I've been waiting a while to post this up. Have had Delrin/aluminum front upper control arm bushings installed on my '11 Nismo for a year and about 10k miles now. Also several other bushings, but I'll leave those for future threads.
Comparison of oem bushings with Delrin/aluminum bushings.
This is the bushing kit, 12 pieces in total, with the bushing removal tool (not included).
Overall driving impression has been great. Not a big difference in feel over stock, but steering response does seems a little more direct, with no noticeable increase in road noise. The car isn't that quiet as we all know, so it's tough to make it noisier! Under braking there's less twitchiness, which was likely caused by small changes in caster.
What's very noticeable is how smooth the arm travels up and down with the Delrin bushings, but without freeplay in any other direction. With the stock rubber bushings, it was difficult to swing the arm (which adds an unknown spring rate to the suspension), but the arm would deflect front/back, in/out, and was able to twist the bushings which would cause small changes to caster and camber while driving.
There is zero squeaking or clunking, which people might have experienced on other cars. That's usually the result of bushings being too tight, or too loose. All these parts were taken out to measure them after 1 month of use, after 6 months, and after a year. Even with 10k miles worth of LA roads, canyon carving, and 3 track days, all dimensions are within .0005" (half a thousandth of an inch!) of new, and still silent.
Installation is pretty easy, took about 2 hours with the proper tools. Once the arms are off the car, removing the OEM bushings is pretty easy using a press and custom machined removal tool. The arms are too nice to subject to the typical burning and chiseling method. The Delrin bushings slide in with light force on a press, or can be tapped in with a rubber mallet.
If anyone wants help removing the bushings, send me the arms and I'll press them out with the special tools.
Here are the 4 bushings disassembled, and the removal tool. The Delrin is self-lubricating so no messy grease is required (which would attract dirt), and the sleeves are 7075 aluminum. The Delrin spacer and the lip on the main bushing get rid of the original gap that allowed the arm to move front/back.
Quick video of the overall removal/installation process:
Any questions, feel free to post or PM me.
Front lower shock bushings have also been replaced with Delrin/aluminum, but I didn't think it would be worth making a new thread for. Also have Delrin/aluminum front lower control arm bushings, but that thread will wait...