achris

Hello to all of you from Athens Greece.

I just finished suspension work on my new 1988 911 Carrera 3.2.
Here is what I have installed :
Sanders hollow torsion bars, front 22mm, rear 29mm.
Stock sway bars, front 22mm, rear 21mm with new bushings.
Bilstein front HD, rear Sports.
New Neatrix bushings rear.
New stock swaybar drop links.
New swaybar bushings f/r.
New ball joints front.
Turbo tie rods.
Bump steer kit.
Wheels are Fuchs 7''/8''x16'' with 205/55 and 225/50 street tires.
Corner balanced and aligned : Euro height F:25,5, R:25, Camber F:-1,R:-1,5, Toe F:0, R:+10', Caster 6,05.
The result is lots of oversteering ! After reading older posts, I thought this is a proven combination. Did I do something wrong ? Should I try a rear 18mm sway bar (I have one left from my previous '83 SC) , or go for a 20mm one ?
Any other suggestions ?

Chris
'88 3.2 Euro
('83 SC Euro - sold)

Peter Zimmermann

Chris: If the tires are new give them a couple of hundred miles to break in. Using stock sway bars isn't the right thing to do, you have to get adjustable bars and start using them and tire pressure changes to tune the suspension. Also, in an effort to tighten the front you might consider switching from HD to Sport shocks. Also, switching to 245 rear tires can help. Don't be too disappointed, the hard stuff is done!
Pete

achris

Thanks for your advice. My tires (Pirelli P Zero Asymmetrico) are 1 year old and I used them on my 83 3.0L SC, with 22/28 solid bars, 22/21 carrera sways and HD/sport shocks with excellent results, meaning only slight understeering.

Well, oversteering on slow turns (up to 60mph) makes a lot of fun, but it gets sometimes scary, mostly on higher speed cornering.

I plan to recheck height, because the rear has already settled by 0.5" in a couple of weeks. Then I will corner balance and align again. Would more positive rear toe (toe in) decrease oversteer ? How much more ?

For 245/45 tires I think I need 9" wheels, very hard to get in Europe.
In case of adjustable sways f/r, which ones are better ? Weltmeister, TRG, 20 or 22mm ? Do I get them in Europe ?

Shocks are brand new, so I would rather keep them for a while.

Regarding tire pressures, I already increased rears from 2,5 to 2,6, and wait for the next chanche to escape from work/wife/3kids to drive at the coastline near Athens by night and see what happens.

Next track event is in less than 10 days...

Chris

JV911

Yiasou re, ti kanis?

welcome

Joseph Mills

Chris,

Your new torsion bar combo could bring about a bit of oversteer (compared to stock), but not what you seem to be indicating.

From your tech info, what jumps out at me is the rear toe setting.

I interprete "R:+10' " as "toe out". Do you mean "toe in"? Check with your tech guy.

R toe out is wrong and will produce oversteer. Try zero R toe and see how it works.

The rest of your settings look cool.

Joseph
88 Carrera
AXhound

69 911E -
75 914-4 -

2002M3Drew

You have to be more specific...WHEN is the car oversteering? Off-throttle mid-corner? Under acceleration? If you have trailing throttle oversteer, that is what the car is supposed to do when you set it up the way you have. If you don't like that setup, go with adjusable sways F&R and dial out the oversteer...stiffer front to rear sway bar bias. I wouldn't go with a softer fixed sway in the rear. (A 27 or 28mm rear torsion might have been a better choice for you...)

achris

Yiasou JV911 ! Thank you all for your responses.

Josev, I was not present during alignment, I just ordered the settings. Next week I will go to the shop for alignment and stay there...
I know what I need is toe in on the back, but I thought toe in is a positive value. Right ?

2002M3Drew, to be more specific : I always brake before the turn, to adjust speed, leave the brakes and keeping stable mid-throttle I turn in. At this stage, the front is now very responsive and the back breaks out. Then I have to counter steer to control the initial movement on the back. Is that expected for my setup, and is it right ? I think being neutral, having all four wheels at the edge of grip, is the quickest way to go through a turn.

In case I use all power at this stage, the car will go sideways through the turn, controlled with counter steering, all happening at low speed turns in second gear, but this is just show, not really quick.

My fear is what will happen on high speed turns. Will the oversteer be controllable ? I dont want to test this on the street, and the next track event is in 10 days or so.

Joseph Mills

To me, -toe is toe in, +toe is toe out, like -camber/+camber.

Make sure your shop did NOT set R toe-out... I would suggest to not track the car until this is resolved.

Joseph
88 Carrera
AXhound

69 911E -
75 914-4 -

achris

Thank you for this suggestion, I will visit the shop for alignment again on Monday anyway.

I did a little search and found this :

"Toe (automotive)
From Wikipedia, the free encyclopedia

Toe is the symmetric angle that each wheel makes with the longitudinal axis of the vehicle, as a function of static geometry, and kinematic and compliant effects. This can be contrasted with steer, which is the antisymmetric angle, i.e. both wheels point to the left or right, in parallel (roughly). Positive toe, or toe in is the front of the wheel pointing in towards the centreline of the vehicle. It can be measured in linear units, at the front of the tire, or as an angular deflection."

So according to the wikipedia, +toe is toe in. The factory specs mention front toe +15' (total), rear toe +10' (per wheel), which is slight toe in for both front and rear. I asked the shop for : front 0 toe, due to turbo tie rods, bump steer kit and harder torsion bars, and rear factory spec.

Anyway, I agree with you, the shop could have set toe out, so I will have to check and align again.
Any professional suggestion regarding toe settings ?
Do you agree that more toe-in front and rear would decrease my oversteering ?

During the weekend I will play around with tire pressures, front less, rear more.
I will let you know what happened.

Thanks again
Chris

2002M3Drew

Thanks for the clarification, Chris.

I would say that if you are getting your corner entry speed right and then turning under moderate throttle, and the tail is coming out on you, you probably should be following the advice of the others here and check the rear toe setting. I think 1/16 to 1/8 in per side should do the trick. These cars have a tendency to go to a "toe out" condition under braking, so my experience has been that you want to start off with a decent amount of toe in so that under braking and turning on the track, I am not thrust into a large toe out condition.

Out of curiosity, if you add more throttle (squeeze) when the tail starts to drift, does it take a set or continue to oversteer further? If you are turning without enough throttle, the car with those stiffer parts might rotate a bit...they like to corner under throttle to set the tail.

achris

Thanks for the advise 2002M3Drew.

If I keep the throttle steady after the initial drift, and countersteer quickly, the back comes in again.
If I squeeze the throttle, it continues to oversteer, controlled by both throttle and countersteering, which is a rather unstable condition. This lasts of course until there is no more power to give, with second gear at rev limit when going out of the turn. But the 911 is not ment for drifting. My brother's lightweighted E46 M3 is the better choice for drifting through each and every turn. Throughout the years of driving the 911 fast, I was taught to follow lines on the track, brake only on the straight, going slow in fast out at the turns. Choosing the right entry speed is just a matter of practice.

I have been facing ... 180 degrees rotation in the track at the beginning, with stock suspension and much less track experience. It happens if you brake hard mid-turn, or after uncontrolled oversteering. With 40/60 f/r weight ratio, the back tends to go faster than the front, if it suddenly looses grip. It's not a big deal in second, but it is totally unpleasant if it happens in third with say 80 to 100mph. That's why I want to avoid this initial oversteering.

The '83 SC that I had since 2002, and which I sold last December (solid bars 22/28, carrera 22/21 sways, same Bilstein HD/Sports, same wheels and tyres) used to be mostly neutral, maybe a little bit understeering. Oversteering would require much more effort also due to less power.

I got the blue '88 Carrera in November 2006, and just completed the mods. Thought that Sanders hollow bars with 29mm in the back would produce same neutral behaviour, because of the additional 50kg weight of the Carrera, but ... I got oversteering. Even with the same set of wheels and tyres, which I kept from the SC. Something must be wrong with the alignment.

Anyway, this was a long post, sorry.
I will report after checking alignment again next week.

Chris

Joseph Mills

Hopefully, it will turn out to be a simple correction in your alignment (I would have them confirm every adjustment they made, while you're there if possible).

However, a few other options to reduce your oversteer that you might consider, if the problem is not the rear toe setting.

You can reduce your front camber a bit (in your case 1/2 degree).

For setting your tire pressure, drop a pound in the F for every two pounds you add to R. You may end up with a 10-12# difference F/R.

You could hunt around for a 28mm T-bar. While this is a more expensive option, it would certainly reduce oversteer.

Adjustable R sway is a quick bolt on and less expensive than F (which is a "thru body" style that requires some cutting/welding, etc). This would give you some balancing adjustment that might be all you need.

If you don't mind a bit more engine sound, you can remove 35# from the rear of the car by removing the firewall pad behind the rear seats (which also theoretically nets you 3.5 additional HP).

Adjust your driving style. You mentioned it was hard to oversteer your SC because it didn't have the power the Carrera does. Is there a chance you may be using too much of the Carrera power? Maybe roll on the throttle a bit lighter coming out of turns?

Almost forgot... my Ray Scruggs 911 suspension book states for a competition setting R toe: 0 to -1/8" (Use toe-in if too much power on oversteer).

Good luck!

Joseph
88 Carrera
AXhound

69 911E -
75 914-4 -

achris

Thanks Josef, very informative.

Rear adjustable sway bar is probably the next mod to follow, but again I will have to choose the strength. 19mm or 20mm should be ok for my car, do you agree ? Peter suggested to go adjustable on both front and rear, but I also don't want to cut/weld anything on my car...unless there are other options.

Ed Hughes

IMO, 22/29 should produce a slight oversteer on corner entry. One thing you might try is an adjustable front sway, which is what Tyson Schmidt over on Pelican (I hate saying that company's name!) recommends for a "mildly tracked" car.

Joseph Mills

Chris- IF your car was perfectly balanced now, I think that an adjustable R swaybar would be a good addition to all the other upgrades you have made. You could set it stiff to provide oversteer that would give you good rotation for slow speed AX turns (where our cars tend to push in stock form), and soften it to decrease oversteer for street or higher speed turns for DE's.

However it may not be able to "cure" your car's current tendancy for oversteer, because the higher spring rate of your 29mm torsion bar may just diminish the effectiveness of the swaybar. Make sense? If you choose to get an adjustable R swaybar, I'd go with 20mm.

A F swaybar like Ed suggests is a good tip, and will get you there also (and provide a greater range of adjustment), but I don't think Ed noticed that you prefer not to make the modifications necessary to install a thru body F swaybar. I do not know of ANY adjustable F swaybars for the stock location.

IF it turns out that the oversteer issue is not due to an alignment issue (R toe-out, etc.), I would consider just biting the bullet and going to a smaller R torsion bar. Not what you want to hear I know.

I'm getting ready to start the suspension on my 88, so this thread and your outcome is of great interest to me. I'm planning on a 21/28 combo for AX, because I'm concerned that 22/29 or 22/30 will be too stiff for the street.

Maybe what I need to do is go for a ride in a 22/30 setup and get some direct experience.

Let us know what happens at the alignment shop.

Joseph
88 Carrera
AXhound

69 911E -
75 914-4 -