STX Rules and Setup Questions

[jprice130]

@Turkish, I know your question about the LCAs was around class legality, but I was curious why you were thinking about getting them with the Tarmac springs? Since the Tarmac springs only lower about 0.8", I think the resulting rear camber will be close to what you need.

Are you anticipating that you will want to reduce negative camber? add negative camber? or just even out left to right? The reason I ask is most folks that get aftermarket LCAs do it to reduce negative rear camber when they lower their car beyond 1" and that won't be a problem with the Tarmac springs due to their mild drop.

[Turkish]

Originally Posted by jprice130

@Turkish, I know your question about the LCAs was around class legality, but I was curious why you were thinking about getting them with the Tarmac springs? Since the Tarmac springs only lower about 0.8", I think the resulting rear camber will be close to what you need.

Are you anticipating that you will want to reduce negative camber? add negative camber? or just even out left to right? The reason I ask is most folks that get aftermarket LCAs do it to reduce negative rear camber when they lower their car beyond 1" and that won't be a problem with the Tarmac springs due to their mild drop.

I am anticipating a desire to add either more negative or positive camber to my setup. I was looking at rear LCAs and camber plates for the front. I purposely didn't order either as I want see how it comes out after the springs settle and drive it to see how it handles with oem settings. I generally like whiteline as a company and was looking at their LCAs before I really settled on a suspension. Now that I am autocrossing, I have to reanalyze all my future mods.

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[jprice130]

Originally Posted by Turkish

I am anticipating a desire to add either more negative or positive camber to my setup. I was looking at rear LCAs and camber plates for the front. I purposely didn't order either as I want see how it comes out after the springs settle and drive it to see how it handles with oem settings. I generally like whiteline as a company and was looking at their LCAs before I really settled on a suspension. Now that I am autocrossing, I have to reanalyze all my future mods.

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Yeah, those Whiteline LCAs definitely look nice and they certainly have benefits beyond just camber adjustability. With that said, they are over $400 and I think you're doing the right thing to get your Konis/Tarmacs installed first and then see where you stand then. You may find you're alignment is good and you could spend that $400 somewhere else. If the alignment isn't what you want, they're easy to install after the fact.

[piknockout]

Originally Posted by ABQautoxer

FWIW your Day 1 video looked like you were afraid?

Fixed that for you. Really just lack of trust in the car and in my own abilities. Only second weekend in the car and second event of the year. The rear of the car was very stable and easily controllable if it came out at all.

[was385]

Finally got my first chance of the season even if it was in the mid-40's. Took 1st out of 7 in STX (the twins swept the podium) and 15th of 89 in PAX at our humble local club. This is my first time on Z2s after running almost all stock last year so I'm still feeling out the limits of the tires and the rest of my setup.


This is the best run of the day for me. Please feel free to offer any critiques because I'm still very new to this. Just from looking, the slalom was off a bit and I do have a tendency to turn the wheel too far.


[ame="https://www.youtube.com/watch?v=BrEwaLvzH3U"]Subaru BRZ STX Autocross (Stratford, CT 3-23-14) - YouTube[/ame]


And as great as it was, I learned very quickly that the stock pads just aren't going to cut it on this setup. I was standing on the brakes with almost no effect, so Ferodo DS2500s and ATE 200 have been ordered.

[Kido1986]

The stock brakes work decent. I'd suspect that car needs a fluid change more than the pads. However, that's a good pad choice if you're going to do them (I run those myself)

[was385]

Originally Posted by Kido1986

The stock brakes work decent. I'd suspect that car needs a fluid change more than the pads. However, that's a good pad choice if you're going to do them (I run those myself)

The pads do have 22k miles on them and yes, the fluid is probably big. I took a ride in the second place STX car (FR-S) who was running DS2500 pads and he could brake so much later than I was able to that I decided it was worth the slightly increased cost.

[mrazny]

Originally Posted by Turkish

They also stipulate routinely through the rules that you cannot change suspension geometry. So I was trying to see if that would be considered changing the suspension geometry.

The philosophy isn't stated, but I'd agree that the STAC is not looking to allow changes to suspension geometry, but without the end of the camber allowance stating in part 5 the only change to "suspension geometry" should be incidental to the length of the arm. If that arm allows relocation of the actual shock mount, well you're now into shock allowances and comes back to what I was talking about in the first post...

"Does anything else in the rear of the car need to be modified to use your part?"

Method of attachment of the shock changing counts as "modified" in my book. Shock allowances talk about no change in geometry as well.

SP went into swaybar allowances, but endlink attachment isn't going to get a change in geometry and is free anyway, but is a good avenue to be diligent about.

The one thing to point out though is Bushings are very free, including doing offset bushings. offset bushings change *everything* on the e36. There's no global stipulation on suspension geometry that limits this. The limitation would have to exist within the section on bushings. Just so happens that the Camber allowance and shock allowance specifies to not mess with geometry.


If I were fabricating a camber arm that my shock attaches to, you set it for stock, and then you create the length adjustment in a helpful way (inboard or outboard) for that shock mounting, and it's then incidental to the length. If you create adjustable locations for shock mounting, now you've gone too far.

The one thing this arm creates is uncertainty. You may have it in the stock geometry location, but you *could've* had it in the wrong spot. Might invite protests from the thinner skinned folk. And the devious might use the adjustment to cheat then rest before impound. I wonder if that would lead committees onsite to ever lean on the "guilty til proven innocent" judgement... If I were trying to make sure all interpretations were to the letter, I'd plug the attachments out of stock geomtery to prove i couldn't have cheated. you might be asked to prove that the geometry stayed stock too. That's be some more "not fun".

(que talk of how it's not fair to have an aftermarket part disallowed that's readily available )

[Wepeel]

It's an interesting case. Whether there are multiple alternate mounting holes for the shock/swaybar or not, camber adjustment via lengthening/shortening the lower arm (which all of these control arms do) will modify the motion ratio. Albeit by small amounts, but change it nonetheless.

The same thing actually happens with a camber plate on a strut - the modified angle changes motion ratio and mucks with roll center height, but that's known for all struts and camber plates and they specifically allow modification/relocation at the strut top for camber/caster (or whatever else), within the bounds of the factory clearances.

The issue with the lower arm is, probably not all cars have the shock/spring/coilover mounted to the arm that is being lengthened shortened which is the case here. If there was an adjustable upper arm it would be a little more clearcut.

Interesting.

[Turkish]

On an interesting note, I saw a FB post indicating that they were considering amending the ST rules to allow oil coolers since they are not considered a performance modification.

[FastWhite]

It is in the latest Fast track. It is asking for comments on an engine, trany and power steering oil coolers including oil to water systems. Robi spec radiator. At least that is the way I read it.
This would be good because all that puts the twins in CSP. Now we can stay in STX. if it goes thru that is.


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[xwd]

You still can't replace the radiator.

[FastWhite]

Ah good point. Then exclude the Robi spec radiator. But the rest still applies.


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[Turkish]

I was looking at my oil temps while autocrossing yesterday and my temps were fine while auto crossing, but I do a lot of long distance driving and it would be nice to be able to install one for that purpose and not have it put me in csp for when I autocross.