MechEngr1287

I may have missed this information at some point; Just curious, do we know how much lower the GT4RS Ride height is set at compared to the GT4?

FrenchToast

But if you are changing the brakes, you likely need to change the bias and ABS programming.

I don't know if the 5-bolt hubs would actually bolt on, or are even designed for the higher loads of the RS. Only speculation!

Also, unless the Porsche factory does the modification for you (through Exclusive), then you'll likely void numerous parts of your warranty.

First, I can tell you that even if you are a Porsche employee you can't just 'grab the drawings.' So you won't obtain any drawings.

The centerlock hub cannot be adapted for 5-bolt use, as the area where the 5 pins are located is not designed for the tension, compression, and bending loads that come with attaching the wheel to that flange. Those loads are instead going through the center nut drive. The 5 pins on a centerlock are working mostly in shear. The flange does take some load under cornering but isn't designed for the wheel to be attached there.

In short, the flange on a centerlock hub is very thin and will not support a wheel attachment. You need a hub designed for 5-bolt attachment. You can ask Porsche Motorsport for suggestion on the conversion but they will likely keep their mouth shut for liability reasons.

TXshaggy

You can see roughly what’s involved in a 997 CL conversion couple threads up.

CXX is only trim and paint — they don’t do any mechanical work; unless your last name is Porsche.

Ksdaoski

Best bet to try out a 5 lug conversion, is to head to a shop that works on GT4 CS cars. Have access to motorsports parts, and can try things out and test a wider range of parts, than most.

jmartpr

Same height.....when they say 30 mm less is from a regular Cayman

Puggz

Correct, one reason why I would NOT go for the nose lift.

jmartpr

Same here.....the rear diffuser is more of a problem than the front splitter

very green R

As shown in the quoted link above it is a part swap out but still takes 3 to 4 hours of labor per corner, plus add a 4 wheel alignment when all done.
From post #91 in the above link here is the parts list for a 997 and 2011 pricing as a Rennlist special buy from Suncoast:
Post #91
I just arranged a RENNLIST Group Buy with SUNCOAST for those interested in doing the 5 lug conversion.

You will need two of each of the following ......plus bolts or studs/nuts:

997-341-605-01 Front WHEEL HUB $264.22
999-053-054-06 Front WHEEL BEARING $ 52.49
997-331-605-00 Rear WHEEL HUB $290.51
999-053-055-02 Rear WHEEL BEARING $ 67.17

On the listed parts above, this saves you over $400 off MSRP pricing and over $55 off the current Suncoast pricing.

Call Ric Knab at SUNCOAST at 877-923-1700.

Its great that someone figured this out in 2011. Thank you TX Shaggy for replying to my post with this valuable info.

very green R

But the front splitter on the GT4RS extends further forward from the front tire contact point than on a GT4 so the front splitter will scrape easier on the GT4RS. As someone pointed out earlier in this thread once the front splitter is clear by using the lift lower the lift so the rear diffuser has less chance of scraping.
Any thoughts on this approach?

Federico Tofani

EXACTLY

jmartpr

That works but I think this will be a personal decision on how and where you use your car.....In my case I don't mind the occasional slight scrape, will happen anyway, vs adding more complexity, weight and cost to the car.
It's not like the splitter extends another 6" it's a just a bit more.

very green R

I share your thoughts and I'm conflicted on whether or not to get the lift because I hate adding weight.
In fact I like to take weight off my car, 116 pound total. My Cayman R weighs 2900 pounds, with AC, pdk, stereo, and all fluids except just a few gallons of gasoline in the tank.

Replacing the center front splitter may not be that expensive. 10 months ago for a 718 GT4 my local dealer quoted $281 retail. A 991.2 GT3RS is $320. So the GT4RS center splitter piece should be close to these prices.
Also the GT4RS does not extend as close to the ground along the central portion giving more clearance to perhaps compensate for the forward extension over the GT4.
In an earlier post someone stated the rear diffuser cost $530, so safer to not have the front lift and not have to worry about timing lowering the front lift to give clearance for the rear diffuser.
I am over analyzing. I just need to get an allocation, make a decision on the front lift then drive tons of miles and enjoy the car and not worry about scrapes on the front splitter or rear diffuser.

FrenchToast

997 hubs are completely different than GT4 hubs and won't work.

very green R

I have given up the idea of the conversion from centerlock to 5 lug. I will just deal with the centerlocks. Also Ive only had three screws or nails in any of my tires among my family cars over the past 20 years and I carry a tire plug kit and another sealant beside what came from Porsche, so I think I will be OK with centerlocks.
I guess it is a marketing decision by Porsche that centerlocks are desired by GTxRS customers. But it would be nice if centerlocks were standard, but 5 lug with different style wheels were a no cost option on all GT models. This is the way the 992 GTS and 992Turbo are able to be configured with 5 lugs as a no cost option. (I realize the 992 is higher volume so more wheel choices are possible there due to tooling cost spread. )
The 5 lug set up is lower weight according to the 997 conversion study. So for weight savings alone, Porsche should allow the 5 lug,
Rotating unsprung weight is the most important place for weight savings.
Also since the RS is destined for track use, tire changes are so much easier and more reliable with 5 lug.
PDK is the only transmission because it fits with the track character, so why would not 5 lugs fit for track use?
Even Ferrari with such cars as the F8 Tributo are 5 lug.
Sorry for the rant if you have read this far. I hope Porsche reads this.

ExMB

^

The problem with this is, even so its true, is that only a small percentages will be tracked when compared to the overall built. More will be attending coffee and donut events and weekend drives and for them CLs look cooler. Plus most will never lift a finger to do such work themselves. They have someone else do it.