Author Topic: 930/934 cv's VS u-joint 1/2 shafts  (Read 10191 times)

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borris

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930/934 cv's VS u-joint 1/2 shafts
« on: September 14, 2008, 01:20:04 PM »
I prefer cv's over u-joints but a lot of people are using uj shafts now. What's your opinions and pros/cons of each?

Odyknuck

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Re: 930/934 cv's VS u-joint 1/2 shafts
« Reply #1 on: October 22, 2008, 07:36:13 AM »
I dont have any experience on the "U" joints and half shafts however I have heard that they are not as strong as a good race prepped 930 setup. I do know that a halfshaft setup is around $1200.00 versus a 930 setup taht can be had for around $700.00.
You can get more travel with the half shaft setup .

Offline fabr

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Re: 930/934 cv's VS u-joint 1/2 shafts
« Reply #2 on: October 22, 2008, 10:12:07 AM »
I dont have any experience on the "U" joints and half shafts however I have heard that they are not as strong as a good race prepped 930 setup. I do know that a halfshaft setup is around $1200.00 versus a 930 setup taht can be had for around $700.00.
You can get more travel with the half shaft setup .
I've talked to a lot of people that have run both.I feel that most peeps like the uj's because they don't need to lube them nearly as often and when needed it's a simple matter and much less messy.So the uj's get the nod due to that for a lot of people.
  As for strength I don't know if the uj's or cv's are "stronger" but IMO only they are both up to the task if properly built.There have been many POS uj shafts offered in the last couple of years tho from supposedly reputable suppliers.
   More travel? This is something that I'm not really convinced of.I'll concede a modified uj yoke can accomplish more angular misalignment. Something on the order of 25* cv max  vs 32 or so for the uj. But does that gain as much travel as many think? I'm of the opinion it does not. Why? Due to the the pivot points of the cv and uj being different the cv axle will be longer. That allows nearly the same travel with uj axles @32* as cv axles @25*. These numbers are not accurate but in general are close enough to make my point. Yes, if you run uj's you can run more angle yet but it's not really a good idea. At least not according to uj manufacturers. So to me the only question is which one will transmit torque most efficiently at normal running angles?   .
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

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"I fear the day that technology will surpass our human interaction. The world will have a generation of idiots" Albert Einstein  (IT'S OFFICIAL THAT DAY IS HERE NOW!)

LiveWire

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Re: 930/934 cv's VS u-joint 1/2 shafts
« Reply #3 on: October 22, 2008, 02:10:36 PM »
I'll be running CVs capable of 45 degrees at about 32.

Offline fabr

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Re: 930/934 cv's VS u-joint 1/2 shafts
« Reply #4 on: October 22, 2008, 02:57:43 PM »
Non plunging with slip shafts?
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
"I fear the day that technology will surpass our human interaction. The world will have a generation of idiots" Albert Einstein  (IT'S OFFICIAL THAT DAY IS HERE NOW!)

Offline Punkur67

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Re: 930/934 cv's VS u-joint 1/2 shafts
« Reply #5 on: October 22, 2008, 06:59:33 PM »
I know the u joint setup with a plunging shaft has issues with high horsepower and heavy cars. The issue is when the car is under enough acceleration the splines in the shaft can bind up, not allowing the shaft to plunge, which in turn does not allow the suspesion to cycle down till some of the load is removed either by the tire slipping or coming off the ground or coming off the throttle. This was told to me by a big suplier of this product. He said for light cars or cars producing less than 200hp they have had no problems like this but on the big v-8 cars it has been a problem. I only know 1 guy who ran these for a season and after more u joints than you can shake a stick at he went back to 930s. He has also running a mean cast iron sbc. HEAVY!!!
Its better to be a smartass than a dumbass!

Offline fabr

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Re: 930/934 cv's VS u-joint 1/2 shafts
« Reply #6 on: October 22, 2008, 07:39:44 PM »
Names?
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
"I fear the day that technology will surpass our human interaction. The world will have a generation of idiots" Albert Einstein  (IT'S OFFICIAL THAT DAY IS HERE NOW!)

Offline Punkur67

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Re: 930/934 cv's VS u-joint 1/2 shafts
« Reply #7 on: October 22, 2008, 11:18:40 PM »
The product was from extreme performance.
Its better to be a smartass than a dumbass!

455bird

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Re: 930/934 cv's VS u-joint 1/2 shafts
« Reply #8 on: October 23, 2008, 01:30:39 AM »

LiveWire

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Re: 930/934 cv's VS u-joint 1/2 shafts
« Reply #9 on: October 23, 2008, 08:28:58 AM »
Non plunging with slip shafts?
Yes. The key when using slip shafts is to not take advantage of the amount of plunge they are capable of. If you have 3" of plunge, then it will take 6 times as much force to slide the splines as if you had 1/2" as well as produce significantly more heat.

Comparing my setup to the one pictured, the male spline is closer to the pivot point on that end. Plus as you pointed out earlier, the pivot points of the CVs are closer to the drive flanges and wheel hubs at their respective ends giving a longer shaft between the pivots. With a longer shaft and most of it being the female end, I have a larger air gap inside the female end. This reduces the pressure increase as it is compressed and therefore side load on the joints. Using a larger, thinner wall tube also increases the air gap.

Offline fabr

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Re: 930/934 cv's VS u-joint 1/2 shafts
« Reply #10 on: October 23, 2008, 09:11:37 AM »
I've heard reports of serious side loads being placed on trans with slip shafts due to friction and air trapped inside and causing bearing failures usually when used with trailing arms. Do you run yours with trailing arms or a arms/5 link?
« Last Edit: October 23, 2008, 09:13:18 AM by masterfabr »
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
"I fear the day that technology will surpass our human interaction. The world will have a generation of idiots" Albert Einstein  (IT'S OFFICIAL THAT DAY IS HERE NOW!)

Admin

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Re: 930/934 cv's VS u-joint 1/2 shafts
« Reply #11 on: October 23, 2008, 11:06:02 AM »
my drak is basicly semi trailing arms, as it is a 3 link, it plunges pretty good and the trans bearings are holding up just fine...

Offline fabr

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Re: 930/934 cv's VS u-joint 1/2 shafts
« Reply #12 on: October 23, 2008, 03:31:52 PM »
Big cars not babies.LOL!!!!!
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
"I fear the day that technology will surpass our human interaction. The world will have a generation of idiots" Albert Einstein  (IT'S OFFICIAL THAT DAY IS HERE NOW!)

Admin

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Re: 930/934 cv's VS u-joint 1/2 shafts
« Reply #13 on: October 23, 2008, 03:45:48 PM »
I've heard reports of serious side loads being placed on trans with slip shafts due to friction and air trapped inside and causing bearing failures usually when used with trailing arms. Do you run yours with trailing arms or a arms/5 link?

well you didn't say big cars, and your asking livewire, Who in which builds the car i have, so wanna reprhase?

Offline fabr

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Re: 930/934 cv's VS u-joint 1/2 shafts
« Reply #14 on: October 23, 2008, 04:51:23 PM »
Hehehe. ;D
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
"I fear the day that technology will surpass our human interaction. The world will have a generation of idiots" Albert Einstein  (IT'S OFFICIAL THAT DAY IS HERE NOW!)