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#1
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Transient Vibration
On my 996 Race Car I have been chasing a vibration/shaking issue to no avail. The vibration comes on only between ~85-95mph then goes away. It started about a year ago but i cant correlate it to any changes in the car and it has not gotten any worse over the year. From the drivers seat it feels like its coming from the body of the car - not the wheels as the steering wheel isnt shaking.
- problem occurs at these speeds regardless of gas/brake/coast - braking is smooth without shudder and replacing rotors had no impact - problem occurs regardless of which wheels I have on the car - all four wheel bearing have been replaced this year - all suspension parts are tight and i dont see any worn bushings. Ideas?
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Carmine 1999 996 Carrera - White Pepe - 2011 Carrera S - Grey Previously: The Vaporizer 2009 Carrera Metallic Black Totaled by the Police: 2009 Carrera Black "Racing isn’t supposed to be stodgy. It’s supposed to be so goddamn wonderful batshit you can’t stand it, all noise and rumble and burning money and cavitating testicles." |
#2
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Ryan (Wahooooo....) '19 991 GT3 RS Weissach '08 997 PCA H class '89 930 Targa '18 F150 Raptor '16 991 GT3 RS '18 991 GT2 RS '16 AMG GT S '10 997 GT3 RS '07 997 GT3 '09 Aston Martin DBS '96 993 H Class '14 F150 Raptor |
#3
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in classic Charlie fashion he told me to "stop complaining and drive the car" last fall. i am taking it in for another issue next week but if I can troubleshoot and deal with it myself thats a good thing.
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Carmine 1999 996 Carrera - White Pepe - 2011 Carrera S - Grey Previously: The Vaporizer 2009 Carrera Metallic Black Totaled by the Police: 2009 Carrera Black "Racing isn’t supposed to be stodgy. It’s supposed to be so goddamn wonderful batshit you can’t stand it, all noise and rumble and burning money and cavitating testicles." |
#4
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You could try putting a dial indicator on each wheel hub. Maybe you have one that is slightly bent.
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2016 GT4 warp 7 1999 SPB warp 2, maybe 1973 914 2.0 1/2 impulse if it ever gets out of space dock Previous: 1973 914 1.7 1/4 impulse 2012 Cayman R warp 4 2006 Cayman S warp 3 1999 SPB warp 2, maybe 1966 911 warp 1.5 |
#5
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we have checked to make sure that the hubs are straight (sorry left that off the list). it seemed like an unlikely candidate given that the vibration only appears in that one narrow speed window.
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Carmine 1999 996 Carrera - White Pepe - 2011 Carrera S - Grey Previously: The Vaporizer 2009 Carrera Metallic Black Totaled by the Police: 2009 Carrera Black "Racing isn’t supposed to be stodgy. It’s supposed to be so goddamn wonderful batshit you can’t stand it, all noise and rumble and burning money and cavitating testicles." |
#6
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You appear to have eliminated almost everything with your testing - good job. I'm going to say axle(s). They appear to be the only thing spinning that would only appear at a specific speed (as opposed to Engine RPM). Coming from the car (and not your hands) would further indicate the rear of the car.
Otherwise I will go with Pucker Flutter
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Martin 2011 Cayman S (Gone) - Hardtop Blechster 2006 Cayman S (DD) 2016 Mazda CX-5 (Her DD) 2002 Boxster S (Gone) - Ragtop Blechster - Pura Patina! Dorkiphus: I buy it for the articles Last edited by N0tt0N; 07-09-2018 at 02:08 PM. |
#7
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axle was my guess also...had a similar problem on a van once though at lower speed....
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Tito 82 911 SC with 3.2 73 RSR project 97 328is 99 328is 97 Lexus SC300 Manual 86 TL (gone) 993 (gone) 75 911S (gone) |
#8
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Check all the plastic under trays and fasteners. Check the 1/2 shafts. Check all the motor and trans mounts for both bolt tightness and condition of the rubber/ isolation system.
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http://vimeo.com/29896988 “Those that can make you believe in absurdities can make you commit atrocities.” Voltaire. "There is grandeur in this view of life...." Darwin. The mountains are calling and I must go. “The earth has music for those who listen” Shakespeare. You Matter. (Until you multiply yourself times the speed of light squared. Then you Energy) “We’ve got lots of theories, we just don’t have the evidence’. |
#9
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Don't go below 95 mph...
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David D. '87 Targa - 2021 quickly disappearing... |
#10
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<Hagar voice on > “I Can’t drive....... 95!”
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http://vimeo.com/29896988 “Those that can make you believe in absurdities can make you commit atrocities.” Voltaire. "There is grandeur in this view of life...." Darwin. The mountains are calling and I must go. “The earth has music for those who listen” Shakespeare. You Matter. (Until you multiply yourself times the speed of light squared. Then you Energy) “We’ve got lots of theories, we just don’t have the evidence’. |
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