[Supershafts]

Once we get our new cnc machines up and going we'll be making shafts, they will be a little different then this one though.

How long was this driveshaft? We have 3.5" aluminum driveshafts in GTO that are 50+ inches that handle 700-800 hp no problem.

Thanks
Chris

GTO is totally different..... The GTO can use a different slip yoke, the Caddy can not as it does not share the exact same trans.

The caddy needs a slip sleeve style AL shaft, which is a few hundred more right there.

The CF shaft is the same issue and would start at 3.750 outside diam...

The shaft in this car is 3.5"


Becareful when doing these mods, because as i seen 1st hand at some other shops expertise of squeezing a hanger in there and making me chase a vibration and wasted time until i thoroughly looked at what the other driveline shop did....problems solved....



As for the wanting to do 150 mph.... it is not the speed of the car that is the issue it is the speed of the shaft at 150 that is the issue...

So if you know what rpm you are at and at 150 mph in 1 to 1 then i can tell you what you need for that speed...

Safely the AL 3.5" shaft will spin faster then stl, 4" AL would be the end all to any hp/rpm issue, but the room restraints in the tunnel and a need for solid or atleast nylon bushings at the rear diff would most definitely be required.


As of now i have another caddy and i have come across broken case diff mounts at the upper pin location.
Has anyone else suffered this issue, i already have the fix for this car without him needing to buy a new diff housing.
Has anyone else that is racing there Caddy noticed or had the same issue with the front mount bushing of the diff housing ? ? ?




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[Supershafts]

I'm curious as to how much power this will free up.

I'll tell you that tomorrow, i'll weigh the old factory shaft and weigh what is replacing that and what a Al shaft would weigh compared to both....

As for the OP's car, his issues were vibrations from lack of expertise in whoever did that original design....

That shaft wasn't lighter then the factory shaft, it was heavier though, so it would have robbed some hp compared to the factory weight, however with the unlivable vibration issue from just a lack of knowledge made that shaft useless.

I expect that the non lightened stl shaft in the OP's car is not lighter then the factory shaft, it is way lighter then the other aftermarket junk that was in there, however it is stronger and doesn't incorporate a flimsy hanger bearing with the ability to shred itself under severe racing conditions.


Driveshafts are just a tube and go...so becareful who does what... I have seen other shops do stupid shit, just because they have no clue, and when a shaft comes apart from a speed related issue, you can die...




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[Supershafts]

What, exactly does this mod do for you? I can't see the benefit. The "improved driving" of letting out the clutch/no clunks" etc...didn't that come from the diff bushings?

The mod made for this car lost the flex coupling, and lost the hanger bearing and rzeppa head assembly...

Overall between the factory shaft and the shaft i used in the car it is probably around the same weight as the original.
I could lighten the stl shaft up some more and make it come in a few pounds lighter.
The AL shaft or Cf shaft would be lighter, but there both going to be very tight in the tunnel and need to shave the tunnel at the hanger bearing structure points. (Cf is 3.750 diam / AL 4" diam)

I did another caddy the other day and im looking into yet another way to get around the front tripod set up a totally different way....

Now the other issue is cost....

What i did for the caddy the other day was a huge diff in cost to the caddy replacement, and if he should later on upgrade to the single pc shaft he just needs the front fix i go with which will save him money since the rear section can be used on the new shaft...


Pretty much the benefits are cost, and there is some performance benefit since you lose the flex disc.

Just be a little questioning of what someone does..... For the length the shaft has to span in 1 pc and what the car is capable of a single piece less then 3.5" diameter is pushing safety...
A 3" single pc shaft in stl i wouldn't do....

 

[Supershafts]

K I thought so but wanted to confirm . Super shafts what's the going rate for a aluminum shaft ?

I honestly don't know, the 4" is a very tight fit and the rear needs to be held much tighter then it is with the factory set up.. (which is another thread/issue)
I can tell you the mustang which also has the slip sleeve dilema is around 690, but the caddy has the rzeppa end to deal with and the fixed end tripod at the trans...that's going to add to the cost, and then the hanger structure is another issue to lose

If you guy's ever blow up your trans, lose that particular style t56 and get the slip yoke version.

The shaft can be so much lighter with the slip yoke version over the fixed style shaft
Every pound is equal to 20 lbs carrying in the driveline.. so losing 10 lbs in the driveline is like losing 200 lbs of carrying weight.

 

[Supershafts]

The 4" would fit, but it won't be a take the factory shaft toss it to the side and bolt the 4" in, it would require a solid mount/brace at the pinion housing, and the hanger structure needs some attention...

They don't make a slip sleeve for the 3.5" AL shaft, they make a reducer for the 4" slip sleeve to 3.5", but once you add that it up the cost and it's no longer lighter then a stl lightened 3.5" shaft.

CF is the other option, but at twice the cost of AL, and 3.5 times that of stl.

As for the keeping the diff from becoming it's own self help grenade, it needs a fairly simple brace at the front pinion to the frame support to keep it solid.
Im working with another Cad on that issue.