May 26, 2016 6:44:28 PM
May 26, 2016 6:47:54 PM
May 26, 2016 6:54:42 PM
So why would 80 track hours on a GT4 CS be less stress on the engine than 80 track hours on a Cup car? Both engines are being subjected to the same, really hard usage for 80 hours. Why would a Cup car wear out sooner aside from it maybe just being more powerful?
Obviously a Cup car will cost more if they just use more expensive parts for the hell of it, but I'd think that in theory a Cup car would be built to last more miles on a track than a road car.
The parts are lighter to allow more revs and power but also need replacement more often. They are made knowing that they will get replaced before they fail. If you do a 24 race in a cup car you need to redo the engine. If you do a bunch of 3-4 hour races you need to redo it after 30-50 hours. Sprint races at a Club event? You can probably get 80 hours and up to 100 hours if you're just tootling around at track days.
It's really about load and duration of load that wears them out faster or slower.
And yes, if you track a GT4CS for 80 hours I'd do a leak down test and a lab test of the oil. I bet you'd need to refresh the engine in the near future. Same goes for a street GT3 or a base Carrera 2.
The thing is you're not revving to over 9000 all the time in the street engines and you're not downshifting at 8500 rpm to get engine breaking going into a corner in a street car.
Past-President, Porsche Club of America - Upper Canada Region
Plus the moment you start looking at the Porsche Motorsport catalogue, you really need the big check book. I would imagine a Cup engine rebuild would set you back by $35-45K, at least, and then you also need to do the gearbox which would be another $20-30K. In the Cayman CS you will not get anywhere near these figures for the engine and the gearbox is not straight cut etc, so also here you should be able to save quite substantially.
Last year at Paul Ricard we participated in a 24 Hours race and had an Audi R8 team in our garage. They were testing a gearbox for Audi and the talk was that a new gearbox would be $80K ...this is obviously GT3 material which I would assume a tad more expensive than a Cup car, but the message is that the moment you start looking at Motorsport parts, you really have to take a deep breath.
May 26, 2016 8:35:37 PM
"McLaren Design Night" in Zürich. Presentation from Mark Roberts (McLaren Design Operations Manager) about the development process and Daniel Wright (McLaren Clay Modeller). Unveil from the 570GT. Truly fascinating and beautiful cars!
Thanks BjoernB for organising
2015 981 Cayman GT4 | Powerkit White - The fastest car on Rennteam
2013 Audi S3 | Glacier White
noone1:So why would 80 track hours on a GT4 CS be less stress on the engine than 80 track hours on a Cup car? Both engines are being subjected to the same, really hard usage for 80 hours. Why would a Cup car wear out sooner aside from it maybe just being more powerful?
Obviously a Cup car will cost more if they just use more expensive parts for the hell of it, but I'd think that in theory a Cup car would be built to last more miles on a track than a road car.
Cup engine parts are not designed to last, they are made as light as possible to last only the required time, like all race stuff, remember the old F1 qualifying engines which were designed to only last 1 qualifying session?
noone1:So why would 80 track hours on a GT4 CS be less stress on the engine than 80 track hours on a Cup car? Both engines are being subjected to the same, really hard usage for 80 hours. Why would a Cup car wear out sooner aside from it maybe just being more powerful?
Much of it is because of revs. The forces in the motor are equal to the mass of the moving parts time the square of their speed. More revs = much more stress (twice as fast is 4 times as much stress). GT4 CS only revs to 7,800 rpm and most of the Cup revs much higher. The Cups also have lower and closer gearing that allows them to stay near their higher redline more of the time.
Another more cynical reason is that the Cups (all but 991) are built on the Mezger platform where the cylinders can be replaced and the engine rebuilt. You want to rebuild the motor before something really bad happens that could damage some of the parts you want to re-use (like the case, crank, rods, etc.).
With the GT4 CS, the motor is not rebuildable - you replace it. So there is not much harm in running it until it dies (or makes less power), since you need to pay for a whole new motor anyway (which is less than the cost of a Mezger rebuild).
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16 Cayman GT4, 73 Carrera RS 2.7 Carbon Fiber replica (1,890 lbs), 06 EVO9 with track mods. Former: 73 911S, Two 951S's, 996 C2, 993 C2, 98 Ferrari 550, 79 635CSi
May 26, 2016 9:25:36 PM
May 26, 2016 9:59:20 PM
Now that I think of it, 991 Cup also uses Mezger right? Just the 991 GT3R uses 9A1, I think...
16 Cayman GT4, 73 Carrera RS 2.7 Carbon Fiber replica (1,890 lbs), 06 EVO9 with track mods. Former: 73 911S, Two 951S's, 996 C2, 993 C2, 98 Ferrari 550, 79 635CSi
May 26, 2016 10:14:51 PM
May 26, 2016 10:58:14 PM
bluelines:
Not to belabor the stowage space question.... but this pic from Bluelines shows the new 570GT model's sideways glass hatch, with what the reviews are claiming is 7.8 ft3 of space (not counting front boot). The following pic is of the 570S model, which has a vertical rear window and rear deck entirely devoted to engine dressing - clearly the rear shelf, if any, is not intended for storage in the S model. The utility is nice.... but not sure why they also gave this new GT model more understeer as default, slower steering rack, and softer springs. Mclaren assumes all who occasionally put an extra bag or two into their cars do not care as much about handling and must want a GT.... The perma-glass roof with no blocking sunscreen would also be a deal-breaker for me.... will be interesting to see to whom this model ends up being sold to.
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2011 Range Rover Sport S/C, 2009 Porsche 911S