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Does 991.2 4 with PTM also comes with LSD?

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Old 02-09-2017, 01:12 AM
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Greenfall
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Default Does 991.2 4 with PTM also comes with LSD?

I am deciding to buy a porsche 4.
According to the article I found on porsche's website for the PTM on 911 carrera 4http://www.porsche.com/canada/en/mod...anagement-ptm/
"...... the electronically controlled and fully variable multi-plate clutch distributes drive force between the permanently driven rear axle and the front axle....."
It mentioned the multi-plate clutch here. And according to my understanding, that is one type of Limit Slip differential am I right? So A base 911 carrera 4 should be standard with a LSD. However, I found no where on the tech sheet of 911 4 mentioned LSD and I can find it on 911s'.
Then my next question is, what does porsche torque vectoring plus really do in this car?
Since PTV can vary power sending to each rear wheel, and PTM was only mentioned to distribute power between front and rear. Does it infer PTM only has one central LSD and PTV plus will add another LSD among rear axial?
The reason I want to add PTV is only for the LSD comes with it. So my final question is, how many LSD does PTM comes with? Only one in the center or two or, sadly, ZERO?

Last edited by Greenfall; 02-09-2017 at 01:28 AM.
Old 02-09-2017, 06:47 AM
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randr
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In my handbook (Australian edition) - PTV with lockable diffs is available as an option on the base 4S (but not on the base C2S)
Old 02-09-2017, 09:09 AM
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kayjh
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PTV and PTV Plus are both options on the C4. I just ordered this model and didn't select either option. Most people here say you can drive a C2 in the winter getting by with snow tires. I'm betting a C4 will be a rock star on slippery surfaces without any additional help for the differentials. What does your SA say? My SA never mentioned the need for the option. I'm in western Canada where we have at least 5 months of snow.
Old 02-09-2017, 09:56 AM
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subshooter
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You need PTV to get LSD. On a C4, PTV is an option. On an C4S/C2S it is standard.
Old 02-09-2017, 10:29 AM
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jimbo1111
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PTM manages the torque to the front wheels and how the 4wd is distributed. On previous generation cars ptv and lsd were not offered on the base car. "Not sure on new gen". The S cars with MT had a mechanical lsd with ptv and PDK cars had a fully electronic ptv setup. Non mechanical. ptv is a technology that controls the inside wheel around turns with the braking system. It induces oversteer and brings the rear of the car around. Similar to how someone operates a wheel chair to make a turn. Lsd operates on a clutch and allows slippage of the inside wheel. It eliminates screeching of the inside tire while cornering because both tires are traveling at the same speed. The clutch relieves the inside tire of torque in order to slow it down and stop the screeching.
If Porsche offered an lsd setup on the base car I'd be all over it. I'm not a fan of either ptv or rws. They artificially shift the rear engine bias on the 911 to try and make it more mid engine. I find that I'm happy knowing where the engine is and except the fact that the 911 chassis was never perfect. These technologies have really turned me off with the 991.
Old 02-09-2017, 10:32 AM
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tstafford
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Originally Posted by jimbo1111
PTM manages the torque to the front wheels and how the 4wd is distributed. On previous generation cars ptv and lsd were not offered on the base car. "Not sure on new gen". The S cars with MT had a mechanical lsd with ptv and PDK cars had a fully electronic ptv setup. Non mechanical. ptv is a technology that controls the inside wheel around turns with the braking system. It induces oversteer and brings the rear of the car around. Similar to how someone operates a wheel chair to make a turn. Lsd operates on a clutch and allows slippage of the inside wheel. It eliminates screeching of the inside tire while cornering because both tires are traveling at the same speed. The clutch relieves the inside tire of torque in order to slow it down and stop the screeching.
If Porsche offered an lsd setup on the base car I'd be all over it. I'm not a fan of either ptv or rws. They artificially shift the rear engine bias on the 911 to try and make it more mid engine. I find that I'm happy knowing where the engine is and except the fact that the 911 chassis was never perfect. These technologies have really turned me off with the 991.
Great write up.
Old 02-10-2017, 12:50 AM
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babyjocko
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Made me look. I thought you were talking about acid.



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