Hi guys.

I have hardly ever visited the 911 section here as I am always on the 930 section.

Iirc I run .1 on the front and 1.1 on the rear on the street (I had it set about 5 years ago now). The negative thing to this I noticed was that it reduces straight line braking distances. It seemed more noticable in the wet. Overall I get good tyre wear on the street and the steering wheel has a good feel when cornering, too little camber up front can be felt through the steering wheel imo. Cornering is excellent and improved from the stock 0 front camber.
Also at the same time I had the car corner balanced and also had the castor set to max the holes would allow.
Can anyone comment if for the street having even more castor and less camber would give me better braking and still allow great cornering with good feel at the steering wheel ? Can I rob Peter to pay Paul ? Or is there a problem doing this ?

Great topic.
TIA
My car is a euro ROW zzz '84 model year 3.2 carrera sport coupe.

 

-2 front, -2.2 rear. Tire temps are typically about 10F more one the outside (than inside) on the front, 5F higher on the outside of the rear. A little more camber is needed for next season.

 

What about the settings for the best ride and all around use?

 

Keith: We had lengthy discussions about that, with many different people, and decided that it just wasn't worth taking a chance on. Our conclusion was that once the arm was tweaked the metal was affected in an unnatural way. On one side of the bend it was compressed, the other side was stretched. In each case we felt that the metal was already weakened, so even if heat was used to regain the arm's original shape the damage was already done. We made our scrap metal guy happy, they didn't pick up chunks of aluminum that large often!
Pete

 

Pete,

Thank you for the input. That was my concern with a part of this type. I have seen manufacturers do some pretty aggressive tweeking on the assembly line. It is amazing how calibrated a hammer can be in the right hands. I'll probably just hold on to them as last gasp repair parts.

 

Excellent point, and you've answered it yourself. Alignment settings, not unlike most (if not all) mechanical parameters, are the sum of a set of compromises. Suspension stiffness vs compliance, engine HP vs. longevity, we could go on forever.

Yes, 0.0 camber will yield shortest braking as you are maximizing (and making more "even" across the tread) your contact patch onto the asphalt. But the "cost" is paid at the moment you bend the car into a turn, weight transfers, and your contact patch on the more-critical outside tire is now diminished considerably. Hence, the desire for negative camber to "even out" and maximize the contact patch on those outside tires (which are doing the lion's share of holding your car to its line) as the car "rolls over" due to the lateral load. Robbing Peter to pay Paul?

Castor will not affect braking distances, but will affect steering "weight" and feel, both on-center as well as cranked into a bend. Castor also affects the steering wheel's self-centering tendencies. As a general rule, more castor will get you more on-road feel with more self-centering, but at the cost of a heavier wheel and more "twitching" (or should I say "movement") of the wheel with road irregularities, especially when cornering.

Toe in (or out) will also affect/determine straight-line stability which, of course, you must weigh against your desire to actually turn the car. Which is why avid auto-X guys will have markedly different toe settings (and camber, too) as they "want" to rotate their cars more quickly and don't have the long straights to have to worry about high-speed stability; your dedicated "track" guy, OTOH, would find such a car twitchy, uncomfortable, or even dangerous (so to speak).

Sorry if this is a bit long (and pedantic), as I obviously am trying my best to avoid having to work right now But the short answer (too late ) is yes, all settings are a compromise. The trick is to find the best compromise which suits your needs.

...ok,ok, I'll get back to work, sheesh.

Edward

 

Hi Edward,
Thanks for your reply. I understood all that you said, thanks.

I was just wondering if I could run 0 camber and run a lot more castor. Then when I am braking I have near 0 camber and when I am cornering (providing I have the wheel turned, which as you know isn't always required in a 911 ) the castor will give me some negative camber.
Would this work at all or not ? It costs far too much money to do this to find out it doesn't work
I note the 964 cars have a totally different setup and I think they run negative castor compared to us !
Ah, I see you also have a 993, so maybe you can explain how that setup works.

I would love a 993 rear setup in my 930 I have seen pics of a car that was done.

Note, 930 not a 964

TIA

 

Anyone ?

TIA

 

Does lowering a 911 automatically increase negative camber in the front and rear? My previous car, an e36 m3 was lowered and it greatly increased negative camber...i was doing -1.5F and -2.5R on that car.

 

Jack says "for the street". Does this mean that you realign to different settings for track days. If so, what sort of numbers are we talking now?

 

Only the front camber will increase. Also the toe will change.
On the rear only the toe can change. Shouldn't be much change.

All depends on how much lower you want to go.

If you lower the front you could fit spacers under the rack. This may save you having to have your toe checked if you know it is fine at present.
You will have to have the car cornerweighted after adjusting height.

 

My set up.

Alignment spec Front: Caster 5.7 degrees, Camber -0.6 degrees, Toe 0.05"
Rear: Camber -1.0 degrees, Toe 0.05"

More camber = higher tire wear rate

I agree that it is too aggressive for the street. What are your corner weights?

 

Nathan: Everything changes when ride height is altered, and requires alignment equipment to re-set all specs. Regarding those specs, factory settings deliver the best street performance. Any changes to those settings mean that you will compromise something else - such as your wet braking. With a bit more negative camber your car will perform better in ideal track conditions, but lose a little distance under wet braking. When you lower the car it enables you to achieve more negative camber. The toe will also change at all four corners when the car is lowered, so consideration must also be given to that spec with regard to what you expect the car to do. Regarding caster, the 964 spec is 4 degrees 25' (+15', -30'). Edward's post above is very well put, and if you're going to stray outside the boundaries of acceptable practice you should set up an arrangement with an alignment shop, start a log, and begin experimenting.
Pete

 

Thankyou for the replies.
I just looked in the manuals at wheel alignment specs for the front caster it is 6 degrees so not a great difference, less than I thought. I thought there was a more dramatic change between the 911 & the 964 than that.

IIRC I had my camber set at -0.1deg front and -1.1deg at the rear. I know I had the caster set to max but I have a feeling it was only at the max. spec. recommended. I did not have any holes slotted !
I can tell you that I noticed the difference in straight line braking, it was not as good.

 

Pete, we actually have one of the said jigs to measure the straightness of the rear control arm. I had no idea it was so rare. Supposedly we used to have both the SWB and LWB version, but we could only find the LWB one, which didn't help cuz the reason we were looking last year was to find which of our stacks of SWB banana arms was the straightest for a customer's '59 356A which we converted to early 911/912 rear suspension and 5 spd 901 . . . . will be very fun if we ever get time to finish it!

Sorry to revive such an old thread . . . .

---Chris A.