Ryan's 2012 128i MSport STX / Daily Driver Escapades

[RyanDavies]

Originally Posted by Kgolf31

Lol, just saw this.

That's a bold claim, if I had a better West Day 1 then yes that would be a better statement.

For reference having one wheel at 30 minutes of toe-in isn't ideal.

I think I'm aware of that . I think there was a lot left out day 2 for the BMW that you weren't able to capture because of the handling condition. A *lot*.

So, neither Kyle or I were so low that the control arms were beyond parallel to the strut at terminal roll, creating the camber loss condition you describe (you can learn a lot by removing springs and moving the suspension through its travel). Camber gain is better at higher ride heights, but that's still not the primary factor for raising it up. Roll center.

[RyanDavies]

Did a bunch of testing this weekend.

- The new tune from Epic Motorsports is awesomesauce. No question they're the ones to go to...

- I'll be returning to the RE71R for a number of reasons.

- The balance and transitional ability of the car are now very, very good. Won't be changing spring rates again.

- Last remaining steps are to get the exhaust built and the light battery in before Wilmington. I'm sure I'll do the latter, but the former has turned into some degree of logistical nightmare, so it may be a "saw the rear muffler off" before Wilmington deal, just to drop weight and free up that bottleneck a bit.

I've got one local event up in NJ this coming weekend to make the current baseline work on RE71Rs, hoping that's enough....

[RyanDavies]

Staying on Bridgestones. Car is working pretty well now, after this weekend. Got to hang with and race against Kyle in Pittsburgh this weekend.

I think we've arrived at very similar setups, skinned a little bit differently. Time to finish up a couple things this week. Next weekend's Wilmington ProSolo should go well for both of us.

[RyanDavies]

Kyle did rather well at Wilmington (2/18). I did not (7/18, car finished 4/18). Some pretty substantial setup issues reared their heads, I felt I drove fairly well given the issues with the car. The course slightly favored the BRZs over the 128s, but the win was possible even given that. Kyle faced some setup issues as well, (I at least think!) less epic than mine, but drove very, very well around them.

[u2b]https://www.youtube.com/watch?v=CokyNO86Jfc[/u2b]

I've pinpointed them down to some fundamental misunderstanding about how my shocks were valved, made adjustments, and hoping to get them tested out this weekend on both concrete and asphalt. Car simply wouldn't bite in when you wanted it to, yet was skiddish on exit, as can be seen in the video. Basically just had to park the car to get it to turn, and transitions were hilariously bad.

Also managed to scale the car tonight. Luckily ended up at 50.5% left weight (very good, IMO), and hit cross weight at 50% pretty easily, only had to adjust the RR corner. 2960 is my present race weight, with a bit to drop beyond that with some other little tweaks to the car. I think a zero-option car COULD hit 2900. Would require a very light battery, aluminum brakes + two-piece rotors, a no rear bar setup, etc. I was happy to just be under 3000. I have premium sound and xenons, which combine to add a little over 20lbs to my car. No idea what the electronics required for comfort access add, but probably not very much. I'm happy with the weight at present, it's actually less than I was expecting.

[Taskmaster]

Weight including the driver?

[RyanDavies]

No. The car is built to the STX rule set, I can't think of any car where you could pull 350lbs out of it in ST trim versus stock .

Car is realigned as of today. Nothing crazy, but did get to use tire wear and pictures from Wilmington to ensure proper camber settings on a high grip (1.28 sustained G) environment. 3.0 front camber, a very small bit ( 1/32 or less) total toe out up front, 7.5 degrees of caster. 1.7 degrees rear camber, and a bit under 1/16 of total toe in rear.

Hoping for some dry weather this weekend for some Saturday concrete and Sunday asphalt testing, but it's looking unlikely. M

[tuj]

RyanDavies how are you setting your cross-weights? There is an alternative method that might help you.

[RyanDavies]

It was very close (49.4 or so) as it was before any adjustments. Just dropped the RR perch two turns, done.

The front perches can barely be moved (two turns in each direction due to tire clearance at full tire deflection), so I knew going in that adjusting the rear was my only option. Luckily I didn't have to change it much. Would have considered a 25lb stagger in front spring rate to solve if it was more of an issue (softer on right side).

[tuj]

Are you maxed on your front perches for clearance (and then travel) ?

[RyanDavies]

Clearance, yes. I could make minor modifications if needed. I'm at the correct travel for bump stop engagement immediately before coil bind as well. Reducing height would result in no additional travel.

[Taskmaster]

Originally Posted by RyanDavies

No. The car is built to the STX rule set, I can't think of any car where you could pull 350lbs out of it in ST trim versus stock .

Car is realigned as of today. Nothing crazy, but did get to use tire wear and pictures from Wilmington to ensure proper camber settings on a high grip (1.28 sustained G) environment. 3.0 front camber, a very small bit ( 1/32 or less) total toe out up front, 7.5 degrees of caster. 1.7 degrees rear camber, and a bit under 1/16 of total toe in rear.

Hoping for some dry weather this weekend for some Saturday concrete and Sunday asphalt testing, but it's looking unlikely. M

I have no idea how much a stock 1 series weighs, which is why I asked.

[chris82]

Originally Posted by RyanDavies

Clearance, yes. I could make minor modifications if needed. I'm at the correct travel for bump stop engagement immediately before coil bind as well. Reducing height would result in no additional travel.

You have bump stops???? Odd, you will not bottom out on the JRZ anyway. My RS1, RS2, nor the RS Pro have them, front nor rear. Superior shock design

[RyanDavies]

You'll get coil bind though...I run the bump stops to prevent that up front.

[chris82]

Originally Posted by RyanDavies

You'll get coil bind though...I run the bump stops to prevent that up front.

Did JRZ put them on? I have never gotten coil bind

[RyanDavies]

Do you run the perches above the tire to fit 255s, thus requiring 6in springs in the front?

You should *never* be on the stops. I don't engage mine ever. However, running a stiff bump stop to engage immediately before coil bind prevents the spring or damper from being damaged. I've never gotten there, and don't anticipate it happening. I don't understand why you would elect to not run stops, I can't imagine saving a quarter ounce of unsprung weight a corner is worth it.

[tuj]

Originally Posted by RyanDavies

You should *never* be on the stops.

E82-specific or in general?

[RyanDavies]

You can intentionally set up a car to ride on the bump stops if the rule set restricts you from changing springs (very common in EStock Miatas, change bump stop rate and run a ton of rebound in the shock so it jacks down).

Circle track cars do it too.

If you *can* set the car up to not be on stops, make sure it is never on them, but get long enough stops to ensure no coil bind and so the tire can never make contact with a hard part on the car.

[tuj]

The reason I ask, is because in stock classes, we intentionally modify the bumpstops to be of different densities to provide more spring rate. (and you are right, I'm thinking of ES Miata's in particular)

[chris82]

Originally Posted by RyanDavies

Do you run the perches above the tire to fit 255s, thus requiring 6in springs in the front?

You should *never* be on the stops. I don't engage mine ever. However, running a stiff bump stop to engage immediately before coil bind prevents the spring or damper from being damaged. I've never gotten there, and don't anticipate it happening. I don't understand why you would elect to not run stops, I can't imagine saving a quarter ounce of unsprung weight a corner is worth it.

I ran a 6" but don't remember where the perch was.

[justint5387]

Lurking here since I am looking at a e82 for my gf. West coast people are slow!

[RyanDavies]

I like my car a little bit more than a BRZ on BFGs . Won't do that again.

See you in a few months and try to avoid corner workers until then mmmk? .

[RyanDavies]

Continuing on with the weight reduction, I've done a little more figuring out about how one could get lower.

As posted above, I'm at 2960 now.

Here's what's too heavy that could be reduced further:

1. Front rotors. I know that we can get a 300mm two-piece rotor to drop 5lbs a corner or so up front of rotating, unsprung mass. Just have to get someone to make it. Working on this now. There's 2950.

2. Aluminum calipers. They weigh 2.3lbs less a piece than the OE calipers, and are very cheap (I got mine for $70 for the pair). 2945.

3. Xenons and Premium Sound add 20lbs to my car. 2925 there.

4. Battery. I have a heavy 21lb battery. 15lbs is doable, but it'd be really neat to get one of those 5lb Shorais confirmed to work with our charging systems. That'd be 2910.

5. Seats. I know I'm over 25 now, and will probably be more so when I swap in Sparcos this week, but that will pretty assuredly make it so if you did the right stuff with bracketry, you could get the car under 2900.

I actually don't think I'll save much on an exhaust that'll pass sound over what I've got now, so that'll be exclusively for power. Trying to think about anything else I could do, mostly as a thought experiment.

After radically dropping rebound all around (the upper 50% of JRZ settings are completely useless in any scenario I could ever think of), and increasing front compression, my car now sweeps and transitions much better at the two lots I've tested it on, while maintaining excellent power down. It'll be *better* than it was in Wilmington this weekend in Toledo, hopefully it's as good as it was this weekend.