acsX

What else should I replace? I plan on replacing the bushings with the LCAs with completely new arms for the front. Not sure about for the rear if I should I get new ones or replace the bushings + rebuild the ball joints (I have no experience with). And I should replace the tie rods correct? Anything else I should conquer while down there?

adam_987.2

Drop links and sway bar bushes.

Zach L

If I was going to replace the front LCAs, go with GT3 arms for more camber adjustability.

acsX

Already plan to with Tarret GT3 rubber ends for the GT3 arms (which I have on order somehow, everything is very backordered).

ekam

The GT3 LCA is a must-have for anyone who's not only driving straight with their 987... these cars needs moarrrrrr camber.

BWJones

If one wanted, say... to dial in less camber to reduce wear on the inner shoulder of the tires, then could the GT3 arms help there?

Zach L

I don't believe so... not any less camber than the standard LCAs. The increased camber from the GT3 arms is acheived by adding shims to effectively make the arms longer. With no shims at all I believe they're the same length as the standard arms.

Although the standard alignment setting have a relatively large amount of camber in the rear, if you're getting excessive inside wear on the tires you may want to check your alignment. Look specifically at toe. Also, you may consider running tires with a symmetrical tread pattern. That way you can swap them to the opposite wheel on the same axle, which puts the inside on the outside.

ekam

The large amount of rear camber is there so when you accelerate the rear squats and becomes neutral camber.

joliver3

This is not correct. When the rear squats (wheels go into jounce), the negative camber of an independent suspension will generally become more negative. As evidenced if you've ever seen a BMW sedan driving around with a full load of passengers and cargo.

The large amount of rear camber is actually there so that when cornering, the rear wheels will still retain some negative camber and provide some cornering thrust and keep the contact patch more evenly loaded. When the car corners, the kinematic increase in negative camber (relative to the sprung mass) of the heavily loaded outside wheel moving into jounce is not enough to completely offset the roll angle of the sprung mass (less than 1 deg. of negative camber increase per degree of roll), and the net result is a reduction in the amount of negative camber of the tire relative to the road. The compliance of the tire and suspension bushings under lateral load will also tend to reduce negative camber.

Strut suspensions, like the Boxster and Cayman, are one of the most difficult layouts to get large amounts of camber gain unless the strut axis can be tipped inward (as BMW used to do / maybe still does do on the front of their cars with inline 6's). This is actually one of the main handling advantages of a double A-arm or multilink suspension -- greater camber gain and camber stiffness. You could design a multilink to have more than 1 deg. of camber gain per degree of roll, but then you'd likely end up with other issues, like directional stability over bumps, tire wear while driving straight on less than perfectly smooth roads, etc.

ekam

https://www.pelicanparts.com/techart...-Alignment.htm

"The rear wheels should be set from the factory for a slight negative camber (about -1.5 degrees), as the trailing arms tend to bend slightly outward as the car accelerates under power. Since one half of the wheel is mounted firmly on the ground, the top of the wheel has a tendency to twist outward when power is applied. Setting the rear wheels to have a slight negative camber means that under power they will be mostly neutral."

Racer Boy

joliver3 is correct, and that quote from the Pelican article doesn't make any sense. The more compression you get in the rear suspension, the more negative camber you get. Think about what happens when your car accelerates - the front rises, and the rear squats. Thus, more camber when accelerating.

acsX

Also which loctite should I use on the threads of suspension parts (if any at all)?

Hokie987.1

I'd say blue if any. From my understanding you should use red only on parts you never ever intend to take apart again.

joliver3

I think the quote from the Pelican article makes a little sense. When I replied earlier, I was only thinking about the statement that the negative static camber is to compensate for what happens when the rear squats, which is still incorrect, but I wasn't thinking about camber change due to acceleration forces and suspension compliance. But I can't see the trailing arm compliance resulting in anything close to a degree or two of camber change. Plus there will be some compliant change in toe under acceleration as well, so maybe what the Pelican article was trying to say was that the net of the negative static camber and the compliance camber change offset the compliant toe change (to some greater or lesser degree), resulting in less net lateral force under acceleration.

Our cars probably don't squat much in the rear due to a combination of low c.g., stiff springs, and (I assume) some decent anti-squat rear suspension geometry, so there probably isn't a lot of kinematic negative camber increase under acceleration, but it's still very unlikely that there's any kinematic negative camber loss either.

I still believe the large negative static camber is primarily for cornering effects, as evidenced by all the people who increase negative camber to reduce outside edge tire wear on their track cars.

acsX

Since I'm down there replacing suspension parts currently, should I replace the caster control arms? Not sure how to tell if they're still good. Do regard they have 102k miles on them. Same thing for the rear control arm links.

Another question, would Tarett swaybars work on stock drop links for Cayman R ride height or are the adjustable drop links required?