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Cayman GT4: Where are we up to now?

Ralph, Better not say that to a Romanian.....it Google translates to dumbass.! [obviously American English] Jeff
 
With too much time on my hands I thought I would see what was available in the way of technical data on Porsche's UK and (more informative USA) sites in respect of DFI models which I have summarised on the table below.
981thru991SpecificationsS.jpg
The data sources are shown on table above. The interesting points for me were - all PDK gearboxes use the same size clutch, from 997.2 3.6L 345hp 390Nm thru to 991GT3 with 475hp 440Nm (not sure this informs on gearbox internals though), - the current range (981 and 991) use a Continental ECU, not Siemens, and - rear brakes on 981CS look puny v fronts compared with 911 front/rear sizes Anyway, as I said too much time at the moment...
 
Don't know what conversion factor used for the PDK dimensions but the figures in your table don't make any sense![:-]
 
Absolutely- but the table supposedly gives the metric/imperial sizes not 2 different sizes in the same dimensions.
 
Ralph, The Cayman 987.2 sales booklet says that an ME 7.8 [Bosch?] DME is used on the 2.9L whereas the 3.4L uses an SDI 3.1 [Siemens?] DME. Also, this site indicates that the Siemens EMS SDI 3.1 DME is also used on the 997.2 [with the exception of the GT3]: http://aimsportsystems.com.au/download/ecu/stock/porsche/Porsche_997_MK2_Siemens_EMS_102_eng.pdf The Cayman S front brake discs are 318mm/28mm and the rears are 299mm/24mm but the rear discs on the Cayman are 4mm thinner than those of the S, so I would think that the same applies to the 981 Caymans. The apparently puny rear brakes on the Cayman compared with those fitted to the Carrera presumably reflects the significantly different weight distributions of the two cars, the Carrera's rear weight bias requiring a greater rear braking effort. Jeff
 
Jeff, It is interesting - I saw the Australian site and downloaded various of their pdfs but was really interested in find out whether there was any data on PDK commonality or otherwise. The data I logged was all from the Porsche USA press release sub-site which got me some PDK info and all the other data. I assumed the front/rear disc size reflected the F/R weight distribution but how much is the difference Carerra to Cayman? My 997 GTS cab was F/R 613kg/996kg which is 38%/62% weighed at Centre Gravity My 981 Cayman S is F/R 632kg/798kg which is 44%/56% weighed at Regal Motorsport The percentage does not seem a lot but actually there was an extra 200kg on the rear, no wonder I had to be careful to avoid heavy braking unless in a straight line.
 
PCCB are 350mm all round, My Spyder has those. I expect the gt4 to have 350mm front disks., sack that, looking at your chart prob 340mm disks
 
Yes, from the pics the GT4 looks to have the 6-pot 340mm steel front discs from the 991S/GTS/GT3. It'll probably stick with the 299mm rear discs. Jeff
 
ORIGINAL: ralphmusic Jeff, I assumed the front/rear disc size reflected the F/R weight distribution but how much is the difference Carerra to Cayman? My 997 GTS cab was F/R 613kg/996kg which is 38%/62% weighed at Centre Gravity My 981 Cayman S is F/R 632kg/798kg which is 44%/56% weighed at Regal Motorsport The percentage does not seem a lot but actually there was an extra 200kg on the rear, no wonder I had to be careful to avoid heavy braking unless in a straight line.
Click to expand...
Ralph, I was originally thinking that the difference could also reflect the amount of anti-dive built into the respective rear suspensions. However, I seem to recall reading that for the Cayman most of this was carried by the front rather than the rear suspension. Jeff
 
Brake sizes all pics with 20" wheels.. Standard 330mm
IMG_0353s-1.jpg
RuF are 350mm
RuF3800SWheelDisc.jpeg
These are much bigger
Porsche-Cayman-GT4-4.jpg
More like Turbo 380mm?
 
that cannot be 350mm can it ? 350mm on a 20" 981 they fill my 19" lol , not sure I like 20" wheels or 20" tyre prices !!!!
NewCaymanS_05-L.jpg
 
Interesting indeed, the RuF image in the previous post is of an actual 3800S, their brochure says 350mm - below is a picture from their brochure which I have just rechecked as 350mm
RuFWheelsBrakes.jpg
Strange... Anyway the various images of prototypes show front and rear discs that appear larger than 350mm.. what do you think from the images?
 
ORIGINAL: ralphmusic Jeff, It is interesting - I saw the Australian site and downloaded various of their pdfs but was really interested in find out whether there was any data on PDK commonality or otherwise. The data I logged was all from the Porsche USA press release sub-site which got me some PDK info and all the other data. I assumed the front/rear disc size reflected the F/R weight distribution but how much is the difference Carerra to Cayman? My 997 GTS cab was F/R 613kg/996kg which is 38%/62% weighed at Centre Gravity My 981 Cayman S is F/R 632kg/798kg which is 44%/56% weighed at Regal Motorsport The percentage does not seem a lot but actually there was an extra 200kg on the rear, no wonder I had to be careful to avoid heavy braking unless in a straight line.
Click to expand...
interesting when my spyder was motd at the opc recently on the braking print out there are the corner weights and the total is 640kg front and 760kg rear(i presume this weight included tester).why would the front be heavier than above?
 
My 997 PDK was with 50% fuel, luggage, no driver and my 981 PDK was same except that it had 90% fuel. Porsche quote total weights for both DIN ( Car with 90% fuel, no driver, no luggage ) and EC (Car with 90% fuel, 68kg driver, 7kg luggage) The USA site shows Curb weight for a Boxster Spyder as 1277kg manual/1303kg - Curb weight being DIN + 10% extra fuel so if yours at 1400kg did not have a technician in it it will indeed be porky. My 981CS at 1430kg with some luggage is heavier than Porsche's 1370kg which seems logical given it has electric memory seats, motors in the headlights and mirrors, full satnav, jukebox etc
 
Must have included tester (otherwise how would he have done the brake test!) my car must have a dry weight of circa 1295 kg standard car plus radio/PCM and Aircon added equals circa15-20kg no other heavy extras.there was no luggage and less than half a tank of fuel
 
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