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GT2, GT3, RS and Cup Car Discussions Discussions on all topics related to all Porsche GT vehicles |
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#16
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Re: Diff Is Gone
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Fatih Selekler 997.2 GT3 |
#17
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Re: Diff Is Gone
guard and done - should be on the Porsche option list imho
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#18
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Re: Diff Is Gone
X2
I've gotten some questions about my diff and specifically the durability due to the response I gave FTS earlier in this thread. I should clarify that I don't believe the Guard internals failed after only a few events; i.e. it wasn't a product defect or weakness. I now understand better and believe my issue was break in. I've been a willing participant in "tuning" the GT2 chassis with my shop; I did not send my diff to Guard. My shop has been trying different settings including ride height, spring rate, alignment and preload & ramps on the differential. In this case, we tried an initial amount of preload which ended up losing friction after a few track days. Not a problem for me because I knew we were trying different settings. We've since repacked and added more preload which feels great. I will continue to monitor but expect great durability. |
#19
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Re: Diff Is Gone
Once the issue is identified as the clutch packs in your case BMan, I don't think we ever thought that the Guard "internals" had failed you, by that I mean the ramps. Clutch packs will wear out of course and at least will need re-adjusting from time to time. I am not sure I understand the breake-in "issue," but no worries.
Similarly, the Porsche diff internals may very well be perfectly fine on my car, and it really is just the clutch pack that needs to be replaced and pre-load to be adjusted. So, Porsche vs. Guard diff --> the same function IMO. I do not know if Guard, OS Giken or who ever else is more "durable" as a complete unit, but at the end they will all wear most likely, nothing is permanent, similar to brake rotors IMHO. Any way, we'll see how your unit continues to perform and once I receive the new clutch packs from my dealer and we open up the diff, I'll report back about the Porsche "internals."
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Fatih Selekler 997.2 GT3 |
#20
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Re: Diff Is Gone
One of the service items I plan to when the motor is dropped for the coolant fittings is to have the PMNA clutch packs installed. Receiving my quote for this yesterday, the shop stated they can do the old 4 plate design, or the new (as of 2010) 8 plate design.
Per the shop, and I hope I get this correct, is that with the new 8 plate design the plates are thinner but more durable with more surface area. This will be the route I will likely take. I have to magine with my driving and setup, they should last me several years. |
#21
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Re: Diff Is Gone
I think that is what I have.
If I understood it right everything insidethe housing was replaced (Parts cost $2400.00)if that makes sense. Note, I have no idea what it all looks like and marginally understand how an LSD works. Orbit told me that I have the same as in a CUP car. HUGE difference in the car with 38/52 (I think that means lockup % under braking and throttle), but I think they initially packed or ramped? it too tightly: -Impossible to get the car turned, forget about T1 and oak tree. -Cars ass was planted SOLID, as long as I was on throttle or under braking, I could do whatever. -Once hot, the rear axle would be locked. I would come of the track and with minimal steering input the car would go clang, clang, clang. You could feel the wheels turning same speed. The backed off something, the ramps or less tightly packed? Whatever but the clanging went away, the rear got less planted and I can take tight corners again. Honestly I think the car was so much faster through long sweepers at Sebring, Road ATL and VIR that laptimes would be similar, even when having to park it at tight corners...
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Peter National PCA Instructor. Pics and youtubes ==> Daily driver '10RS white/gold. White OEM RS roll bar, red schroth seat belts, CUP LSD, lip and Gurney, Sharky, V1, K40 laser blocker. Sold '07GT3 white |
#22
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Re: Diff Is Gone
In our discussion, I did ask about ramp rates, and was told that the rates will not change when using the PMNA clutch packs, only more friction and that it will last longer / more durable, which suits me fine for my usage.
I don't think the LSD is holding me back right now, but its not often that I will have the opportunity to have this kind of work done, so its a 'while you're in there' service. |
#23
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Re: Diff Is Gone
Trying to learn more myself. After the LSD's been driven, especially hard, it will likely lose about 10-15% friction from the initial bench packing. So the tricky part is deciding how to pack the plates to allow for break in while not over packing at the same time.
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I had the same opinion and diff wasn't high on my list of needs. But now having driven a few events I am surprised how much of a difference it makes with braking stability, putting down power and even stability under modulation (climbing the esses ). Here's some pictures of my diff |
#24
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Re: Diff Is Gone
I picked the car up today from the dealer with the new clutch packs in the diff. Porsche of Tyson's has been so good in dealing with the whole thing, very appreciative of the work they did. Unfortunately, we could not get the Motorsports one as we could not exchange parts and I had to dish out $2250, which I hadn't planned on, and with other priorities, I passed on it, so we got the stock ones.
I wasn't expecting it, but I could almost immediately feel the difference. I got aggressive on couple of tight street corners, and the diff working was quite pronounced actually. So, let's see how many more corners it is going to last, it might make it to VIR next week We also talked about having a Tech Day on the GT3 there. They have quite a bit of information they were quite anxious to share on the technicals of the GT3 engine and drivetrain. I think it is a great idea, so we'll schedule one in the coming months, it would be an interesting and different type of event.
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Fatih Selekler 997.2 GT3 |
#25
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Re: Diff Is Gone
Fatih, very interesting that just replacing the OEM is so noticable..
It is hard to feel how it slowly loses it's function as it is so gradual. Try to keep notes on it, I am curious how long it actually works (A little). How many (track) miles on yours before you replaced it?
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Peter National PCA Instructor. Pics and youtubes ==> Daily driver '10RS white/gold. White OEM RS roll bar, red schroth seat belts, CUP LSD, lip and Gurney, Sharky, V1, K40 laser blocker. Sold '07GT3 white |
#26
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Re: Diff Is Gone
4 days on my repacked diff, 1 VIR and 3 Mid Ohio.
Feels great! I am guessing it's broken in slightly because it had considerable understeer at VIR but became more manageable at Mid Ohio. |
#27
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Re: Diff Is Gone
It sounds like the more aggressive LSD setup (w/ Guard or Motorsports internals) is great for stability but not good for tight corners. Does that mean it would not be a good idea for cars that's also used for autoX?
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#28
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Re: Diff Is Gone
I've only AX'd once, so I am not the best to comment. You don't have to set the diff overly tight; like mine. I'd suggest talking the Guard and asking their opinion on how to set it up for AX.
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#29
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Re: Diff Is Gone
Well, it will be a mixed use car.. autoX + DE.. so I wonder what's the way to go..
As of now, all the alignment setup for my car is leaning more toward DE.. for autoX, just drive "around" that.. |
#30
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Re: Diff Is Gone
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Fatih Selekler 997.2 GT3 |
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