Handling question
10-23-2007, 07:05 PM
#16
here's a pic of my ABS pump, drivers side of the front trunk. See the 4 lines going into the bulkhead? 1 for each brake caliper w/ M220. 2 of the lines go to the back, they come through 2 p/v off the pump, see the 2 cylinders bolted to the ABS?
non M220 will have only 3 lines, 1 w/ a p/v going to the back brakes which are on a single circuit.
10-23-2007, 07:06 PM
#17
I'm Still Jenny
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ABD is a sort of stability control through the differential. Brakes one wheel or the other, I believe. Man, those Germans just LOVE acronyms..
10-23-2007, 07:13 PM
#18
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Thanx for the pic, it really helps, and I deffinitely know i dont have ABD, because the car can go sideways for quite a while. A bit snappy but that's what you get with a rear engined car.
10-23-2007, 07:22 PM
#19
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Whether or not the car can go sideways won't tell you if you have LSD/ABD. I've had 2 993's with ABD and only saw the ABD light go on 1 time; on ice at 2 mph. It's pretty much useless.
10-23-2007, 07:27 PM
#20
[QUOTE=2ndof2;4705911]The car was properly aligned by someone at the porsche dealership including KT, but as I wrote earlier I have virtually flat camber in the rear. QUOTE]
Do you recall your camber (F and R) and which sway bars you have? Lowered to RS height, 1.2 degrees might be the absolute minimum you could go in the back and, if you dialed in a matching amount of camber in the front, it might induce a bit of oversteer. A little lighter sway bar might keep your butt planted.
Do you recall your camber (F and R) and which sway bars you have? Lowered to RS height, 1.2 degrees might be the absolute minimum you could go in the back and, if you dialed in a matching amount of camber in the front, it might induce a bit of oversteer. A little lighter sway bar might keep your butt planted.
10-23-2007, 07:30 PM
#21
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haha wow, well, I've never had any light on while going sideways but when I get my car I'll check to see the ABS pump. But what I´ve learnt from the cars that I've driven is that they wont go sideways smoothly or for long without an lsd. I've read that Open differentials slow one wheel down, like a primitive kind of stability control.
10-24-2007, 03:07 PM
#25
Three Wheelin'
Thread Starter
[QUOTE=jimbo3;4706251]
I don't have the numbers handy on the camber settings but they are the factory M030 bars. There's a range for RS spec and my car is at the top of that range in the rear so I probably have less camber than a car at the bottom of the RS range with all of the standard (non-RS) factory suspension bits.
The car was properly aligned by someone at the porsche dealership including KT, but as I wrote earlier I have virtually flat camber in the rear. QUOTE]
Do you recall your camber (F and R) and which sway bars you have? Lowered to RS height, 1.2 degrees might be the absolute minimum you could go in the back and, if you dialed in a matching amount of camber in the front, it might induce a bit of oversteer. A little lighter sway bar might keep your butt planted.
Do you recall your camber (F and R) and which sway bars you have? Lowered to RS height, 1.2 degrees might be the absolute minimum you could go in the back and, if you dialed in a matching amount of camber in the front, it might induce a bit of oversteer. A little lighter sway bar might keep your butt planted.
10-24-2007, 05:15 PM
#26
Drifting
haha wow, well, I've never had any light on while going sideways but when I get my car I'll check to see the ABS pump. But what I´ve learnt from the cars that I've driven is that they wont go sideways smoothly or for long without an lsd. I've read that Open differentials slow one wheel down, like a primitive kind of stability control.
10-24-2007, 09:01 PM
#27
Three Wheelin'
2ndof2, so does your rear end come loose or are you referring to a kind of yaw when you turn in hard and really get on it?
Even after my alignment - when I hit my favorite on-ramp in the morning and floor it with some steering input, I can feel the car squat down and then start turning in or yawing a little more than I expect, requiring me to take a tad of steering angle out of it. Driven a bunch of rwd cars but never felt it before.
dave
Even after my alignment - when I hit my favorite on-ramp in the morning and floor it with some steering input, I can feel the car squat down and then start turning in or yawing a little more than I expect, requiring me to take a tad of steering angle out of it. Driven a bunch of rwd cars but never felt it before.
dave
10-24-2007, 10:38 PM
#28
[QUOTE=2ndof2;4709127]
I don't have the numbers handy on the camber settings but they are the factory M030 bars. There's a range for RS spec and my car is at the top of that range in the rear so I probably have less camber than a car at the bottom of the RS range with all of the standard (non-RS) factory suspension bits.
My height is at top of the RS range, also. I can't get any less than 1.4 degrees in the rear, but some can get as little as 1.1 degrees. If you're running with alot of camber on the front, you may want to either decrease it or increase the rear or a little of both. I suspect that you might want to start with a little more camber in back (1.5?) as you mentioned that the car has minimal camber all the way around.
Stock M030 bars are 22 in front and 20 in rear. By itself, this combo tends to induce some understeer. Other than making sure you don't have a problem such as a broken drop link, this isn't likely to be a source of the problem.
I don't have the numbers handy on the camber settings but they are the factory M030 bars. There's a range for RS spec and my car is at the top of that range in the rear so I probably have less camber than a car at the bottom of the RS range with all of the standard (non-RS) factory suspension bits.
Stock M030 bars are 22 in front and 20 in rear. By itself, this combo tends to induce some understeer. Other than making sure you don't have a problem such as a broken drop link, this isn't likely to be a source of the problem.
10-25-2007, 02:38 AM
#29
Three Wheelin'
Thread Starter
jimbo,
Everything is in good shape underneath. I recently replaced the front drop links and the rears look good so its probably not induced by a broken part.
black ice (dave) ,
The car really doesn't yaw that much with the setup I have but if I had to say if it is or isn't when its stepping out I'd say it "is".
There's been some good feedback so thanks guys. My main concern here was that not having LSD was allowing the rear end to get more loose than it would otherwise under heavy throttle in a turn. I think its mostly happening on occasion just due to giving the car too much power and losing traction. Centrifugal force does the rest. Can't say I'm very concerned that I have a major handling problem on my hands but its pretty clear that if I ever wanted to bring this car to the track or drive it near the limits of adhesion very often, a more aggresive camber and probably different sway bars would be in order along with much better tires like Michelin Pilots. The one thing I can say is that even when this thing starts to swing the back end wide it still feels under control and doesn't cause a panic. My 928 was much more prone to understeer so this is a much different sensation. Its all good!
Everything is in good shape underneath. I recently replaced the front drop links and the rears look good so its probably not induced by a broken part.
black ice (dave) ,
The car really doesn't yaw that much with the setup I have but if I had to say if it is or isn't when its stepping out I'd say it "is".
There's been some good feedback so thanks guys. My main concern here was that not having LSD was allowing the rear end to get more loose than it would otherwise under heavy throttle in a turn. I think its mostly happening on occasion just due to giving the car too much power and losing traction. Centrifugal force does the rest. Can't say I'm very concerned that I have a major handling problem on my hands but its pretty clear that if I ever wanted to bring this car to the track or drive it near the limits of adhesion very often, a more aggresive camber and probably different sway bars would be in order along with much better tires like Michelin Pilots. The one thing I can say is that even when this thing starts to swing the back end wide it still feels under control and doesn't cause a panic. My 928 was much more prone to understeer so this is a much different sensation. Its all good!
10-25-2007, 09:54 AM
#30
Rennlist Member
2nd,
I would have a really good mechanic drive it or maybe an experienced DE/race person. Maybe you're really pushing it hard and there is no issue or maybe there is. I tracked my 993 for three years without a limited slip and, other than right rear wheel slip in tight, right-hand corners that resulted in a loss of forward movement, I never had much of a burning desire to get an LSD. In other words, the car felt like a normal, great-handling 993 should without any excess oversteer.
I would have a really good mechanic drive it or maybe an experienced DE/race person. Maybe you're really pushing it hard and there is no issue or maybe there is. I tracked my 993 for three years without a limited slip and, other than right rear wheel slip in tight, right-hand corners that resulted in a loss of forward movement, I never had much of a burning desire to get an LSD. In other words, the car felt like a normal, great-handling 993 should without any excess oversteer.