View Poll Results: What differential do you use?
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STR Prep - Differential Discussion
10-20-2011, 11:13 AM
#11
I don't like OS Giken's response. Road racing is very different wear than autox and durability road racing means nothing for autocross.
I had the same BS from DriveShaft Shop with the "1000hp hubs" that repeatedly broke with 330whp and 315/30/18 A6s. I went through 6 hubs before they acknowledged there was a problem. Up until that point, they said it wasn't their fault and blamed everything from the installation to axle nuts.
I don't buy the "low oil" line. Runs are so short and far between that lack of oiling shouldn't be a factor.
I had the same BS from DriveShaft Shop with the "1000hp hubs" that repeatedly broke with 330whp and 315/30/18 A6s. I went through 6 hubs before they acknowledged there was a problem. Up until that point, they said it wasn't their fault and blamed everything from the installation to axle nuts.
I don't buy the "low oil" line. Runs are so short and far between that lack of oiling shouldn't be a factor.
10-20-2011, 12:22 PM
#12
Registered User
Any link to the OS Giken failures? I tried searching and only found a few posts in a thread saying "my diff failed" -without any explanation of what failed or pictures.
I've been using OS Giken for years in many different applications including a 800whp Turbo NSX with zero issues and practically no measurable wear. They are awesome high quality units with a TON of adjustability and tuneability. I havn't heard of any OS Giken failures ever and am interested in seeing what happened in these AutoX examples...
I've been using OS Giken for years in many different applications including a 800whp Turbo NSX with zero issues and practically no measurable wear. They are awesome high quality units with a TON of adjustability and tuneability. I havn't heard of any OS Giken failures ever and am interested in seeing what happened in these AutoX examples...
10-20-2011, 03:50 PM
#13
The failure according to Mark at Toyota Tsusho America (OS Giken's US distributor) is "cooking the oil" due to limited fluid capacity, which in turn can and did lead to a side gear failure. They are apparently now shipping units with strengthened side gears.
I would love to see pictures as well
I would love to see pictures as well
10-20-2011, 10:32 PM
#14
Thread Starter
I would question whether or not it is autocross runs that cause them (OSGiken) to fail? Not everyone that uses them for autocross has had failures. Is it really the long trips to get to events (i.e. Tours/Nationals) that have them spinning with no significant variation in speed for many hours at a time on the highway that causes the problem? Variation in speed, stopping, accelerating would likely help oil move around aiding in lubrication and cooling?
I would guess that for most racing applications the cars are transported to events thus by passing the sustained highway scenario.
I would guess that for most racing applications the cars are transported to events thus by passing the sustained highway scenario.
10-21-2011, 05:15 AM
#15
Registered User
I would question whether or not it is autocross runs that cause them (OSGiken) to fail? Not everyone that uses them for autocross has had failures. Is it really the long trips to get to events (i.e. Tours/Nationals) that have them spinning with no significant variation in speed for many hours at a time on the highway that causes the problem? Variation in speed, stopping, accelerating would likely help oil move around aiding in lubrication and cooling?
I would guess that for most racing applications the cars are transported to events thus by passing the sustained highway scenario.
I would guess that for most racing applications the cars are transported to events thus by passing the sustained highway scenario.
1qt of fluid isn't much but I would really like to see pictures of exactly what failed and maybe diff temps if anyone recorded them.
10-21-2011, 07:29 AM
#16
Another email from Mark Mendoza @ OS Giken
The OS failures were hidden within a few different threads. I'll see if I can dig them up later today.
I have had a lengthy discussion with OS Japan about this and they are confident that the new design S2000 LSD will be much more durable than the current version. That being said, the only true test for this will be through our customers, who have only started equipping them recently. One customer should be receiving his very soon now and we are looking forward to seeing how he does with it installed.
As far as any guarantee, please understand that these parts are meant for race-use, and as you well know anything can happen in a race environment. OS designs and builds parts to be as durable as possible while offering the best performance, but cannot guarantee that the unit will last forever. (Although, for the vast majority of our LSD customers, it does.) We have been fortunate to have been able to build a solid reputation for offering the best LSD on the market, and it is very unfortunate that the S2000 users have had their faith in OS shaken due to the recent string of problems with the SCCA crowd. Needless to say, this has raised attention all the way to the president of the company and we are doing our best to offer a viable solution.
FYI, since its release in Japan about 10 years ago the OS LSD has been the most popular choice for S2000 owners by far, as all the other clutch-type LSD manufacturers have had a lot of unit failures in the field.
Currently I have a few of the old-design S2000 LSD in stock, but will most likely request to return them to Japan in exchange for the new design. All new incoming inventory from Japan will be the new design. We expect normal inventory items to start arriving in December (estimated).
If you do choose to go with an OS LSD, just specify to your dealer that you need the new-spec version and we will be sure to comply. Most likely, we will only have the new version in stock anyway. If you like, you can contact me when you are ready and I can coordinate your order through our local dealer and I'll make sure that you are getting the new-spec version (we don't sell direct to the public).
Design-wise, the only shared part between the old and new type are the pinion gears. Side gears on the old unit were a 2-pc design but the new one is a larger 1-pc design which is much stronger; the remainder of the unit had to be redesigned to accommodate the larger side gears. As with all OS gears, they are raw-forged, chemically heat-treated, etc. Basically, as strong as can be made. The new-design version also uses a new type of cone spring which has a thicker diameter, so that would be the easiest visual cue for a new-type unit without actually opening it up and checking the side gears, etc.
If you need additional info just let us know!
As far as any guarantee, please understand that these parts are meant for race-use, and as you well know anything can happen in a race environment. OS designs and builds parts to be as durable as possible while offering the best performance, but cannot guarantee that the unit will last forever. (Although, for the vast majority of our LSD customers, it does.) We have been fortunate to have been able to build a solid reputation for offering the best LSD on the market, and it is very unfortunate that the S2000 users have had their faith in OS shaken due to the recent string of problems with the SCCA crowd. Needless to say, this has raised attention all the way to the president of the company and we are doing our best to offer a viable solution.
FYI, since its release in Japan about 10 years ago the OS LSD has been the most popular choice for S2000 owners by far, as all the other clutch-type LSD manufacturers have had a lot of unit failures in the field.
Currently I have a few of the old-design S2000 LSD in stock, but will most likely request to return them to Japan in exchange for the new design. All new incoming inventory from Japan will be the new design. We expect normal inventory items to start arriving in December (estimated).
If you do choose to go with an OS LSD, just specify to your dealer that you need the new-spec version and we will be sure to comply. Most likely, we will only have the new version in stock anyway. If you like, you can contact me when you are ready and I can coordinate your order through our local dealer and I'll make sure that you are getting the new-spec version (we don't sell direct to the public).
Design-wise, the only shared part between the old and new type are the pinion gears. Side gears on the old unit were a 2-pc design but the new one is a larger 1-pc design which is much stronger; the remainder of the unit had to be redesigned to accommodate the larger side gears. As with all OS gears, they are raw-forged, chemically heat-treated, etc. Basically, as strong as can be made. The new-design version also uses a new type of cone spring which has a thicker diameter, so that would be the easiest visual cue for a new-type unit without actually opening it up and checking the side gears, etc.
If you need additional info just let us know!
10-21-2011, 07:42 AM
#17
I would question whether or not it is autocross runs that cause them (OSGiken) to fail? Not everyone that uses them for autocross has had failures. Is it really the long trips to get to events (i.e. Tours/Nationals) that have them spinning with no significant variation in speed for many hours at a time on the highway that causes the problem? Variation in speed, stopping, accelerating would likely help oil move around aiding in lubrication and cooling?
I would guess that for most racing applications the cars are transported to events thus by passing the sustained highway scenario.
I would guess that for most racing applications the cars are transported to events thus by passing the sustained highway scenario.
Mark actually mentioned that significantly less than a quart of fluid fits - he actually said less than 800cc.
10-21-2011, 08:10 AM
#18
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The failure according to Mark at Toyota Tsusho America (OS Giken's US distributor) is "cooking the oil" due to limited fluid capacity, which in turn can and did lead to a side gear failure. They are apparently now shipping units with strengthened side gears.
I would love to see pictures as well
I would love to see pictures as well
10-21-2011, 08:15 AM
#19
Originally Posted by IntegraR0064' timestamp='1319154627' post='21088216
The failure according to Mark at Toyota Tsusho America (OS Giken's US distributor) is "cooking the oil" due to limited fluid capacity, which in turn can and did lead to a side gear failure. They are apparently now shipping units with strengthened side gears.
I would love to see pictures as well
I would love to see pictures as well
10-21-2011, 08:34 AM
#20
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Originally Posted by Banannie' timestamp='1319213440' post='21090004
[quote name='IntegraR0064' timestamp='1319154627' post='21088216']
The failure according to Mark at Toyota Tsusho America (OS Giken's US distributor) is "cooking the oil" due to limited fluid capacity, which in turn can and did lead to a side gear failure. They are apparently now shipping units with strengthened side gears.
I would love to see pictures as well
The failure according to Mark at Toyota Tsusho America (OS Giken's US distributor) is "cooking the oil" due to limited fluid capacity, which in turn can and did lead to a side gear failure. They are apparently now shipping units with strengthened side gears.
I would love to see pictures as well
[/quote]
It looked like they used a generic side gear with an application specific piece pressed in for where the axles come in (yes, I know, not a very technical description, but hopefully you get it). Where those two metals met, it very clearly failed and sheared apart. Once the side gears failed, they took out the spider gears, and the whole thing got chunky - quick.
I hope to have the new diff very soon... unfortunately our season here is almost over
