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What is stronger CV's or U-Joints???


80LS1T

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Ross,

 

I have a questions regarding your CV adapters.

 

I have 1973 240Z with a stock drive-train (R180 UJ half-shafts, etc...).

 

I will be putting in a R200 (75-83 280Z-ZX) and would like to upgrade to the 280Z stub axles.

 

What exactly do I need to complete the conversion to CV half-shafts?

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hmmm im running stock (old) ujoints and axles from a 280z.... have be doing 5000-6000 rpm launches and havent broke one yet...knock on wood and running loow 11 sec 1/4 mile... on the 27th of this month will be the test. bigger injectors bfg DRs @ 18 PSI launching at 6000 RPM Im either going to get a 10 sec slip or destroy a u joint in the attempt rockon.gif

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  • 2 months later...

I am running 475 foot pounds of torque through my cv type half shafts and have had no problems with them. I dont see the rational that universal joints are stronger then the CV joints. Think about this, a universal joint has two ends with caps and roller bearings that connect them together. The CV joints have three stubs with roller bearings connecting the ends together. We are talking about 30% more metal area connecting the two parts together. I'm not a rocket scientist, but it seems to me the more metal contact area you have the stronger the part will be, it's like comparing a stock Nissan drive line universal joint to a chevy or ford universal joint, there is simply more metal there and the universal is bigger and beefier. a 5/8 peice of round stock is stronger then a peice of 1/2" round stock because there is more metal there, same concept with the universal/cv joint situation. Now there are other considerations like hardness of the metal to deal with, the harder the metal the more apt it is to break under a shock condition then a softer part, but the fact that there is more contact points and metal contact area on the CV joint leads me to believe they are much stronger then a universal joint from the get go.

just my 02

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Has anyone had custom halfshafts built to use chevy u-joints? Aside from the guys that have swapped entire IRS systems in. I guess the u-joint flange to the four bolt datsun pattern is the issue? Would need an custom adapter similar to the jtr driveshaft flange. Maybe it would be more expesive than just doing the CV swap, but it seems that if you were running 1310 u-joints on the halfshafts they wouldn't be breaking??? I don't know, but I will have to deal with this soon.

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you can either have the halfshafts modded to use 1310s, or you can have the vette halfshafts shortened and rewelded to fit z flanges with mods for the four bolt flange to work, i believe any driveline shop could do it, but it wouldnt be cheap. i think halfshafts are plenty strong for a tough street car, but yeah they can prove to be the weak link when you start putting the power down.

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  • 4 years later...
Sorry to bump a really old thread but I'm curious as to who out of these people are still running halfshats with OEM style U-joints. The people talking in this thread are putting down alsmost twice as much torque than I am with much harder launches, I'm curious to see who has broken.
I do not no about these guys but with our car we went a 9.21 @153 mph in the quarter. Our car dynoed at 566 RWHP and with NOS it went to 698 RWHP. We did this last March at SEZ. We have since changed to the 300ZXT CV axles and have had no problems. We did break 6 or more ujoints with the halftshafts. Jerry
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It is a known fact that u-joints seem to fail more often than the CV's in general use. This is primarily due to the small size of the stock u-joint and operating angles. This is escalated as hp/torque goes up in a hybrid vehicle. The early factory CV's are an improvement in angularity operation but I doubt they are any stronger than the u-joint design. The later factory CV's (300ZXT) seem to be stronger as indicated by those users having lower failure rates. All of this is speculative as quality, maintenance, etc. also play a role. The cost of conversion is not $$ friendly but everyone is happy with the results. I chose to do a custom CV conversion using my own adapters and 930 CV joints. There CV's are normally found in the Porsche 930 turbo coupes and are rated around 600hp. My conversion ran about $1000 total for all parts (CV's, boots & flanges, axles, billet material, machine work) and machine work. While that is ridiculously $$ the end results is a near bulletproof halfshaft. The weak link now is the 280Z stub axle. You can look at my setup in the gallery.

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It is a known fact that u-joints seem to fail more often than the CV's in general use.

 

Its is a know fact that something seems to do something?

 

FYI... more Datsun people run u-joints then CVs, probably an order of magnitude more. That would support your "fact" that u-joints fail more often then CVs because there are more u-joints out there to fail. You can also say, based on the population distribution, that its known fact that u-joints seem to last longer, seem handle more hard drag strip launches then CVs, and seem to fall on peoples toes more often then CVs. :D

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It is also a know fact to us, it is the angle of the u-joints that create the breaking issue. CV joints are more forgiving. If you limit you Z-Car squat and try to keep the u-joints level at a hard launch then they do hold up, we have proven this.

 

Just my 2cents worth.

 

 

John

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Okay, I'll take your lashing, John. Maybe I should have chosen my words more carefully. Yes, more u-joints are more in service than CV's in the earlier cars. Yes, the u-joints do appear to hold up better than CV's in hard launch applications. The CV's do provide better augularity which increases their life span not necessarily their strength though. The OEM CV's are not the strongest design out there. I chose to convert after losing two u-joints in normal use. I don't drag race my vehicle but do drive it hard at times. I followed in BlueOval's basic design with my own 930 conversion. For me it was about building a better halfshaft which will provide for long life with minimal service required even if abused. When laying a stock u-joint, OEM tripod CV, and 930 CV side by side it is easy to see the difference in girth, engineering, and strength. I don't think a CV conversion is a bad choice for most people in here. The end result desired should dictate what direction to go, u-joint or CV. Lastly, I run spicer u-joints in the front axles and driveshafts of my hybrid Land Rover. With final gearing in the 60:1 range these u-joints take a heck of a lot of abuse while off-roading. I've only lost these (three in 5 years) due to excessive angles/torque, or contamination. That is testimony to a u-joint's durability.

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Well I think I've decided to rough it out and take the high road. I'm gonna do the R230 package swap that Ross sells. This will eliminate the weak stub axle Which is a concern of mine in upgrading. I'm NA right now and don't make huge numbers but i plan to be in the 400-600 mark when i go turbo so I want something to take that lashing.

 

I myself have broken 3 sets of U-joints within 7 months of play/daily driving. No clutch dumping just spirited driving.

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