unimpressed: Schotz was the only guy using a Torsen in T2, and proved it was faster than the clutch/cone/spool diffs the rest of the f-bodys were using at the time. Driver feel often makes more difference than data when it comes to lap times, if you are not comfortable you wont push it. However, if there is a better mouse trap a bit of driver retraining and chassis tuning can pay off.John Coffey wrote:I've had access to wheel speed data logs from a World Challenge GT Viper team that tested the OSG Super Lock against two other diffs. Per the suspension engineers involved the traces from the OSG were far smoother and showed more consistent and repeatable lockup and more neutral behavior (less push) on deceleration then the other two diffs involved in the test. I do not have those traces to publish because the team considered that information proprietary and a competitive advantage. But, even with that positive data the driver's had a more difficult time turning fast laps with the OSG Super Lock then with the other two diffs. I never heard the reasons why or if things got better with tuning. Unfortunately the team eventually folded like many other WC teams in this economy.
My conclusion from this bit of information was that the engineers were impressed with the OSG Super Lock, the drivers were not as impressed. Maybe it was because of the change in vehicle behavior after racing three years with the other two diffs? Maybe the Super Locks needed more tuning? Maybe the suspension needed some adjusting to work better with the Super Lock? I don't know.
Currently pondering pulling the clutch diff out of the H Prod car in favor of a Quaife. I like gear diffs on throttle.