What are your suggestions for alignment settings?
 

Just curious what you guys are using for your front and rear alignment settings for the street. Live around good twisties in the foothills. I have the following:

7/9 wheels with Yoko ES100
Slightly lower than Euro height
21\27 TB's
Custom valved Bilsteins for this setup
polybronze bushings
stock SB
Turbo tie rods

Will soon be heading for alignment and need to make up my mind. Suggestions\comments always appreciated.

Front toe..."smidge" of toe-in...1/16 to 1/8" measured at tire diamter..or 5 minutes each wheel.
Front caster...max... ( say 6-6.5 degrees). More important to get both sides as equal as you can, instead of going max.
Front camber...lots options...30 minutes ( 1/2 degree) negative...up to 1-1.5 degrees if looking for VERY aggressive driving. If you drive more sanely..the greater neg camber will wear inside edges.
Rear camber.....= front camber for "neutral" cornering.....or 1/2 degree more negative to impart a small amount of stabilizing understeer. 10-15 minutes total toe ( total for both sides).

---Wil Ferch

Does that mean less understeer?

What I mean is that if you go very aggressive on negative camber, the tires would be rolling pretty much on their inside edges....not good if you MOSTLY go in a straight line..but darn near perfect if you CORNER near tha car's limits all the time ( "aggressive") because now the tire contact patch is more "square" to the ground when the car is leaned over that much.
Might that be a bit clearer?
--- Wil Ferch

But who really cares if the contact patch is more square to the ground, if it doesn't improve adhesion and reduce understeer, where's the performance edge for aggressive driving?

I always thought that the factory settings already took into account cornering forces that would result in the optimum vertical tire contact patch because of the 6 degees of caster.

frt

1/16-1/32" toe in
max caster (but equal)
Camber -1 -- -1.5 deg

Rr

1/32 toe in
Camber -1.5 -- -2 deg

Most people recommend the camber on the front being about 1/2 degree more negative than the front, but some recommend equal camber settings frt to rear, so I suppose that would depend on your driving style. More neg camber in the rear than the front would make the car more prone to understeer than oversteer. Keep in mind that the weight distribution and the gas and brake pedal have a big effect on the attitude of the car, possibly a better way to try to balance under/over steer would be to get an adjustable swaybar for one end of the car (probably the rear)

STLRJ:
What's that you say????

..."who cares if the contact patch is square to the ground?...if it doesn't improve adhesion..."

I give up... ( don't take this wrong, but) do you have any idea what you're saying ???

---Wil

Don't get upset...but you increasing negative camber does reduce your contact patch so braking is compromised as well as cornering since you are now starting out with your wheels out of vertical.

If you started with your wheels vetical as factory specs suggest, you will maintain your contact patch square to the ground as the caster adds the right amount of negative camber as the wheels are turned off center.

But if you have too much negative camber to begin with, you end up having too much negative off center reducing your contact patch even more...

Do you have any idea what the relationship of caster has with camber as the wheels are turned off center?

Thanks for all the info! One of the reasons I asked this question is because I am stepping up to 9" wheels and it was my understanding that you use less camber with wider tires. Since I will be using 245's on the rear, I was thinking about 1/2 degree front and 1 deg rear or even 1 deg all the way around. I'll be doing a lot of weekend trips with the car so I don't want to get too crazy and waste tires needlessly. On the other hand I want it to handle nice.....Too bad you always have to sacrifice something!

street settings are humble compared to track. rear tire psi would be my concern for rear tire life. I'd probably use a temp probe, or at least a thread depth gauge to monitor how the threads were wearing.

STLRJ:
Yes... I do understand the relationship between caster and camber as the wheel is turned off center....

I'm simply asking you to review your own first sentence, when taken in absence of all the later things you say.... it made no sense... OK?

So what's the problem? All settings are a compromise. The factory settings are OK for a wide range of driving conditions, but for "spirited" driving, an increase in the amount of negative camber is usually considered a fair trade-off of increased capability in the corners...balanced by more tread wear. I was saying that 0.5 degrees negative camber for front ( and either 0.5 or 1.0 negative for rear), would improve cornering and would be a performance enhancement setting. As a sub-set....you could use 0.5 both front and rear if you'd like your high speed turns fairly neutral...but feel free to go 0.5 more negative in the rear ( edit: rear then is 0.5 more negative than what is chosen for front)... if you feel more comfortable with some built-in high speed understeering tendency....slightly slower but more stable and forgiving. In this context, you can go yet more "extreme" by using as much as 1.5 degrees front camber...and likewise either 1.5 ( or 2.0 ) for the rear...with the admonition that these are *extreme* settings...and if you find yourself not curving through mountain canyon roads a lot, but instead find yourself on Freeway straights...you'll likely wear out your inside 1"-2" of tire. Simple and clear enough I thought....obviously not. Agreed...if your simply going in a straight line and running extreme negative camber...you risk having less "square" contact patch available for braking...no issue.
----Wil Ferch

Here in Houston ALL roads are VERY flat and VERY straight. My car is set to -1 frt and -1.5 rr camber and I have even tire wear. I, unfortunately, don't get to AutoX or DE my car.

Just as a data point: stlrj is something of an iconoclast when it comes to suspension settings and theory.

If I could boil his theories down (probably inaccurately, but as well as I can manage), it would be that 40 years of track/performance development work on 911 suspension does not apply to street driving, where he feels stock settings are best.

I think stock settings have a little built in understeer ?

84toy:
If you're running 245's on 9'" in the rear...this is very much like a Turbo car, and those shouldn't run "as much" negative camber as the narrower body cars with lesser tires..

... as a generalization.... :)

RoninLB...basically yes, if you really look at factory settings, Porsche not only set the car up for "average" conditions, but also dialed-in a bit of low speed understeering characterisitics to combat the inherent , final oversteering tendencies our cars have. Note that front camber ( factory, depending upon year...is about "0"..and rear camber by factory goes as high as 1 degree negative....relate these numbers to my text and you'll see it will undrsteer more using factory settings).

---Wil Ferch

thanks for the confirm

I know that stock settings have built in understeer and increasing negative camber doesn't help!

And stock settings are the best compromise for those who imagine that they drive more aggressively than they think, since stock setting already give you 1 1/2 degrees of negative at 20 degrees of turning angle...more than you'll ever need for aggressive cornering.

I might even agree that stock settings are optimal for a street driven only 911, especially for the significant population that doesn't plan on ever pushing their car to its (very high) limits. As Wil correctly pointed out, all setting are a compromise. In fact, I would assert that there is an approx. 1:1 trade-off between ultimate cornering performance and highway (straight line) manners in a 911. Increasing neg. camber in the front will increase front GRIP and reduce understeering, (to answer stlrj's question), but cause car to be more "darty" on typical freeway surfaces. Or not "track" as well, put another way. And reduce braking performance, as contact patch is reduced, (in a straight line).

Without going into a long, boring treatise into 911 suspension development and the inherent engineering challenge of a rear-engine performance car, suffice it to say that stock settings are not optimised for cornering performance, they are optimised for safety. Mostly safety from lawsuits from unsuspecting owners driving tailights-first into cement walls.

Stock 911s on the track are understeering pigs, period. They handle like pig slop when pushed by a capable driver. You don't have to agree with me, stlrj, I'm right. :) Stock settings are to ensure understeer when some average Joe turns the wheel a little too quickly on the suburban freeway cloverleaf. :cool:

Not true! Try driving your car set up like this in the rain on a freeway cloverleaf and you'll see what I mean.

If negative camber was the solution to understeer, then why haven't I found it on any search no this BB?

Besides, I already tried it and it doesn't work!

Well said speeder..

It's so nice of STLRJ to decide....for us...that the factory settings are "the best compromise "....

STlRJ...two items for you to consider:
1.) A compromise is just that...a trade-off of known characterisitics for a given purpose. Unless you know "my purpose"..please don't tell me what "my" best compromise is... K?
2.) Giving you full credit for your admitted knowledge as to the camber change with steering wheel crank angle... do the numbers you quote take into account the suspension changes ( in position) that occurs as the car "lists" in a corner?...or do your calculations ignore this fact? There are two different answers if you did ( or did not) take this into consideration. Similarly, how much lean do you figure? Oh?...with "stock" torsion bars? Fatter torsion bars? This too makes a difference. How can you make such sweeping generalizations? Better yet, why not discourage any questions on this board as to suspension settings? Simply not necessary.....just look at the factory manual !
Regards,
--Wil Ferch

I think the factory, you know, the folks designed the car, already factored in all the body lean into their calculations for optimum alignment so we don't have to be engineers to drive the car.

"O ye of little faith"

Ohmygosh, this is starting to sound like the E-ram thread :)

Conspiracy theory: stlrj==Mark Kibort

Precisely....so if we're running stronger torsion bars...OR if we're using the car in a way ( track and street vs street only) other than the ASSUMPTIONS made by the EXCELLENT factory engineers...then the EXCELLENT settings that the EXCELLENT engineers made... is not so EXCELLENT any more...isn't it....it would seem that a different set of "compromise" settings would then have been made by the EXCELLENT factory engineers...no? Look at what the factory does ( differently) for a late street 911 vs a late Cup car, for instance. Same settings? No way !

Is any of this getting through ?? Not taking anything away from the EXCELLENCE of the factory's work, don'tcha know.... ??

---Wil

Excellent factory engineers? Come on.

Don't forget the impact of 'excellent' liability-oriented lawyers and actuaries. Understeer is safer, for ordinary users.

Stock settings would be great if the car was running 11" wide racing slicks on the front with really hard torsion bars and 14" racing slicks on the back. Then we would want next to no camber.

This is amazing, to try to say that the best handling specs for our cars are the factories just seems crazy. Everyone knows that the factory settings are a huge compromise.

So what have you come up with to improve on understeer?

See above :)

way up towards the top

closer to equal camber settings front to rear, but the best bet is an adjustable sway bar and a knowledge of vehicle dynamics and dynamic weight distribution/change.

I'm no expert, but I do know just enough to be dangerous. ;)

Wil, factory settings non the less...yea way.

STLRJ:

????

Your rebuttal to my point that the "factory" has BOTH street settings for street cars and ....more aggressive settings for Cup Cars....

...tell me again how this contradicts what I'm saying ????

You, sir...seem incorrigable...and seek merely to find a fight.

The fact remains that all settings are compromises, and the factory stock settings are fine for the ASSUMPTIONS made as to how the car is to be used. The original poster made some rather significant modifications such as torsion bar upgrades and other things... that clearly place him towards a "fringe" use....more like fast, aggressive track work. Therefore ANOTHER set of settings would be more appropriate..the same way the factory has a different set of "settings" for their Cup or racing cars. Yes indeed, two ( or more) sets of "factory" recommendations....depending upon USE.

At this point ...I remain only clinically interested as to how your mind works, and would not desire a another counter-point from you on the technical merits of your objections, since you haven't been able to do so this far !

I'm done...spent....

To the rest of the gang.... Merry Christmas !!!

---Wil Ferch

Wil, didn't mean to get you upset, but I just prefer the factory assumptions over anybody elses including your own.

Just my opinion...

Merry Christmas

You prefer factory's assumptions of "my" ultimate use....

...rather than my own assumptions ...on "my" use ??

Good grief, and good bye !!!!

Have a happy holiday and a mind-expanding new year !!

--- Wil

Alllllll rightyyyyy then.

Awesome, we now agree to disagree.

What were those settings again, I've forgotten.

Don't start....:)

I think that an obviously young guy needs a lot of patience..
And a young guy should sometimes be more respectful.

How 'bout those Seahawks, eh?

How 'bout them Bears too? Won ANOTHER game! :eek:

I have a car similar to 84toy in that I have upgraded shocks, torsion bars, lowered ride height (no corner balance). My car got set up with factory specs. and it understeers mightily in lower speed cornering. Very annoying. A few high speed corners here and there have shown that some oversteer is out there to be found, but it comes with a light feeling front end. The front tires don't seem to "dig in" very well, feeling squirmy. Tires are fresh Kumho MX's on 6/7 Fuchs with 205/55, 225/50 respectively. Also feels the same with Yoko ES100 on 7/8 951 phone dials using 205/55, 245/45 sizes.

Just my experience. Dunno if different alignment will help my condition. Those guys out there tearing up the track with tilted-in wheels might be on to something though........... :confused:

Green Bay is going to have to sit down very hard against Da Raidahs for the SeaHawks to get anywhere...we'll see.

Tonight, on a very special Monday Night Football...

Jw