Ben22

Hello all,

The French guy is back asking questions...

I changed my set-up but feel a little uneasy with my new changes. I would appreciate all inputs!

I was faster last time at Button Willow, but I'm not confident with the way the S is behaving.
Since my very first time at BW, my best time was around 2.11, I added the following sway bars combo for a time of 2'08.7

Mods:
-Front lip
-Test pipe
-Cat back exhaust
-APR GTC-200
-MY05 shocks / SWIFT springs
-08 CR wheels / staggered

Used to be on 03 front and rear sway bars.

Now:
-MY08 Front CR sway bar.
-MY04 Rear sway bar.

I also added a hard dog roll bar and removed the rear interior trim.

-New Z1 tires
Front 225
Back 255
I keep them around 37deg when racing, sometimes less in back than front (35).

# -3 camber all around, very little toe in in front and back (aligned by West end).

The car feels faster, but the rear despite being way more controlable, feels looser.
I have that "floaty" feeling?

For example at BW last week-end, car was very floaty, borderline oversteering at the Bus Stop turn before the Lost Hill turn. I had to track out to the right to make sure to not upset the balance.
Car was loaded on the right side, pushing hard, not like last time when I didn't have that feeling I was slamming the car through every turns? (hitting bumpstop and then almost bouncing).
Even my wife was a little bit more uncomfortable than usual. She felt the car was less steady, screaming tires more often, lighter too.

So am i faster and floaty doesn't mean it'll snap?
Maybe that feeling on the track of heavily loading the S on the springs is a good thing? I don't have to worry about a snap oversteer this way? more progressive?

I'm debating, since i'm still staggered and a super stiff front bar might not be the best, to maybe go back to:

-MY03 front sway bar?
-MY03 rear sway bar?
-Combo of 03 sways?
-Combo of 03 front / 04 back?

-Stiffen the rear by adding some rear strut bar? lower beam bars? etc?

What do you think would be the best? No coilovers option since i'd like to stay in Street / Spec CR class.

I would sincerely appreciate your help in the matter. Will get the car ready for WSIR

Cheers,

22B

MY2000 Front 28.2MM T5.0 Rear 27.2MM T5.3
MY2002 Front 26.5MM T4.5 Rear 27.2MM T4.5
MY2004 Front 26.5MM T4.5 Rear 25.4MM T4.5
MY2006 Front 26.5MM T4.5 Rear 25.4MM T4.5
MY2008 Front 27.2mm Rear 25.4mm
CR2008 Front 28.6mm Rear 26.5mm
CR front 19% thicker wall than std.2008, rear the same wall thickness as std.2008

http://www.swiftsprings.com/file/ss.pdf

Ben22

It would be fast and easy to try going back to a softer front sway bar, but I'm not sure it will help.

-Fil (from Ben's computer)

VitaRenovatio

A softer front sway bar will only worsen your oversteer issue. You stiffened up the front and softened the rear with your change in sway bars, which should shift the balance towards more understeer, not oversteer.

But I think you are also forgetting one other thing: you are running quite a bit of camber now, and equal camber front and rear. What camber settings did you have before?

1) If you had less camber in the front before, and now you have the same camber front and rear, that effectively increases grip at that end and will shift the balance toward oversteer.

2) If you had less camber overall before, you should note that increasing camber will make the car a bit trickier to drive at the limit, as the drop-off in grip as you exceed the limit of the tires will be more abrupt.

Another suggestion is to see if adjusting your bumpsteer kit might fix the issue. I wish I had the chance to ride in your car, but in general I like it slightly loose, and see faster lap times that way at BW.

Ben22

I used to be on -2 front and -2.75 back camber before.
Also Fil had a good point, Darren at West end did set-up my rear BSK.

The only time i lost it and spun at BW was at the end of cotton corners because i munched on the berm too much and threw the back end in the air on the way down...

So it does make sense, trickier at the limit, now i need to learn how to drive

Much appreciated Nam! See you all Sunday,

I'd love for you to drive my car, as i also would love for you to ride with me to show me the lines?

VitaRenovatio

I'm afraid I won't be much help at WSIR, as I'm probably a good 3 seconds off pace there. The hot shoe for WSIR is Si (nsxtacy). We'll both need to pick his brain.

bellwilliam

I will give it a shot. you had less front camber before, now you have equal camber. everything else equal, you will oversteer more.

but I am not sure you are feeling the oversteer. car is very sensitive to rear toe. you might have too little toe in.

I also find your hot tire pressure is a little lower than normal. if I remembered correctly, Z1 liked ~38-39 hot on a s2k. and you should always err on high side, where you lose very little time, but you get sharper steering input. never on the low side where you lose speed fast and steering numbs.

you also changed brand of tires, that would also change the balance. some brand's 225 is wider than normal, while same brand's 255 is narrower than normal. some brand have different compound between different sizes. e.g. 195/50/15 R1R is softer compound than 205/50/15.