Questions: DIY Setting Up My Suspension
 

So I just went through the whole suspension refresh thing. I did it all myself, including caster and camber setting, ride height adjust and alignment. I went with 21/28 mm sway away torsion bars front and rear, new ER bushings all around, Bilstein yellow in rear and green in front, (I believe that's sport/hd). And a whole bunch of other stuff.

I lowered the car a little, I'm at 24.5" to the fender lip in the front and 24" in the back, so sitting reasonably level. Camber at -1 degree in the rear and no toe, and zero camber in the front with 1/8 overall toe-out. I'm running BBS 16x7 and 8s with Continental Extreme Contacts in stock size.

For weight, I've removed the front spare, and the front and rear condensers + compressor from the AC - but I left the lines for now.

Initial impressions were good, slightly stiffer than before, but much tighter. I think the lighter front weight contributed to some squirreliness at speed. I was also getting a constant rightward drift, even though alignment seemed really dialed in.

I then installed the Carrera front spoiler (no tail or duck for now). Instantly the car feels more planted at 50-60, and that endless drift to the right for some reason is gone. It feels *better* at speed, but still slightly weird at above 80. So a few questions:

1. Why would the front spoiler get rid of drift? What could be happening aerodynamically to my car?
2. What can I do to get a little more of a planted feel in the front? Add some forward rake? camber?
3. Is 1 degree of rear camber for fun hill highway driving enough?

I was following a friend in the same car as mine, but with a Carrera tail and coilovers, his camber looks like around 3 degrees and maybe slightly lower than me, but he just looked much more planted in the sweeping curves.

Just looking to see what I can do with the gear I have to make driving my car as enjoyable as possible, and learn something in the process. Last few months doing the suspension have been fun.

Cheers.

The darty feeling at freeway speed is likely due to the toe out.

Dunno why a front spoiler would stop a drift.

I lowered the front end on my car and I believe toe moved in and created a floaty kind of pointy feeling when driving. Wouldn't stay on course. Did the wheel alignment at West End Alignment in Gardena. Perfect!

You should have no toe out the front. Some use toe out for autocrossing, for better turn in. But generally it is not desirable. I would recommend about 1/16" total toe in in the front.

You have a low ride height. As long as you can tolerate the harshness you will be OK.

As far as rear camber goes, I think 1* negative is a good starting point. Pay attention to your tire wear. If the outside of the tire is showing wear you could go with more negative. It mostly has to do with your tires and how you drive.

Like others have said, you should not have tow out on the front. I run about 1/8” toe in up front and about a half degree negative camber. In the rear, I have 1.5 degrees negative camber. Makes for a fun street car...IMHO.

Your ride height is a bit low. Do you have bump steer spacers up front? If not, and you are getting “kick back” through the steering wheel then you might want to consider the bump steer kit.

The other thing you may want to consider is corner balancing your car. I did some suspension work on my 911 during the COVID lockdown and corner balanced it just two weeks ago. The corners were not out to bad, just needed a few corner height tweaks and now it handles very sweet. Lots of threads here on corner balancing.

Happy motoring!

similar set up/parts, not yet on the road yet
 

i have heard many recommendations to drive the car for a "little" bit before trying to set the ride height and corner weighting, "to let things settle",

how many miles? how significant a change is likely.

thanks, chris

Thanks for the feedback all. I set the toe out in the front as per the alignment book that is lurking around here in the forums, but if I need to go toe-in, I will. 100% agree with the corner balance, but I've decided pretty much that this car is going to be 100% DIY. It's a pain and sometimes I hate it, but I always come out the other side a better steward of the car. So until I can afford scales, strings rulers are going to have to cut it.

Re: stiffness and bump steer, it definitely feels stiffer but doesn't seem to "crash," it's just tight all around and I like it unless the roads are just really bumpy, which, usually they aren't around here. I haven't really felt any bump steer at my current ride height, but I do plan on going about a quarter inch lower and realigning as soon as I can borrow a fender roller. I just want to see if adding a little rake helps it all around, I can always come back up.

Thanks for the insight on the camber, don't see any undue wear yet, but I may go that extra half degree. As I understand it, no toe on the back, correct?

Finally, @chrismorse - for the ride height settling, I had it up on stands the other day to install the spoiler and when I set it back down, the front was sitting an inch or so high, but by the next morning it has settled back down. After the suspension install - the torsion bars haven't settled in any measureable way I can see, after about 400 miles of driving. I wonder if torsion bars are different, or if the harder overall spring rate makes them different to say.. lifted trucks, which definitely do settle.

Chris,

You are correct. After completing suspension work, you do want the suspension to settle before corner balancing. I put a couple hundred miles on my 911 before putting it on the scales. I don’t think you really need to go that far for things to settle. Just take it out for a spirited drive on some twisty roads and things should be settled by the time you get home.

Like I said earlier, my car is spirited street Use only. Could I have gotten by without a CB...yes. But being the anal perfectionist I am, I wanted it balanced. 😉

Do a search for Chuck Moreland’s post about balancing using the trianglization (sp) method using a floor jack. That should get you close enough.

Your torsion bars are not that stiff - if you have a level floor, setting the ride height using the factory method (torsion bar centers) should get you close enough on the corner balance. I did that for a decade with a street / track car, and never had issues.

I think a little bit of toe-in in the rear is better than straight ahead.
I also agree that a little toe-in in the front is preferable to toe-out, except for autocross use.

1/2 deg camber difference front to rear should be sufficient for predictable limit behaviour. With your 1 deg difference, and the front at 0, your front tires will not grip like they should at the limit.

Your car rolls 3+ degrees during 1g cornering, with a lowered suspension your camber compensation in the front is near zero ... so the outside front tire ends up near +3 deg to the road during cornering.

I think -1 front, -1.5 rear, is a good street setup. The relatively narrow tires don't wear too unevenly with those settings. YMMV!

Awesome. Thanks. I had the car up and down 100x during alignment. Mainly during setting the rear. Even with grease bags I feel like the rear binds up and doesn’t really shake out without a drive. But if anyone knows better and has a tip - I’m all eyes.

Even re-indexing is a fairly simple job now with an air ratchet and some patience. The only thing that is really THE most annoying is setting up string where it’s perfectly parallel to all hubs. For front and rear I’m using some pipes at the front and back of the car. Then string at hub level. It’s. Fine. But jostling anything or raising the car means I spend ten minutes realigning. I was considering building a wood frame I could make perfectly square then some kind of threaded rod combo to touch the hubs equidistant in front and rear. That way even if I moved something it would just come to aligning the rods to the hubs. But if anyone has a simpler setup. Again. All eyes.

I made my own camber plate with some steel, bolts, and a wixey angle finder and it works fine. I’ll readjust based on the -1 and -1.5 suggested above.

Thanks again.

Once you have a baseline, you can usually make a couple of adjustments relative to it.

So, after the car is in the air and everything is accessible, measure camber with an angle gage on the rotor, and toe with one of those spirit levels with a laser attached, and noting where the dot ends up. Make the changes to the alignment.

For camber, the angle change can be read directly.

For toe, 58.7 * [distance the laser dot moves] / [distance from the hub to where the laser dot projects] is a decent approximation of the angle change.

I found that these angle changes, measured with the car in the air, track pretty well with changes from baseline that you will measure once everything is reassembled and the car was driven for a bit.


Strings are a PITA. Make yourself a set of toe blocks to read toe. I will take some pictures of mine. Doesn't give you toe relative to the car centerline, but in the front it doesn't matter, and I expect the rear doesn't get adjusted too often.

The suspension settling initially is due to the lateral scrubbing the tires need to do.. rolling the car gets rid of most of that. After that, the bushings will need to find their happy spot, and that seems to take some driving. In my experience, anyhow.

Won’t a rotor in the air have positive camber? Or are we just measuring camber on the ground and then adjusting relative to that on the rotor. So essentially I know If my wheel on the ground camber is -1 and I want -1.5 then I put it in the air and zero the rotor at whatever position it is then just set my camber another -.5 relative to that using the rotor as my magnet. Because if so and that actually works that’s brilliant.

fwiw, i set up my green car with just over -1° in front and almost -2° in back. same size TB's as you and lower ride height as my tires are a little shorter.

just changed my rear tires @ 8K as they were worn out. wear pattern was nice and even across the tire. spirited driving with no track time, and the extra camber allows a bit more rubber without rubbing...

Here's a possible solution to your lack of scales. Just a trip to IKEA and some Mr. Olsen ingenuity...

http://forums.pelicanparts.com/porsche-911-technical-forum/629644-home-made-corner-scales.html

Drifting to the right is caused by the crown in the road.. the center of the road is usually higher than the shoulder..so driving strait the car drifts right..

If you just have to input small correction to cancel the drift you're ok

Exactly that. It's not 100% accurate, but it's darn close, and more important it will be symmetrical side to side.
Make sure to keep the level vertical - the more negative camber you add, the more error is added by even a few degrees off vertical. It is also required that the suspension not move vertically relative to the car. Usually not an issue, but if you are using a jack to move parts or if you end up unbolting the shock (rebound stop) for some reason, it's something to be aware of.

In my 30+ years of Porsche ownership I have used front toe out on all cars that have been driven in AX and/or on track. 99% of these cars were also driven on the street commuting.

I have been doing my own set up for 25+ years.

The inventor/owner of SmartRacing Products is a friend-- instructions for SmartStrings and SmartCamber can help even if you don't use those products (which I think are great by the way). And there are some Youtube videos that you may want to watch.

Feel free to send me a PM... I have a lot of experience with set-up.

Looks like a great product. But 500 bucks is bonkers when I can just build my own setup. Appreciate the offer for help tho. Will definitely reach out.

Toe block. You need 2 of them. Any material works as long as it is straight and stays straight.

Bump them up against the sidewall of the tire on each side. The notches are for hooking a tape measure in. Height needs to be low enough to be able to get a tape measure under the car, otherwise higher is better.

Measure front, measure rear. The difference between the two measurements in inches is degrees of toe for each wheel if you make the blocks 26.5" long where the tape measure hooks in.

http://forums.pelicanparts.com/uploa...1596054624.JPG