Summer 2023
As we head in middle of summer, time for an update!
In the previous post, I forgot to mention I had a little slip up at Turn 8 at Thunderhill. I was a little antsy and turned a tad too early into the turn. Unfortunately, I was committed and past the apex is just a concrete drop resulting in a fun loud noise and a hop. I got lucky with the aftermath damage but I managed to destroy my under tray and bend 2 of my wheels. I ordered two new Titan7 wheels after they were reported to be 1 minor bend and 1 trashed. The minor bend one will end up being a spare. Since it was time for an alignment check, this was a perfect opportunity to get going on my suspension changes going.
Minor changes ahead
## Suspension changes
Here we are, finally installing a set of springs. I have a few objectives here. The first and foremost was to soften the car but still stiffer than my original 400/700 lb/in setup. The other was moving the ratio closer back to flat ride a bit as the car felt odd on freeway overpass junction bumps, etc at high vehicle speeds. The ride quality left a lot of confidence off the table.
- 8KG/mm 6" free length and 14KG/mm 8" free length springs
- 2.5" hyperco helper springs
- new standard length Ground control rear weight jack rods to accommodate 8" springs. (Previously cut them to accommodate 9" springs)
Overall, the install was uneventful as it was simply a spring and threaded rod swap.
Alignment at VT Motorworks. I opted for about -3/-2 F/R camber, 0 toe up front and minimal toe in the rear, 0.05'. It is a mild alignment and should help with turn in while keeping it fairly stable at high speeds compared to a toe out front alignment. Initial impressions are this is the sweet spot for a "Dual Duty" spring rate. It's just stiff enough for track use for 3-4 events /year but still tolerable on the road. I'm loving it so far! I think I found a dampening setup that will work and mitigating the large oscillations when going over overpass junctions bumps at over 70mph. In turn, this will also help stabilize the car at high speed uneven surfaces on track days! Win win!
Of course when I come home from the shop, car goes lights up on the dash; a bad rear wheel sensor. After an initial check, I'm pretty sure the other rear side failed compared to the original one that failed last time around.
##Tray
So because of my 2 wheel offroad excursion, I also decided to get a Pinnacle Motorsports under tray.
Pros: I like the better ground clearance and lightweight metal tray.
Cons: I don't like how all these metal trays seem to buckle the front bumper and even leaves an odd gap in the middle.
For now this will do, perhaps I'll think of something to fab up the gap as I dont have a lip to cover the hole up or maybe look into the turner motorsports one. That one looks like it addresses my cons about this piece but additional money.
2023-07-19 Sunwise VIP Laguna Seca Day
Thanks to my wife's new purchase, I was fortunate enough to be part of a VIP track day held by one of the local dealership groups Sunwise. They own 3 BMW dealerships in the area and invited clients to a rally/track day.
FCPEuro coming in hot with some replacement fluids right before the track day.
My wife's new M4 (which goes us the invite) and my M3 filling up for the Rally at Costco Gas baby!
The day before, we had a rally down to Monterey with the group of BMWs invited. It was fun but traffic put a hinder on the overall fun. If I were to do this again next year, I will skip the rally part.
slcook54 also joined in on the fun, it was good times!
The goal of the day was to tune my suspension and get a feel for how fast this new repaved track felt like. The initial street settings 9R/8C, 8R/5C settings felt pretty good and I added about 3 more clicks of compression in the rear. Since the private day had us running at the top of the hour, I felt like we had plenty of time to test! I didn't expect to reach the suspension settings so quickly.
After 2 sessions, I even ended up with being in the 1:42s! I was excited and decided to try for a faster lap mid-afternoon when the tank light was just about to trigger. I threw down a 1:41.80 and was stoked. Car felt soft enough to grip while stiff enough to not feel like I was rolling over. Final session, I decided to take out my wife's M4 comp out and did a 1:41.1 without even trying hard..Those cars are so fast.
slcook54 was a celebrity with some of the folks there and pushing some 1:37s borderline 1:36s! I think next time around he is going to hit that and then some!
Post-analysis: what attributes me going from 1:45.680 to 1:41.80?
PS4S vs RE71R
Change spring rates? 400/700 to 448/784
ST60 DTC-60 to APRacing 9660 3.12
Better nut behind the wheel
I would argue that the biggest one is the tires and driving confidence. I hope to continue this trend and fine tune the lap even more next month! I'm very happy with that time as I always felt 1:45 wasn't good enough.
# Spare Diff
As part of the 4.10 upgrade in the future (whenever that may be), I split a stock E92 diff with an E46 buddy of mine. He took the 3.85 and I kept the rest of the parts. I haven't decided what I want to do yet, I suspect I may build a custom ZF LSD that is better for track use but has OEM-like maintenance intervals. This plus solid subframes will be cherry on top to a fun "M3CS".
Cheers!