Today's quest for 12s got expensive :(
04-11-2010, 10:58 PM
#21
Mach I Section Moderator
Join Date: Mar 2007
Location: round abouts these parts
Posts: 7,140
04-11-2010, 11:09 PM
#23
6th Gear Member
Thread Starter
Join Date: Feb 2007
Location: North Carolina
Posts: 11,302
I'm going to top my car out from time to time as long as I have an open road with nobody on it. I'm not saying its a safe practice or good for my personal health, but this kind of stuff is often discussed in this section. There are quite a few of us speed demons in the S/S section. If I wipe out, break my car, or get busted, I can't blame anyone but myself. However, as I stated, I am respectful of others that want no part of it and never pull stunts like that near other drivers.
She'll be back on the road tomorrow hopefully. I can run the stock DS until I decide which way I want to go with this deal. I'm thinking bout just doing adjustable control arms to fix the pinion angle, and having a driveshaft guy repair the one I broke and see what happens.
She'll be back on the road tomorrow hopefully. I can run the stock DS until I decide which way I want to go with this deal. I'm thinking bout just doing adjustable control arms to fix the pinion angle, and having a driveshaft guy repair the one I broke and see what happens.
Last edited by Stkjock; 04-12-2010 at 11:05 AM.
04-12-2010, 09:50 AM
#27
6th Gear Member
Join Date: Nov 2007
Location: Montaner
Posts: 6,193
Frankly. You're lucky to be alive man. I'd be kissing the ground after that one. Going that fast, having it come apart near the front yoke... Holy ****!!
If it were me I'd think about just spending the money on a new one. Don't get a cut down ranger shaft. Don't buy another second hand who knows what happened to it part.
Since you have an aftermarket flange you might wanna consider something that is designed to work with that. The Steeda (axle-exchange) is one that comes to mind.
Anything that comes with an adapter or is designed to mate with the stock flange isn't going to just drop right in and work correctly AFAIK.
Glad you're not pushing up daisies dude. Seriously.
If it were me I'd think about just spending the money on a new one. Don't get a cut down ranger shaft. Don't buy another second hand who knows what happened to it part.
Since you have an aftermarket flange you might wanna consider something that is designed to work with that. The Steeda (axle-exchange) is one that comes to mind.
Anything that comes with an adapter or is designed to mate with the stock flange isn't going to just drop right in and work correctly AFAIK.
Glad you're not pushing up daisies dude. Seriously.
04-12-2010, 12:42 PM
#30
6th Gear Member
Join Date: Apr 2007
Location: California
Posts: 10,468
A good MMC shaft is like $800 without a yoke or joints.
And the critical vibration speed is just like with valve springs, or a crankshaft. Every metal part has a natural frequency that it vibrates at, like a tuning fork. In the case of a driveshaft, vibration is caused by the rotation and the accel and deccel from the angular velocity of the u joints(Any u joint angle other than true 0 actually causes each end of the shaft to speed up and slow down rather than rotating smoothly). That creates a vibration at a certain frequency that moves up and down the length of the shaft. The vibration critical speed is based on material, thickness, length, diameter, weight etc. Once the vibration that's created reaches the same frequency as the shaft's natural frequency(or a crank, or valve springs etc) the forces from the vibration begin to amplify rapidly until the shaft fractures. Basically it's like the fat lady singing a high note and shattering a crystal glass.
Stock steel shafts are stronger than aluminum, they're less likely to break under heavy power applications like launching on sticky tires, but they have a lower critical vibration frequency than aluminum. So a stock steel shaft is more likely to break from high speed vibration(directly associated with mph) than aluminum. Lower gearing in the diff makes the engine rev higher, and thus the DS spin faster, so more gears moves the vibration frequency that's created up to closer to natural of the shaft, for the same mph(which is why a car with 4.10's at 125mph is more likely to fracture the same shaft than if it had 3.27's). Chrome moly shafts have more strength than stock steel with a higher critical speed than aluminum. Then you have MMC(metal matrix composite, usually aluminum that's "alloyed" with composite materials) with has more strength and a higher critical speed than CM steel, and then at the top of the heap is the insanely expensive carbon fiber shaft....but, it's the king of the hill in terms of power and vibration resistance.
And the critical vibration speed is just like with valve springs, or a crankshaft. Every metal part has a natural frequency that it vibrates at, like a tuning fork. In the case of a driveshaft, vibration is caused by the rotation and the accel and deccel from the angular velocity of the u joints(Any u joint angle other than true 0 actually causes each end of the shaft to speed up and slow down rather than rotating smoothly). That creates a vibration at a certain frequency that moves up and down the length of the shaft. The vibration critical speed is based on material, thickness, length, diameter, weight etc. Once the vibration that's created reaches the same frequency as the shaft's natural frequency(or a crank, or valve springs etc) the forces from the vibration begin to amplify rapidly until the shaft fractures. Basically it's like the fat lady singing a high note and shattering a crystal glass.
Stock steel shafts are stronger than aluminum, they're less likely to break under heavy power applications like launching on sticky tires, but they have a lower critical vibration frequency than aluminum. So a stock steel shaft is more likely to break from high speed vibration(directly associated with mph) than aluminum. Lower gearing in the diff makes the engine rev higher, and thus the DS spin faster, so more gears moves the vibration frequency that's created up to closer to natural of the shaft, for the same mph(which is why a car with 4.10's at 125mph is more likely to fracture the same shaft than if it had 3.27's). Chrome moly shafts have more strength than stock steel with a higher critical speed than aluminum. Then you have MMC(metal matrix composite, usually aluminum that's "alloyed" with composite materials) with has more strength and a higher critical speed than CM steel, and then at the top of the heap is the insanely expensive carbon fiber shaft....but, it's the king of the hill in terms of power and vibration resistance.