PST Carbon Fiber Driveshaft
 

Ok guys installed my PST carbon fiber driveshaft, now as some of you know the shaft does not come with instructions, I mean 4 bolts... how hard is it?! HaHa

Required Tools:
14mm Wrench
14mm Socket
Extention (I used a 4in)
0-100 Ft LBS torque wrench
Wooden Hammer
White out

Removing the old shaft is easy and CAN be done with the car on jack stands but trust me WAY easier to put the car on a lift.

First we lifted the car up, (leave the ebrake off)
Break the torque on the (4) bolts (14mm) that are on the Rear Diff leave one bolt in hand tightened.

Hold the shaft up while you remove the carrier bearing 2 (14mm) bolts

Remove last bolt on the Rear diff holding up the shaft.
(you MIGHT have to loosen your mid pipe, our Perrin Res Midpipe had to be loosen to let the bearing through)

Once Bearing is out slide the shaft out of the transmission (some oil will come out not much though)(lightly tap the drive shaft with the wooden hammer to help it come out of the rear diff)

Do the steps in reverse to install your new drive shaft!!

Torque bolts on drive shaft to 55FT LBS
(mark ONE bolt hole with white out where it connects to the rear diff this will be explained later)

http://i77.photobucket.com/albums/j6...1/IMG_1665.png

Now this is the bit that we had to figure out on our own!

PROBLEM!!!!
At around 70-80mph there was a vibration not crazy but you could tell that something was not right. Had to talk to a few people at Subaru and PST to figure out what was going on... we found that the shaft can be installed 4 different ways, so if one way did not work, rotate the plate 90 degrees (where your white out mark comes in) and test drive again. Make sure you torque the bolts back down before test driving again until you find a rotation with little to NO vibration.

It should feel smooth not harsh or noticeable.

Once we got it all figured out everything felt much better no more vibrations at 70-80+ and the car feels more alive than it did not like it was dragging its feet... haha

As always feel free to ask questions, and anyone who is in the San Diego area that would like to feel it or need help with the install let me know!

BIG shout out to the guys at Frank Subaru who always get me great deals on performance parts for my BRZ really wish more FRS guys went there HAHA!!!

And Rally Sport Direct who again get great deals on awesome parts!!!

What other mods do you have on the car?

Can you explain this in more detail? What feels different? Do you feel any preload and release in the driveline when launching hard? Do you genuinely feel it's worth the price tag?


I've been reluctant to buy one since carbon driveshafts are typically half the weight but twice the diameter (or more). Physics says this would negate most or all of the weight savings. But, perhaps it works more efficiently on our cars due to the low curb weight.

Here's a good article on the subject of rotating mass: http://www.w8ji.com/rotating_mass_acceleration.htm

Read "Drive Shaft Example" toward the top and "Rotating Mass" toward the bottom.

I believe the PST one is close to stock diameter?

I've only seen the Powertrain Industries and Driveshaft Shop shafts in person. If PST is as small as stock then that could easily make the physics issue moot.

DSS was a reasonable size but I didn't like their carbon layup. PTI had forged ends but the tubing diameter was massive. That leaves PST.

Looking forward to what @crank can add.

I havent been doing hard launches yet I will try a few on the way to work but the best way I can explain it is that it does feel abit like a preload on the drivetrain, and the throttle response has increase across the entire powerband. even at cruise speed and you want to pass someone the power is right there instant waiting to be used.

Yes it is very close I will get the measurements later

And yes to me worth every penny!!

Nice info and thanks for posting!! I was not aware the initial placement during install could make a different which could be adjusted (plate rotate) if needed as you noted.

What's the weight if these carbon drive shaft?
I've read stock is about 25 lbs and there's an aluminum drive shaft thats about 12 lbs

Quote:

Originally Posted by 07jazzrs5gt86 (Post 1136788) What's the weight if these carbon drive shaft?

the shaft is 13.9lbs and is close to the stock diameter I will try to get a measurement next time I have the car up for an oil change which is coming up

what is the cost of the aluminum shaft? and is it really 12 pounds? whats the diameter?

Just over 12 lbs I think and from the picture, the diameter looked quite larger. Also just over $400 IIRC.

Not sure about the diameter but the price is very attractive
Here's the tread
http://www.ft86club.com/forums/showthread.php?t=44150

Here ya go.

http://www.ft86club.com/forums/showthread.php?t=44150