IcemanG17

I know Devek sold kits to pin the weissach axle in place to it functions like a conventional suspension without the passive toe changes....but how do you tell if you have one?

My racer is quite loose......more than any other 928 racer I have ever driven, I am wondering if the pinned axle would cause this?

Anyone have pics of a pinned axle?

terry gt

it was a 1/4 " bolt in the front joint of the lower arm

Hilton

Um.. look at it?



(pic from this old thread: https://rennlist.com/forums/928-foru...this-bolt.html)

Lizard928

What are your alignment settings?

How low is the car? Any bump steer mods?

What is the valving on your current shocks, and spring rates to accompany them.

IcemanG17

no bump steer...but I haven't noticed it,nor has Sean who drives my car a lot....

alignment is slight toe out (1/16") in front with LOTS of camber...at lower ride height above 4'...at current ride height (from bottoming out issues) its around mid to low 3'.. Rear is around 2.5' camber with a slight toe in 1/8 inch at about 145mm ride height (measured from stock locations) tires are 275/645-18 all around...i have early S4 upper A arms with the longer lower OB lowers..which increases the camber by quite a bit

Shocks are heim jointed Bilsteins with 800lb front 400lb rear springs with valving to match....I just had shocks redone last year.... Valving is about as stiff as they can make it for rebound...

Lizard928

Have you measured the range of motion on the ball joints to ensure there is no binding at maximum compression?

James Bailey

he said it was loose....not under steering.

I do wonder if the loose over steering feeling might just be from the newly built transmission with the 80 % limited slip setup that I think you have in it

john gill

Is it loose all the time ? ie entering or exiting the corner
on trailing throttle ?
heavier throttle?
DId I see one side toe in and 1 toe out ?

IcemanG17

yes I have a Doc Brown rebult G28-03...he did not specify how tight he made the LSD, just that it is better, which is good enough for me..... In terms of handling it works like this....I know at all times that if I add steering it will TURN....for example, when in turn 2 at Thunderhill....about 7 seconds at 75-80mph around 1.5+G....if I don't like my line I can tighten it up, at any point, but the tail probably will come around....its the same in almost every corner....I always have more steering available, which I like quite a bit really....

In terms of putting power down on corner exit, the car is great....it really gets off the corners well....excellent really...for such a modestly powered car... It takes a very heavy foot to kick the tail out under power.....most of the "loose" comes from steering input

justaguy

Brian
Reattach the rear sway bar and see what it does to your times. Loose feels fast and it's fun to drive but I think you'll be faster with the rear bar attached.

My yellow car has the pinned rear suspension and no sway bar it is extremely difficult to drive but the 550 hp might have a lot to do with how loose it feels.

I'll try and get you a picture of the pinned axle.

James Bailey

It will be interesting to reattach the rear bar.....it may well make it worse. how much neg camber in the front ? What front bar are you running ? tire sizes front rear ? tire pressures ?
What are you doing with the throttle as you change your line , turn in more ?
what are your corner balance numbers ???

FredR

Brian,

If you are pulling 1.5g's you must be doing something right. All things being equal, it sounds to me as though you are simply undertyred at the rear. With relatively lightweight weight and such rubber up front, surely you would need something closer to 310 section on the rear to keep up with the front grip?

Presumably you have a stiff front bar controlling things or is the lack or rear links the arbiter of such?

Regards

Fred

James Bailey

If as he mentions he can turn in more pretty much anywhere then his front has MORE grip than rear has lateral grip if the rear end starts to come around if he tightens the line. The trick is to fix the problem / balance the car but not screw up the other end of the car in that quest

IcemanG17

I run about a bit more negative camber in front.....around 3.5 front to about 3' rear....the tires are 275/645-18 Pirelli DH slicks.....same tires as the Ferrari cup and GT3 cup run....but I get them used

Spring rates are 800lb front (soon to be 1000) and 400 rear....front bar is a devek bar set to about medium....rear bar is stock but has adjustable "ott" links....

An interesting bit of data is while the tires are "square" with ideal pressure of 30psi hot the tire temps are quite different.....the fronts are barely at 160f, the bottom of the ideal range according to Pirelli and the rears are just at 200f, Pirelli recommends 230f max....

Another interesting bit of data is I do run staggered setup on occasion, when my pirelli supply is low...I run the yokohama GT3 cup tires of 240/640-18 front and 280/650-18 rear, all hard compound. I don't like this setup, while it handles well, it will understeer much more in slower speed corners that I don't like.....in high speed corners it seems fine...but I don't drive this setup very often since its seans tires-wheels.....I would imagine the smaller front tire will increase its temps, to make it more even with the rears?

The next test is to install the 1025lb front springs.....in theory that should reduce steering a bit, but the main reason for the heavier springs is to reduce bottoming out at high G, high speed corners... If the rear axle has the devek pins......do I just remove that screw to make it function like a normal 928?

justaguy

Brian is your rear bar connected?