Bill Verburg

..., even if you didn't want to know anything about them

964 Cup the lightest possible setup .4oz, this is Cupcar's setup, He was kind enough to sell me an extra set of the top parts, the bottoms are cut down oe's



Here are the tops and a set of oe bottoms that need to be cut down


Here are oe 993RS w/ oe 993 % 964 Cup tops


the RS are much lighter than oe
993RS

oe993


Again Cupcar to the rescue, he was kind enough to scribe some oe RSR rears and supplied the cut down result to me, Tanks again!!

RSR top oe 993 rear bottom


Cupcars completed RSR rear, Fire braid compleats the install

jscott82

amazing....

Any idea why they bothered to cut them down? I would have assumed they were just removed altogether.

JPS

^^+1

Mike J

Gee, I ran the Targa without them for 30,000+ miles - not sure what they are even there for.

:-)

jdistefa

Heat & debris shield for the outboard camber control arm bushing? Just a guess, although I know that the heat in that area can definitely cook the abs speed sensor.

Cupcar

The rear plates protect the rubber boots covering the control arm ball joints from disc heat.

The upper front plates protect the ABS sender and wires, the lower front plates protect the rubber boots on the lower control arm joint and idler arm joint from disc heat.

Macca

I've run 4000 km (2000km fast road and track) without them. Did a lot of research on this in 2010/11 and after reading these forums and the 964 forums discovered may 10s of thousands of km have been driven on track without them to no detriment....

bobt993

Backing plates do help prevent damage to the ABS sensors from hard driving,racing. Especially with higher temp racing pads. The ABS sensors are also more difficult to remove when the plates are missing (due to heat soak).

Cupcar

The gold cadmium colored plates that are shown on the rear suspension above I sourced from Porsche motorsport and are 993 RSR/Cup parts. As one can see they are simple modified stock parts. The black plates for the front in the top picture are 964 RSR/Cup parts and appear are bespoke pieces not modified OE stock parts. The 993 RSR with 270 mm front discs has a backing plate in front as well with a ducting system to the disc.

So, since they went to the trouble, I suspect Porsche had their reasons for keeping the plates, perhaps the issue is during pit stops when the car is sitting for a time with hot brakes?

Who knows? I tend to follow what Porsche does rather than experiment.

Macca

It makes more sense they are protecting a sensor. Removing them has saved weight and increased cooling (especially the front rotors which have a plumbed in brake ventilation kit which before was deflecting air largely to a surface protected by an alloy shield). Some people said they were there to aid wet weather braking, some said to prevent stones getting caught up there. The racers I talked to said neither of those issues were apparent with them removed and they ran cooler. No one mentioned having to periodically replace abs sensors either for that matter but most I talked to had only run 993/964 as track cars for a few years.

Its good to finally have a logical explanation for their function on both factory road and cup cars...

Macca

Cupcar. I used to agree 100% on this OE thing. But over the years Ive witnessed first hand how people like Robert Linton and Colin Belton have taken the OE product and modified it to benefit (and in some cases as with Lintons work the factory race teams have bought his idea and technology). Of course Im not talking the backing plates. I think these were left of most likely for a good reason and ask me what it is if I need to replace my abs sensors in October after our 6 day Targa NZ in the 993!

I think the eye opener for me was when my wife and I had dinner with Bob Garrettson in February. He told me many stores of how the factory came to the US with the 934 and 935 and those cars when they arrived really had some issues still present (aero and power). Bob and others directly applied changes to the bodies and engines which were immediately feed back to the factory race teams.

This is why Porsche needs to go racing. Unless you have a significant racing presence you don't have independent teams to help you think outside the square on improving your product and suggesting simple fixes and solutions to improve performance and efficiency - often feeding down to not only factory race cars but production cars too.

In New Zealand we call this the "number 8 wire philosophy". Number 8 wire is fencing wire. Its an old joke a Kiwi farmer can fix almost anything with a length of number 8 wire! We dont have alot of wealth and for many years we didn't have the technology so as a nation we are a bunch of garage hobby engineers (or we were). Thats how we produced Chris Amon, Bruce McLaren and Denny Hulme from a nation at that time of 2 million people who were relatively poor. Theres still a whole inductry down here making alloy D type Jag replicas for wealthy US collectors hand beating the alloy panels on wooden bucks LOL!

Sorry for the sidetrack...Bill great work - another detail comes to light and is recorded. Your are our fountain of knowledge with this RS/RSR stuff - keep up the good work!

Cupcar

Is the Targa NZ the track event that goes on the roads near Craggy Range Winery in Hawkes Bay?

No question Porsche has room for improvement. Of the people you mention, one is a friend and I have met the other, so I have heard the stories. I heard Al Holbert apparently had to practically rebuild the first 956 cars before he felt safe in them.

Frankly, I know I won't ever really "need" most of the mods I do, I just like doing the mod after researching and procuring the parts.

Macca

Cupcar. Hear you on the mod list. Im entirely on the same page LOL!

Excellent knowledge! Yes that's the Targa NZ. Takes place over 6 days (two of which are in the Hawkes Bay). 850km over 28 closed road stages of various length scattered around the North Island with around 2000km of driving in between. For us it will be an endurance event of man and machine....hope we dont regret removing those backing plates!

Cupcar

My son worked at Craggy and told me "dad there is some kind of race that goes on the road over across the river", so I went over and drove the road.

It looks to be challenging and if one were to get off that road though...bad news.

Macca

Yes. That road has claimed a few cars over the years - ones that need fishing out of the water afterwards!