My track day journal. new update 11/20/2017

[pal]

I have been running my Z4MC with 400lb springs at all four corners, Rogue Engineering RTABs, -2° camber up front with zero toe and factory settings in the back. For wheels and tires, 245 on an 8.5" rim up front and 275 on a 9.5" or 10" wide rim out back. These are on KW Clubsport dampers. I feel like a wimp with these rates compared to all you guys, but there I said it ?

The car is neutral and has a touch of understeer at the limit which gives me just that tiny bit of margin to collect things when they start to go. And I can fine tune with tire pressure differential and damper settings. The car would be super twitchy with higher rates out back and square tire setup; a Z4MC is not an e46 M3 or e92 M3 which are way more forgiving due to the long wheelbase and easier to drive as you sit close to the center of the car.

[AriuSen]

Sound of car

[AriuSen]

just a small update....I went to the track this past weekend and the car felt amazing! I finally got my suspension dialed in!
My car feels very neutral now, and I dont have crazy oversteer anymore. the biggest difference was going with 1/8th toe in...it really helps with corner exit a LOT. thanks everyone for this tip
Also, one thing that helped me was going with only +2 compression rear and +3 compression front...that killed my crazy oversteer too and it feels more neutral now.
Now I am getting more and more confidence with the car to push harder and hope to lower another 1 2 second next time.

now some pictures from this weekend.
co-founder of stoptech and their race car miata engine 1300lbs..




a nice z4m race car. was doing very good in BMWCCA race and endurance too

[AriuSen]

bimmer challenge trophies are the best!
very proud to represent z4m!

[crfine88]

Originally Posted by AriuSen

bimmer challenge trophies are the best!
very proud to represent z4m!

Very cool, congrats!

[inTgr8r]

+1 very cool.
Those trophies are great.

[Finnegan]

Originally Posted by AriuSen

bimmer challenge trophies are the best!
very proud to represent z4m!

Excellent! I love these! Well done.

I'm happy the rear toe-in settings helped, and we can add another data point to that set-up factor.

I'm happy to hear that the suspension is finally getting to where you like it. Remind me, what spring rates did you finally settle on?

This is been a really good thread for information sharing and gathering information about set up.

[AriuSen]

Originally Posted by Finnegan

Excellent! I love these! Well done.

I'm happy the rear toe-in settings helped, and we can add another data point to that set-up factor.

I'm happy to hear that the suspension is finally getting to where you like it. Remind me, what spring rates did you finally settle on?

This is been a really good thread for information sharing and gathering information about set up.

yea.... it helped a lot..... another thing I forgot to mention is driving style.... you guys were right.... i used to do a lot of trail braking and it was hard to control the car.... i am now adapting to brake earlier but go on gas b4 or on the apex......so what i noticed about compression on jrz, is that 1 clicks makes too much difference compared to rebound.... so since I having too much oversteer with +3/+3, decided to do +4/+3.. stiffen 1 click on front to understeer a little more and then played with only rebound.... im still using 600/700....i still think 550/650 would be the best cuz of some moments when I hit the bump. I will update once I try 550/650.
my car is - 3.5 front and - 2.7 rear... my tire wear are very very good.

[Vanne]

Alex, awesome mate that your getting the car sorted mate. very good car control and congrats on the trophies mate. (West coast represents!!! )

[AriuSen]

So I went to spring moutain near vegas this weekend, and I loved the track! didnt have time to upload video of the pb, but will do later on.
Just a quick update on maxxis RC-1...the first day, they are not very grippy, but the second day is amazing!!!!

also got new rims with offset 28 and im using a 3mm spacer all around now instead of the 10mm

here is a newbie video from my phone of my trip!

and this is a close call almost crash into a s2k...that is a turn that you just tap the brakes to go full throttle for the main straight and he almost stopped the car! got very scared

[The HACK]

Did you guys stay at the condos on site? It is the best idea since sliced bread.

True ballah status.

[Boundless]

Can you plz share your camber/caster/toe/etc settings for track ?

[86Zed]

Originally Posted by AriuSen

a nice z4m race car. was doing very good in BMWCCA race and endurance too

This is my coworker and friends car (also my donor RPI exhaust). Good to see it out in it's proper environment!

[AriuSen]

Originally Posted by Boundless

Can you plz share your camber/caster/toe/etc settings for track ?

camber is -3.5 front -2.8 rear. the wear on tires is very good

zero toe front and 1/8 toe in

springs settings is 600/700, but i think its a little stiff for our cars....ideally i would try 550/650...need some time off to change my springs....i am having to run very soft compression due to my springs rates being stiff...if i stiffen just a little, my car starts skidding and i hate that. doesnt get the grip I want in high speed corners.

I ran nt01 and now running maxxis rc-1....i ran with them 33 hot
and with hankook rs3 35 hot

Stock sway bar front and rear....I think they are stiff enough...have very little body roll.

[inTgr8r]

Originally Posted by AriuSen

camber is -3.5 front -2.8 rear. the wear on tires is very good

zero toe front and 1/8 toe in

springs settings is 600/700, but i think its a little stiff for our cars....ideally i would try 550/650...need some time off to change my springs....i am having to run very soft compression due to my springs rates being stiff...if i stiffen just a little, my car starts skidding and i hate that. doesnt get the grip I want in high speed corners.

I ran nt01 and now running maxxis rc-1....i ran with them 33 hot
and with hankook rs3 35 hot

Stock sway bar front and rear....I think they are stiff enough...have very little body roll.

Did you try without the rear bar yet?

[Boundless]

AriuSen
Thnx for sharing!

Originally Posted by inTgr8r

Did you try without the rear bar yet?

After installing LSD from E30 to my Z4 3.0si. I had to run one track day without rear bar. And I can say that rear end becomes little bit loosy. Specialy in fast corners.

[inTgr8r]

Interesting!

the OP is running very stiff springs, removing the rear bar will help tame the rear end for him.

I'm Not sure what you experienced or what other suspension you are running so your situation may be a little different.
Generally a stiff rear bar adds to oversteer and a soft bar (or no bar) increases under steer.

I'm currently running no rear bar and love it with my set up.

[AriuSen]

Originally Posted by inTgr8r

Did you try without the rear bar yet?

Originally Posted by Boundless

AriuSen
Thnx for sharing!



After installing LSD from E30 to my Z4 3.0si. I had to run one track day without rear bar. And I can say that rear end becomes little bit loosy. Specialy in fast corners.

I was going to try that, but I forgot to take my race ramp to do at the track.
One question.....without rear sway bar, can I still intentionally break my rear loose by going on gas more?
Cuz I like when on long sweeper a little oversteer to point and go.
If the rear is too planted, I feel im slower on certain turns.

[inTgr8r]

Yup, still have on throttle oversteer.
It just doesn't snap as much.

[F360C]

Originally Posted by inTgr8r

Yup, still have on throttle oversteer.
It just doesn't snap as much.

Same here... no rear bar on my car. I had the GC soft bar set to its softest setting when i was running 525/650. When i went 600/750 i gained traction up front at the expense of the rear end. Spoke with Jay at Ground control and he said to take the rear bar out. Did that and I gained a bunch of rear end traction.

[AriuSen]

So today I went to bimmerfest2016 and they were running another bimmer challenge at auto club speedway.....very scary track since its an oval track and you enter the turn at about 145 to 150 mph and go down to 130 at the apex with the wall right next to you.
I ran before, but with the e92 and I had traction on cuz I didnt know how to drive rwd and car was all stock.
This track is not favorable for z4m at all....high speed corners and lot of long straights...I think e92 m3 are the most favorable since its so stable on high speed and has lot of power.
Anyway, I started running +5 comp +8 rebound and car felt so terrible so twitchy and so scary to push...any little input on steering wheel was scary....so for session 2 I lowered comp +2 and reb +13.....car felt absolutely amazing! was planted and no more crazy oversteer and I could push harder and harder on fast corners.
I noticed that I need to run low comp and I always do best time....so I am starting to guess that this car was suppose to be run with around 400ish front and around 500ish rear cuz I wish I could use +5 comp, but my car never feels good in any track.

this bimmer challenge was veeeery close one cuz everybody was doing 1:54ish, but I think senna got into my body and did 1:52.6 lol.
It was a nice day for sure!! Car felt great...and last session started to play around a little, but this car is so bad to drift......e92 was super easy and fun!
torque88 t-shirt company used my car before the event for some modeling lol
video of the track day

[longress]

Nice lap!