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I'm a long time track rat, and recently picked up a 2015 Cayman GTS w the X73 suspension. I've done three track days so far and found the handling to be excellent.

I recently received an email from Suncoast Porsche that featured a sale on the "Rear Reinforcement Strut Upgrade" for the 981. I did some research but didn't find any discussion of this upgrade or mention a problem with the 981 rear suspension not being stiff enough.

Anyone know of any rear suspension stiffness issues or have any experience with this brace upgrade? As I mentioned above, my GTS handles great and is very nicely balanced. Stiffening the rear typically dials in more oversteer, which in my (limited) experience does seem not necessary or desirable.

-eland
 

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I'm a long time track rat, and recently picked up a 2015 Cayman GTS w the X73 suspension. I've done three track days so far and found the handling to be excellent.

I recently received an email from Suncoast Porsche that featured a sale on the "Rear Reinforcement Strut Upgrade" for the 981. I did some research but didn't find any discussion of this upgrade or mention a problem with the 981 rear suspension not being stiff enough.

Anyone know of any rear suspension stiffness issues or have any experience with this brace upgrade? As I mentioned above, my GTS handles great and is very nicely balanced. Stiffening the rear typically dials in more oversteer, which in my (limited) experience does seem not necessary or desirable.

-eland
I stiffened up the rear a lot because that's where all of the weight is. The nose is so light under throttle, it's just going along for the ride. The Tarrett Engineering rear spring hat did the trick:



http://www.planet-9.com/981-cayman-and-boxster-competition/172746-boxster-track-build-3.html


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I saw that piece too and was wondering if it is a stock piece from the GT4.
I'd fully recommend the upgrades I did:

JRZ RS1 touring
Tarrett rear spring hats
Tarrett GT3 competition control arms (x4)
Tarrett adjustable rear track rod (toe control)

Car rides like it's on rails and compresses more comfortably than OEM suspension, while also rebounding more quickly. Steering is even more direct.


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Schnell has a bar that goes on the underside of the car to keep things tight. It is like one in the front of cars that go between the shock towers to stiffen the chassis.
I have it and am happy with it. My car was lowered and it occasionally hits the ground, but has held up.

I also have a BGB harness bar that provides a stiffness increase between the top side of the rear shock towers.

So I am covered top and bottom of the rear suspension.

I also have the Schnell front bar and like it a lot.

V6
 

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Back to the original question! Will adding this brace provide any benefit? Is there any weakness in this area that this solves? I believe this brace is used on higher HP versions than the standard 981 cars?? So,,,,if I spend the $155.00 what will it do for my car? Will the ride be impacted? Will the car corner flatter? Will my wallet be lighter with no benefit? Anyone done this mod? Inquiring minds need to know! Thanks!
 

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Back to the original question! Will adding this brace provide any benefit? Is there any weakness in this area that this solves? I believe this brace is used on higher HP versions than the standard 981 cars?? So,,,,if I spend the $155.00 what will it do for my car? Will the ride be impacted? Will the car corner flatter? Will my wallet be lighter with no benefit? Anyone done this mod? Inquiring minds need to know! Thanks!
What problem are you trying to solve? If it's deflection of the suspension in 1.5g banked cornering, you can first replace the rubber in the suspension. No point in stiffening the left-right up just to have all of the force exit out the bushing. Which is why I made my original suggestion about where to tighten things up.


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Back to the original question! Will adding this brace provide any benefit? Is there any weakness in this area that this solves? I believe this brace is used on higher HP versions than the standard 981 cars?? So,,,,if I spend the $155.00 what will it do for my car? Will the ride be impacted? Will the car corner flatter? Will my wallet be lighter with no benefit? Anyone done this mod? Inquiring minds need to know! Thanks!
I saw the same advertisement. It didn't look all that substantial, so I was skeptical.
I raised this very same question on the PCA Cayman forum... the comment I got back was, essentially: "... snake oil, don't bother". Apparently the part has been around for a while.

D
 

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Back to the original question! Will adding this brace provide any benefit? Is there any weakness in this area that this solves? I believe this brace is used on higher HP versions than the standard 981 cars?? So,,,,if I spend the $155.00 what will it do for my car? Will the ride be impacted? Will the car corner flatter? Will my wallet be lighter with no benefit? Anyone done this mod? Inquiring minds need to know! Thanks!
As I suspected it is part # 31 under rear suspension on the GT4 it is not shown under the S or GTS.
REAR SUSPENSION for 2016 Porsche Cayman
 

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If you drive on the street, it likely makes little to no difference. If you go to the track, then it will probably help some, and it will help cars with X73 and or other modified suspension more than a stock car. It will stiffen the rear of the chassis and obviously does have some effect otherwise Porsche would not put it on a GT4. It does not stiffen the rear suspension as some people may be thinking. It does help to eliminate some chassis flex though, which makes the rear platform of the car more stable, which allows the actual suspension components to do their job better and maintain more stable suspension geometry. The end result at the track will be a car that keeps it tires flatter and more parallel to the ground, which equates to more consistent and greater grip.

If you are in a stock car and pulling .8 Gs on a freeway ramp, probably don't need this. If you are at the track and pulling 1-1.2 repeatedly, it would likely be of some help. If you have a modified car with Comp R tires and are pulling 1.3-1.5 Gs on the weekends, then it will make a difference. How big of a difference is up to each us to decide. In the latter situation, the $115 plus install will likely be considered a bargain mod and save you that in tires in a year or two if they don't wear out so quickly.

If you have (-2 to -2.5) degrees of camber in the rear of the car, but if it rolls over 3 degrees during hard cornering, then you are at (+.5 to +1) of camber and burning up the outsides of your tires. As the brace gives you more torsional rigidity, it may per se reduce the body roll in a corner by a quarter to half a degree and allow more surface area of the tire to stay in contact with the road. These are by no means exact numbers, but just used for illustrative purposes. Black Knight is all braced up everywhere and he can notice it.
 

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As I suspected it is part # 31 under rear suspension on the GT4 it is not shown under the S or GTS.
REAR SUSPENSION for 2016 Porsche Cayman
My worry is does the part fit a 981 non-GT4? The rear suspension is different between models. I'd have to check the other major parts vs a 981 or S to see if they are the same.

The other question is how does it mount? Are there bolts to other body/suspension parts and do the existing parts have the holes needed? If not, you may have to drill and weaken another part that was beefed up on the GT4.

V6
 

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If I had to do it over again, I'd go that route. I bought the Fabspeed tow hooks and then the Schnell bar (first version). They mount to the same studs. As a result, there wasn't enough threads to secure the nut fully when both are installed. I had BGB replace the bolts/studs with longer ones and now all is secure. I know Schnell redesigned the bar to fit their tow hooks.

The bar is the lowest thing on the underside and it constantly is getting scraped, which is why I want to raise my car 1/2 inch. One of these days I am going to have to replace the Schnell bar as it is pretty beat up right now (In fact, I hit it this morning coming out of a parking lot).

V6

This also works well, and you get rear tow hooks for the unexpected.

View attachment 157298
 

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I contacted Suncoast regarding which model this part is sourced from, and was told "We get this part from 2017 and up models." So I assume it is a stock 718 part that is install-able on 981's. Maybe a deficiency discovered in the 981 and rectified for the 718?
 

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Checked with another source and I'm told that the part shows to be on the 718 and the 981 Spyder. He says there are 2 different versions. Awaiting further clarification, I'm guessing the 981 and the 718 versions are unique, hence the two versions.
 

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Or one for a PDK and one for a manual. When doing my suspension upgrades to X71 we looked at a Boxster Spyder rear adjustable roll bar but it did not fit because the PDK hangs down lower than the manual.
 

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So this is all I know as of now, from my source. They are on the 718's, and the 981 Spyder. There are 2 part numbers for the Spyder, and usage is based on VIN#. There is a separate number for 718. He can not only, not tell me which one would fit my 981 base, he also can't tell me if it fits at all. Suncoast offers one they say fits the 981's.

So, I have no definitive answers. Sorry.
 

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The other thread for this topic has a link to Suncoast's product page with a clear photo of how it attaches. IMO, the only thing we need to know is the distance between the holes on the rear swaybar bushing mounting points, left to right side and vertical spacing. Anyone with a GT4 want to volunteer measurements we can compare to our non-GT4s?

If it fits, I like it as I can then remove the Schnell bar that hits the ground (sorry Lemon!) as the new bar has no clearance issues.

[Update]

I did order the brace and it is due in on Tuesday. I will install it while I am changing the rear sway bar. I will post photos in my mod thread when it is done.

V6
 

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Real curious on the clearance issues with the PDK transmission. Don't want the motor to hit this when torqued under load, i.e. 1.5 Gs in a high speed corner. Let us know Voyager6. Blazing the trail again.
 
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