991 GT2RS
06-16-2017, 02:41 PM
#1696
700 hp 0-62mph in 2.9 seconds top speed of 212 sounds like a beast
http://www.automobilemag.com/news/20...go-early-ride/
http://www.automobilemag.com/news/20...go-early-ride/
06-16-2017, 03:25 PM
#1697
Don't think they can on a race car as the rear wheels are really tucked in there tight. No room for them to turn.
06-16-2017, 03:28 PM
#1698
Addict
Rennlist Member
Rennlist Member
06-16-2017, 03:43 PM
#1699
Disagree. 911 race engineers have always sought to increase wheelbase in order to improve handling and lower lap times and were very happy when the longer wheelbase 991 arrived. You'd be amazed at lengths that many went to on 997 Cup/Grand Am/R/RSR just to get a few extra mm of wheelbase.
It's almost always best to push wheels towards the corners of any given package. It gives many benefits: reduced weight transfer both lateral and longitudinal (more grip, acceleration excepted). It gives the wheels more mechanical advantage over the polar moment, improving transient response. It improves ride both by reducing frequency over bumps and allowing the use of softer springs: both of these result in more poise and higher grip. It even allows you to juggle weight balance to your advantage. I lengthened the wheelbase in my GT3 engined hotrod by nearly an inch for all of these reasons, and these same reasons drive race engineers to do the same.
In both cases, however, we are improving an existing package rather than starting from a clean sheet. Given complete freedom there are other ways to achieve many of the same goals: keep the wheels where they are but reduce overall length and CG height. This approach isn't available to Grand-Am, RSR, etc, as they are limited by rules (production length, minimum weight, etc). If it was, however, the overall weight benefit, etc would make it extremely tempting.
Smaller cars have huge advantages as a road tightens- just ask the French about the '66 mini cooper, check out the modified classes at an SCCA autocross, shifter carts, etc.
Bigger cars meanwhile gain advantage as a course opens up and speeds increase. Aerodynamics is also a major driver for increased width, as it gives the underbody more surface area with which to make ultra-efficient downforce. Since sports cars on road courses are governed my minimum weight rules they want to make the car as big as allowed to maximize lift to drag ratios and downforce over weight.
End result: classes with weight limits go bigger, classes without often go smaller.
Back to the original question: is the size growth of the 911 driven by performance or increased comfort? I'd argue it's a bit of both. Downforce is a minimal consideration in a road car. Non-downforce road cars that are willing to sacrifice comfort are small: BAC mono, Caterham Superlight, etc. If Porsche had kept the small "shoulders nearly touching" passenger compartment of the original 911 they'd clearly have been able to package a physically smaller, lower CG and polar moment body around them. This in turn would have let them hit the same performance specs as they do now but with a slightly narrower and shorter car. The difference, however, is much less than you might expect:
Modern cars are inherently heavier due to both luxuries and improved safety, and this works much like a "weight limited" racing class. This weight increase along with technology evolution drives a much wider wheel and tire package. My 1969 came on 4.5" wide rims, while the 991 GT2 RS is likely to feature 12.5" rear rims. That means the rear rims together got 16" wider, and handling that increase is likely the biggest packaging problem the engineers face. The have managed to limit the damage: the GT2 RS will likely only grow 11" in width, but that extra space needs to come from somewhere. Up front the luggage compartment, etc is actually getting narrower, so it's fairly easy to give more space to the interior.
So the 911 has gotten heavier in part due to adding comfort, and this in turn has meant it needs wider wheels spaced further apart. The drives a bigger external package with the interior volume likely growing in part as a side effect.
If the new size is an actual performance benefit depends. On a wide road course the tradeoff makes sense- more tire footprint and track means it will be faster every time. On an eight foot wide back-road, however, an extra foot of car width will cut your margin for error in half, so a narrower car will often be quicker even with less grip. Horses for courses- personally I'd wish for a narrow body 911R if the goal is an ultimate fun street car.
Last edited by Petevb; 06-16-2017 at 06:37 PM.
06-16-2017, 04:25 PM
#1700
Rennlist Member
It's correct that nearly all sports car race engineers want to increase wheelbase. However I think the conclusion you'd naturally draw from this, that bigger is better, is generally incorrect. The reasoning behind this seeming contradiction:
It's almost always best to push wheels towards the corners of any given package. It gives many benefits: reduced weight transfer both lateral and longitudinal (more grip, acceleration excepted). It gives the wheels more mechanical advantage over the polar moment, improving transient response. It improves ride both my reducing frequency over bumps and allowing the use of softer springs: both of these result in more poise and higher grip. It even allows you to juggle weight balance to your advantage. I lengthened the wheelbase in my GT3 engined hotrod by nearly an inch for all of these reasons, and these same reasons drive race engineers to do the same.
In both cases, however, we are improving an existing package rather than starting from a clean sheet. Given complete freedom there are other ways to achieve many of the same goals: keep the wheels where they are but reduce overall length and CG height. This approach isn't available to Grand-Am, RSR, etc, as they are limited by rules (production length, minimum weight, etc). If it was, however, the overall weight benefit, etc would make it extremely tempting.
Smaller cars have huge advantages as a road tightens- just ask the French about the '66 mini cooper, check out the modified classes at an SCCA autocross, shifter carts, etc.
Bigger cars meanwhile gain advantage as a course opens up and speeds increase. Aerodynamics is also a major driver for increased width, as it gives the underbody more surface area with which to make ultra-efficient downforce. Since sports cars on road courses are governed my minimum weight rules they want to make the car as big as allowed to maximize lift to drag ratios and downforce over weight.
End result: classes with weight limits go bigger, classes without often go smaller.
Back to the original question: is the size growth of the 911 driven by performance or increased comfort? I'd argue it's a bit of both. Downforce is a minimal consideration in a road car. Non-downforce road cars that are willing to sacrifice comfort are small: BAC mono, Caterham Superlight, etc. If Porsche had kept the small "shoulders nearly touching" passenger compartment of the original 911 they'd clearly have been able to package a physically smaller, lower CG and polar moment body around them. This in turn would have let them hit the same performance specs as they do now but with a slightly narrower and shorter car. The difference, however, is much less than you might expect:
Modern cars are inherently heavier due to both luxuries and improved safety, and this works much like a "weight limited" racing class. This weight increase along with technology evolution drives a much wider wheel and tire package. My 1969 came on 4.5" wide rims, while the 991 GT2 RS is likely to feature 12.5" rear rims. That means the rear rims together got 16" wider, and handling that increase is likely the biggest packaging problem the engineers face. The have managed to limit the damage: the GT2 RS will likely only grow 11" in width, but that extra space needs to come from somewhere. Up front the luggage compartment, etc is actually getting narrower, so it's fairly easy to give more space to the interior.
So the 911 has gotten heavier in part due to adding comfort, this in turn meant it needed wider wheels spaced further apart which made the external package bigger. The interior volume likely grew largely as a side effect.
If the new size is an actual performance benefit depends. On a wide road course the tradeoff makes sense- more tire footprint and track means it will be faster every time. On an eight foot wide backroad, however, an extra foot of car width will cut your margin for error in half, so a narrower car will often be quicker even with less grip (again ask mini). So horses for courses- personally I'd wish for a narrow body 911R if the goal was to make an ultimate street car.
It's almost always best to push wheels towards the corners of any given package. It gives many benefits: reduced weight transfer both lateral and longitudinal (more grip, acceleration excepted). It gives the wheels more mechanical advantage over the polar moment, improving transient response. It improves ride both my reducing frequency over bumps and allowing the use of softer springs: both of these result in more poise and higher grip. It even allows you to juggle weight balance to your advantage. I lengthened the wheelbase in my GT3 engined hotrod by nearly an inch for all of these reasons, and these same reasons drive race engineers to do the same.
In both cases, however, we are improving an existing package rather than starting from a clean sheet. Given complete freedom there are other ways to achieve many of the same goals: keep the wheels where they are but reduce overall length and CG height. This approach isn't available to Grand-Am, RSR, etc, as they are limited by rules (production length, minimum weight, etc). If it was, however, the overall weight benefit, etc would make it extremely tempting.
Smaller cars have huge advantages as a road tightens- just ask the French about the '66 mini cooper, check out the modified classes at an SCCA autocross, shifter carts, etc.
Bigger cars meanwhile gain advantage as a course opens up and speeds increase. Aerodynamics is also a major driver for increased width, as it gives the underbody more surface area with which to make ultra-efficient downforce. Since sports cars on road courses are governed my minimum weight rules they want to make the car as big as allowed to maximize lift to drag ratios and downforce over weight.
End result: classes with weight limits go bigger, classes without often go smaller.
Back to the original question: is the size growth of the 911 driven by performance or increased comfort? I'd argue it's a bit of both. Downforce is a minimal consideration in a road car. Non-downforce road cars that are willing to sacrifice comfort are small: BAC mono, Caterham Superlight, etc. If Porsche had kept the small "shoulders nearly touching" passenger compartment of the original 911 they'd clearly have been able to package a physically smaller, lower CG and polar moment body around them. This in turn would have let them hit the same performance specs as they do now but with a slightly narrower and shorter car. The difference, however, is much less than you might expect:
Modern cars are inherently heavier due to both luxuries and improved safety, and this works much like a "weight limited" racing class. This weight increase along with technology evolution drives a much wider wheel and tire package. My 1969 came on 4.5" wide rims, while the 991 GT2 RS is likely to feature 12.5" rear rims. That means the rear rims together got 16" wider, and handling that increase is likely the biggest packaging problem the engineers face. The have managed to limit the damage: the GT2 RS will likely only grow 11" in width, but that extra space needs to come from somewhere. Up front the luggage compartment, etc is actually getting narrower, so it's fairly easy to give more space to the interior.
So the 911 has gotten heavier in part due to adding comfort, this in turn meant it needed wider wheels spaced further apart which made the external package bigger. The interior volume likely grew largely as a side effect.
If the new size is an actual performance benefit depends. On a wide road course the tradeoff makes sense- more tire footprint and track means it will be faster every time. On an eight foot wide backroad, however, an extra foot of car width will cut your margin for error in half, so a narrower car will often be quicker even with less grip (again ask mini). So horses for courses- personally I'd wish for a narrow body 911R if the goal was to make an ultimate street car.
I too wish Porsches were smaller and at least 400lb lighter. Maybe that's why I'm increasingly eyeing 70's long-hoods and hot-rods like yours. Or maybe I'm just getting old.
06-16-2017, 08:28 PM
#1701
Rennlist Member
I've always assumed the 911 has gotten bigger due to safety requirements, crumple zones, airbags, roll cages, side impact protection, all that good stuff.
06-18-2017, 06:27 AM
#1702
What colour was the GT2 RS at the Forza launch? I am not a fan of the car in that colour.
06-18-2017, 09:56 AM
#1704
06-18-2017, 10:46 AM
#1705
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$160k over, uh? Would love to see Porsche declare open season on flippers:
http://jalopnik.com/someone-is-alrea...-rs-1796078673
http://jalopnik.com/someone-is-alrea...-rs-1796078673
06-18-2017, 10:58 AM
#1706
Rennlist Member
06-18-2017, 01:13 PM
#1707
Burning Brakes
My local GM says 700-750 cars total. Not numbered, but might as well be. If true, very disappointing and makes absolutely no sense to me. That's just handing money to Mclaren (along with enthusiast loyalty). Hopefully Porsche reconsider as they roll them out and, if demand is there, continue production.
06-18-2017, 01:32 PM
#1708
My local GM says 700-750 cars total. Not numbered, but might as well be. If true, very disappointing and makes absolutely no sense to me. That's just handing money to Mclaren (along with enthusiast loyalty). Hopefully Porsche reconsider as they roll them out and, if demand is there, continue production.
06-18-2017, 01:34 PM
#1709
My local GM says 700-750 cars total. Not numbered, but might as well be. If true, very disappointing and makes absolutely no sense to me. That's just handing money to Mclaren (along with enthusiast loyalty). Hopefully Porsche reconsider as they roll them out and, if demand is there, continue production.
Unless they want to pump out a boatload of the .2 GT3 RSs.
06-19-2017, 01:41 AM
#1710
Drifting
My local GM says 700-750 cars total. Not numbered, but might as well be. If true, very disappointing and makes absolutely no sense to me. That's just handing money to Mclaren (along with enthusiast loyalty). Hopefully Porsche reconsider as they roll them out and, if demand is there, continue production.