It's impossible for me to comment on your car(s) in particular, but what i was talking about, was the 155/147/156(GT) TS, and FWD cars in general. I'm no expert, just trying to convey what (i think) i've learned
So feel free to correct me, I'm still very much learning!
I hope we can agree though, that as a rule, all FWD cars reaches the traction limit front wheels first, and thus understeers naturally, and all RWD reaches the traction limit rear wheels first, and thus oversteers naturally. Please disregard any electronic aids, like those found in modern RWD cars, like BMW's. They only understeer, because the electronics takes over, and because this is the safer option in a critical situation.
I've also added stiffer Anti Roll bars and suspension to the rear end only of my TS/V6, but it still understeers when pushed(As expected) The front end of both 147/156/GT is still comparatively very heavy compared to the rear, so i think there is little to be done unless you really get drastic, and start shaving a lot of weight off the frontal area.
Are you sure what you are experiencing is not trail throttle oversteer or trail braking ? This is normally found in RWD cars, but can also be found in well balanced short wheelbase cars.
I have to admit, that i never tracked a 147 TS (only tried a 147 GTA, and a 155 TS) But if you say your 147 oversteers, then i guess it oversteers
. But what is causing it to do this? Will a 147/155/156 TS oversteer, by simply adding a stiffer rear Anti Roll Bar? I think not, but..
Maybe the shorter wheelbase of a 147 would make it more easy to get to oversteer? same for the Sud..? There are lots of other reasons which can make your car(s) oversteer, Basically what makes the car do one or the other is the tyre grip. If for whatever reason your rear wheel grip goes before your front wheel grip, then you got oversteer no discussion.....But my own gut feeling and experience with the 156 tells me,( i might be wrong here) that it is not possible to get a FWD car like the 147, 155 or 156 to naturally oversteer unles you compromise on safety and comfort in a big way. It really must require a very loose rear end or some super duper grippy front tyres/soft front dampers), to get these cars to change their natural understeer tendancies. I dare to suggest, that if your 147 car naturally oversteers, then it is probably out of balance, one way or another, which makes the handling suffer in other areas.
Can i ask how your 147 behaves under hard braking in corners, or even in a straight line? Does it have VDC to help keep it in line? if it does, why does it not prevent oversteer? Are you running same type of tyres, front to back? are the front tyres very worn compared to the tyres? What shocks/springs are you using, Are they all fullly functional? Are you keeping a constant throttle pressure, or do you lift off, perhaps ever so slightly?
On a different note, this thread has gotten me thinking about the whole understeer thing again. I am wondering, if what i have been doing in regards to tyre pressure is actually correct? Last couple of track days, ive tried to increase the rear tyre pressure, and keep the front tyres more or less normal "street" pressure.. Would it in fact not make more sense increasing front wheel tyre pressure, rather then lowering it?
Im fairly sure to reduce understeer you:
soften front end suspension/stiffen rear end suspension
lower front end /raise rear end
But tyres...beginning to doubt if what i was told makes sense.. ?
Originally Posted by alfasud.ti
First of all sorry for the offtopic but i want to reply to Peter.
One question here: is "lift-off oversteer" the kind that is induced by easing off the gas pedal? If so i will have to disagree again. The kind of oversteer i was talking about is not induced by any sort of action from the driver; infact it comes "naturally" when the car reaches its grip limit. The rear wheels just start "sliding" sooner than the front ones.
I am under the impression that "oversteer" by definition is the situation when the slip angle of the rear wheels is bigger than that of the front wheels. The driver experiences this as the car turning "more" than what the angle of the steering wheel would suggest. And this is exactly what i am experiencing.
Have you ever driven an Alfasud? Have you noticed that when entering a corner hard enough it has the tendancy to turn more sharply that what you would expect from the angle of the steering wheel? That's what i'm talking about.
The first time i experienced it was in a hairpin. Of course if you have really too much speed *any* car will understeer, regardless of whether it is fwd, rwd or even 4wd.
IMO a fwd car with an "oversteering" setup will only oversteer at its absolute limit and at that time it will enter a state where its "balance" is very unstable. For instance if the driver gets scared and lets go of the gas pedal the car will most likely spin. On the other hand a powerful rwd car can be forced to oversteer way below its limit and this is a lot safer of course. But even most powerful rwd cars (like BMWs or even Lotus Elise's) are set up to "naturally" understeer at their limit, until their driver puts his/her foot down on the gas pedal. Racing cars are setup like this too i think or else they would be totally undriveable.
PS: Maybe we should take this discussion to another thread?