930CV or 934/935CV

[jpndave]

This may have been covered in depth and if so, please point me in the right direction. I have searched the forums and read everything I can find.

I am building up a Jeep/buggy and have decided to to independant a-arm suspension all around. I may regret it but want to give it a go anyway. I am really torn and uneasy on which of the cv sizes to use. Main concerns are Cost, Weight and Strength of the cv and shafts. I really don't want to design this for the 930 only to find out that there is no way it is strong enough and have to replace everything that I have done. Also, the cost difference is substantial as is the weight difference. I have no problem with upgrading the cages, etc. and am planning on 300M shafts. I need the maximum travel possible to allow the design. The Ford/GM outer cv for the front outer should work depending on which series is chosen.

Specs are as follows:

Projected curb weight 3000lbs.
Engine: 3.6L LLT V6 300-350HP
Transmission: 4L65E
Transfer Case: Prototype Gear driven, 3.5:1 low range
Diffs: Fabricated 9" about 13" flange to flange
35 or 37" tires on 17" wheels
I am targeting 18"+ inches of travel. Hopefully half shafts will be 22-24" long.


Any help or suggestions would be greatly appreciated!

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[Haycock]

what is this going to be used for?

[jpndave]

It is mostly a "toy" project. It will be streetable and also see a lot of time off road, rock crawling, dunes, pre-running, fire roads, etc.

[jpndave]

What kind of power can you put through a stock 930cv, "race prepped" 930cv, "all out" 930cv (4130 & 300M cages, full polish and prep) and the same in the 934/935? Is the CV or half-shaft the weak link? I should be looking at 20-24" half-shafts.

[jpndave]

Has anyone ever used ceramic balls in the CVs?

[Tech Tim]

What are you going to use for the center sections?

For ease of build how about the GM IFS CV shafts?

RCV makes a high strength version that the inner joint goes to 40*. It also has a slip spline in the shaft for any plunge issues you may end up with.

[jpndave]

The center sections will be fabricated Ford 9" about 13" flange to flange. I really like the the RCV stuff but it is rather expensive. I was planning on using the GM or Ford outers with 930 or 934 inners on the front and 930 or 934 on both inner and outer in the rear. Does the 1/2 ton GM use the same 28 spline 930 sized joints that the Ford does?

Will the 930 sized joints be strong enough?

I am trying to maximize the half shaft length to allow enough travel.

[Captain Air Time]

The center sections will be fabricated Ford 9" about 13" flange to flange. I really like the the RCV stuff but it is rather expensive. I was planning on using the GM or Ford outers with 930 or 934 inners on the front and 930 or 934 on both inner and outer in the rear. Does the 1/2 ton GM use the same 28 spline 930 sized joints that the Ford does?

Will the 930 sized joints be strong enough?

I am trying to maximize the half shaft length to allow enough travel.

If you don't want to be able to unlock the hubs, I would use nothing but 3/4T GM. its bigger, stronger, and has the RCV option down the road if you miscalculated.
That said, my project is very similar, (except I'l be happy to keep it under 4000LB) and I'm planning to use 05+ F150 outers to take advantage of the vacuum unlocking hubs. If it turns out to be too weak, its time to start over with the bigger parts.

What I've deduced from all my digging is that for 37's and crawling with throttle, I will destroy parts if I let things go past 23-25 degrees. 930 (#15) joints are theoretically capable of transferring power at up to 45 degrees, but doing so with more than 50HP and 31" tires is at your own risk.
I've actually put the A-arms on hold for a bit, until I've thoroughly beat the CV's in my TTB setup to be sure they can handle me. If that works well, its on to the next step. IF not, I know to start the 4WIS project on the bigger parts. Actually, I'd use the 3/4ton GM parts out back to start with, since they will get the worst of the loading. Breaking front end parts sucks, but not as bad as busted rear axles!

[cdc12372]

The center sections will be fabricated Ford 9" about 13" flange to flange. I really like the the RCV stuff but it is rather expensive. I was planning on using the GM or Ford outers with 930 or 934 inners on the front and 930 or 934 on both inner and outer in the rear. Does the 1/2 ton GM use the same 28 spline 930 sized joints that the Ford does?

Will the 930 sized joints be strong enough?

I am trying to maximize the half shaft length to allow enough travel.

Have you started working on the 9" centers? 13" flange to flange?? I would like to see some pictures, seems norrow.

[Captain Air Time]

RCV makes a high strength version that the inner joint goes to 40*. It also has a slip spline in the shaft for any plunge issues you may end up with.

Anyone seen these in action, running angles even close to 40*?
RCV is not interested in doing custom or one-off stuff, but the price is good enough (if it is actually that strong) to buy the kit and cut your own shafts (or adapt other aftermarket ones)...