RandyL

I have a very cherry 2006 987.1 Boxster S that I've owned for about a year and a half now, It had 24k on when I bought it and 28k now. I am one who selects routes based on the best curvy roads and have a lifelong passion for carving corners on both four and two wheels. My goal with this car is to optimize it as a street handler, not a track car. It may see a PCA DE day once every other year, but optimized street handling is the goal with all the of the qualities that implies. I will be taking it in for an alignment next week and would like some advice on the best camber settings to use F & R.

My understanding is that without installation of LCAs or camber plates the front can be adjusted to -1.5° which seems like it would be about optimum all things considered at this point. I have less of an idea about the rear, what would be a good setting to accompany -1.5° in the front? My sense is -1.0°. There seems to be quite a bit of tribal knowledge on 987 suspensions here so thanks in advance for any experience-based wisdom you would care to share! Any any other advise on alignment settings would be welcome as well.

Randy in Oregon

harveyf

I'm sure you will get specific advise. Some tires give increased cornering grip with increased camber but not all do. So you should probably mention what tires you are running.
Just keeping it simple, if you are running tires that are comparable to those that Porsche speced for your car when originally designed, I would just go with the factory specs. I know that sounds boring but they put a lot of effort into getting the best handling out of the car. To me, the driving that you describe is exactly what Porsche designed for. I'm pretty sure that didn't leave much on the table, so to speak. Now if you go crazy with some barely legal track or racing specific tires, then the answer will change accordingly.

RandyL

Running Michelin Pilot Sport 4S, thanks Harvey!

harveyf

I would consider that tire to be commensurate with Porsche's OEM suspension design parameters. Below is a screenprint of the alignment specs from a shop manual for 2006-09 cars.

Just to go a little deeper into the subject, camber can be split into 2 things. Static camber, under cornering loads, can go to zero as the suspension compresses on the loaded side, placing the contact patch more square to the road. Interesting in the specs below is the rear spec being over -1 deg while front has almost none (-10 minutes or 1/6 of a degree). This probably means the back end rotates more than the front. If you search my website for "camber" there are some old articles I did about camber change versus suspension squat on a Porsche 944. The suspension design minimizes the change but the front is better than the rear, on that car.

From a racing performance standpoint, race tires will develop "camber thrust" when set statically to larger negative values, in the range of -2 to -4 deg. Each tire is different in this regard. This is very useful from a standpoint of cornering force but there are of course tradeoffs, like the inside of tire will wear out quickly. I am pretty sure that Maximum Performance Summer tires, like the 4S, don't benefit from this, as I never see it mentioned for this category of tires.

Finally, as an old guy, I don't like getting anywhere near the limits of adhesion on public roads. The consequences if you get caught out can be expensive, painful, or worse. I save my "pucker factor" for the track, where there is at least some room to recover before you are hitting trees or going over cliffs!

Apex1

Well Harvey, I have a Cayman 987.1S which I have modified for the track 5 years ago using very good products from Tarett. F and R LCA's RACE package. monoballs, and larger end bushings to start with. Then added Ohlin R&T coilovers. Finally Tarett GT Swaybars F and R. This happened over a 4 year period of time researching my current equipment status and what can I do to improve the car's handling besides the driver. Currently my tire selection are Michelin PSS4s' 245/35/18 f and 275/35/18 r on 8 in f OEM wheels 9 in in the rear. RE71RS 255/35/18 f and 275/35/18 mounted on Signature SV 104, 9 in f and 10 in r and Hoosier same size as the RE7RS's mounted on Titan 7 TS5's, 9 in f and 10 in rear. So my tire choice is spring/summer/fall use of the RE71RS, Winter I use the Michelin's and a couple track days are on the Hoosiers which does specify at least -3.0 of front camber. I added a Wavetrac LSD three years ago to augment the tire selection.

The OEM alignment should be -1.5 f and -2.1 r with a slight 2 minutes of toe out in f and some toe in in the rear. You should find minimal inside tire wear using this setup. If you are using the car for spirited canyon driving, you may find the outside tire shoulder being worn using this max oem settings. That's the reason for the Tarett Race LCA's. Not sure you need this spec of LCA's just GT3 models should be fine to control the outside tire shoulder wear. I use -2.6 f and -2.5 r without any issues The car is balanced and find very limited understeer from the LSD with 255/25/18 front tires. The car is setup to do exactly what you are describing. I use a Sprint Booster (red 5) to improve throttle sensitivity to give the LSD a little more torque out of the corners. It all works as I should be wearing a heart rate monitor some days.

harveyf

Cool. Many dollars and track miles later, it sounds like an awesome setup that I would love to experience. You mention Hoosiers, which I think are full on race slicks? They probably love the extra camber. But I am not so sure that your Michelin 4S tires benefit. It's hard to tell, it's not really an apples and apples discussion with all the mods you have done. What tracks do you run at?

Apex1

The Ridge and Pacific Race Ways in Kent. Once or twice a year. I'm into fitness now so my car is my bike hauler. This 987 Cayman model is the last of the Tequipment roof racks on Cayman's. The 981 and later do not have the roof rake supports welded into the top of the roof.

Aussie skypig

How is the ride/comfort with the Ohlins/Monoball set up?
Many people claim the “Cayman R” set up is the sweet spot, but the Ohlins R&T get good reports as well. Because of my bike background - I’d love to end up with Ohlins on my Porsche.

Apex1

While the Ohlins do make an impression, the foundation is the Tarett Cup Race LCA's. They make a difference and add the Ohlin's on top for an even better controlled ride. But if you are looking to add track to your experience then this setup is definitely for you

Dave in Chicago

+1

This

Squeaky

The optimal camber depends on a lot of things including tire size, the conditions it’s used, and driver skill. To find it, you’ll need to probe the temperatures. Frankly, on the street you’re not going to see the limits of your tires, and I’d really suggest you don’t try.

With that out of the way, I would just set the tires to wear evenly. Camber is not really a “front is this so rear should be this” kinda thing. The fronts have an optimal, and so does the rear. How well the front is turning will influence the rear, and vice versa, so you’re constantlyt trying to hit two moving targets. From a performance perspective, optimal camber is far beyond the OEM limits, but since it depends on so many things, many of which are not constant, set it based on wear and call it a day. That way you won’t be chewing through tires.

FlipE

I believe Hoosier still makes "DOT" tires (which they will tell you not to drive on the road), Designated R7 and A7.

They also make "actual racing slicks", which don't even pretend to be DOT legal.