930CV or 934/935CV

jpndave

Well-Known Member
Posts
51
Reaction
1
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!
 
Last edited:

jpndave

Well-Known Member
Posts
51
Reaction
1
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

Well-Known Member
Posts
51
Reaction
1
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.
 

Tech Tim

Well-Known Member
Posts
291
Reaction
5
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

Well-Known Member
Posts
51
Reaction
1
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

Well-Known Member
Posts
89
Reaction
0
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

Member
Posts
20
Reaction
0
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

Well-Known Member
Posts
89
Reaction
0
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)...
 

TyBo1001

Well-Known Member
Posts
200
Reaction
7
I would recommend going with the 934's. 930's could probably handle the HP, but that HP with 3000lbs would make me worry. Better to build around the bigger CV and spend the extra $$ up front, then trying to rebuild it later on, after you have blown out a couple CVs. That is my opinion at least.
 

jpndave

Well-Known Member
Posts
51
Reaction
1
Thanks for that response TyBo.

What about full 930s with 300M cages and shafts? I like the idea of the smaller joints for weight savings as well as the costs. From what I have seen, they appear to be less expensive even comparing 300M 930 joints with stock 934 joints. The weight difference is substantial, over 20lbs just in the joints themselves. I have also read that the 930 joints will handle a few degrees more travel also.
 

FullsizeFun

Well-Known Member
Posts
410
Reaction
5
930's should not be used in anything over 2500lbs or anything bigger than a 33" tire.
934's with 33 spline axles would be the way to go for your setup. Doing it right the first time is actually cheaper than being "cheap" and going with 930's then breaking them on the trail and having to buy 930 stuff twice then end up buying 934 stuff later anyways. Cages are very important too, go with 300M.
RF joints will give you more angle than VL joints. Typically you will use an RF on the outside/steering side, and VL on the inside to take any plunge you might have in your design.
 

jpndave

Well-Known Member
Posts
51
Reaction
1
Ok, so you're suggesting Chevy 3/4 or 1 ton outer joints with the 934 slip joint inside? What kind of angles will the 934 do when race prepped. I have seen 28 degrees for the 930 when properly prepped.

I hate to spend that much and have the extra 50lbs on the car but if it is necessary to avoid breakage, then I guess there really isn't a choice.
 
Top