Got a track related question? I'll try to answer.

[Deraj]

@Porsche Wow, great post. As for my intended use, I am not looking to get into competitions, so classing doesn't concern me. I plan to upgrade parts slowly as I learn the car and improve my driving skills. I have been doing HPDEs off and on for the past 6 years, in FWD and AWD, but never in RWD. Therefore, I want a good platform to learn on, but also one that I can keep as a long term project as I progress in my driving abilities. Regardless of which car I get, I intend on keeping it relatively stock for the first handful of track days, except for brake pads/fluid, alignment, lightweight wheels, and sticky street tires so that I can learn the car.

@CSG Mike, you said that the GT86's advantages were at higher speeds. Is that purely because of the power advantage of the S2000? Or is it that the S2000 has better suspension characteristics so it can carry more speed through the turns? Or something else?

[orthojoe]

@Porsche has a gift for laying things out in a non d-baggy way.

[ZDan]

Originally Posted by CSG Mike

Yes, the CSG BRZ still uses the stock sways. While their contribution to roll stiffness is minimal, we use them to "tidy up" the suspension. In essence, their purpose is to connect two sides to make the suspension work more efficiently, rather than to prevent body roll.

You don't REALLY think that stock rear sway is there to prevent roll, do you? It's got the stiffness of a coat hanger...

Of course the sway bars are there to limit body roll.
Wheelbase is typically ~1.5x longer than track width, so without sways you'd see ~50% more suspension travel in cornering than you would under braking. If you want 1g cornering to use about the same suspension travel as 1g braking, you have to add effective stiffness in cornering to limit roll. Which is exactly what sway bars a.k.a. "anti-roll bars" do. Of course they're also a very handy way to tailoring front/rear handling balance as well, but primary function is to limit roll.

[Porsche]

Originally Posted by orthojoe

@Porsche has a gift for laying things out in a non d-baggy way.

Now, it's my turn. LOL You're much too kind.

[Porsche]

Originally Posted by Deraj

I have been doing HPDEs off and on for the past 6 years, in FWD and AWD, but never in RWD.

Ahh! Well, then you're hardly a beginner. Thank you for your forbearance in listening to all that.

RWD is a more "natural" state, I think, more balanced. You'll take to it like a duck to water. You'll see.

When God created race cars He said, "And let them be rear wheel drive." (With some allowances for AWD on loose surfaces for rally cars.)

I intend on keeping it relatively stock for the first handful of track days, except for brake pads/fluid, alignment, lightweight wheels, and sticky street tires so that I can learn the car.

It's my understanding that the OEM Michelins would serve you well for that purpose. The biggest problem with those tires is chewing up the shoulders well before using up the main tread. You're learning, not looking for best lap times, right?

Actually, the OEM tires are more expensive than Pilot Super Sports, etc. Maybe mount a really stiffly reinforced shoulder track tire on your spare rims and run them on the track, keeping the OEM tires for street use. Mike can give you good advice there.

[jonnyozero3]

@CSG Mike,

Looking for your $0.02. I've seen you mention you recommend a square brake pad setup (same compound front and rear), but not the reason why. Would you mind offering a few comments on why?

I'm choosing pads for the season, got CT 1521 in front for street (in my AP Racing CP8350), thinking CT XP10 in front for HPDE/track use, and really want to do a dual role street/HPDE rear pad if able to save myself the pain of changing the rears in addition to the fronts. I think I'm spoiled by how easy that AP kit is for changing front pads. Anyhow, I'm an intermediate-level guy who gets out a half dozen or so times a year for HPDE. Other than some "meh" Dunlop Sport Maxx RT tires and 18x8.0 wheels, the car is stock. Basically I'm curious how pressing the recommendation is for a square setup for a dude like me.

[u/Josh]

I plan to start tracking my car fairly regularly (~1 per month) and Im considering buying an Essex sprint kit rather than just upgrading pads and fluids. I would be doing it purely for the decreased consumables cost.


The question I have is, I know the CSG car used to have a sprint kit, but I think the new car is using stock brakes with upgraded pads, why?

[solidONE]

Originally Posted by Porsche

Ahh! Well, then you're hardly a beginner. Thank you for your forbearance in listening to all that.

RWD is a more "natural" state, I think, more balanced. You'll take to it like a duck to water. You'll see.

When God created race cars He said, "And let them be rear wheel drive." (With some allowances for AWD on loose surfaces for rally cars.)

It's my understanding that the OEM Michelins would serve you well for that purpose. The biggest problem with those tires is chewing up the shoulders well before using up the main tread. You're learning, not looking for best lap times, right?

Actually, the OEM tires are more expensive than Pilot Super Sports, etc. Maybe mount a really stiffly reinforced shoulder track tire on your spare rims and run them on the track, keeping the OEM tires for street use. Mike can give you good advice there.

Could this not be avoided by adding sufficient amount of camber?

You write very well, sir. Do you have a blog or something? Maybe you should consider, if not.

I tend to think Mr. Rod Millen to be brave, skilled, and old in equal parts. lol

[major quicknap]

Originally Posted by ZDan

Of course the sway bars are there to limit body roll.
Wheelbase is typically ~1.5x longer than track width, so without sways you'd see ~50% more suspension travel in cornering than you would under braking. If you want 1g cornering to use about the same suspension travel as 1g braking, you have to add effective stiffness in cornering to limit roll. Which is exactly what sway bars a.k.a. "anti-roll bars" do. Of course they're also a very handy way to tailoring front/rear handling balance as well, but primary function is to limit roll.

Ummmmmm.... I was referring to the fact that he has 10k front and 12k springs on his car so the the roll bars' contribution to roll stiffness is a much lower percentage compared to stock. I was wondering why he was still using roll bars given how much stiffer his springs are.

[ZDan]

Originally Posted by major quicknap

Ummmmmm.... I was referring to the fact that he has 10k front and 12k springs on his car so the the roll bars' contribution to roll stiffness is a much lower percentage compared to stock. I was wondering why he was still using roll bars given how much stiffer his springs are.

My same point still applies. With stiffer springs, you'll want *stiffer* sways, not NO sways, in order to sufficiently augment roll stiffness. That is, if you don't want the suspension travel you use in cornering to be greater than that used under braking.
No sway/anti-roll bars => you're either softer in cornering than ideal or stiffer under braking than ideal.

[AZP Installs]

In road racing, wheel travel is not necessarily a bad thing believe it or not. Too little wheel travel will cause you to pick up a wheel, and you definitely don't want that, no matter how cool it looks in pics or for kids to post on their instagram accounts...

-Mike Paisan


Maintaining, Modifying and Educating TriState Enthusiasts since 2001.
Like us on Facebook! | E-mail: sales@azpinstalls.com | 725 Fairfield Ave | Kenilworth, NJ 07033 | 908.248.AZP1 (2971) |AIM: AZP Installs
"Race Tested, Enthusiast Approved!"

[ZDan]

Not saying wheel travel is "bad". But of course at the track you'll want much stiffer suspension than stock, and with super-sticky tires, stiffer still. Otherwise you'll use up so much travel under hard braking and cornering that you don't have much left to deal with bumps (in addition to losing time at corner entry and in transitions as well as requiring more static camber due to more roll in cornering).

But in any case, the point is that if you have soft sways relative to springs, or NO sways, you'll use more suspension travel under cornering than under braking at the same g's. You'll be relatively stiffer in braking and softer in cornering. Generally, that implies a less than ideal setup, either it's too stiff under braking or too soft in cornering. In general, if you go significantly stiffer on spring rates, you'll want to go significantly stiffer on the overall swaybar stiffness as well. For rwd, many times all of the additional sway bar stiffness goes to the front (and depending on car and setup, sometimes way stiffer on the front bar and no rear bar).

[CSG Mike]

Originally Posted by Deraj

@Porsche Wow, great post. As for my intended use, I am not looking to get into competitions, so classing doesn't concern me. I plan to upgrade parts slowly as I learn the car and improve my driving skills. I have been doing HPDEs off and on for the past 6 years, in FWD and AWD, but never in RWD. Therefore, I want a good platform to learn on, but also one that I can keep as a long term project as I progress in my driving abilities. Regardless of which car I get, I intend on keeping it relatively stock for the first handful of track days, except for brake pads/fluid, alignment, lightweight wheels, and sticky street tires so that I can learn the car.

@CSG Mike, you said that the GT86's advantages were at higher speeds. Is that purely because of the power advantage of the S2000? Or is it that the S2000 has better suspension characteristics so it can carry more speed through the turns? Or something else?

It's the GT86's aerodynamic stability; the S2000 makes significant front downforce and rear lift from the factory; the GT86 is fairly even. This is also why the addition of a wing alone makes the S2000 so quick on track.

The S2000 will teach you more than a 86 will, but the two cars require distinctly different driving styles.

[CSG Mike]

Originally Posted by jonnyozero3

@CSG Mike,

Looking for your $0.02. I've seen you mention you recommend a square brake pad setup (same compound front and rear), but not the reason why. Would you mind offering a few comments on why?

I'm choosing pads for the season, got CT 1521 in front for street (in my AP Racing CP8350), thinking CT XP10 in front for HPDE/track use, and really want to do a dual role street/HPDE rear pad if able to save myself the pain of changing the rears in addition to the fronts. I think I'm spoiled by how easy that AP kit is for changing front pads. Anyhow, I'm an intermediate-level guy who gets out a half dozen or so times a year for HPDE. Other than some "meh" Dunlop Sport Maxx RT tires and 18x8.0 wheels, the car is stock. Basically I'm curious how pressing the recommendation is for a square setup for a dude like me.

Load distribution. The brakes are sized to provide a roughly even load on the front and rear axles. If you stagger the compounds, the more aggressive compound will do more work, while the other axle does less, resulting in brakes that overheat and wear abnormally.

With the pedal dance, you get a strictly mechanical system, where a balanced compound generally works best, unless you've significantly altered the car's weight distribution.