Teach Me: Driving RWD

Let me start by saying that pretty much all of my driving in anger has been in FWD cars, and low powered ones at that. I have a pretty good handle on the dynamics of a stockish FWD car at the limit, how weight transfers, and how to correct and apply power to get myself out of a corner.
Recently I bought a 911 and I now realize that I know nothing. The dynamics of mildly overcooking a corner and getting the car back in line are way way different and I don't know what the hell is supposed to be going on. As near as I can tell, if I'm into a corner hot and I start under steering, I'm screwed. More brake and weight transfers to the front and I get even more under steer. Throttle in any significant volume just pushes the already sliding tires unless I give it enough to start the rear moving out too, then the whole damn car is messed up.
I think, and this is where I need your help, that I need to manage my corner entry speed much more carefully with RWD. If I do that, then I can roll on throttle earlier, and more, because I'm not screwing with the available traction to the front tires as much as I am with FWD. Is this really what I'm feeling? Is this what I should be doing?

On a 911, you will not only be learning rear-drive but rear-engine also.

Bout to say, its not about rwd, its driving a rear engine car. 911s are a bitch to get rght. Can't drive in anger, must think.

I have nothing to add, except I know what you're going through. 10 years knowing the feeling of FWD, its a bit of a learning curve to retrain your brain for RWD.

I have a feeling my Miata is a bit tamer beast to learn these lessons on thankfully.

The benefit of a 911 is you can get on the throttle much earlier on exiting the corner than in many other setups. There was a great feature about driving a 911 (I believe it was in GRM) that I remember reading over the last year. Someone with a better memory than mine will remember it.

Because the wight distribution and driven wheels are backwards, its to my understanding that you more or less drive a 911 backwards from a FWD car. I.E. DO NOT LIFT.

You're probably used to trail-breaking (as I am) to get the car to rotate. Tough habit to break. I'm no racing genius, but start by braking in a straight line. Be easy on the throttle on exit. I've driven 2 911's at the limit. I love the idea of modulating throttle to get the ass end to do what you want it to, but it does require finesse.

I'm actually quite excited to get the 911 on an autocross course and start to figure it out, but it's more than that. My giant crew cab pickup is also RWD, and despite adding sway bars as thick as my leg and upper control arms that give me oodles of caster, I have perpetually believed that it handled like poop. Except a bunch of what I thought was simply incurable poop on the truck shows up on the 911 the more I try to drive it like a FWD car. In fact, when I really concentrate on driving the truck with deliberate smoothness and not overdriving the front tires on corner entry for a couple of days and I hop back into the 911, as long as I apply the same techniques, the car is brilliant. That's why I'm thinking it's a FWD/RWD difference and I need to think about what the hell is going on.

poopshovel wrote: You're probably used to trail-breaking (as I am) to get the car to rotate. Tough habit to break. I'm no racing genius, but start by braking in a straight line. Be easy on the throttle on exit. I've driven 2 911's at the limit. I love the idea of modulating throttle to get the ass end to do what you want it to, but it does require finesse.

Yes! Trail braking suddenly sucks and I have been trying to figure out the dynamics of why. I'm always initiating the turn under braking with a FWD car, but I really can't do that, can I?

The best way to drive a 911 was described to me as "Use the brakes, then use the weight"

Meaning, 911s have great brakes, so use them, then think your way through the corner, and pick a line that allows you to use the weight sitting over the rear wheels to get great acceleration out of the corner.

And keeping on the throttle would be key to keeping the rear end planted.

Oddly enough, the more I modify the RX-7, the more it seems to want to drive like that. It hates cornering unless it's under power, and then it's awesomely predictable. But you want to wait just a tick longer than in other cars before you feed in that power or it turns into massive understeer.

Brake in a straight line. A 911 is one of the most difficult cars to trailbrake.

Late apex.

Slow in, fast out. Repeat after me: slow in, fast out!

Do not go for throttle until you know you won't have to come off the throttle.

Have fun!

In order to turn under throttle I need to be doing things way way earlier then? And then I make up for that by being able to carry a bit more corner speed because both ends of the car are participating and the fact that I can actually accelerate out of the corner because the weight shifts toward the driven wheels under acceleration?

mazdeuce wrote: In order to turn under throttle I need to be doing things way way earlier then?

Not really turning under throttle, more like throttle after turning. Generically speaking for RWD, turning under throttle leads to understeer - you're unloading the front tires. The 911 has the added bonus that lifting mid-corner can give you an interesting "swing the hammer" effect and reapplying power can be problematic when the drive wheels are sliding.

Now picture these chassis dynamics with an engine with turbo response like a stick of dynamite - light the fuse, wait a bit, then WHAM

So brake in a straight line, apply just enough throttle to get the car neutral while turning in, then increase throttle as the corner unwinds? With the added 911 bonus that if I find myself partway through the corner going too quickly I can't lift or I'll die, plus if I get on the throttle too soon I risk having the car swap ends and the worst thing I can do then is lift, because I'll die.

What year......the old ones were more white knuckled so to say

90, it's a 964 so I've got coils in back and struts up front.

Jaxmadine wrote: Bout to say, its not about rwd, its driving a rear engine car. 911s are a bitch to get rght. Can't drive in anger, must think.

Im going to have to agree with this based on the experience i have with racing RWD. Ive done almost all my racing (99% autocross) in FWD cars, but the times i have co-driven other people's RWDs, i have usually been able to beat the owners' times in their own machines, and i think that alludes to something you already mentioned: a lot of it is not about which wheels are driven, it is about understanding where weight is and how it moves, and it becomes more and more important on cars where it moves a LOT. This is one reason why i think family cars are great things to learn on as they typically have very exaggerated weight transfer. Conversely it becomes more difficult to figure out a car the more subtle its body motions are.

So, considering i came up with FWD and have had nearly 0 problem jumping into a RWD and going fast, i think in your case it IS more about it being rear engine than RWD.

Really, the car ive had the most problem jumping in and learning to drive was an XP class stripped turbo CRX with something like 75/25 weight distribution. Another case of weight distribution and transfer (lift throttle oversteer) being a bigger issue than the driven wheels. I still went like 3 seconds off FTD in it on my last couple runs. That car would have been a lot faster if i had thrown a bag of concrete in the back and swapped the back coilovers out for stock!

Don't ask Ryan Dunn. (too soon? sorry )

In reply to Aeromoto:

Judging by the skidmarks, Dunn likely would have spun, rolled, and possibly survived in an older more oversteer happy/demanding 911. Rather than understeering into the woods and hitting tree dead on at >100mph.

Sounds like 911 issues, not RWD. Every other RWD car I've driven what you're trying to do (trail brake, etc.) would all be the correct procedure.

Everything I have seen of 911s, they are just not that great of handling cars. The Spec 911's all concede that the 944Spec cars are way better handling. At a Porsche Club auto-x with a series of big decreasing-radius turns, driving a Miata completely annihilated the 911-type cars because they just could not modulate the rotation with the throttle like I could in a Miata.

Wow. I've got to drive a later 911, as what you're describing is the polar opposite of my early 911s, which begged to be driven like a FWD car: trailbrake to get it to rotate to the angle you wanted it, then back on the throttle to keep it there. Sounds like the later cars they dialed all the lift throttle oversteer out of it to keep it "safer" for the doctors that were buying them...

I think some of it is learning to be smoother with the throttle as well. When I autocrossed my E30, I initially used my FWD driving style. I spent a lot of time pointed in the wrong direction after spinning off course. With low power FWD cars (a MINI or TDI in HS) I'd use the go-pedal like an on/off switch and I could use the inherent throttle-on understeer to slide the car where I wanted it to be (running ST tires, not r-comps). Getting a RWD car to do this seems to require a much more subtle touch. While I'm generally pretty good at late-apexing, with a FWD car it seems you can be a little sloppier with the throttle whereas a RWD car will punish you if you're off. I think it's better to err on the late side of throttle application and slowly try to get on the gas earlier as you get used to the car.

Unfortunately, the E30 has never managed to stay in one piece long enough for me to be able to practice and learn.

Practice running the Porsche on a racing sim. The GT Legends racing sim has some great physics on the 911's. You will discover all sorts of nuisances that are specific to the 911 after a few minutes of driving near the limit IMO.

Learning to drive RWD is a piece of cake. Learning to drive a 911 (especially older ones) is hard. Good luck.