Limited Slip Diff - Best Option
02-19-2009, 08:32 AM
#16
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Comments please on the different effects of the various units on the car while decelerating ... is balance affected? My general belief is that for LSD to be active you'd have to be on the gas pretty hard for it to engage. Which is not what people usually do at turn in. However, some units will lock and affect weight transfer under deceleration, right? One hopes the LSD is not affecting balance during corner entry ... it should only cause understeer if it's correcting wheel slip, and the car is putting down more power. That's a good thing, and can be dealt with by modulating the throttle. I believe a good LSD mostly makes itself noticed in corner exit, as the driver goes to WOT.
Since my use is street and only casual track, the torque biasing type has a lot of appeal to me. It is strictly gear driven, requires no additives, and will last as long as an open differential. The plate and clutch LSD's need maintenance and periodic rebuilding, so you have to decide if your needs are worth the benefits and expense. I don't do any wet track driving, and the car doesn't have enough power to require a lot of lockup assistance. As long as the inside rear wheel doesn't lift, the TBD should work fine for most folks who have similar needs.
02-19-2009, 10:23 AM
#17
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Comments please on the different effects of the various units on the car while decelerating ... is balance affected? My general belief is that for LSD to be active you'd have to be on the gas pretty hard for it to engage. Which is not what people usually do at turn in. However, some units will lock and affect weight transfer under deceleration, right? One hopes the LSD is not affecting balance during corner entry ... it should only cause understeer if it's correcting wheel slip, and the car is putting down more power. That's a good thing, and can be dealt with by modulating the throttle. I believe a good LSD mostly makes itself noticed in corner exit, as the driver goes to WOT.
Good question about why it was not an option on the 997.1. Probably because very few buyers have any use for it, and do the Germans consider American buyers mostly poseurs? As a RWD car with a rear engine, the 911 puts power down very well with an open diff. Perhaps the absence of LSD on the 997.1 was intended to aid continued sale of the 996 GT3 in 2005? Some buyers might have (rightly) figured that a 2005 S with PCCB and LSD would be a match for the GT3, and a more utilitarian car to boot.
Good question about why it was not an option on the 997.1. Probably because very few buyers have any use for it, and do the Germans consider American buyers mostly poseurs? As a RWD car with a rear engine, the 911 puts power down very well with an open diff. Perhaps the absence of LSD on the 997.1 was intended to aid continued sale of the 996 GT3 in 2005? Some buyers might have (rightly) figured that a 2005 S with PCCB and LSD would be a match for the GT3, and a more utilitarian car to boot.
My 540i is a pain as any time you try to use the monster power of the V8 it just spins the bloody "inside wheel", but in that car I get it, because it is a car that is designed to be driven by a wide array of people and it "safer" to have the inside wheel spin than the car hooking up and treating its driver to glorious power slide. The M5 on the other hand (the car I should have bought) has a LSD as it is designed to be more focused.
Which gets me to my point that, although I understand why they did it, as I indicated in paragraph one, our 911s are also designed to be focused and should have them standard.
02-19-2009, 10:37 AM
#18
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I'm sure Porsche decided to stop having different suspensions for different markets. We never could get the Sport suspension here in the US. Well, now there are universal suspensions for the 997. Stock C2, PASM, and Sport PASM.
02-20-2009, 12:36 AM
#20
Comments please on the different effects of the various units on the car while decelerating ... is balance affected? My general belief is that for LSD to be active you'd have to be on the gas pretty hard for it to engage. Which is not what people usually do at turn in. However, some units will lock and affect weight transfer under deceleration, right? One hopes the LSD is not affecting balance during corner entry ... it should only cause understeer if it's correcting wheel slip, and the car is putting down more power. That's a good thing, and can be dealt with by modulating the throttle. I believe a good LSD mostly makes itself noticed in corner exit, as the driver goes to WOT.
Good question about why it was not an option on the 997.1. Probably because very few buyers have any use for it, and do the Germans consider American buyers mostly poseurs? As a RWD car with a rear engine, the 911 puts power down very well with an open diff. Perhaps the absence of LSD on the 997.1 was intended to aid continued sale of the 996 GT3 in 2005? Some buyers might have (rightly) figured that a 2005 S with PCCB and LSD would be a match for the GT3, and a more utilitarian car to boot.
Good question about why it was not an option on the 997.1. Probably because very few buyers have any use for it, and do the Germans consider American buyers mostly poseurs? As a RWD car with a rear engine, the 911 puts power down very well with an open diff. Perhaps the absence of LSD on the 997.1 was intended to aid continued sale of the 996 GT3 in 2005? Some buyers might have (rightly) figured that a 2005 S with PCCB and LSD would be a match for the GT3, and a more utilitarian car to boot.
Dave
