On midengined cars and driving

[Vantage]

If you're just slowing down to stop at a traffic light, you would only need to rev match for fun. Otherwise you just have to make sure the engine doesn't stall.

[fastliz]

Originally Posted by mrluky

ive always been 'taught' that its better to downshift rather than breaking if you need to slow down for, say an off ramp.

also, look at this video. this guy is definatly letting go of his wheel then grabbing it again when its at the right location

http://ae86levin.free.fr/ueo_style-1.wmv

Downshifting to slow down is NOT better than braking. Despite it being "conventional wisdom," it is incorrect. Using "compression braking" (downshifting to slow down) is harder on your transmission parts, which are much more expensive to replace than brake pads.

In performance driving, downshifting to "compression brake" creates an uncontrolled deceleration which can upset the balance of the car. At high speeds, it's almost a sure way to spin the car.

In performance driving, you downshift ONLY so that you are in the correct gear to exit a turn. This way you keep the RPMs in the fatter part of the "power band."

That's just a quick synopsis of the topic. Do a search, and you'll find tons more.

Mike

[NMRJock]

Originally Posted by mrluky

ive always been 'taught' that its better to downshift rather than breaking if you need to slow down for, say an off ramp.

The brakes are for stopping your car. The engine is for making it go faster. Almost no exceptions.

Originally Posted by mrluky

also, look at this video. this guy is definatly letting go of his wheel then grabbing it again when its at the right location

http://ae86levin.free.fr/ueo_style-1.wmv

Drifting at wild angles is fun, but it is not fast... Letting go of the wheel, or even changing the position of your hands, is usually not advised on a road course.

[David]

Originally Posted by mrluky

ive always been 'taught' that its better to downshift rather than break if you need to slow down for, say an off ramp.

LIke the others have written, you don't want to use your transmission instead of your brakes to slow down. ON the other hand, if you're going down a steep incline, like a mountain highway, you might want to control speed by using downshifting. There, though, the purpose is to keep your brakes from getting too hot. Usually, this isn't an issue, but if someone is really riding the brakes all the way down a long mountain road (and I'm talking about someone overusing the brakes), it could overheat the brakes.

[Trueweb]

Originally Posted by Randy Chase

I have some really bad habits when racing..much worse than thumbs.

Like letting go of the wheel.

It's funny that I've now seen this posted in two places in this thread. A friend of mine always gets harrassed by instructors at track day for just the same habit.

When I ride with him I can't help but laugh. He enters a turn, the car starts to get a little crazy so he lets go of the wheel. The car naturally lines itself back up (I guess suspension geometry does this). He grabs the wheel again as it's spinning back to center. It's hilarious riding with him in an autocross because he's rarely actually holding the wheel. It spins back to neutral so fast he could never do it "by hand". He usually ends up with a top 3 time and that's all classes included. He runs a very slightly modified 240Z.

I haven't seen a good summary on what changes the way a car handles near the limits of traction so I included my experiences below. Very low tech! Of course this assumes you are not changing weight distribution at the same time:

To create oversteering tendencies:
Smaller rear tires or larger front Tires
Larger rear swaybar or smaller front swaybar
Braking or letting off the throttle in turns
Applying enough throttle to break traction on the rear tires in a turn (only affects rear wheel drive vehicles)
Stiffer rear springs or softer front springs

To get a car to understeer:
Larger rear tires or smaller fronts
Larger front swaybar or smaller rear
Applying throttle without breaking rear traction in a turn
Stiffer front springs or softer rear springs

(Please correct me if I'm wrong or add anything I missed. I'm always looking to learn new tricks)

It's really about getting your car out at an autocross and learning it's limits. Then you can try to use some of the simple modifications above to see how it changes the handling of your car. The throttle and brake ones don't even cost any money...

A side note... Applying throttle to a motorcycle in mid-air will bring the rear wheel down, applying the brakes will bring the nose down. Applying the brakes so hard that the rear wheel stops rotating will result in an unfortunate event. Sounds familiar, huh?

My experience thus far with the Elise (Touring package, nowhere near the limits) is that it has very mild understeer unless provoked. An excellent set-up for a street car in my opinion.

[Trueweb]

Originally Posted by David

LIke the others have written, you don't want to use your transmission instead of your brakes to slow down. ON the other hand, if you're going down a steep incline, like a mountain highway, you might want to control speed by using downshifting. There, though, the purpose is to keep your brakes from getting too hot. Usually, this isn't an issue, but if someone is really riding the brakes all the way down a long mountain road (and I'm talking about someone overusing the brakes), it could overheat the brakes.

I'm not a professional or even ranked amateur driver so I'll listen to any advice but my opinion and experience is that a good downshift with properly matched revs will better prepare you for your next move. I believe you should be heel-toe downshifting while approaching a turn. On the brakes hard moving through gears sequentially preparing for the transition from braking to accelerating. If you are slowing for a hairpin turn on a track it might be the difference between 6th and 2nd gear. I would not expect a driver to nail the brakes and then match revs to plunk the trans from 6th to 2nd and exit the turn cleanly.

You need to be in gear before you need to accelerate and drifting in neutral or with the clutch in leaves you with just your tires and suspension to keep handling under control. I'd rather use my engine to slow me along with brakes so I can be prepared to apply throttle to control any handling issues while entering or exiting the turn. Again, correct me if I'm totally wrong.

[GregD]

Originally Posted by MattG

One last note about spinning - Randy's right about having no idea where the car is going to go. However, one technique I've heard of, but thankfully have never tried, is to step on the brakes as hard as you can to lock up all four wheels. At that point, the car will more or less continue in a straight line until it stops.

Please correct me if I'm wrong, but with the Elise's ABS, shouldn't the wheels not lock up and the car will still respond to steering inputs.

Interesting thread, just read it. The above quote was from the second post.

[Randy Chase]

Originally Posted by GregD

Please correct me if I'm wrong, but with the Elise's ABS, shouldn't the wheels not lock up and the car will still respond to steering inputs.

Yes.

[Randy Chase]

As long as you were not driving near the limits, it is not a big deal. The key is smoothness here. You can create instant oversteer at a relatively slow speed, if you mash the brakes in a turn. Not a problem to SQUUUEEEEZE the brakes in mid turn. The more aware you are of weight transfer in the car as you do things, the more things you can do.

[Terminus]

We have been greatly simplifying things in these discussions to make it simple to learn, and give the best rack results for someone new to mid-engine rear-wheel-drive (though most of the pricinpales apply to all cars). Another way of stating the various bits above.

Weight shift from rear to front, either through hard lift of gas, or thorugh adding brake will lighten up your rear end, reducing traction on the rear tires. Sudden weight shift of this type will quickly take you to a state of oversteer, sending you out of the corner backwards.

Just EASE off the gas and EASE on the brakes if you must use them while cornering.

[Vantage]

At the last Club111 event I was getting slight understeer with my base suspenion car on the exit of certain turns, corresponding to my gradual application of throttle. Too much weight transferring to the rear. Very slight understeer on exit seems like it could be beneficial. I've been giving just enough throttle to prevent the car from plowing off line. If some of you guys remember the course, I was full on the power and understeering a bit coming out of hte last gate, shooting for the finish lights.

Would you guys suggest getting on the throttle earlier and harder in order to experience power on oversteer or even a more netural slide? Delaying my throttle application is another option, but that would slowing down, since I'm not exactly plowing.

I'm also thinking of removing a few shims from each of the front corners and seeing what happens.

- J

[Randy Chase]

Justin, remove the shims, that will help.

You have to either reduce throttle or reduce steering input in order to not have as much understeer in the corner. But, experiencing a feeling of the car on the edge of understeer is where you want it to be. Not just hanging the back out.

[Tyger]

Originally Posted by mrluky

and another comment/question:
i drove an elise yesterday and the shifts were smooth and all flawless(stayed under 6krpms). and i was really nervous. but then when i go back to driving my brothers rx-8(not nervous), i cannot get a smooth shift for the life of me. i shift around 6k rpms(9k+ redline). the clutch engages around the last 2 inches of travel(opposite of the elise, almsot) which throws me off a little. i know if i blip the throttle ~3k rpms it would be smoother, but i dont. i wasnt rev matching on the elise, just saying that it was smooth.

Are you talking about upshifting or downshifting??

[CALtd]

Would the shim setup for high speed track be different than AutoX?

[Tyger]

Originally Posted by mrluky

up. ill show you on the 19th.

Okay.
Rev matching is really just for downshifting (to get the engine revs up to the higher level before the wheels put it up there for you). On upshifting your revs naturally drop when you shift, so no reason to try to blip them up first. Just try to be smooth.

[Vantage]

Originally Posted by Randy Chase

Justin, remove the shims, that will help.

You have to either reduce throttle or reduce steering input in order to not have as much understeer in the corner. But, experiencing a feeling of the car on the edge of understeer is where you want it to be. Not just hanging the back out.

Thanks. That is pretty much how I deal with it in the C32. I took a few rides with Neil and Steve, and it seemed like they were able to get some oversteer on entry and sometimes even on exit. Most of the time I could only get oversteer on lift throttle.

Maybe they were trail braking too. Will have to pay more attention next time.

- J

[Tyger]

Originally Posted by mrluky

yah, but if you got the the engine side spinning the same as the tranny, it would be smoother. if u try to grab a fan it would be rough, but if u tryied to grab it while spining on a chain it would become easier

Agreed, but you don't step on the gas to match them on an upshift. Simply taking your foot off the gas and stepping on the clutch will bring the revs down to the range that will match the higher gear, unless you're on the clutch for so long that you go below that range. That's all I meant by being smooth.
Every car has a different feel. You just have to get used to it. When I take the TT back to the city after driving the Elise all weekend, I definitely have to make an adjustment. Last time I started right off stalling the TT!

[raggedy1]

Is there any benefit to our gearboxes to double clutch while we heel and toe? I know double clutching was used in the past before sychronizers were invented, but I've always double clutched my cars along with heel and toeing. Am I wasting my time? I thought I had heard somewhere that double clutching a synchronized gearbox helps save the syhchros from undue wear and tear.


hey! how did i end up in this thread? I thought I was posting on the "found the limits..." thread! oh well...

[Evil Twin]

Originally Posted by raggedy1

Is there any benefit to our gearboxes to double clutch while we heel and toe? Am I wasting my time?l...

No and yes.

Twin

[KLM]

Just read through the whole thread (again) and would like some input my experience.

During my last two track days I have encountered multiple forms of over and understeer which were readily explainable. What has been more difficult to understand and rectify is best described previously by the "pendulum effect" of the Elise in this thread.

On two different days in two different corners of the same track I experienced enough oversteer to warrant (what I thought) a sizable correction. In other situations I have learned a quick, but early correction settled the car. Those saves/catches were generally in slower, tighter turns. In the faster turns, my correction was too large and too late or so it would seem. The response to my attempt to save was tail out in the opposite direction (and another); a car version of a motorcycle tankslapper. What surprised me was during the movements from left to right, while getting progressively smaller angles, there was very little if any "on center" feel. It felt like trying to balance on a knife egde; even the smallest movement had the rear step out. In both situations, the result was a spin. If/When this occurs again, any suggestions? It is clear my gas, brake and steering inputs were incorrect. Should it be "two feet in" if I do not straighten it out after the first correction? That seems like the easy way out and I would like to learn through this experience. Thanks guys.

PS - shims are still in - this is a base car with RAC wheels - contributing factors?
PSS - age of tires were not the determining factor (first event was on new A048 - slide started with lift throttle oversteer / second event six months later on worn A048s exiting uphill, off camber - right rear spinning hard - the fun began when it caught).