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2004 330CI ZHP
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292 Posts
Nice work with the hub stands, those are beautiful. I decided to go with string jigs and corner scale levelers. I don't have access to TIG so I just MIG'd up the levelers with angle iron, and bolted the string jigs together using (very nice) scrap extrusion.





... but one benefit I did have access to was free ball transfers. Someone on campus didn't need them anymore and I was completely happy with taking them off their hands. Each of my levelers uses 9 of them. No way I would've purchased these!

 

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1,211 Posts
Wow. As a mechy I love this. Thanks for posting, both your setups!
The air dam is similar to mine, though I just replaced the entire front bumper since I don't need a street setup on the track beater. I'm building for NASA TT5, still in HPDE 2, but building is half the fun.
922437
 

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2003 330i 6MT, 201k miles
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8 Posts
Late reply, but very cool progress and setup. Looking forward to seeing what's next!
 

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Discussion Starter · #124 ·
Late reply, but very cool progress and setup. Looking forward to seeing what's next!
Thanks! I feel like I'm nearing my ultimate vision of this car. I still have some stuff in the works though. :cool:

I'll post up a short write up from my latest test day soon. I'm getting her all dialed in for this race season.
 

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Discussion Starter · #125 ·
Here is an update following a test day at High Plains Raceway I ran in March. I’ll apologize now for the long read. I didn’t take a lot of pictures, but I did snap the ubiquitous “unloaded and ready to hit the track” shot.




The focus of this day was to adjust and tune the car to dial it in for the upcoming NASA TT race season. I was at the track alone this time so there wasn’t any Porsche GT2/3/4 madness to distract me. I ran my Toyo RR tires for each test session and made single adjustments between runs to evaluate their feel and performance. Weather was perfect and consistent all day- sunny, cool and a light breeze.

Session 1, Toyo RR, Baseline
Best lap time= 2:04.95

This session was all about getting a feel for the car after my new alignment. I also was practicing some techniques I learned from a recent Ross Bentley seminar I attended- Braking and Corner Entry. At the end of my stint, I pulled in to test out my new DIY tire temperature probe.




I pieced this setup together online and it works perfect for my needs. Taking measurements across the face of each tire in the hot pit I’m able to validate my camber and pressure settings. I nearly purchased a Longacre Racing tire pyrometer until I saw that I could just buy a tire probe separately and use a standard K type pyrometer to get the same results for mush less money.


Session 2, Toyo RR, Front Anti-roll bar adjustment
Best lap time= 2:03.88

For this session I moved my front anti-roll bar links to the firmest setting. Traditionally this change will make a car understeer. Over the years I have read that on some strut front suspension cars it may actually INCREASE front grip due to better camber control of the outer tire patch. One way to find out! And… it worked. The car turned in with more intensity and was able to hold its line through corner entry. I experimented with braking and corner entry variations and every scenario produced a better feel than the softer front bar did in the previous session. My best lap times dropped and stayed there the entire run.

This session I also put some flow-viz (oil, chalk powder & alcohol mixture) on the rear wing to see how the air flow was moving on my endplates and airfoil.




I was hoping to get a less ‘runny’ result, but I can at least tell that at my current angle of attack I am not seeing flow separation on the underside of the wing. This means I have some adjustment room to play with. Maybe some other day I will play with wing settings more to experiment with low drag vs. max downforce settings. For now, though, I’m happy with the aero balance. If anything, the rear of my car is a little too planted so I may just back off the angle of attack one more notch to loosen up the rear end and gain a couple MPH on the straights.


Session 3, Toyo RR, Damper adjustment
Best lap time= 2:03.19

This session I cranked up the dampers to near maximum by increasing them front and rear 6 clicks. I wanted to see how this affected corner transitions. The theory is that increasing damper rebound rates can increase grip but would come at the expense of bump and quick transition handling. This doesn’t work on every car and for every shock, but I had a feeling I was slightly underdamped and it was worth testing out. Of course, with my shocks being only single adjustable there is limited tuning potential. I did just find out that Fortune Auto is coming out with a new 2-way shock soon. That might be on the 2022 upgrade list!

Again, I was right. The car was a little more nervous on track but it was consistently faster if I stayed on line. The only time the increased damping negatively affected handling was taking too much curbing on a couple corners. This change definitely put the handling on more of a knife edge but it was overall a positive improvement.


Session 4, Hoosier R7 (scrub in), No changes
Best lap time= 2:02.46

In my last update I mentioned buying a set of Hoosier R7’s to run the 2021 season. I got them mounted up and was surprised to see the difference in total width. This is a stack of 245/40-R17 Hoosiers next to a stack of 255/40-17 Toyo RR’s. Both are on identical 17x9 wheels.






As you can see the Hoosiers are a full inch wider when all four tires are stacked up. The NASA TT5 class limits mounted tire width to 266mm. This setup comes in at 265.9mm per tire. Whew!

Hoosier recommends a single break in run for best performance and tread life. I bolted the tires on my car and ran them according to recommendations- pressure cranked up an additional 4-6psi, slowly bring them to temperature over 4-5 laps, then let them sit and cool 24 hours or more before using again.




Holy Crap!!! Purple crack indeed! I managed a personal best by nearly a second without even trying. On top of that I had a passenger in the car plus some additional items still on the car that I normally remove for a race day. I figure I was nearly 200lb heavier for this run than an actual TT. I can’t wait to get back to the track during a race to see how much more time is on the table.

Here is the lap overlay of my best Hoosier equipped lap [white line] compared to my best ever TT timed lap (new Toyo RR’s, no aero) [red line].




The first thing that jumps out to me is minimum corner speed. The R7’s + aero give me much more speed through all corners. High speed corners have the largest deviation due to the confidence and grip provided by aero. The second half of the lap is where I make up the most time because there aren’t any long straights, just a nice string of medium speed corners.

The second thing that stands out looking at the speed chart is how much speed I’ve lost on the straights. A loss of 5mph doesn’t seem like much, but it’s enough to erase any gains made in the first three corners. Some further testing is warranted to determine if trading grip for top speed improves lap times.



Session 5, Hankook RS4, No changes
Best lap time= 2:06.15

With the day coming to a close I bolted my old Hankook RS4 street wheel and tire set on and did a final short session. My goal was to have fun and focus on driving clean and consistent laps. I try to avoid any ‘hero’ runs at the end of the day when I’m tired and the track conditions are fading. Committing to a short no pressure session helps me cement any techniques I’ve been working on and form final opinions on setup changes I’ve made.

Overall it was a very productive day. I left with a lot of excitement and anticipation for this coming race season.

Thanks for reading, ‘till next time!
 

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2000 328i
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great update with lots of info as usual.

amazing that you kept making changes for the best and improving the lap times
 
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