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GT2 and GT3 owners - Here is the only differential to get!!!

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Old 10-20-2009, 06:22 PM
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Erik@GBox
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Default GT2 and GT3 owners - Here is the only differential to get!!!

Hey there everyone,

I am still trying to get used to the rules of posting here, so forgive me if I ask to you do more work then you needed to.

I posted a great post about the new OS Giken differential in the Porsche Cup Car forum. You need to check it out if you are going to be changing out your differential this winter.

It is the only differential to have, and I think that if you take a good look at the pic I attached to the post you will be able to see why.

The Porsche Motorsport differential is a 8 plate differential, where as the OS has more then double the amount of plates.

Let me know if you need one of these or anything else that would be gearbox related, as this is what we do.

Warmest Regards,


Erik Johnson
GBox Sales Manager
(303) 440-8899 work
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Old 10-20-2009, 06:27 PM
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LVDell
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Erik, sounds like a great product. Welcome aboard!

Any way you could compare, say the following with your product (and cost would be helpful):
1. OEM
2. Cup diff (which I installed in my GT3)
3. Guards
4. Yours

Also, with yours do you need to replace the entire unit or can you just replace the clutch packs?
Old 10-20-2009, 07:41 PM
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TurboCup87
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Originally Posted by LVDell
Erik, sounds like a great product. Welcome aboard!

Any way you could compare, say the following with your product (and cost would be helpful):
1. OEM
2. Cup diff (which I installed in my GT3)
3. Guards
4. Yours

Also, with yours do you need to replace the entire unit or can you just replace the clutch packs?
+1 Part of what is hard for us to know is the difference in cost for the parts, but also what actually has to be done to the car; and what this costs. How long does this diff/clutch pack system last?
Old 10-20-2009, 07:44 PM
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996FLT6
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What's the material used for the casing? I understand it's a 1.5 way diff?mike
Old 10-20-2009, 08:13 PM
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Erik@GBox
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Okay, since we all know that the GT differential is really what any thing is going to compared against, and since this was brought up in another room, I think I can answer your questions with this.

This was in response to the reply that the GT differential could still be considered the best.

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. The PMS differential is just as pricey if not a bit more.
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.

Warmest Regards,


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

Last edited by Erik@GBox; 02-15-2010 at 01:21 PM.
Old 10-20-2009, 08:23 PM
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Porsche917K
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I have no personal experience but I have heard good thinks about the Giken from Steve W. at Rennsport.
Old 10-20-2009, 10:07 PM
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AllanJ
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I don't understand the pros/cons of the different lockup rates are besides the fact I'd want a 40/60 or so diff for street/track use and some folks use 80/80 on track only cars.

What are the different rates for the OS Giken and based on what was described above, is this even an issue anymore? I drive street/autox/track, rain or shine.

(My diff is worn out so it will be replaced this winter with something......)

Thanks,
Old 10-20-2009, 10:21 PM
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roberga
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50/80 for you Allan :-)
Old 10-20-2009, 11:47 PM
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996FLT6
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I would not recommend 80/80 - if u drive in rain( just standing water)- it'll lockup which makes for a swaying rear end- scary- cannot go past 55 mph. 50/80 is the ticket- good street/track manners. Mike
Old 10-20-2009, 11:56 PM
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Crazy Canuck
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Sorry if I'm asking a stupid question (had a few beers tonight) but GT diff? Do you mean stock?

How does this diff compare to Guard?
Old 10-21-2009, 12:49 AM
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AllanJ
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GT = Guard

Thx Gord and Mike.
Old 10-21-2009, 01:11 AM
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P.J.S.
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group buy rennlist special price is what on this? :-)
Old 10-21-2009, 01:30 AM
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iLLM3
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Originally Posted by 996FLT6
I would not recommend 80/80 - if u drive in rain( just standing water)- it'll lockup which makes for a swaying rear end- scary- cannot go past 55 mph. 50/80 is the ticket- good street/track manners. Mike
Mike, what is the stock diff at for a GT2/GT3??

Martin
Old 10-21-2009, 01:53 AM
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IPguy
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Originally Posted by PJS996GT3
group buy rennlist special price is what on this? :-)
+100
Old 10-21-2009, 03:24 AM
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996FLT6
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I know stock diff on 6gt3 is 40/60 don't know bout 6gt2(from memory they are the same). Problem lies in with stock diff the preload is low so still get wheelspin(granted felt stable vs a busted one) Plus the fact that brass stuff it ain't going to last. I would upgrade in a heartbeat when LSD is gone- very scary on late braking and lazy on acceleration out of a corner. Mike


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