Differences between FWD and mid engined RWD
Discussion
Up until April, I've only ever driven FWD hatches, this changed when I treated myself to a Boxster S. Before this the last 2 cars of note were a Clio 182 and 306 Rallye.
I'm not sure how much I should be expecting from the Boxster, but after some fast road driving and a (very short) track session in the Boxster, I'm amazed at just how different it feels.
With the 182 and 306 it always felt like I could throw the car into a corner, and it would stick, and both felt really tight and would communicate any slippage early and allow a degree of correction. They would also communicate the fact that they were gripping, with the 182 espcially, feeling like it was biting into the tarmac.
Now with the Boxster, I've not come across anything like this, it just a lot more on it's toes, and the feedback you get from the car is totally different. I'm not sure if I'm just nervous with it still but it always feels like the back end is trying to overtake the front, but not actually kicking out.
I hope this makes sense, it's very hard to put these feelings into words, but I was looking to see if somebody could help shed some light on the things to look for...
I'm not sure how much I should be expecting from the Boxster, but after some fast road driving and a (very short) track session in the Boxster, I'm amazed at just how different it feels.
With the 182 and 306 it always felt like I could throw the car into a corner, and it would stick, and both felt really tight and would communicate any slippage early and allow a degree of correction. They would also communicate the fact that they were gripping, with the 182 espcially, feeling like it was biting into the tarmac.
Now with the Boxster, I've not come across anything like this, it just a lot more on it's toes, and the feedback you get from the car is totally different. I'm not sure if I'm just nervous with it still but it always feels like the back end is trying to overtake the front, but not actually kicking out.
I hope this makes sense, it's very hard to put these feelings into words, but I was looking to see if somebody could help shed some light on the things to look for...
Sounds like you've driven much nicer cars than me! I've had an Audi 80 (urgh) FWD, a Mk1 MR2 Mid engined roadster and I now have a 200SX (Turbo RWD).
Most of the FWD cars I've driven in anger have felt very nose oriented, that it the center of yaw (the point around which the car feels as though its turning on it's axis) feels very much between the front wheels or somewhere in the dash. Chuck them into corners and so long as they stick, the rest of the car follows on round. When they don't stick they understeer. The exceptions to this are the Clio 182 which my cousin has, and the Ford Focus (old and new) all of which actually have a very exploitable chassis that feels very balanced when loaded and you can actually feel the yaw axis move back into the cockpit when you corner at speed within the limits of traction, and the rear suspension helping the car take set and get around the corner.
The MR2 was a completely different proposition. The centre of yaw actually felt like it was behind you, somewhere in the firewall in front of the engine. I always remember feeling like I was at the pointy end of a missile (Ok, they're not very fast....) It would still understeer if you put lock on too abruptly, but with smooth steering it was possible to load the rear suspension to the point where the back end started to swing and you could use the rear to get round corners. The handling was as you say "on it's toes" and it felt like you could lift the car into an "active" stance into a corner and then use the throttle to balance the car to a much greater extent than in any FWD car. Of all the cars I've driven the MR2 communicated the limits of grip the best, and felt like it had the widest envelope to play with as you neared the limits of grip. I can only imagine an elise is like this, only squared.
Finally I've driven my 200SX for a couple of years now. IT is a total hoot, and VERY rear wheel drive. This is exacerbated by the turbo, because if you wake it up mid corner you suddenly find yourself dealing with a bit more torque than you expected. It's pretty awesome. IT also has a VERY active rear end due to complex multilink rear suspension. You can hunker the car down in tight bends and feel the rear steering to great effect, but if you're over optimisic with the throttle it snaps into oversteer. It also does this with off camber roundabout exits or in the wet. You have to be VERY quick and accurate with opposite lock when it takes you by surprise.
SO where does this leave you and your Boxster?
I'd say having fun! You've got the power to make substantial mid corner adjustments with the throttle, but watch out for inducing oversteer either through lifting off too sharply or over applying the throttle mid bend. You also have very pure steering feel and the optimal balance for a car, with slightly more weight over the rear wheels. It sounds like you're getting to know the car well. Porsche don't make a habit of selling cars that are likely to kill their customers, so trust your instincts and the car will tell you what it can do.
I did a very useful excercise on a skip pan once. The instructor got me to sit in an FWD car and then shut my eyes. He then asked me to tell him when he initiated a front wheel skid (understeer) and then again when he had corrected it and regained control of the car. I sat there for a bit and then he said "you can open your eyes, it's all over". I hadn't felt a thing throughout. We then repeated the excersize in a 3.0 V6 Omega (RWD). You could feel the shimmy as the skid developed (oversteer) and again as control was regained. It is perhaps this sensation you're just getting used to, the feeling of the rear of the car translating sideways as the back wheels get involved in the corner. Interestingly there were 3 of us in the car, and to of us said we prefered the RWD as it gave you more information when it skidded, whereas one said she didn't like it because of the feeling of the bcak end letting go....
Most of the FWD cars I've driven in anger have felt very nose oriented, that it the center of yaw (the point around which the car feels as though its turning on it's axis) feels very much between the front wheels or somewhere in the dash. Chuck them into corners and so long as they stick, the rest of the car follows on round. When they don't stick they understeer. The exceptions to this are the Clio 182 which my cousin has, and the Ford Focus (old and new) all of which actually have a very exploitable chassis that feels very balanced when loaded and you can actually feel the yaw axis move back into the cockpit when you corner at speed within the limits of traction, and the rear suspension helping the car take set and get around the corner.
The MR2 was a completely different proposition. The centre of yaw actually felt like it was behind you, somewhere in the firewall in front of the engine. I always remember feeling like I was at the pointy end of a missile (Ok, they're not very fast....) It would still understeer if you put lock on too abruptly, but with smooth steering it was possible to load the rear suspension to the point where the back end started to swing and you could use the rear to get round corners. The handling was as you say "on it's toes" and it felt like you could lift the car into an "active" stance into a corner and then use the throttle to balance the car to a much greater extent than in any FWD car. Of all the cars I've driven the MR2 communicated the limits of grip the best, and felt like it had the widest envelope to play with as you neared the limits of grip. I can only imagine an elise is like this, only squared.
Finally I've driven my 200SX for a couple of years now. IT is a total hoot, and VERY rear wheel drive. This is exacerbated by the turbo, because if you wake it up mid corner you suddenly find yourself dealing with a bit more torque than you expected. It's pretty awesome. IT also has a VERY active rear end due to complex multilink rear suspension. You can hunker the car down in tight bends and feel the rear steering to great effect, but if you're over optimisic with the throttle it snaps into oversteer. It also does this with off camber roundabout exits or in the wet. You have to be VERY quick and accurate with opposite lock when it takes you by surprise.
SO where does this leave you and your Boxster?
I'd say having fun! You've got the power to make substantial mid corner adjustments with the throttle, but watch out for inducing oversteer either through lifting off too sharply or over applying the throttle mid bend. You also have very pure steering feel and the optimal balance for a car, with slightly more weight over the rear wheels. It sounds like you're getting to know the car well. Porsche don't make a habit of selling cars that are likely to kill their customers, so trust your instincts and the car will tell you what it can do.
I did a very useful excercise on a skip pan once. The instructor got me to sit in an FWD car and then shut my eyes. He then asked me to tell him when he initiated a front wheel skid (understeer) and then again when he had corrected it and regained control of the car. I sat there for a bit and then he said "you can open your eyes, it's all over". I hadn't felt a thing throughout. We then repeated the excersize in a 3.0 V6 Omega (RWD). You could feel the shimmy as the skid developed (oversteer) and again as control was regained. It is perhaps this sensation you're just getting used to, the feeling of the rear of the car translating sideways as the back wheels get involved in the corner. Interestingly there were 3 of us in the car, and to of us said we prefered the RWD as it gave you more information when it skidded, whereas one said she didn't like it because of the feeling of the bcak end letting go....
Edited by WeirdNeville on Monday 5th November 09:58
Thanks for the response, and taking the time to make sense of what I was waffling on about!! It's posts like yours that remind me why PH is such a good resource for this kind of thing.
I think the sensation I'm not used to is being pushed round a corner, rather then being pulled round. This coupled with not being willing to find the point at which my new pride and joy breaks traction means I'm forever thinking that the back end is about to step out. The only time I've lost any traction, has been on a roundabout, in the wet, in 2nd and when I forgot which car I was driving.
Where did you do your skid pan exercise? That sounds like it could be the thing for me to do to learn the signals the car sends when the back is about to go.
I think the sensation I'm not used to is being pushed round a corner, rather then being pulled round. This coupled with not being willing to find the point at which my new pride and joy breaks traction means I'm forever thinking that the back end is about to step out. The only time I've lost any traction, has been on a roundabout, in the wet, in 2nd and when I forgot which car I was driving.
Where did you do your skid pan exercise? That sounds like it could be the thing for me to do to learn the signals the car sends when the back is about to go.
Well, first I started a new job, then after a year they let me drive a stripey car, and after I'd driven one for two years without crashing it they sent me on a course to learn how to drive a stripey car very fast without crashing it (hopefully)....
oin short there are much quicker and easier ways to get on a skidpan course! There are a few about, you'll have to search to find one near you.
oin short there are much quicker and easier ways to get on a skidpan course! There are a few about, you'll have to search to find one near you.
Without having driven a boxter, I would guess that compared to the other two fwd cars you're used to the boxter will have a lower polar moment of inertia which will make it respond far quicker to yaw input - it'll feet twitchy and relatively unsettled on the limit if you aren't used to it. The rwd will probably mean that the throttle control is more complicated because you can provoke oversteer with too much or too little power, and when it's oversteering you will have to actively balance the car with steering and throttle input, unlike a typical fwd car which has to be severely provoked to do anything but understeer. You need to develop the rear wheel drive mindset so that your body knows how to react when the back steps out - your fwd reactions will be all wrong.
Skid pans are huge fun, and very useful in learning to deal with skids in the low grip conditions where they are most likely to be induced, but I think you might be better looking at this thread:
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
theboyfold, just sounds like you've got too used to FWD cars really. No crime in that.
Comparitively you can just throw a FWD car into a corner (and 4WD for that matter) but it won't be the fastest way round. RWD is harder, but always has the potential to be faster and is easier to get better corner speed, especially on the exits. If it feels like it's steering from the rear then that sounds exactly right. It's going to feel twitchier, but you're probably going significantly faster round the corners without realising it.
After a while you'll really get to appreciate the extra feedback and will come to rely on it and use it. Maybe you'll get to the point where you'll start to use the on-tap oversteer to get that extra turn rate (like the Stig does on TG). Sometimes you want the backend to overtake the front, a bit.
I think as John Watson once said - if an F1 feels stable and safe, then there is something wrong with it.
btw, you don't need a skid pan. Just find an empty carpark when it's wet. I used to do that all the time in my 2hundy.
Comparitively you can just throw a FWD car into a corner (and 4WD for that matter) but it won't be the fastest way round. RWD is harder, but always has the potential to be faster and is easier to get better corner speed, especially on the exits. If it feels like it's steering from the rear then that sounds exactly right. It's going to feel twitchier, but you're probably going significantly faster round the corners without realising it.
After a while you'll really get to appreciate the extra feedback and will come to rely on it and use it. Maybe you'll get to the point where you'll start to use the on-tap oversteer to get that extra turn rate (like the Stig does on TG). Sometimes you want the backend to overtake the front, a bit.
I think as John Watson once said - if an F1 feels stable and safe, then there is something wrong with it.
btw, you don't need a skid pan. Just find an empty carpark when it's wet. I used to do that all the time in my 2hundy.
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