mathisengineering

I'm selling front and rear factory 997 RSR uprights - $900 each. I have a lot of them so don't assume I'm sold out when this thread gets old. These allow you to lower your street, cup car and early R or RS cars quite a lot without messing up the geometry. They use the late GT3 street car bearing so you can press in your hubs and stubs (street car or center lock). These come with the bearing retainer plates and the 6 bolts.

All previous GT3 suspension and steering arms work. The rear wheel bearing is larger than the 996 RSR but the ID is still the same so your hubs still work. All hub offsets are the same.

Brake caliper stud spacing is:
Front 8.25"
Rear 5.125"

These fit 996, 997, 986, 987 cars.

link to additional parts we have for sale:
https://rennlist.com/forums/porsche-...ce-wheels.html

mathisengineering

mathisengineering

I also have new OE bearing sets for these at $375 per car.

IPguy

What is the C-C dimension of the caliper studs, f & r?

mathisengineering

Brake caliper stud spacing is:
Front 8.25"
Rear 5.125"

The rsr uprights use Alcon, Brembo or Peformance friction calipers that are drilled using inch equivalent spacing. The street and cup cars use metric equivalent spacing. It's easy to adapt from one to the other.

Mark

sany601

I'm planning to put RSR uprights on my 2005 996 Cup Car.Do I need to change subframes and brake callipers???

mathisengineering

You don't have to change out either. Your subs will work but you will have to make adapters to make your calipers work with the different stud spacing used on the rsr uprights.

sany601

So, you want to say that subs are the same like in Cup car,and I can lower the car same as 996 RSR ????

mathisengineering

There is a reason Porsche made RSR sub frames but sometimes the differences are very small.

The front RSR sub frame has the same pick up height as the cup car. They are 6 bolt frames that don't work on the 00-01 cars. I think the rack pickup location is raised but you can do that with spacers and longer bolts. I also think it's thicker and stronger than stock but I'm not sure about that.

The rear RSR sub frames have more differences. I do think the pickup points are heigher than the late cup but I'm not totally sure. There is also a round hole and built in spacers where the rear toe links bolt in (not the slots like stock and cup subs). The rear is a lot more complicated so I'm not as sure about the differences. I'm running RSR all around so I haven't compared between the two on a car.

Bottom line, there is a very big difference between 996 cup and RSR uprights in terms of getting the car down. The 997 RSR uprights are the same as 996 RSR except the rear bearing OD increased in size so they are the best option if you are willing to make caliper adapters to make the change over. You will have to do that with either RSR upright design.

Mark

sany601

So,looks like I need to change complete everything .
Thanks for advice.

Taisan Porsche

Hi there,
assuming this is installed on a 2008 cup, what is the ride height reduction?
The other thing is that my cup rides on Michelin 25, 30. I suppose the tires will scrub the wheel well?
If the lowered cg or the other minute geometry of upright enables a 2 second lap time reduction at a 2 minute circuit this is a very good investment. If 1 second then it would be something that needs to think carefully.
I use my 996 R and 997 cup for races only.

Sam

mathisengineering

Sam,

I don't have much in the way of cup parts so I don't know the difference in ride height between the 08 cup and 08 rsr. I have provided pretty good pictures so you may be able to look at these and figure it out. You can only be the judge as to tire clearance.

I got out of F1 car design a long time ago so I'm not going to claim to be an expert. However I would like to add a few tips with regard to the difference between the Cup and RSR parts.

These parts do a lot more than simply lower the car. The basic idea of the change is to be able to lower the car while maintaining the front to rear roll center height difference and keep the camber gain proper for the car. The change to roll center heights as you drop your car is not minute at all. It's rather draumatic and very sensitive to ride height.

If you simply lower a cup car lower than stock, the front roll center quickly hits ground level and the rear keeps going down towards the ground which tends toward equalizing the front to rear roll center heights and that makes the car push. The rear needs to be higher than the front and the ARB's are designed for the difference at stock ride height.

Lowering a cup car makes the rear camber gain much faster in the rear so the car will tend to run on the inside edges of the tire with large negative camber gains. That wears the tires out prematurely and may make the the rear work better depending on the tires. In the front, lowering reduces or even reverses the negative camber gain with bump. All of this leads to push.

The cup cars are designed with a lot of front end push already to keep the cars relatively safe for gentleman racers. Most mods folks make to these cars leads to more push. The biggest difference with the rsr is that they drive much more neutral with the assumption that pros are driving them. The subs, uprights and balance of tire widths all contribute to that. I can't promise you 2 seconds a lap but I can say they didn't provide totally different parts on the RSR for marketing purposes. Porsche has a strong following for good reason in that they pretty much maximize performance for a given design objective. If your tire size and cup car wheel wells don't allow you to drop the car, don't change the uprights. You are about as good as you can get right now. If you can drop your car, changing these parts is your best option and it's far better than simply lowering the car.

Mark

Rickard 993 Turbo

These parts are perfect for a 996 car that like to modifie on a 997 the uprights are the same except for the caliper studs.

mathisengineering

OK Rickard, Now you've done it. You made me actually check the Porsche specs on the 08 Cup car and the 08 RSR because I know the 997 RSR uprights do not have the same geometry as the 997 cup uprights. They look similar but they aren't the same. The brake stud spacing is different, the roll center heights are different and they are designed for different ride heights.

08 Cup Ride height F 77mm R 115mm
08 RSR Ride height F 68mm R 82mm

That should give folks something to check to see if tires clear etc. I agree that the difference between the 997 rsr and the 996 cup, R, and RS parts is particularly large.

A 5mm change in lower control arm height at the upright translates 5x or more in roll center height. That creates a big difference in car balance and should give us pause in generalizing that parts look kind of close so they are the same.

Mark

Rickard 993 Turbo

Some extra info

RSR messure rideheigt from the floor, not the cup so not easy to compare... same at the rear...

So your messurement are of,sorry

also this is from 08 RSR maual

Ride height 60 mm 70 mm Front axle: Under floor
Rear axle: Centre of under floor