Recently I walked into my office and found a rather long box sitting next to my desk with the label “PST” on it, gave a quick peak inside and sure enough there was a whole bunch of carbon in this box. Yes, our carbon driveshaft has finally arrived!! I was super anxious to put this on, so I called over to Ziptie DynoWerks, our local shop with a Mustang Dynamometer, and they were kind enough to let us install the carbon shaft at their shop so we could get a good before and after. A few days of impatiently waiting like a kid before Christmas, it was finally time! I swung by work early to grab Justin so he could set up the cameras and help with anything needed. We packed up our gear, loaded it all in the BRZ and we were off to Ziptie DynoWerks. Once we arrived we decided to do a baseline so we could get a good before and after reading, so we strapped our BRZ down and let it rip. We did a few runs, as we always find the car makes the most power on the 4th run as the car gets nice and warm and loosens up. We made 161 HP on our final pull and decided it was time to install the PST carbon Driveshaft on the car. The install is super easy and Ziptie DynoWerks was kind enough to let us use their facility even though they knew we would make a mess….and we did haha. The old driveshaft removal literally takes about 30 minutes, and it is always helpful to have a buddy in the car to set or release the E-brake so you can spin the shaft to get to all of the bolts, this is where Justin’s E-braking expertise came in handy. Once all 4 driveshaft to differential bolts are out, you remove the 2 bolts that hold the carrier bearing to the chassis, pop the shaft free from the differential and the driveshaft should slide right out of the transmission.
Next, pick up that new, pretty, and superlight carbon shaft and slide that sucker in! Bolt it all up and marvel at how awesome you are. By the time my ego was nice and inflated, Justin and Ziptie DynoWerks already had the car back up on the dyno and strapped down. Now I am getting excited, not only because I would like to see at least some gains, but there is always that chance that you botched the install, and let’s be honest, seeing a driveshaft come off when the car is doing 100+ MPH would be cool to see, or at least cool to tell your friends about when they visit you in the hospital. My luck was strong this day as the car managed to stay together and after 4 pulls we saw a peak HP of 165 HP, or a gain of 4HP. I was hoping for a bit more, but I was excited as is to see any gains at all, so it was a good day.
We had already weighed the PST Carbon shaft and it came in at a featherweight 13.9LBS and now with the stock shaft off, we weighed it using the same scale, I was surprised to see the scale read 24.14LBS as it really did not feel that heavy to me. Either I ate my vegetables that day, or was just feeling extra strong, but I have to agree with what the scale says, as they never lie, where I have been known to stretch the truth just a bit
. Now it came to the most difficult part of the whole process.. Math. As I struggled to do even simple subtraction, I had a flash back to grade school and my teacher drilling us on math problems saying “You will need to know this stuff by heart, it’s not like you can carry a calculator around with you every day”. Proving her wrong, I whipped out my phone/calculator, punched in a few numbers and voila, the PST shaft is 10.24 pounds lighter than stock.
Finally all the work will pay off, I actually get to beat on the car.. err.. I mean, “test” the new driveshaft drive shaft of course, as this is a strict scientific comparison with absolutely no horseplay. Pulling out of the shop, my first impression was that it did indeed feel just a bit more eager to accelerate, which was expected. Being light with the throttle as the car warmed up, I made my way to a place where I could open it up a bit. Ah yes, the Freeway on-ramp, the ultimate, legal, 0-65MPH testing ground for a slow car. Going through the gears the car felt great, I felt the car was quicker to accelerate, and with less fuss too, and even outside of the brunt of its powerband. Now I am not going to say this made a night and day difference, but taking over 10 pounds of rotational mass off the drivetrain did make a noticeable difference for sure, and I love it! Harsh shifts seem less obvious to the driver as I felt the shaft take up a bit of the shock from the drivetrain, some hard/mis-shifts were on purpose, some on accident, but the shaft seemed to do a great job as smoothing them out. Overall I was very impressed, the install is very easy and straight forward, the gains are there, and can be felt without changing the characteristics of the car. The car is the exact same, but now with just a bit more… of everything. I love lightweight mods, anything to reduce weight is a huge plus in my book, I mean we bought this car because it was lightweight, not because it was fast, right? Well, something about being able to add even more to that just makes me feel good.
If any of you guys are interested in learning more about Light Weight Driveshafts, check out the writeup that we did a few months back explaining some critical points
As always stay tuned for more updates, and let us know if you have any questions.