Stock. I have found nothing definitive enough to get me to spend money on another.

 

I never thought I would like a "soft" bar, until I put on 900lbs front springs! By soft I'm talking about the 4th setting on a 1.25" solid bar.

 

"soft"? Your "soft" setting is ~300lbs "harder" than what I'm running. You've been running without a rear bar, right? Though the roll rate bias is shifted, my settings with the 06 rear bar should produce similar total roll rates.

I've been slowly working in tuning changes and the 2011 Houston National Tour was our first event with both a 5500 RPM VTEC and an 8400 RPM limiter. The onset of VTEC is smoothed and lower, but I haven't logged RPM to determine how much time is spent in the 5500-6000RPM range. This was also the first course since raising the limiter to take advantage of our 62MPH 2nd gear.

We run against Dan and Jason all the time and this was one of the first times we kept up with Dan. Hard to say if it was because of my recent ECU changes, their setup, or our setup.

Jon Pomrenke/Robert Irish 2006 S2000
Moton Clubsports
anti-roll bars F/R: Gendron bearing 1.25"x0.25" @6/stock
ride-height F/R: 13.0"/12.9"
springs F/R: 850#/750#, 7"x2.5" + helpers
toe F/R: 0"/1/4"
camber F/R: -2.4*/-2.2*
17x9 6ULR w/ 255 Dunlops @35psi
intake stock, exhaust stock
VTEC 5500RPM, REV LIMITER 8400RPM, timing altered for lower VTEC engagement

Jason Minehart/Dan Pedroza 2007 MX-5 5SPD
Moton Clubsports
17x8.5 OZ w/ 245/35 Toyos
OS Giken diff
intake, full exhaust, tuning and raised rev limiter

 

Hi guys,

So.... I'm trying to decide on whether to get an OS Giken. Some people say it's absolutely necessary, some say it's not. I think universally people agree that their driving style needs to be adjusted for it. So, since I don't yet have much seat time in my car, I figure if I'm gonna get one, now's the best time, so I can learn the car and the diff at the same time. That said, the one event I've done in the car I didn't have a wheelspin problem like I had with my stock class AP1's... Thoughts?

Annie Bauer

 

I have your excel sheet. So I know your roll rates

I'll try going softer. Transitions just feel so good with a good about of bar. As for the miata bar. I just put it on the other day.

 

I've heard the differentials transform the car and will require a lot of setup work to adjust to the new diff. Based upon that alone you would be wise to do the diff first. The rumor is that you can get on the gas earlier, the car becomes more predictable, it stops wheelspin, and you can be abusive on the wheel without upsetting it.

However, after roughly six months of careful suspension setup changes, my car was nearly dialed in (back in October). I feel like my car allows early throttle, is extraordinarily predictable, exhibits no wheel lift or subsequent spinning, handles my level of abuse (which is softer than a lot of drivers), and has worked beautifully on every surface I've encountered so far.

In short, nobody knows. My car is still underpowered and overweight, yet has shown to be fast.

 

Wow, thanks for posting your setup. What setting are you running on the gendron? I'm guessing that's what the 6 means - is that full soft?

 

The more power you add, the more the diff becomes important.

You have a lot left on the table currently. VTEC is about 1500RPM too high.

Probably about 30+ ftlbs of torque in the midrange, which will make putting power down an issue on street tires. Then you'll put the diff and start all over with setup.


Like I've said before, the car was never better than with the OSGiken, 900F/850R, no rear bar, stock front bar. On the stock diff, every time we wanted to touch the gas pedal the car would just step sideways instead of going forward. Even with the Giken, I had issues at Lincoln with this



I still have my OSGiken diff in a pumpkin, I've been waiting for Geoff Walker to get back to me but I haven't heard anything from him in about a week.

Anyone can PM me if interested.

 

Thanks Nick. I've been suspicious of what adding power will do as well as removing the 60lb exhaust from the back. My focus on suspension and omission of power would certainly explain why I've not yet seen a need for a diff.

I love the idea that 30+ ft-lbs, up to 160 total, is tough for street tires to handle

Did you do an off-the-shelf ramping of the diff or did you get it tuned?

 

I disabled a clutch pack, if I were to continue I'd replace the spider gear springs with something stiffer to smooth out the lockup even further.


You can do the tuning yourself, its very easy to take apart and play with. Just need to make sure you keep it clean.