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Discussion Starter · #1 ·
I have an old 74 Chevy crew cab I'll be converting to short box. Putting LS 5.3 with turbo in it, 4 l80e, 4.10 gear may go to 3.73. What are options for 2 piece? Shooting for 90-1000 at crank.
 

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Why a 2pc ?

Options are a 1pc conversion, or a heavy stl 2pc or a half and half which is half stl and half AL.

Get a length from trans seal to center of joint at the diff and i can give you more detailed options

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Discussion Starter · #3 ·
Right now its about 109" I'll lose 14-15 shortening the frame then lose 1-2 putting 4l80e in (th400 in now) so somewhere around 95" .
 

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At 95" from seal to center of joint you can do 1pc in CF or you can move the hanger crossmember and do a 2pc w/stl front shaft and AL for the major section or a AL 2pc.

What are you going to use the truck for ?

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Discussion Starter · #5 ·
It'll be a street truck. Something to cruise around in and beat corvettes and maybe grudge race. I've got a fox body I was going to put this in then just picked up this truck and thought it would be something different. Might go to the track once or twice a year. It'll probably have a trans brake on it.
 

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Ive had 2 x 2 piece shafts on my car from two different companies. Both excellent I might add.

A 1 piece simply wasnt an option given the speeds I needed it to turn. Although mine is only around 57" or so

First was made by Carolina Driveline http://carolinadriveline.com/

I only later changed this as found a company offering a larger diameter centre bearing, which potentially allows for a stronger setup.
Not that the first gave me any problems anyway

Second and current shaft was by Inland Empire Driveline http://www.iedls.com/

So far both shafts have been used to close to 10,000rpm and 200mph.

Both are plain simple heavy steel, 1350 joints, 3" tubes

Nobody else back then even wanted to help. All the big names, Denny, MW etc had no interest whatsoever in building me a 2 piece shaft.

Although I see some companies do now offer alloy 2 piece shafts. No idea how strong they are
 

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Big names are simply big advertising, 57" isn't really long thats simply even on the cheap side a 4" stl shaft for those rpms. No need for a weight and power robbing 2pc.

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There is when even a 3" is a tight squeeze.

Even a 3" 1 piece would touch the chassis at near max axle travel. So larger diameter without lots of cutting of the chassis wasnt an option.

The 1 piece started to vibrate like mad around 5200rpm, which was a pathetic 120mph it's critical speed was just far far too low.

2 piece gave me the fitment I needed, and also easy access to the rpm's I needed

yes I'd like to lose some of that weight, but until I find an alloy or CF 2 piece in 3" that would be a direct swap, and handle 1000+ with 100% safety...then they are a no go.
 

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you could run a 1 pc CF in 3" at 65" and have 0.0 issue at that rpm

What exactly are you doing and what is the vehicle ?
My problem is, CF is expensive, and Ive seen CF shafts break. They simply dont inspire confidence for the money.

Plus a 3" 1 piece still fouls the chassis anyway...and if CF touched, it would shatter.

It's an old UK Ford Granada ( nothing like the US version )

It's just a fun street car I use for mucking about, a little drag, some sprints and hillclimbs and occasionally 1/2 mile, 1km and standing mile stuff. All rounder really.

The 2 piece steel has been faultless...but it is damn heavy.
 

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It certainly looks nice....but those lobro type joints would worry me too !

Dare I ask what sort of price ? And what sort of power/torque/usage are they rating it to ?
The CV's are used often and I don't recall seeing any failures. Being 2 piece with dual CV's price is around 1500.

It was built for a 5000lb car with 900hp, I didn't ask what the max power rating was.
 

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Those are rzeppa joints, and they aren't breaking easily, those will stand to more than a 1350 series joint.

Carbon fiber can be done in less than the normal and more than the normal tube diameters you see, the issue is there are no already made ends for them and most shops don't have the ability or knowledge of how to make and why it needs to be for a given area so thats why you only see 3.5 and 3.75.


Im not familiar with a UK granada, i'd have to see the issue in the shaft tunnel and the suspension travel to see what could be modified to lose that 2 pc.

As for the one above, another issue with what vehicle ? and why that was done.
 

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Im not familiar with a UK granada, i'd have to see the issue in the shaft tunnel and the suspension travel to see what could be modified to lose that 2 pc.
Simple as this, I am not cutting the chassis to make a 1 piece fit. It isnt a case of what could be modified...I see no sensible reason to.

The car originally had an IRS, and a small tunnel because there would be little shaft movement. Moving to a live rear axle obviously changed that
But the tunnel is still pretty much factory and will remain that way, handbrake cables and mech also run very close.

I could modify the exhaust to allow for a 3.5" rear section though and it would probably be ok though. It's about 28" from centre of the UJ to UJ
That would kill some weight and be a simple bolt in job.

The front section from trans to centre bearing clearance around that is very tight so would be difficult to go larger diameter.
 

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Simple as this, I am not cutting the chassis to make a 1 piece fit. It isnt a case of what could be modified...I see no sensible reason to.

Performance is a reason, making it better is another. Performance is why you started playing with it and modifying it in the 1st place.

Same as why the OP asked this question.

Every car and truck i have converted from multiple piece to singles all got better acceleration and mpg, that's enough reason isn't it. Losing the hanger bearing that simply doesn't last long under hard acceleration and it's drag is another reason.
Most require a very slight modification.

A live axle doesn't necessarily have tons of movement, that's all dependent on the suspension, plenty of cars with live axles that have hardly any movement.

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Performance is a reason, making it better is another. Performance is why you started playing with it and modifying it in the 1st place.

Same as why the OP asked this question.

Every car and truck i have converted from multiple piece to singles all got better acceleration and mpg, that's enough reason isn't it. Losing the hanger bearing that simply doesn't last long under hard acceleration and it's drag is another reason.
Most require a very slight modification.

A live axle doesn't necessarily have tons of movement, that's all dependent on the suspension, plenty of cars with live axles that have hardly any movement.

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It's enough reason only if the gains justify the expense and work.

Spending $2k to gain 1mpg, maybe even 2mpg....kind of hard to justify that one.

As for actual performance gains, actually if there is some real back to back info on that one I would be interested.

The engine/box/axle in my car are all non original. The steelwork on the car is all original apart from from what I altered to install the axle some 10 years ago.
Space has always been tight, that's just the way it is. I'm not butchering the car to make things fit. If I ever have to go that far, I'll do a mid-engine conversion and stick a transaxle into it instead.

The axle doesnt have tons of movement, but it has enough that at present a 1 piece 3" shaft will foul before full suspension loading is reached. The first shaft I used was a 1 piece, speed was limited to 120mph before critical speed was an issue, and the shaft would make contact with the body at times. Not the end of the world with steel...with carbon it would mean instant destruction.

Clearly using a larger shaft will make that even worse...and alu would be just as fragile I think

The original IRS...would have had no movement, hence no need for a large tunnel. It also only had tiny exhausts, relatively small box etc.

But as said...IF the rear section could be upgraded at sensible money to carbon or alloy, with a 100% guarantee it would not fail, I'd maybe be interested in that.

That could be value for money in my eyes.
 

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If you lose weight you can expect gains.

I don't know what you are using the car for but, you would lose half the weight of what you have by simply using a 1 piece in stl, so you'll gain a tenth there. AL isn't fragile.

There are to many pieces missing here to even figure what you need.


2mpg adds up, and depending on use that can be quite a lot of money over the course of a year.

I was waiting for the butchering term to be used, there is no butchering in making room unless you're a butcher, some enthusiasts would say you already butchered the car by putting a live axle in over the Irs.
 

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minimal cutting was required to fit the axle, and at the time 10 years ago it was the cheapest and seemed best solution. I didnt cut any key structural areas back then, and I'm not about to do it now either. Hence 1 piece is not an option.

If I was to do it again today I would use an IRS, or if money was no object just convert to mid engine and transaxle. Wouldnt care so much about cutting then....although at that stage would probably build another car instead

As said, I use the car for many things, road, street, drag, mile, race track etc etc 0.1s over a 1/4 is not enough reason to make me change.

2mpg is say a 10% saving. Over a year at 5000 miles a year, even with our extortionate fuel prices here which are far higher than the US....it's still take 10-15 years to recoup the cost of a shaft

Al is more fragile...at least when browsing forums I see a lot more twisted and broken alloy shafts than I do good old steel

But as it seems people do now make 2 piece alloy and carbon shafts, at some point this may be an upgrade option....but again I think my concerns are real.

10 years ago the big name companies wouldnt even consider making me a 2 piece in steel because they didnt believe they could make one strong enough for whatever reasons.
So it will take some convincing that the new alloy and carbon shafts are strong enough. But at least they are making them.
 
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