2pc vs. 1pc driveshaft

[ODN13x]

I am curious as to what are the pros and cons (if any) to switching to a 1pc driveshaft as apposed to the facory style 2pc?

[Doc]

Well a 1-piece should be lighter, smoother and more efficient if it's balanced properly. Chevy chose a 2-piece because it's easier to control harmonic vibration issues that way. I'm getting a 1-piece carbon fiber here shortly so hopefully in the next few weeks I'll have some data as to how much improvement it makes. I'm expecting an increase of power to the rear wheels of anywhere from 2-4% due to the combination of lighter weight and improved efficiency.

[Merc]

I have a one piece from the Driveshaft Shop on the way as well. Should be installed late next week. Installation pic's will be in Pumpkin's build thread. Check it out if your interested.

[ProudLS]

I would like to know too Please keep us posted.

[hypurone]

[ODN13x]

Looking forward to seeing some results....thanks for the feedback

[BMR Sales]

The two main reason to run a 1 piece driveshaft is that there is less rotating mass which helps the car accelerate faster and with a 1 piece you dont have a carrier bearing or the rubber donuts to deal with. The one place a 2 piece does shine is the fact that they have higher critical speed rating then the 1 piece but most guys will never come close to seeing the maximum critical speed of a 1 piece driveshaft. We run a 1 piece driveshaft in our 2010 Camaro because of the turbo 400 transmission we run in it.

[ProudLS]

Originally Posted by BMR Sales

The two main reason to run a 1 piece driveshaft is that there is less rotating mass which helps the car accelerate faster and with a 1 piece you dont have a carrier bearing or the rubber donuts to deal with. The one place a 2 piece does shine is the fact that they have higher critical speed rating then the 1 piece but most guys will never come close to seeing the maximum critical speed of a 1 piece driveshaft. We run a 1 piece driveshaft in our 2010 Camaro because of the turbo 400 transmission we run in it.

So what's the maximum speed that we can go with the 1 piece driveshaft?

[flyby]

I installed DSS 2 piece and even with the upgrades to the carrier bearing it still rubbed with light to moderate acceleration (below4k). Replaced with a DSS 1 piece works perfect. (640 rwhp)

[BMR Sales]

Originally Posted by ProudLS

So what's the maximum speed that we can go with the 1 piece driveshaft?

There are a lot of variables that go into figuring out maximum critical speed. Material used to build the driveshaft, wall thickness of material, and length are contributing factors. So each driveshaft will be different.

[Driveshaftshop]

This is a question we get allot, this is our take on the subject. to start driveshaft technology has come a long way since the 1st gen Camaro's. although thru the years Gm has always used a single shaft with 2 U-joints (although there was a odd 6cly shaft on the last generation cars that had a 2 piece and a CV but it was a disaster) they used them until the last generation of cars. In the past a 2 piece shaft was used when the overall length of the tube was too long and would hit critical speed (the speed where the tube goes into a jump rope affect and will break) jump forward to the "Modern Muscle cars" and all of them have 2 piece shafts. Yes the Mustang-Chryslers and the Chevy cars of today all have a 2 piece shafts, but not all have it for the same reason. The Mustang has a very heavy shaft that had a 9lb Harmonic damper in the back shaft (the entire shaft is about 49lbs) its used to calm the harmonic vibrations of the motor. You can put a single shaft in there cars but there are a handful out there that have such bad harmonics that it needs that heavy shaft to calm the problem. The Chrysler is a different story, the chassis is made by Mercedes (its a E class car underneath) and has the problem with length so a single shaft would not be able to be used. Both the Chrysler and the Chevy use a rubber drive called a Guibo joint (believe it or not that is the correct term) these joints are designed for torsional dampening (not vibration) or in other words when you put the car into gear it takes the slap out of the drive train and will give the car a smother transition of power, its great in a luxury car but in our opinion it has no place in the performance world. now the real reason we believe the 2 piece shafts are being used on the new cars is harmonic and vibration dampening. All of the new cars coming out are uni-body and built so tight that the smallest amount of harmonics from the Engine/Drive train will find its way into the drivers cabin. Think about when you started changing the suspension parts to polyurethane and felt the cars rough edges more, think back to the old days when a solid motor mount was used and how it would be felt thru the entire car (keep in mind the older cars had frames that were isolated from the body with rubber mounts) so keeping this Harmonic monster under control is a big job and the driveshaft being a hollow tube acts like a speaker or broadcaster of the harmonics in the system. so jump forward to the question, it all depends on the car and what its being used for. a 2 piece shaft will have
a greater critical speed but at the cost of weight (and the hanger jumping up and down) the single shaft will be more responsive to throttle input and be lighter so in a drag car or a fast street car there would be advantages.

The critical speed of the single shaft will depend on quite a few things. The drive train manual covers many of these including
material density,material type,modulus of elasticity. The other factors that come into play are mounting points, are they moving or or rigid. The rear gear, tire diameter also will have an Effect. i know im getting real technical but there has been some bad info floating around some other forums' and i thought you guys might want to know the real deal. On top of all this you have mounting of the shaft, this believe it or not will also affect the outcome and its why we use the Billet plates and not a traditional yoke, since we have taken delivery of the high speed balancer we have come to realize just how "off" a pinion yoke can be. When we 1st received the machine we had to make our own balancing fixtures and went right ahead and used some billet yokes. I will not tell you the name of the manufacturer but we tried more than one but always had the same result, if the part was taken off and put back on it didn't center itself the same. We have been doing some testing for some of the bigger NASCAR teams being were here in the Charlotte area and after checking them we were surprised to find they have a tool that sits into the pinion yoke to check run out (a funky ball looking thing), some pass and allot don't make it, in fact they match the shafts run out to the pinion yoke run out. After realizing the yokes would not work on the balancer we decided to use billet plates with flanges. It was a perfect match every time. The Camaro had the rubber drives (Guibo joints) from the factory and the one real nice thing about them is there is a pin in the middle, this pin is a precision 16mm part that is ground on center with all the internal bearing journals of the trans and diff shafts.
To put it clearly its a perfect point to pick up a center line so we make the plate to pick up the center line for both the CV mount and the flange mounts. This along with either of the shaft will produce a vibration free shaft, so if high speed is what your after (were talking over 200mph) the 2 piece could have one draw back but we have addresses it, the fact that anything with a slider will become unstable after 5000rpm (due to the play needed to slide). we have installed a set screw on the 2 piece system to be tightened after install to stop this instability. As for the single shaft we are using a high speed CV that has virtually no play and it is about the most stable thing we see in the balancer at high speed (right up to 9500rpm). Our single aluminum shaft is rated for about 200mph with a 3:54 rear gear, the higher the numeric number the lower the mph (a 3:73 gear will change it by about 400rpm so its a little lower) of coarse a carbon fiber shaft will spin about 25% higher (using a .89 safe factor) so there you have it, hope i didn't go to far.....

3-1/2 aluminum, best bang for the buck @ 17lbs




2 piece 4130 chromoly a little heavier but stable



3-3/8 diameter Carbon Fiber, spins faster and has cool factor .....

Originally Posted by ProudLS

So what's the maximum speed that we can go with the 1 piece driveshaft?

[BLWN SS]

Why dont you offer the 1 piece aluminum for the automatic?

[Driveshaftshop]

Actually we do, i will make sure its put on the site tomorrow morning. its the same price

Originally Posted by BLWN SS

Why dont you offer the 1 piece aluminum for the automatic?

[olblue75]

Can they be painted or powder coated