S2-3456789-K

Hi everyone,

I started my SOS build nearly a year ago, as documented in this build thread:
https://www.s2ki.com/forums/s2000-fo...build-1149172/

Besides initial IAT issues, which I can only attribute to not fully bleeding the system, I've had an entire summer/fall season of trouble-free driving.

I've put the S away for the Ohio winter, but the last time I drove it, which was on my way home from work, the car made a screeching/chirping noise, sporadically, when the car was at or above ~4000 RPM. I took a recording and attached it to this post. There seems to be a very slight hesitation that accompanies the noises, and what you'll hear in the audio file was taken at highway cruise speed. It would be of great help if anyone can help me troubleshoot this noise. I will not be able to drive or work on the car for at least a few more months as I had shoulder surgery a month ago, but I want to come up with some ideas sooner than later. And of course, if this is a known issues among the SC community, then even better!

Another note: I'm running the SOS kit with 4" pulley, stock MAP sensor, ID1000's, AEM 320 pump, and dual BOV's (turbosmart dual port on 1" port, and stock on 3/4" port). I'm hoping it's a MAP sensor issue, or maybe the stock BOV is acting up. I hope it's not the supercharger unit itself that's gone bad...

S2-3456789-K

It's warmer out, and my shoulder is feeling better, so I decided to spend some time looking for the problem again. I had some worst-case theories, but none of them made sense with everything I was hearing and feeling in the car. As it turns out, it was right under my nose. The bolt that screws into the supercharger impeller shaft backed out, and the key that locks the pulley in place on the shaft also came out. My guess is that at idle and very low engine speeds, the friction between the pulley and the shaft was enough to spin the charger. This is why everything sounds and looks normal when I was inspecting it initially - I even felt for air coming out of the BOV. At higher engine speeds, the pulley would start to slip/grind on the impeller shaft, causing the chirping noise and hesitation everything it would slip and catch.


You can see the damage to the pulley.


The damage to the impeller shaft is not bad. There's some residue from the pulley's paint, but it did not affect installing a new pulley.

SOS sells the pulley installation kit for $10, and I took the opportunity to buy the 3.4" pulley & belt. All-in-all, it was easy to correct after I spotted the problem, but it was so obvious that I overlooked it initially.