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

[86Zed]

Originally Posted by AriuSen

Next track day on 6/24/17 was LAGUNA SECA

Thanks for the vids OP, glad to see someone else out there representing the M Coupe! Takes time to pick up any new track, and occasionally you have to experiment on a turn resulting in a slightly unqiue line... I have dipped the 2 right tires into the dirt on the corkscrew, narrowly avoided the Zanardi move. Afraid my personal lap times are much slower

Originally Posted by M3 Number 86

Bmw CCA schools are shit. Every student who comes out of there thinks they are superior than others when in fact they are completely egotistical.

I mean he's doing pretty much 1:50s in this car. I know a couple 1:49 drivers in similar e46 m3 there but they are running similar setups. That's pretty much almost as fast as you can go in the car. :

Agreed that the BMW CCA school (and any event) can be a mixed bag - best to find a group of people and instruction you trust.

There is more time to shave off in the Z4M platform - a colleague of mine regularly hits 1:37/1:38 with a similarly setup car (aero [non-active], stripped interior, cage, slicks). He also has ran Laguna Seca many, many times.

[Rick F.]

Originally Posted by AriuSen

Wow. That is really interesting what you said.
I was talking to jrz suspension who knows a lot about setting up the car and is funny that he said the same thing as you.
That once I was able to dial my car without the bar, that I should put it back and soften the springs to get the same feeling.
Are a pro driver or something?
Cuz it was always nice to read your comments

So I couldn't figure out what happened in spring mountain about my fuel starvation. And I drove in other tracks here with less than 1/4 tank and it was totally fine. :

Alex,

I raced with the SCCA for 10 years (but did only one pro race, at Road Atlanta). So I'm not a pro driver. However, I did manage to win the Mid-Atlantic Road Racing Series championship twice in the Spec Racer class, and I qualified for and ran the National Championship Runoffs in 1986. (No, I didn't win. But I did beat both Dorsey Schroeder and Robbie Buhl in that race. Both of them went on to very successful pro careers.)

Anyway, I learned a lot about car setup, and I based my advice for your car on that experience. It would be a fair amount of work to implement my advice, since it could involve several rear spring changes--but it might pay off.

I raced on east coast tracks and never made it to the west coast ones where you run, so I can't advise on the best lines. I will say this: you have fantastic car control. Every time I think you're going to spin out for sure, you manage to get the car back in line, and almost always without going off track.

Having said that, you also manage to get into such situations a lot more than usual! That's probably 75% due to your car's setup (too much rear stiffness) and 25% from trying so hard (a.k.a. "irrational exuberance," which can be a lot of fun so long as you don't crash!)

Finally, a comment on someone else's comment about my advice. I wasn't recommending softening the rear shocks, I was recommending softening the rear springs. If your shocks are adjustable, I suggest getting the springs and bars balance sorted out with the shocks always in the middle position and then fine-tuning the shocks.

Most importantly, keep having fun!

Rick

[AriuSen]

Originally Posted by 86Zed

Thanks for the vids OP, glad to see someone else out there representing the M Coupe! Takes time to pick up any new track, and occasionally you have to experiment on a turn resulting in a slightly unqiue line... I have dipped the 2 right tires into the dirt on the corkscrew, narrowly avoided the Zanardi move. Afraid my personal lap times are much slower

Agreed that the BMW CCA school (and any event) can be a mixed bag - best to find a group of people and instruction you trust.

There is more time to shave off in the Z4M platform - a colleague of mine regularly hits 1:37/1:38 with a similarly setup car (aero [non-active], stripped interior, cage, slicks). He also has ran Laguna Seca many, many times.

Yea that is a fast laptime! I beleive you are talking about Ace?
He?s fast driver.
Hopefully with aero I will be able to do 1:38!
Funny how the first time I didn?t like laguna seca, maybe because I wasn?t pushing enough, the second time, I realized it?s my favorite track ever! I can?t wait to go more!

[AriuSen]

Originally Posted by Rick F.

Alex,

I raced with the SCCA for 10 years (but did only one pro race, at Road Atlanta). So I'm not a pro driver. However, I did manage to win the Mid-Atlantic Road Racing Series championship twice in the Spec Racer class, and I qualified for and ran the National Championship Runoffs in 1986. (No, I didn't win. But I did beat both Dorsey Schroeder and Robbie Buhl in that race. Both of them went on to very successful pro careers.)

Anyway, I learned a lot about car setup, and I based my advice for your car on that experience. It would be a fair amount of work to implement my advice, since it could involve several rear spring changes--but it might pay off.

I raced on east coast tracks and never made it to the west coast ones where you run, so I can't advise on the best lines. I will say this: you have fantastic car control. Every time I think you're going to spin out for sure, you manage to get the car back in line, and almost always without going off track.

Having said that, you also manage to get into such situations a lot more than usual! That's probably 75% due to your car's setup (too much rear stiffness) and 25% from trying so hard (a.k.a. "irrational exuberance," which can be a lot of fun so long as you don't crash!)

Finally, a comment on someone else's comment about my advice. I wasn't recommending softening the rear shocks, I was recommending softening the rear springs. If your shocks are adjustable, I suggest getting the springs and bars balance sorted out with the shocks always in the middle position and then fine-tuning the shocks.

Most importantly, keep having fun!

Rick

Really wise words
Thanks for the advices and compliments

Impressive resume you got! I wish I could do some racing too. I plan on doing Miata wheel to wheel next year. Will be fun!
I did a lot of gokart since young so hopefully I will be able to use few things I?ve learned when I do w2w.

Must?ve been amazing those times you were taking this hobby seriously, and pretty impressive that you won races, because I watch my friends doing w2w, and it?s really really hard to be top 3. Everybody is so good.

I agree with you. Some of the slides was due to stiffer springs, and others due to overdriving the car haha. But the good thing is that the z4m really forced me to be a better driver by being smoother on turns.

Another big mistake I was making that I realized yesterday was that after finishing reading a book written by the founder of jrz suspension, he mentioned many many times in the book how teams had wrong concept about tuning a car.
He says that many shops used to think that in order to absorve bumps better, and have more grip, you are suppose to lower compression and raise the rebound a lot, when the correct is having the compression higher and rebound lower, I beleive you know the reason. Too long to quote haha.
And that is exactly the mistakes I used to make until yesterday! Always though comp had to be as low as possible and reb high, and the book clearly says that with this setting, you car really upsets on bumps and loses grip.
He mentions in the book that with oversteer, raise compression in the rear, when in fact I?ve been lowering compression lol. So all these times I?ve been doing all wrong!
So I am so excited to go out again and test what I?ve learned.
I added aero and I?m even considering removing the aero to set up my car again.

[AriuSen]

new update =)

This past weekend I tried lowering my camber. Noticed after talking to jrz, that I was running compression too low, and to compensate that, I was getting more camber, when the correct thing to do was raise to compression more and reduce camber for more braking and straight grip. Really really felt much better with high compression....running +6/+7 out of 11. Used to run +3/+4 before. Another major thing I noticed is that with higher compression, your car dont get upset as much going over bumpy areas.....car was so much smoother, and more confidence inspiring to drive since i wasnt too scared the car would snap over bumpy areas. I went up to +8/+9 to see how it would feel, and the car started to lose grip faster...so dialed back to +6/+7 and left it there.

Managed to get a 1:50.7!! My goal is 1:49. From the video I noticed I lost a lot of time with those counter steers, but thats because the track was a little cold.
Regardless I am very happy im going in the right direction.

As usual I had some "o sh*t moment, but thats the cost of finding the very limit of the car.

and my PB

[AriuSen]

New UPDATE 11/20/17

Some big changes I made. when I hit 1:50 at buttonwillow, I had front bar on softest and no rear sway bar. Car does feel good on high speed corners, but I was lacking that amazing nimbleness feel that my car had before. Therefore I felt that my car was really slow on tight corners and weight transition. So places where my z4m had the advantages over e46 m3, was actually slower with no rear bar......since I had a wing to keep me planted on high speed corners, I decided to put my rear oem bar back and put the front sway bar on stiffest. Another reason I added the rear sway bar, is because SOCAL tracks are super bumpy, and without the bar, the bumps would upset my car pretty bad since the stress was being loaded fully on the springs.
After I added the rear bar, my car feels a lot more confident going over bumps.

Another big change I did is actually thanks to the pro driver Ace, who used to own that red z4m full race car that was sold couple of months ago.

Since I put the rear bar, I was worried the car would feel twitchy again, so I decided to try what Ace told me. Going stiffer springs in the front than the rear, which made my car SUPER balanced now. I managed to hit 1:49 for 2 reasons. 1-my car was nimble again, so i was faster on tight corners. 2-my car was feeling so neutral, which gave me confidence to push in places I used to be scared before. Now the car is so balanced that I am actually purposely inducing oversteer to rotate the car, which I was not confident to do that before. With the rear bar, and stiffer in the front, and more compression, I changed camber too.

Camber: -3.7
Zero toe front
1/8 total toe in rear.
700 lbs springs front / 650 lbs springs rear
Stiffest Hothckis front bar / OEM rear bar with upgraded bushings.

1:49 lap.....I beleive 1:48 is possible if I driver better.

[AriuSen]

chasing that R8.......too fast for me haha
plus few shots of my car with a shot of my wing on braking mode.

[wdb]

Your inside front tire is 3 inches off the tarmac in that one shot! Pretty stiff front swaybar.

[AriuSen]

Originally Posted by wdb

Your inside front tire is 3 inches off the tarmac in that one shot! Pretty stiff front swaybar.

yea haha...you actually reminded me of something....that track I had OEM sway bar from E46 M3 and not z4m with OEM bushings....after doing some research, I found out the e46 m3 is 20% softer than the z4m!

the next track (laguna) which I will upload soon, is the track that I put the OEM Z4M with poly bushings....hoping to get some shots at that turn to see if its lifting...btw from all the shots, thats the only turn that my car was lifting....maybe could be because its a hill?
thanks for poiting that out

[AriuSen]

Next track day with SPEEDSF in Laguna Seca on 11/18

What mods my car has right now and settings.

Weight:
2800lbs no driver with half tank of gas
weight ratio F&R - 52/48

Suspension Settings:
-3.7 camber front / -2.8 camber rear
0 toe front / 1/8 toe in rear
max caster (I beleive its -6.7)
Tires Pirelli scrubs 265 square with apex sm-10 18x10 et 25
Hotchkis front bar stiffest / oem rear sway bar
Rebound at +11/+10
Compression +5/+6

Mods:
JRZ RS PRO
GC race camber plates
Hyperco springs 700/650 lbs both 5" without helper spring
GC endlinks
PFC BBK with PFC 07 pads (the best bite)
GC rear camber arms (I DONT RECOMMEND IT)
GC rear shock mounts
Hotchkis sway bar in the front / OEM rears
Vanne magical strut bars
AKG diff and subframe solid bushings
CAE shifter with OEM DSSR (one of my best mods)
AKG engine and trans mounts poly 75D (very recommended)
Stack gauges
Braille battery 13lbs.
Turner RTAB (might go with vorshlag)
EPIC tune
Supersprint race headers - SS section 1, 2 with RPI muffler
Trackspec motorsport hood vents (helps with understeer and temps)
Bimmerworld thermostat and bypass valve (greatly reduced my oil temps)
CSF Radiator topped with distilled water + water wetter (not sure I would recommend the radiator....would keep OEM.....temperature is lower with distilled water + water wetter)
CF roof from group buy
Fancywide diffuser
Varis front bumper
Aeromotions active wing with custom uprights
APR wing's gourney flap
Custom front splitter in Alumalite
Ravenol 10w60 Engine, transmission and diff fluid

Laguna Seca is one of my favorite track.....Its funny how this track looks so much easier than buttonwillow, which is known to be the most technical track in socal, but there are some tricks in that track that I still have to learn with more seat time....this time I was braking way earlier before corkscrew because I had aero didnt want to break my splitter.
Anyway, they had a 105db sound limit, and with RPI my car is very loud so I was hoping I would pass sound.

With Pirelli slicks, I need about 3 4 laps to get them up to temp when the weather is around 50-60s so I can start pushing harder, and at the 4th lap of first session, I managed to do 1:37.5 but on the 5th lap, I was black flagged for hitting 109db lol. you can see my car was understeering in some corners and I had a big oversteer turn 11.
After that, my PB attempt was pretty much over, as I had to short shift and hug the left side of the track to be as far as possible from the tower after turn 5. So who knows if I could’ve got a 1:36, as I was still getting 1:37-1:38 all day.
Since the settings felt amazing in buttonwillow, I didn’t change anything except for the rear sway bar. Wdb reminded me that I put M3e46 rear bar for buttonwillow, but found out later that the z4m rear bar is 20% stiffer. As I was having a little of understeer, I put the z4m one with poly bushings.
Now I can tell that my car is very close to be perfect for me handlingwise.

Questions....for those who run aftermarket rear bar, what brand do you have? I hate OEM bar.....the OEM endlink is so weak...I managed to snap 4 already. I need an aftermarket bar close to OEM rates so I can use adjustable endlinks.

Enjoy the video, and please....feedback tips etc is always welcome from anyone

1st video. my PB

Video of how loud my car is

video of my wing working

[dre99gsx]

How did you get your weight down to 2800 sans driver? 3250ish stock Z4M, that's 450lb. I can only image that you have no AC, interior is stripped (not much of it anyway), Airbags gone, ABS gone, Passenger seat gone, no radio, etc etc?

Love the wing setup! And that car IS loud. My Z4 with straight pipe (no muffler or resonator) on the 2J sounds like a muffled jet compared to what you guys can do on normally aspirated S54s. Jealous

[AriuSen]

Originally Posted by dre99gsx

How did you get your weight down to 2800 sans driver? 3250ish stock Z4M, that's 450lb. I can only image that you have no AC, interior is stripped (not much of it anyway), Airbags gone, ABS gone, Passenger seat gone, no radio, etc etc?

Love the wing setup! And that car IS loud. My Z4 with straight pipe (no muffler or resonator) on the 2J sounds like a muffled jet compared to what you guys can do on normally aspirated S54s. Jealous

my car without aero with AC and heater, it was 2760lbs actually.

I removed my AC and heater, but added aero, and car went to 2800lbs.

I have no radio, speaker, airbags, passenger seat, I have ABS, I have dashboard and pedals haha,
My wing is pretty heavy due to the module =( diffuser is also pretty freaking heavy.
Now the only way to shave weight is lexan windows, cf parts, remove some wiring, and get a S65!! haha...i wish this last mod was easy
btw, i still drive to the track with 4 track tires in my car lol ill take a picture later when I load my car to go to the track

[Vanne]

Originally Posted by AriuSen

chasing that R8.......too fast for me haha
plus few shots of my car with a shot of my wing on braking mode.

Man, that top photo!!!!!!!!............. HOLY SHIT!!!!!!!!!! ALEX!!!!!
YOU ROCK MAN!!!!


edit:loools!! Vanne magical strut bar....

[Rick F.]

Alex,

Your Z4M finally looks really well balanced at Laguna Seca--congratulations!

You had a better line than the two cars ahead of you and were catching them up in the corners. But they appeared to have even more power than a Z4M (which is saying a lot).

Anyway, I'm glad you have your car pretty well dialed in. How you fit four slicks into the Z4 is beyond me. I used to drive my Solo I Datsun 510 to the track with four shaved radials in the trunk, but they weren't very wide and it was a fairly large trunk. I'll admit that I got pretty tired of changing the wheels and tires twice a day, even with an air wrench!

Keep having fun--and think about SCCA Spec Miata!

Rick

[mainsoda]

I think they black flagged you becuase your engine sounded too amazing.

[AriuSen]

Originally Posted by mainsoda

I think they black flagged you becuase your engine sounded too amazing.

haha.....yea car sounds pretty mean, but from inside, it doesnt sound that good lol

[AriuSen]

Originally Posted by Rick F.

Alex,

Your Z4M finally looks really well balanced at Laguna Seca--congratulations!

You had a better line than the two cars ahead of you and were catching them up in the corners. But they appeared to have even more power than a Z4M (which is saying a lot).

Anyway, I'm glad you have your car pretty well dialed in. How you fit four slicks into the Z4 is beyond me. I used to drive my Solo I Datsun 510 to the track with four shaved radials in the trunk, but they weren't very wide and it was a fairly large trunk. I'll admit that I got pretty tired of changing the wheels and tires twice a day, even with an air wrench!

Keep having fun--and think about SCCA Spec Miata!

Rick

Yea, I am really happy with how the car is behaving now. Just need very very minor tweaks now.
Spec miata is my next plan!! you just read my mind!

[Beedub]

that pic which the front wheel off the floor is insane!! lol!!!

why dont you recommend the Gc rear camber arms??

why are you running stock ARBS?? not uprated....

( FWIW i run stock z4m bars and im REALLy pleased with the uprated suspension and stock bars, i think it works really well) i may run the coupe rear sway as its slightly thicker is believe.

[AriuSen]

Originally Posted by Beedub

that pic which the front wheel off the floor is insane!! lol!!!

why dont you recommend the Gc rear camber arms??

why are you running stock ARBS?? not uprated....

( FWIW i run stock z4m bars and im REALLy pleased with the uprated suspension and stock bars, i think it works really well) i may run the coupe rear sway as its slightly thicker is believe.

haha thanks.
The reason I dont recommend is because they make sooo many clunking noises.....my friends replaced the arms to turner, and the clunks stopped.

The reason I run stock bar in the rear is because as you might know, my car always had more oversteer than understeer, thats why I tried removing the rear bar, but had issues on bumps and low speed corners.
Another reason is because I dont know why the aftermarket bars are so much stiffer in the rear than the fronts
I wish they kept OEM front and rear balance, but for example, Hotchkis.
they say.
FRONT BAR STIFFNESS OVER OEM: 11% / 28% /39%
REAR BAR STIFFNESS OVER OEM: 79% / 105%

That doesnt make sense!.....So I am worried that if I add aftermarket rear bar with that much increase in stifness, my car will be all over the place again.

Right now, my car is very close to being perfect for me. I only have a very tiny understeer on high speed corners (mid-corner) and I presume that I can fix with better bigger front splitter.

Correct. the M bar is stiffer than non M z4. However, I did some reasearch and I think the rear bar is not the same.
e46 m3 are the same as z4m.

[Beedub]

Originally Posted by AriuSen

haha thanks.
The reason I dont recommend is because they make sooo many clunking noises.....my friends replaced the arms to turner, and the clunks stopped.

The reason I run stock bar in the rear is because as you might know, my car always had more oversteer than understeer, thats why I tried removing the rear bar, but had issues on bumps and low speed corners.
Another reason is because I dont know why the aftermarket bars are so much stiffer in the rear than the fronts
I wish they kept OEM front and rear balance, but for example, Hotchkis.
they say.
FRONT BAR STIFFNESS OVER OEM: 11% / 28% /39%
REAR BAR STIFFNESS OVER OEM: 79% / 105%

That doesnt make sense!.....So I am worried that if I add aftermarket rear bar with that much increase in stifness, my car will be all over the place again.

Right now, my car is very close to being perfect for me. I only have a very tiny understeer on high speed corners (mid-corner) and I presume that I can fix with better bigger front splitter.

Correct. the M bar is stiffer than non M z4. However, I did some reasearch and I think the rear bar is not the same.
e46 m3 are the same as z4m.

ARI i have the z4mR, so i believe our front cars are the same, but the rears are slightly diff, sorry if you thought i was Non ///M.....

i believe MR rear is 21.5 MC is 22mm?? i could be wrong however....

Thanks for the detailed reply, makes total sense!

[AriuSen]

NEW UPDATE 09/01/18

So I went to BUTTONWILLOW once again to see if I could lower 1 sec and do a 1:48.
Since I was having a little bit of understeer on high speed corners, I decided to lower my front canister psi from 280 to 220 as canister simulates spring rate.
I didn't change anything else from my 1:49 lap as I was too lazy and busy at work.
To my surprised I ended up doing a 1:47.8 ???
Somebody can correct me if I'm wrong, but I've been told that this is the fastest laptime ever in a NA s54 and possibly s65 car. The fastest time known to me was a 1:48.00 in a e36 with s54 full race car with around 2500lbs.
I was very shocked as from my 1:49s data, I couldn't see a 47.
The z4m is just unbelievable. The z4m was always known as a bad track car, but now I beleive this car is a MONSTER track car.
I am now lost as to how I am get to 1:46 without messing up with the engine.
Carbon fiber fenders? Trunk? Wider tires? Lsd 3.91 diff? ?

[dc_wright]

Originally Posted by AriuSen

NEW UPDATE 09/01/18

So I went to BUTTONWILLOW once again to see if I could lower 1 sec and do a 1:48.
Since I was having a little bit of understeer on high speed corners, I decided to lower my front canister psi from 280 to 220 as canister simulates spring rate.
I didn't change anything else from my 1:49 lap as I was too lazy and busy at work.
To my surprised I ended up doing a 1:47.8 ???
Somebody can correct me if I'm wrong, but I've been told that this is the fastest laptime ever in a NA s54 and possibly s65 car. The fastest time known to me was a 1:48.00 in a e36 with s54 full race car with around 2500lbs.
I was very shocked as from my 1:49s data, I couldn't see a 47.
The z4m is just unbelievable. The z4m was always known as a bad track car, but now I beleive this car is a MONSTER track car.
I am now lost as to how I am get to 1:46 without messing up with the engine.
Carbon fiber fenders? Trunk? Wider tires? Lsd 3.91 diff? ?

Nice! I think that was one of the smoothest laps I've seen you run in the laps you've posted. Sometimes overdriving the car and having to be on and off the throttle getting through the corners can feel fast but cost you time....