racer

* stock class SCCA? or PCA? or???

Is there a reason you are focusing on 2003-4 vs 2000-2002? Sure the glass window and minor hp bump are nice, but not sure there are any other benefits, vis-a-vie autocrossing.

BigEnos

Yeah, SCCA stock class. All theoretical at this point as I'm driving a mustang in street prepared this year, but I've been driving ponycars for years and I'd like to try something different and go back to stock class. Yeah, the power bump is the main reason I'd focus on those years. Any reason to think differently?

I started out looking at Cayman S in A-stock, but the 'vette is a lot less money and is very competitive. The CS boxster seems overlooked.

Han Solo

You could put the M030 option on a Boxster that didn't originally have it and still be SCCA Solo Stock class legal. However, you would need to get ALL the M030 parts on. Alternately, you could put a heavy front sway bar on and be legal. I'd look for an adjustable bar though, as going to stiff is going to make the car under steer even more than it already does. The GT3 5-way is popular on the 987 series cars. You'll be stuck with stock springs but shocks are open. You can not change the struts to coil-over adjustables but if you check out this thread...

http://www.planet-9.com/cayman-boxst...t-project.html

...I'm about to load dual adjustable Koni inserts into my Cayman S struts.

The place to start on a stock Boxster are tires. I've found the 285/30 18 rear and 245/35 18 fronts in Kumho R-compound tires will give you the best life and grip for regional events. We got 100+ runs on those last season. If you're doing National Tours, you'll have to run Hoosiers in the same size. Those are expensive, very grippy but start to fade quickly after 25-30 runs.

Han Solo

Interesting... is that the case on all PSM cars (gen1, gen 2, Boxster, Cayman, etc.)? We typically autocross a '99 Boxster and a '07 Cayman S with PSM off but I've never seen the indicator light come back on on the PSM button after braking. So you're saying that it reactivates and is running in the background without illuminating the button light? Or turning off the PSM Off symbol on the gauge face?

Han Solo

Just say RTFM...

The following functions stabilize the vehicle in
emergency situations, even with PSM switched off:

– When PSM is off, the vehicle is stabilized as
soon as one of the two front wheels enters the
ABS control range.

– When PSM is off and Sport mode is on, the
vehicle is stabilized as soon as both front
wheels enter the ABS control range.

One-sided spinning of the wheels is reduced,
even with PSM switched off, to enable optimum
traction on all drive wheels.

So apparently it is functioning in the background during those situations. I've had co-drivers who told me they thought there were some PSM effects happening even with it turned off.

BigEnos

Thanks for the info. Han!

Just to add, it has been recommended that you will be able to change a *single* bar in stock class starting in 2013. Generally the BOD accepts committee recommendations so I'd expect this one to pass. This could help the understeer and tire wear issues the boxster might have. See the Nov. 2011 fastrack for details.

I get 60-80 competitive runs out of A6s on my Camaro. Pretty much until the grooves are gone they work well. I have a hard time believing a 400lb lighter mid-engine sportscar will be worse, though I do have double wishbones vs. struts, so the camber curve is a lot more favorable.

sjfehr

M030 consists of springs, shocks, rear sway and front sway. Per SCCA stock class rules, shocks are free, as is one sway, so all you really need is official US M030 springs and one sway, and the rest can be whatever aftermarket (or ROW M030) parts you want.

It's counter-intuitive, but a properly set GT3 front sway bar reduces understeer in camber-limited Boxsters by reducing dynamic camber loss. A rear sway would do a better job reducing understeer, but I fear it would cause wheelspin. How well does Porsche's electronic traction control work, is it enough to make it worthwhile to change the rear sway than the front?

Full disclosure: I autocross a non-M030 '04 986S in SCCA BS; the only mod I made (besides tires) was to add a GT3 front sway bar and Tarrett droplinks.

BigEnos

sjfehr, I had the same experience when I ran a 35mm front bar on my car in stock. It definitely improved tire wear and grip for all the reasons you list. I wasn't sure a Boxster would react the same way. Good to know it does.

racer

And don't forget that "stock" boxsters can achieve very little negative camber. I could only get about -.7 or -.8 degrees camber up front and about -1.8 rear.