Erik@GBox

Hey there everyone,

So I have finally gotten my status adjusted so there should no longer be an issue with posting this Great News for Porsche Owners and Racers.

There is a new Limited Slip Differential that in my opinion is in a class of it's own now available though me here at GBox.

The company that has developed this differential is called OS Giken. Check this out:

Os Giken has been producing professional racing differentials since 1975. They are manufactured in Japan and made available here in the states through Toyota Tsusho America, Inc.

The Super Lock LSD is a patented revolutionary breakthrough in clutch type limited slip differential design that allows the differential to have twice as many friction plates compared to conventional designs. (Meaning twice as many plates as all other currently available designs.) This design enables 100% full locking as well as unparalleled durability.

It features an Innovative lock timing control system that while under low or normal load conditions, allows the differential to function as a normal open differential, however once load is applied, it smoothly transforms into a 100% fully locking diff.

There is no better differential on the market in my opinion, and with a price of $1,790.00 it is even Very affordable in the differential market. If you have a G50, GT2, GT3, etc. and you have decided that you would like to upgrade to a bulletproof LSD, this is the one you want.

If I can help anyone with one of these please let me know.

Warmest Regards,


Erik Johnson
GBox Sales Manager
(303) 440-8899 work
(303) 895-4828 cell
www.gboxweb.com

Erik@GBox

So the reason I thought that everyone should see this is due to the recent discussions about differentials breaking housings, as well as prematurely wearing out.

I thought that I would add a couple of things here that should help to calm a couple of concerns.

In the 9 year that OS Giken has been producing these differentials, they have never had one failure. Now that is not just for the Porsche offerings, but for everything they build. In discussions with the company, they have had these differentials in cars exceeding 1100 HP. Not ONE failure, and to date not One rebuild. These are products of the highest quality, as such we will extend a 12 month, 12,000 mile warranty on all of these diffs.

Warmest Regards,


Erik Johnson
GBox Sales Manager
(303) 440-8899 work
(303) 895-4828 cell

Erik@GBox

Darn it. My status is not reading correctly I am sorry all. I promise I truly am a vendor now.

Erik Johnson

Erik@GBox

cool it is fixed. Thanks guys.

Erik@GBox

Now offering a rennlist group buy. Get in touch with me for details on this or check out some of the other posts in other rooms, as well.

Warmest Regards,


Erik Johnson

Red9

Erik-how does this LSD compare with the GT? Is it a direct competitor? What is the race track comparison? What about high performance road car.
Is it suitable direct replacement in a CupCar?

Erik@GBox

Hey there RED9,

Here is how this differential compares to the Porsche Motorsport, and Guard Transmission differential.

I posted this in a couple of the other rooms too, but here you go. The beginning of this was in response to the generally thought of opinion that the GT differential is still one of the best differentials on the market.

Believe me I understand where everyone is coming from here, but take a look at the OS Giken here, and I am sure that you are going understand where I am coming from with regard to saying that even the GT differential, which has always been a very good option in the past does not hold a candle to this differential.

A very bold statement I understand. But since it has been now brought up here are some things to consider when comparing these two.

The GT Differential has always had a similar design the Porsche Motorsport differential, that being a plate type ramping differential. It made it's mark here with the ability to custom choose between two different ramp angles within the same differential. Usually 40/60 and 80/80 but certainly a couple of other options as well. It also features 4, 6 or 8 plates internally, that is 2, 3, or 4 plates per side. It also features a more aggressive friction composition to that of the Porsche Motorsport diff.

Here is the rub. The GT differential has on average a 65 to 85 lbs. breakaway preload. This has shown to cause a couple of issues. The first being that as you enter into a tight turn your car has to overcome this preload in the process of turning in. So what right? That should not make much of a difference. Well actually it does. The more preload there is the harder it will be to get the car to turn, but this is not usually much of a problem as you get used to the differential, and modify your driving to compensate. What is a problem is the material that is removed from the plates inside the differential ever time this happens.

The Porsche Motorsport differential utilizes carbon as the primary friction material in their differentials, the GT diff does not. They use a moly blend, which is then plasma sprayed onto the plates to cause a friction material. This material is highly coarse and reacts in a way to not only lock the differential, which is good, but also remove metal from the opposing plates, which is bad. This combination of friction material and removed metal goes where?? Through out the gearbox, very bad. It especially goes directly into the input and pinion bearings, where it begins to cause problems inside of them as well. VERY VERY Bad.

So how is the OS Giken different? If you review the pic here, you will see that on the ramps themselves are counter springs that help you pull the ramps back to neutral when there is no force applied to them. It essentially reduces the breakaway to a very minimal amount, it basically opens the differential up, releasing the plates, so that you do not get unneeded lockup, and as a result unneeded wear. The friction material is again carbon, but due to the amount of plates which is more then double the GT or the PMS, as well as the way the differential works, they do not suffer from premature wear. Nor do they require the rear of the car to overcome excessive lockup in order to turn the rear end. (the difference in speed between the left and right tire.)

I understand that in the past we have all, including me always gone to GT for the strongest best differential made. I have for years recommended only them for racing applications. However with this new offering, as well as the difference in cost between the two differentials, I can not see how anyone could still do this.

GT Differential, $2,400 to $2,800 give or take.
OS Giken Differential $1,790.00

In the nine year that OS Giken has been making differentials, they have exactly ZERO failures. Now to make this completely understood, that is not just in their Porsche diffs, that is for ALL of their differentials across the board. That to me is pretty impressive.

Check out this pic, I think that if you have ever been inside of a Porsche LSD, no matter who built it, you will see, there is no comparison, and for the moment, no competition to this differential.

I hope that this answers your question here Red, I would not hesitate to put this into any racing application, but check your rules to make sure that there are not restrictions first. These differentials have shown no failure rate, even when put against 1100 HP engines. I think that is pretty impressive. What do you think?


Warmest Regards,


Erik Johnson
GBox Sales Manager
(303) 440-8899 work
(303) 895-4828 cell

Red9

Are there any Porsche racing applications that can show real experience using this LSD?
Not trying to be a smart a..... -- my questions will save you answering the same question a thousand times!

analogmike

One of the fastest air-cooled non-turbo 911s in the country is running this diff. He may not want me to say who he, is but he is rarely beaten by anything but a 997 GT3 cup or GTA car.

Erik@GBox

There are many racing applications that I am aware of, but it would out of place for me to name names here. I hope that you understand.

Erik Johnson
GBox Sales Manager
(303) 440-8899 work
(303) 895-4828 cell

Paul Guard

Although I am retired from Guard Transmission, I don’t like hearing that the products I helped develop are being held up in a negative light. Let me correct the inaccuracies that have been excitedly presented as facts.

First of all, only Porsche street cars (intended for street use) come equipped with carbon friction discs. Track use will fry carbon friction discs pretty quickly, which is why all Porsche track cars utilize a far more aggressive friction disc (far more durable and functional than a carbon disc). When I was with Guard Transmission, I would rebuild perhaps 3 or 4 Porsche street LSDs each week, replacing the carbon discs with our own Motorsports style discs (which also require using our harder REM plain plates). This makes a street LSD far more trackable, although certainly not on par with a complete Motorsports LSD (whether that be a Porsche Motorsports or Guard/GT unit).

Given the fact that a good used Porsche street LSD upgraded with Motorsports style friction discs will perform properly for many times longer than any LSD equipped with carbon friction discs (30,000+ miles for street use), no shop should ever talk their customer into replacing an OE street LSD with a less versatile product. And, if they should sell that customer any aftermarket differential without offering him something for his removed OE LSD core (or returning it to him to sell on e-bay), well … that just isn’t right.

Regarding the number of plates in an LSD: In my experience, the number of plates makes little difference in the service interval of any LSD. Service intervals are far more affected by the type of friction material in the unit. (In every street LSD with carbon discs that I’ve rebuilt, the service interval was at least quadrupled by replacing the carbon street discs with Motorsports style friction discs … and as I‘ve already said, performance was greatly enhanced at the same time.) Although my company used to offer an LSD that would accept 24 plates (12 friction + 12 plain), we never had a shop ask even once for this many active discs to be installed. The Porsche engineers (who are pretty smart guys), have never seen a need for more than 8 friction discs (+8 plain plates) in their Cup or GT3RSR race cars.

It’s worth stressing again that a conventional LSD can be set up in any number of ways by varying plate, disc, and belleville washer thickness, number of active friction discs, ramp angles, etc. There is no single set-up that is perfect for every user, so the ability to adjust an LSD to different settings (and the ability to later change those settings) is important to most shops, and certainly to any race team. Set-up versatility in any track LSD is essential. Any Porsche owner who has only an open diff will of course see some level of improvement with almost any LSD or TBD that they choose … but the smart owner who’s interested in aftermarket differentials, will only deal with a mechanic who can intelligently discuss the pros & cons (quality, price, intended usage) of each choice with him.

When it comes to LSD and suspension set-up, BMC&G is by far the most experienced of any shop in the U.S. Since Brian has taken LSD tuning to a new level through his interaction with every U.S. Pro race team as well as Porsche engineers in Weissach, I naturally value his opinion on various LSD types more than any other shop. According to Brian, extensive testing was performed by Porsche Motorsports in which he was the service technician … once in early 2008 with an ’07 GT3RSR, and again in late 2008 with an ’08 GT3RSR. Porsche gathered every different LSD type that they could find … factory LSDs, aftermarket LSDs, high priced LSDs, moderately priced LSDs, and even one low priced LSD. Onto each of these LSDs was installed a ring gear*, bearings, and the required shims. Each LSD was pre-measured and set up to quickly fit into the same transmission. (*Eight R&P sets were selected with identical R factors, because comparative testing had to be performed in a single day.) Different pre-measured internal disc and plate stacks were assembled for each tunable LSD, which would allow for quick changes in stack preload (breakaway torque) during the test period. The drivers were shielded from knowing which unit they were testing or not testing. Each mini test session was comprised of a 5-lap run, with all results being data logged. There was about 20 minutes spent between each test session installing a different LSD.

1) The lowest lap times and highest driver satisfaction were obtained with Ricardo's new viscous type LSD. This is a near perfect LSD for a number of reasons that don’t need to be fully explained here. Suffice it to say that the ultimate in performance does not come cheap. The cost of this LSD is well over $20,000.

2) A group of LSDs virtually tied for a very close 2nd place behind the viscous unit. These LSDs all had high breakaway torque settings, with the only exception being a very high quality German made LSD with zero preload. All of these LSDs had Motorsports type friction discs. While the handling characteristics of the car varied slightly between LSDs, the lap times were virtually identical.

3) Further testing was performed using lower breakaway torque values with any of the above LSDs that would allow such adjustments. In each case, lap times were significantly slower at these reduced pre-load settings.

4) Singled out by its slow lap times and worst exit understeer characteristics was the lowest priced LSD. Porsche actually spent a little more time testing this unit than some of the others, because they were intrigued by the low cost … not because they were impressed with its “counter springs” or the 20+ plates in it. However, each time the driver was sent out with this unit, he returned to the pits with a “thumbs down” in regards to its track performance. Obviously, no Professional Porsche road racing team would ever run one of these LSDs, despite its low cost.

When the day comes that a vendor can truthfully claim that the LSD they retail has replaced Guard’s as standard equipment in every RUF Rt12 Turbo, I will concede that this product is probably as strong as a GT LSD. When that vendor can further claim that their LSD has replaced Porsche’s LSDs in Professional road racing cars, I will also concede that this is the new standard by which LSD comparisons should be made. In the meantime, I feel that I am certainly within my rights to defend any product (that I helped develop) from being unjustly slammed on Rennlist by one of its sponsors.

Paul Guard


______________

“Remember Jerry … it isn’t a lie, if you believe it.” George Castanza, Seinfeld

Paul Guard

Mike ... I know you mean well, but ask your buddy to tell you which LSD he would have chosen if he could have had ANY of them for free.

Erik@GBox

Well I was really hoping to avoid getting into a pissing contest with you here Paul, so I will try to address your obviously well thought out comments here with some of my own.

First of all, as you very well know I have recommended and sold a great many of the GT differentials in the past, and have always held them to be one of the best differentials on the market. However, your view point of my sales ability has always been a biased one and some of your comments of the past certainly border on being bigoted, and self serving.

Had you been the one to develop this differential, (the OS Giken) and brought it to market, you would not be saying a thing about my comments. But due to the fact that another company has brought out some competition to you now, and due to the fact that I have been fortunate enough to have found this product, you now look to cast not only our company but also me personally and professionally into a poor light. Really? Do you really have nothing better to do in your retirement then to engage in this obvious smear campaign?

It should be noted here that I have nothing but respect for Paul Guard and Guard Transmission, but after having to deal with this for several years now, enough is enough.

I noticed that you refrained from talking too much about what the OS Giken actually brings to the table here. I am guessing that this is due to the fact that you really don't have much space here to criticize.

So let us you and me set the record straight for everyone here. Porsche street differential, as well as Porsche Motorsport differentials, until recently, have been using carbon as the primary friction material in their differentials for years and years. Of this I am sure you will agree, as your prior comments here said that you had in the past been rebuilding and upgrading these differentials with your more aggressive friction and plain plates, replacing the carbon ones.

This has since changed, Porsche now uses a Brass friction material that that is actually quite similar to their synchronizer material, (see pic) The reason behind this is two fold. With the addition of greater HP and Torque the past Carbon plates were simply not holding up under the stress, and maintaining a locked state during track application. This better friction material would allow the Porsche differential to increase it's grip without having the need to completely redesign the internals to allow for more plate internally. Here is the more important consideration though. The main reason for going to a brass friction material is to ensure that as the differential sheds material, which all differentials do a certain degree, that material does not work in a detrimental way to the rest of the gearbox. Brass is soft, and thereby does not create the same amount of detrimental particulate as say, a steel friction disc. As the brass is soft the risk of pushing materials, ie steel from the plain plates, and Moly from the friction discs, into the gear sets and bearings, is minimal.

Paul does make a very good observation here that a upgraded differential with a more aggressive friction material will allow for the differential to last a great deal longer, especially in a street application. His comment regarding a shop, presumably us here, offering a product, to our customers, that would be less versatile to their OEM LSD is almost laughable. Anyone who has done business with us here will attest to the point that we are a quality shop, with the highest levels of customer service and integrity. If anything here, I am trying to educate and share a product here that offers more durability and versatility, NOT less.

Regarding the number of plates in a LSD, and how that number effects the service interval and durability of a differential, I think we will just have to agree to disagree on this point. That you have not seen a differential's service interval increase with the reduction of plates, simply does not follow logical thought. By increasing the number of friction plates and plain plates in a differential, you effectively reduce the amount of work that the differential is required to do, you also reduce the amount of heat generated internally to the differential, due to the balance of work load throughout the greater number of clutches. A greater number of plates also increases the reliability and general operation of the differential to hold a greater amount of HP and Torque during track application.

Here is the real reason why the GT differential, as well as the Porsche Motorsport does not utilize more plates, they have not figured out a way to get the differential to release it's pressure once those plates have locked up to each other. This is the greatest advance that the OS Giken offers in their differential. The ramps on the OS Giken differential have counter springs that effectively allow the differential to re-open when the amount of torque is reduced to the differential. This is in my opinion, the advancement in mechanical differential operation that should be noted and is not available in any other differential. This allows for a very minimal amount of preload to be needed, which allows for greater feel and car control. The car does not need to have to overcome the locking effects of the differential, (which sheds metal and material in the process) when the car is not under heavy torque load.

This allow the car to turn in more accurately, and also allows the differential's durability to increase exponentially. It is effectively not having to continue to work against itself when there is no need, as when in a tight turn.

I would completely agree regarding the point made that no differential is going to be perfect for all users. This is one of things that really made the GT differential worth exploring. The multiple ramp angles cut on to the GT differential, gave the driver the ability to customize the diff to his or her own driving style. Guess what, the OS Giken is completely adjustable, as well.

Paul I will not even discuss with you the differences in our professional abilities, as this will never be something that you and I are ever going to see eye to eye on. The fact that you would even go there in this discussion does not become you.

The idea that the only company competent enough to educate a customer on their options, good, bad etc, as well as the costs involved, is BMC&G and Brian Copans, really says a lot about how you feel about the people that have purchased, installed, and recommended your products for so many years.

Now before this gets out of hand, as well, Brian Copans has certainly earned the respect that he gets, and his list of accomplishments is something for any dedicated Porsche Company to strive for. Saying that he is the only company who can correctly setup a differential, as well as intelligently discuss the differences between differentials, however, pretty arrogant Paul. I would certainly think that there are any number of time tested professionals out there that can offer these services, not just us here at GBox, and to be honest, I find your thoughts on this to be insulting not only to me personally, but to every builder out there who has put in the time.

Lastly here, I doubt that you will ever be able to admit that the GT products have real competition in the market place now. I fully expect that you will continue to cast negative comments on the competition, no matter who they are. Especially so when they are poised to take a great deal of attention away from you.

So be it. I will not continue to compare and contrast your delusions with reality any longer. This dialog has become non-productive and simply does not justify my spending any more time on it with you.


Warmest Regards to you all here and I appreciate your patience today with me.


Erik Johnson
GBox Sales Manager
(303) 440-8899 work
(303) 895-4828 cell


PS sorry the pic would not load.

Paul Guard

This is absolute insanity. While trying not to step too directly in the poo, I’ll again try to correct the inaccuracies that have been presented as facts.

Porsche Motorsports has never utilized carbon as the “primary friction material” in their LSDs. As I’ve said, only Porsche street LSDs (meant for street use only) utilize carbon friction discs. Furthermore, Porsche Motorsports has NOT recently gone to a brass friction disc. Only two years of Porsche street LSDs had brass friction discs … most recently one year of 996 street car production. (Porsche returned to a bonded carbon disc with the next year’s model.)

Porsche track (race) cars use upgraded friction discs from the MOTORSPORTS division … thus these discs are called “Motorsports” friction discs. The distinction between “Street” and “Motorsports” appears to have been muddled time and again, either out of ignorance, or to mislead the reader into believing that carbon has always been the standard for a Porsche racing disc. Once again with emphasis : Porsche’s Motorsports LSDs all use a more aggressive Motorsports friction disc, not a carbon (nor a brass) friction disc.

Porsche has always been open to different LSD designs, and the concept of fully unlocking the discs is nothing new. The use of the Drexler LSD by some Pro race teams is a prime example of this experimentation. Every one of our LSDs has a similar option, and in fact we had an experimental “Torque-Flow" flow LSD (that adjusted through a small window in the side cover) over five years ago. So to say that Porsche and Guard have been “unable to figure out how to do this” is absurd.

Regarding the versatility of an OE street LSD: These can normally be upgraded with Motorsports internals … 2, 4, 6, or 8 friction discs, any thickness of Belleville washers … even different ramp angles, if desired … how much more versatile can you get ? People can go to any shop they want to have these upgrades performed … I have no secrets, and there’s certainly no reason you “gotta call me”.

For the record (and dozens of customers from over the years can back me up on this): Whenever I learned that a potential customer (calling for one of our 4340 Chromoly units) already had a factory LSD (either “Street” or “Motorsports"), I always offered the FAR less expensive option of rebuilding their existing LSD. ALWAYS. EVERY TIME. I usually ended up selling one of our units, but not because of a hard sell on my part.

As for the suggestion that I only value the opinion of Brian Copans, or that my reference to BMC&G is somehow a slap in the face of all the other shops who have been loyal customers over the years … this is a sophomoric argument. Brian was the person installing all the various LSDs into the RSRs for testing … the guy making all the adjustments to all of those LSDs in the most comprehensive comparitive testing between the various LSDs ever performed … who else would I be referencing for the results of those tests ? Should I have pretended that I was privy to all of this inside information because I’m such a special guy?

All these soap box theatrics using words like “bigoted", “biased”, “self-serving", “obvious smear campaign”, “differences in our professional abilities”, “laughable”, “arrogant”, “delusions with reality” … OMG, man !! .. have you totally lost it ? The only reason I’m even here is because you stepped over the line when you proclaimed to the world that a GT LSD “does not hold a candle to (your) differential.” If you “didn’t want a pissing match", is this something you should be spouting? Did you think that just because I’m retired, I would have no comment ?

As for your “having to deal with this for several years now, enough is enough” … All I ever did was to once give you a mild scolding for breaking the rules that every other vendor follows on the Pelican board, and yet you’ve continued to bombard Pelican with your “sneak infomercials” (complete with glossy photos), with one as recently as two weeks ago. Why do you feel that you’re so superior, that the standard rules of conduct somehow don’t apply to you ?

All this stuff about me feeling threatened about the competition is ridiculous. I’m retired. In my last post I specifically suggested that someone in the market for an LSD should go to a shop that will intelligently balance what the customer’s needs are against what’s available … someone like Steve Weiner / Rothsport is just one example. They sell the same LSD that you’re promoting, but they remain objective toward ALL brands of LSD because their goal is long term customer satisfaction, not currying favor with a Master Distributor in order to win exclusivity of Porsche-specific product. None of this is to say that I don’t have respect for “your shop”. I have a great deal of respect for Stan. He’s a wonderful individual. I wouldn't mind seeing him get a more mature individual for the sales division.

Just so we understand one another … so long as you don’t reference a Guard/GT product (directly or veiled), or spout total inaccuracies about factory parts in any of your future infomercials, there’s no reason that you’d be reading a response from me again. Rennlisters are smart enough to sort through the BS on their own.

Paul Guard

______________

“Remember Jerry … it isn’t a lie, if you believe it.” George Castanza, Seinfeld

Erik@GBox

Rennlisters are smart enough to sort through the BS on their own. I completely agree with you. As such I see no reason to discuss this with you further.

Have a good retirement Paul.

Erik Johnson
GBox Sales Manager
(303) 440-8899 work
(303) 895-4828 cell