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Every time I pull out of the driveway, I'm reminded of the bit of flex the 991 has, as the car creaks off the incline. Has anyone considered, or installed a bolt-in roll bar and seen an improvement? This one won't be tracked.. would it be worth the hassle?
That’s not a cage, it kind of looks like a do-it-yourself kids swing set in the back seat? Please don’t.
I’ve had my 991.1 GTS on the track and it doesn’t seem to flex much at all? Could be something else you’re hearing? Noise from suspension, spring mounts, or something in that area?
Every time I pull out of the driveway, I'm reminded of the bit of flex the 991 has, as the car creaks off the incline. Has anyone considered, or installed a bolt-in roll bar and seen an improvement? This one won't be tracked.. would it be worth the hassle?
Short answer- no, not worth the hassle.
Longer answer: bolting leaves room for movement and is less effective, but a fully welded in cage tied too the suspension pickups could increase torsional rigidity by ~50% or possibly more. Very expensive to do right, hurts NVH (noise, vibration, harshness), reduces safety on the street (mainly due to an increased risk of your head hitting the cage), plus it’s very difficult to significantly increase stiffness without blocking some of the door, impending access. Now consider that the 991 has a torsional rigidity of 30,359 nm/degree. That’s very high for a steel chassis car, and higher even than the carbon chassis Carrera GT (26,000). It’s also almost 3x the Cabriolet’s 11,700, and those are still pretty drivable.
Lots of minuses, very few pluses and in the real world you’re unlikely to notice (you’re likely to get more creaks with a cage, not less). If you really want stiffer consider upgrading to a 992- that’s almost certain to come with a more rigid chassis (and a bunch of other goodies you will notice).
Longer answer: bolting leaves room for movement and is less effective, but a fully welded in cage tied too the suspension pickups could increase torsional rigidity by ~50% or possibly more. Very expensive to do right, hurts NVH (noise, vibration, harshness), reduces safety on the street (mainly due to an increased risk of your head hitting the cage), plus it’s very difficult to significantly increase stiffness without blocking some of the door, impending access. Now consider that the 991 has a torsional rigidity of 30,359 nm/degree. That’s very high for a steel chassis car, and higher even than the carbon chassis Carrera GT (26,000). It’s also almost 3x the Cabriolet’s 11,700, and those are still pretty drivable.
Lots of minuses, very few pluses and in the real world you’re unlikely to notice (you’re likely to get more creaks with a cage, not less). If you really want stiffer consider upgrading to a 992- that’s almost certain to come with a more rigid chassis (and a bunch of other goodies you will notice).
08-11-2018, 08:41 PM
Flex- cage it?
