964RS - first drive...

[Laurence Gibbs]

Certainly the adjustment made would make sense.you had too much oversteer which you reduced by making the back grip more than the front (in relative terms) restoring a little understeer. I fully agree with your thinking about requiring a hint of understeer at those corners this is something I have heard before. As best i understand it convention is that you look to the opposite end of the car to where your problem lies i.e. too much understeer stiffen the back too much oversteer stiiffen the front etc. So i would guess the same effect could be acheived by softening the front and leaving the rear as is which is almost (i think) what i was suggesting in the first place. I don't know though if the cornering speeds would be as great with it that way round? Assuming my thinking is correct!

 

[PhilRS]

ORIGINAL: Laurence Gibbs
too much understeer stiffen the back too much oversteer stiiffen the front etc. So i would guess the same effect could be acheived by softening the front and leaving the rear as is which is almost (i think) what i was suggesting in the first place. I don't know though if the cornering speeds would be as great with it that way round? Assuming my thinking is correct!

hhmmm, with the same hypothetical car, oversteer if front roll-bar softer than rear roll-bar; understeer is front roll-bar is stiffer than rear roll-bar.

BTW, I have seen 964 RSs on a dry track with full soft roll bars front and rear (which is a typical rain set up). These cars had been set up by reputable people... who might not want the owners back in the workshop with a rear-damaged car []

In one "good" story of wrong set-up, I had my black RS fitted with H&R dual-springs all round by a respectable racing outfit. However, to lower the chassis to CUP specs they had fully compressed the "helper" spring!

 

[Laurence Gibbs]

I am pretty certain i have this round the right way. Here is a quote from Adrain Streathers book "to decrease understeer stiffer rear sway bar to decrease oversteer soften rear sway bar" I think I could quote from a few others if I had the time.but heres one more "too much stifness at the rear will cause oversteer" Bruce Anderson.
The helper spring is another widely misunderstood term. There are helpers i.e. they help increase spring rate and there are tenders (I may easily have this round the wrong way) the tenders (assuming i got round it the right way) simply stop the spring from falling out of it's seat when the main spring is unloaded they are afaik designed to be fully compressed when the car is at ride height, they do have other reasons for being there i think. The full technical reasons for the helpers or tenders would take a fair bit of explaining and I could'nt do it easily without a lot of referal to books on the subject.

 

[RSGulp]

And to think all I said was the ride wasn't any harsher than our Cooper S![]

My girlfriend actually rolled the previous car - a Mini Cooper... ...it lost front wheel traction on a sharp and uneven left bend, went across the other side of the road, up a bank and onto it's roof. Maybe the RS and Cooper standard suspension set-ups have more in common than I first thought!?[]

 

[Laurence Gibbs]

an extra quote "The key to the design of both helper springs and tender springs is that they are wound from flat wire. Thus when loaded the springs compress until they completely bind up into the shape of a small disc. The helper spring in particular is meant to be entirely compressed when the car is at static ride height. A tender spring may not be fully compressed at static ride height but will quickly become so as the suspension goes into bump. When a helper spring is completely compressed it essentially forms a small "spacer" about 3/8" tall. A tender spring is made from thicker wire and so does not compress quite as flat (around 1" to 2").

 

[Laurence Gibbs]

ooops sorry yes just been thinking about it and softening front would have reverse effect. Don't know what i was thinking. Rest of theory correct though Hopefully.[]

 

[lee fulford]

Rich....I don't suppose you thought your original question would get so technical....I can change that.

PhilRS....I had the same kind of experience happen to me on the road......The same piece of road I drive again and again in many different cars (some quite hairy)

I was traveling round a right hand corner....not a sharp or long corner and not particularly fast but the road dipped and I was heading for a brick wall momentarily when the front wheels hit terra firma I was off again in the right direction but not after checking my pants.

Fact is I generally find the RS suspension near on perfect for my kind of road work but that frightened me. The Turbo with is 25 profile tyres is probably as bumpy if not worse but much more compliant and forgiving if that makes sense. For that reason you need to be constantly alert when driving the RS...Respect it for what it is.....a track car but easily useable everyday.(except when the salt man's been out)

 

[PhilRS]

ORIGINAL: lee fulford

PhilRS....I had the same kind of experience happen to me on the road......The same piece of road I drive again and again in many different cars (some quite hairy) 

I was traveling round a right hand corner....not a sharp or long corner and not particularly fast but the road dipped and I was heading for a brick wall momentarily when the front wheels hit terra firma I was off again in the right direction but not after checking my pants.

I cannot believe that we are the only two drivers willing to explore the boundaries of RS handling!? []

 

[SimonExtreme]

ORIGINAL: PhilRS
I cannot believe that we are the only two drivers willing to explore the boundaries of RS handling!? []

Nor can I. I have actually tried to reproduce this reported behavior and haven't managed it! I have had the car do many other things, mainly to do with the rear moving around and the best view straight up the road being through the door window[]

Having said that, the car does move around underneith you rather a lot and I would certainly say that, in the words of "The Time Warp" you can get a "jump to the left and a step to the right". However, I have never found that placing my hands on my hips and pulling my knees in tight has helped at all. As for the pelvic thrust, trying that when I have the harness on would drive me insane, so I won't be doing the time warp again! (Yes, I have finally lost it [])

 

[Laurence Gibbs]

Phil,
given the above quote i'm really interested in your reasoning on why having the spring compressed was wrong?

 

[carreraboy]

ORIGINAL: PhilRS

ORIGINAL: lee fulford

PhilRS....I had the same kind of experience happen to me on the road......The same piece of road I drive again and again in many different cars (some quite hairy)

I was traveling round a right hand corner....not a sharp or long corner and not particularly fast but the road dipped and I was heading for a brick wall momentarily when the front wheels hit terra firma I was off again in the right direction but not after checking my pants.

I cannot believe that we are the only two drivers willing to explore the boundaries of RS handling!? []