CV angles (Plunge vs. non-plunge)

[D.Mavis]

I could be mistaken but I believe that plunging and non plunging cv's are available in 930, 935, and size 30 bolt patterns and dimensions. I think the max angle before things hit in a non plunging is 40 degrees and plunging its around 28 degrees?

But I hear that class one cars usually stay in the 22 degree max angle range on a plunging cv because if they go higher the power they are running makes the cv's unreliable.

so my question is: is there a geometry difference between the plunging and non plunging cv that makes a non plunging stronger at higher angles? or if a plunging cv cant live past 22 degrees then a non plunging cv cant either.

Lets assume plunging is not an issue (I want to use this on an A-arm rear which will not have any plunge and any incidental plunge would be taken by slipping between the shaft and star splines.)

Since I dont need the plunging I'd like to save money and not use mid board hubs, since this would shorten the axle lengths I'd need to go to a higher angle. Whats the highes angle a non plunging 935 can opperate at in a class 1 type 4 seat prerunner???


Thanks

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[partybarge_pilot]

It all depends on how much power your running through them. Power=heat, lots of angle=heat. Add the 2 together and it will cook any CV. On a light car with little power you can run 45*. on a heavy car with lots O'power, not so much.

[D.Mavis]

So lets say its a class one car with 450hp and it was running 934 plunging cv's that were found to be able to opperate at a max angle of 21 degrees, before they became unreliable. now we switch to non plunging 934 cv's (we are ignoring plunge or dealing with it some other way).

Can we opperate the non plunging cv's at a higher angle ?

[ACID_RAIN28]

There is a huge geometric advantage to a non plunging CV, it is in the ball track design, the non plunging are a "straight" cut track and the plunging are "cross" cut. Plus they can be run with more angle and live through more abuse. We ran ours at 37.5 degs on the size 30

[D.Mavis]

Acid-Rain---
Thanks for the info, what type of vehicle (power and weight)were you running the size 30 cv's at 37.5 degrees, and how many degrees do you think you could have run that set up to if they were plunging size 30 cv's?

Thanks for the real world answer.

The straight vs. angled ball tracks are definitely a geometric advantage that I had not thought about. The more angled the track the higher the contact stress between the ball and track, for a given shaft torque.

On a side note I was thinking that the enemy of CV longevity is heat because it decreases the effectiveness of the grease. With a plunging set up the shaft splines slip through the star as well as the the balls roll in the track because of articulation and more so because of plunge. Thats got to heat up that cv a lot. With a non plunging cv the only ball rolling is is due to articulation and there is no slipping of the shaft through the star. I would imagine a non plunging cv would run a lot cooler. Obviously you have to have a slip joint in the shaft or eliminate the need for plunge.

[partybarge_pilot]

Acid-Rain---
Thanks for the info, what type of vehicle (power and weight)were you running the size 30 cv's at 37.5 degrees, and how many degrees do you think you could have run that set up to if they were plunging size 30 cv's?

That would have been Phluegers truck. I think they originally started out with more angle than that.

[Red_beard]

What is a size 30 CV?

[Triaged]

What is a size 30 CV?

A GKN designation. They make many different types and sizes.

[partybarge_pilot]

A GKN designation. They make many different types and sizes.

What he said.... Actually, 930's technically aren't named that, they are series 15 CV's that just happened to be use on a 930 Porsche........

[jpndave]

There is a huge geometric advantage to a non plunging CV, it is in the ball track design, the non plunging are a "straight" cut track and the plunging are "cross" cut. Plus they can be run with more angle and live through more abuse. We ran ours at 37.5 degs on the size 30

Thanks for the info here!

Does anyone have real world angle/strength numbers on the plunging/non plunging for size 21 and size 15?