93z vibration
#1
10-04-2009, 01:02 AM
93z vibration
93 Z28 6speed and when I get around 100 or faster there is an awful vibration/drone it will go faster but it is loud and sounds bad. Anyone have any ideas??? The tires are new and the car runs great
#4
10-08-2009, 08:53 AM
Join Date: Oct 2007
Location: The 'Burbs of Chicago
Posts: 18,306
^ Something in that driveshaft link doesn't add up mathematically...maybe
It says: "The stock steel driveshaft in the 1982-2000 Camaro and Firebird is 2-1/2" in diameter and has a critical speed of 7177 RPM. This is as fast as it should turn. While this may seem high, there is another factor to consider. At approximately half of critical speed - which is 4784 RPM - annoying vibrations can begin to occur.
Half of critical speed is only 92 MPH with a 3.73 gear."
The rear gears don't change the rpm ratio between the engine and driveshaft. That ratio would always stay the same in any one given gear. I need to figure out the rest of what they're saying by figuring what the final drive would be.
If I'm not mistaken, in 4th gear, the six speed is at a 1:1 ratio. At 92 mph, would the engine be turning 4784 rpm's? I'll hafta look at that later to satisfy my own curiousity.
It says: "The stock steel driveshaft in the 1982-2000 Camaro and Firebird is 2-1/2" in diameter and has a critical speed of 7177 RPM. This is as fast as it should turn. While this may seem high, there is another factor to consider. At approximately half of critical speed - which is 4784 RPM - annoying vibrations can begin to occur.
Half of critical speed is only 92 MPH with a 3.73 gear."
The rear gears don't change the rpm ratio between the engine and driveshaft. That ratio would always stay the same in any one given gear. I need to figure out the rest of what they're saying by figuring what the final drive would be.
If I'm not mistaken, in 4th gear, the six speed is at a 1:1 ratio. At 92 mph, would the engine be turning 4784 rpm's? I'll hafta look at that later to satisfy my own curiousity.
Last edited by Camaro 69; 10-08-2009 at 09:01 AM.
#5
10-08-2009, 12:35 PM
Join Date: Oct 2007
Location: The 'Burbs of Chicago
Posts: 18,306
OK, you know me, I like to analyze stuff. So I did the calculations...
With 25.5" tall tires (the norm), the driveshaft would be rotating 4521.6 rpm at 92 mph (the driveshaft sellers scenario) with 3.73 gears. Definitely short of their "critical mass" number used to scare you into buying one of their driveshafts. You would have to be using tires a fraction taller than 24" to come up with the number they did. Oh well, skewing numbers sometimes does have a tendency to help boost sales!
At 100 mph (the O.P.'s speed), the rpm's would be 4,914.8 rpm's. But, that's assuming he has 3.73 gears.
I would be more suspect of the u-joints being bad, as opposed to the driveshaft as a whole.
With 25.5" tall tires (the norm), the driveshaft would be rotating 4521.6 rpm at 92 mph (the driveshaft sellers scenario) with 3.73 gears. Definitely short of their "critical mass" number used to scare you into buying one of their driveshafts. You would have to be using tires a fraction taller than 24" to come up with the number they did. Oh well, skewing numbers sometimes does have a tendency to help boost sales!
At 100 mph (the O.P.'s speed), the rpm's would be 4,914.8 rpm's. But, that's assuming he has 3.73 gears.
I would be more suspect of the u-joints being bad, as opposed to the driveshaft as a whole.
Last edited by Camaro 69; 10-08-2009 at 12:38 PM.
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