Alignment questions

[Kirk]

IF I recall correctly, yes I believe -1.5 degrees of camber is possible in the front with the stock suspension, but it's been years since I had a stock suspension - first lowering springs and then coilovers, so I could be remembering wrong. I was thinking of checking the Boxster Spec board to see what those guys run, but they're all using PSS9 coilovers....

Having so much negative camber in the rear is more a function of having the car lowered so much rather than a desire to actually run that much negative camber! When you drop the Box to an extreme level you're going to have high negative camber in the rear if you're also going to adjust the toe to slightly in. The two (camber and toe) are very much tied together. The only way to dial out some of that negative camber is with adjustable toe arms so that you can get BOTH good toe AND less negative camber. I don't have adjustable toe arms and don't really care to get them as the high negative camber in the rear does not concern me (as in, I don't care about the cost of higher tire wear).

The general consensus on how much negative camber you want is as much as possible. This is for track and autocross though. You have to be willing to throw away some money on tires to run this way. If I was going to seriously track my car I would slap the Schnell camber plates back on the front and run around -2.5 degrees of camber. Right now though I'm just autocrossing and not too serious about it, so I've got a more mild setup in the front. I have heard many times that slight toe out in the front will help with autocross, but again I've chosen to set my car up more for the road and secondarily for autocross, so I've made some compromises.

Hope that helps.

If you want to autocross and track your car - here's what you tell the alignment shop:

Max negative camber front and rear
Zero toe in the front
Slight toe in at the rear

IMHO....

Kirk

[demick]

Max camber I was able to get with a stock '04S suspension was -0.8deg. Doesn't seem that -1.5deg is in the realm of possibility unless the suspension is modified, or unless lowering the car adds neg camber (I'm not sure if it does or not).

[Adam]

Originally Posted by demick

Max camber I was able to get with a stock '04S suspension was -0.8deg. Doesn't seem that -1.5deg is in the realm of possibility unless the suspension is modified, or unless lowering the car adds neg camber (I'm not sure if it does or not).

Demick, did they mention how much rear camber was possible? Thanks!

[demick]

Demick, did they mention how much rear camber was possible? Thanks

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I did my own alignment. I was only trying to increase front camber. I measured rear, but didn't want to increase it for tire wear reasons (I forget off the top of my head what the measurement was, but I'd guess around -1.5deg). So I don't know what the max is. I'd be hesitant to go more than -2 to -2.5 deg on a street car.

Was was really interesting, is after setting the front camber to max (-0.8deg), the toe changed drastically (gave me about 1.2" of toe out!!). I expected the toe change, just not nearly that much. Needless to say, I reset the toe to zero, but not after driving 40 freeway miles and competeting in an autox. Craziest thing is that the handling on the freeway wasn't half bad with that huge amount of toe out. Go figure.

[Adam]

Originally Posted by demick

Demick, did they mention how much rear camber was possible? Thanks

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I did my own alignment. I was only trying to increase front camber. I measured rear, but didn't want to increase it for tire wear reasons (I forget off the top of my head what the measurement was, but I'd guess around -1.5deg). So I don't know what the max is. I'd be hesitant to go more than -2 to -2.5 deg on a street car.

Was was really interesting, is after setting the front camber to max (-0.8deg), the toe changed drastically (gave me about 1.2" of toe out!!). I expected the toe change, just not nearly that much. Needless to say, I reset the toe to zero, but not after driving 40 freeway miles and competeting in an autox. Craziest thing is that the handling on the freeway wasn't half bad with that huge amount of toe out. Go figure.

Interesting, with that much toe it should've been all over the place. Do you have any ideas why Porsche would dial in - camber in the rear, but not the front from the factory?

[demick]

Originally Posted by Adam

Interesting, with that much toe it should've been all over the place. Do you have any ideas why Porsche would dial in - camber in the rear, but not the front from the factory?

Front wheels generally don't need as much neg camber as rears, because they have caster. With caster, when you turn the front wheel, the wheels lean into the direction you are turning - essentially giving you neg camber on the outside wheel and pos camber on the inside wheel. Exactly what you want when you turn. The rear doesn't have this, so it has to be built-in.

[Adam]

Originally Posted by demick

Front wheels generally don't need as much neg camber as rears, because they have caster. With caster, when you turn the front wheel, the wheels lean into the direction you are turning - essentially giving you neg camber on the outside wheel and pos camber on the inside wheel. Exactly what you want when you turn. The rear doesn't have this, so it has to be built-in.

Cool, thanks for the explantion. Caster is the hardest thing for me to wrap my head around. I've been researching it online trying to get a better understanding.

[Kirk]

Originally Posted by demick

Max camber I was able to get with a stock '04S suspension was -0.8deg. Doesn't seem that -1.5deg is in the realm of possibility unless the suspension is modified, or unless lowering the car adds neg camber (I'm not sure if it does or not).

Yes, lowering the car adds more negative camber. Just look at the Porsche specs for stock, RoW, and RoW sport. As the car gets lower the camber specification goes more negative.

I'm going to assume then that I'm wrong here about being able to get -1.5 degrees of camber stock in the front. My recollection must be a bit fuzzy because, again, my car's been lowered for a few years. I'm 99% sure that -1.5 is the max you can go with lowering alone. The Boxster Spec guys are trying to get max camber and I think this is the most they can get with just PSS9 coilovers. To get more they either use camber plates or GT3 control arms.

I've driven with slight positive toe in the front and I don't like it one bit. The car gets real darty on the highway. It may be ideal for a dedicated autocross car, but I don't think it's probably ideal for a street driven car or for a higher speed track setup.

Kirk

[brp987]

Does anybody know? Do gt3 arms start at 0 camber and go further negative with each shim, or start positive and go negative? My eibach'd car is at -2.8 (rear) and I'd like to get it to -1.5.

Is there any way to get stock camber on a lowered car if your adjusters are max'd out?

[Adam]

Originally Posted by brp987

Does anybody know? Do gt3 arms start at 0 camber and go further negative with each shim, or start positive and go negative? My eibach'd car is at -2.8 (rear) and I'd like to get it to -1.5.

Is there any way to get stock camber on a lowered car if your adjusters are max'd out?

I believe you can dial out camber or dial more in with camber plates. Also I think to get everything lined back up from the drop many people install aftermarket drop links.

Just to update the thread I took my car in for an alignment a couple months back and the most negative camber they could get up front was -.5. However, it had about .5 degree of positive camber on each front wheel when I took it in so there was about 1 full degree difference and it did handle better. Rear camber was -1.5 so I just left it there.

[Adam]

Thanks Kirk, yes that was helpful. Correct me if I'm wrong, but you're saying Boxster owners generally run less front camber than rear because they simply can't get as much up front. It seems Porsche gave the car adequate negative camber in the rear, but failed to give it any up front from what I see. Why would they do that?