utkinpol

Can anybody with extensive auto-x experience here try to summarize a (possible) set of core differences between approaches to making a fastest possible line at auto-x compared to how it gets explained at DE events?

I sort of start to see by now where it does intersect and what is a bit different considering no one wants to teach newboons at DE how to drive 10/10 and what it takes to maintain car control in a slide if it happens as most of those students will end up with car in a wall - but can anybody here with solid experience on both track and auto-x try to summarize it all - I mean core differences to overall approach in trailbraking, car positioning, weight transfer, etc, all those nice little details? If it sounds as a possible thing to summarize.

Scootin159

For the most part, all of the vehicle dynamics are the same. The way I like to put it is HPDE is like autocross in slow motion. You're doing all the same stuff, just all your inputs are more spaced out.

Joe Weinstein

I'll just type some stuff until I have to get back to work, so I may miss stuff. Do ask
questions after...

Autocross is at speeds and locations where the danger is essentially eliminated, so it
allows/requires rabid attack modes. This allows one to hone the 10/10ths edge by
shooting for it instantly and trying to stay there 100% for a minute of concentrated
action, with more decisions per second to be made than just about any other racing
sport, and instant feedback, which helps learning. Going to 10.1/10ths just means you
spin or hit a cone, and only going to 9.8/10ths means you lose, and see it in your time
by the end of the minute.
DE is much more inherently dangerous, so just about no one really goes 10/10ths for
one whole corner, let alone a whole lap. It's always at best 9.8/10ths to leave that little
margin for error. Sure, for most of the turn you may be cornering at 10/10ths of what
the car can do, but how much did you leave on the table in the braking zone, and did
the line you hit lead you to track-out right at the edge of the paint strip, with no room
for error or even to lift, or did you have a foot or more of track left to the outside? Also,
inherently for high speed corners you must get the car's speed correct for the corner
*before* turn-in, so there is more smoothness needed for track runs, and the car
takes a set for a comparatively long time in a corner. Autocross is all tight stuff where
trail-braking, steering with the brake and throttle takes up most of every corner. Again,
in autocross you are on the edge all the time, and because it's at low speeds, the relative
power you have from the car is a much bigger factor. In DE, even a hot car can only
moderately (comparatively) alter it's weight transfer with throttle, compared to autocrossing
a V8 or turbo car where you simultaneously attack to the very edge of adhesion at every
instant, and have a car that can break the tires loose with power at any time if you tip the
pedal in 5 degrees too far or don't dial out the steering exactly in sync with adding power.
That develops very sensitive control.
In DE you always get to feel the power of the car and can enjoy catching and passing a
car (if/where permitted) because of it. You very rarely get unbridled acceleration in autocross
for more than a second or two, so if you're used to feeling the power of your turbo on every
onramp, autocross may feel like you're a heavyweight boxer trying to show your moves with
roller-skates on, and there will be some attitude adjustment when tiny delicate miatas and
civics beat you.
Slides in DE are huge red flags of something that went basically terribly wrong, and get
you lots of immediate negative attention, if not big bodyshop bills. Slides in autocross are
on a gradient, with some smaller ones expected or even necessary, or at worse a sign of
someone not quite at exactly 10/10ths, but in no way different than someone who smoothly
lost .3th of a second on the same corner by only being at 9.5/10ths. In autocross you try to
*stay* between 9.8/10ths and 10/10ths all the time.
DE allows you to do the same corner innumerable times and easily lets you know very well
(eventually?) where you want to put the car and to concentrate on how the car reacts to how
you're trying to do that, as opposed to autocross, where you usually get 3 shots (and one on
cold tires!) at a complicated corner whose entry and exit are intimately affected by the prior
and subsequent corner, which requires a sophisticated (compromised) line because of that,
so unless and until you develop the extra ability required by autocross, to intimately learn and
remember an autocross course's 15-30 interlinked and inter-dependent corners and absorb
the differences in surface and camber changes, and develop an exact plan of attack during
the one or two times you get to walk the course, you will always be compromised while driving,
spending a half-second here and there wondering where the car should be, that you won't be
driving your best.
And of course, autocross is real competition. Everyone is trying to be absolutely as fast
as they can at all times. DEs have a broader mix of attitudes, with some simply enjoying the car
at 7/10ths, some thinking they're winning by passing the 7/10ths folks etc.

And some of the skills and attitudes learned in autocross are not always appropriate for
DE, but will come up during emergencies, such as unexpected spins in front of you or
a deer jumping out in the road. I would be worried about an autocrosser being too
aggressive initially on track, as soon as the higher speeds no longer intimidated them.

It's definitely a nicer environment usually in DE, on a real race track with pretty corners
and checkered flags and people wearing fancy race suits and stuff. Autocross photographers
have to choose their angles carefully so there are no port-a-potties or dumpsters in the
background.

Jim Michaels

I think almost all of the general principles are the same. The finer differences seem to me to be due mostly to the following.

First, Part of the contest is to see which driver can figure out the specifics of how to minimize his time in his car on this particular course. Each driver has only a few runs to figure it out, and properly execute his strategy. Even after walking the course several times, I know I'll still have to revise my initial plan according to what my car "tells me" during the first and subsequent runs. Sometimes I finally figure it all out only after I've completed my competitive runs (we sometimes have "fun runs" afterward). But I'll never see that exact course again.

Second, the turns are tighter and the straights are shorter. Novices have a tendency to go too fast in the slow sections (thus unsettling the car), be hesitant to maintain full throttle as long as possible down the straights (don't trust late braking), and not look far enough ahead to determine where they need to be when they exit that section. A bit of oversteer can be scary in fast sweepers on track, but, in autocross, a little oversteer can be used to get through the tight sections quicker.

Almost all track principles still apply; including what you mentioned (positioning, weight transfer, etc.).

2002M3Drew

I see them as two completely different disciplines. The car control skills that are developed in autocross are essential for DE (and street), and the sense of momentum gained in DE is helpful in autocross. Smoothness on the controls is important in both, as is looking ahead/ocular driving technique. Other than that, I don't see the two lines crossing.

Goals in DE are developing a line that is both fast and repeatable, lap after lap. The line in DE is about carrying the greatest amount of momentum, with one lap leading directly into the next. A tight or pinched line is going to be, in most cases on a road course, slower than a lap where the driver can use all of the track and carry the most momentum. The faster, straighter line through each corner will also preserve the equipment better than a tighter line with higher lateral g-loads (and tire temps). The consequences in DE at higher speeds of a line that is pinched or not smooth can be not only slow, but dangerous. A car brakes and accelerates better when the wheels are straight, and it is more likely to be slow or succeptible to spins when the wheels are turned. If you watch a car qualifying for a race, you will see a wider. more flowing lap with faster speeds through corners than you will see in the actual race, where positions are being defended by taking a tight line.

In autocross, it is almost impossible to overcome distance added to a course by driving a wider line. Many autocrossers believe that you add 1/10th of a second per cone for every extra foot the car is off the cones (assuming the cones are on the proper line of a given course). Throughout a run, those 10ths add up quickly. On a skidpad, you need to driver several MPH faster for each extra foot you add to your radius. While car control and smoothness are still important, a tight, concise line is essential to be competitive. Since each run is a separate event, thre is no consideration for a "flying lap."

I've instructed many dedicated autocrossers in their first DE events, and I usually notice how they dive into corners early and tend to throw the car around more than average. It may display good car control, but it isn't fast. Conversely, when DE people try their hand at autocross the first time, they usually try to find ways to "straighten" out the course as much as possible, even if that means adding distance by taking a wider line. This is not fast in autocross, as you just don't have enough "track" overcome the distance added to your driving line.

cohare

^^ its funny you mention this, you are certainly right. I have done a fair amount of autocrossing with the intent of learning the car in order to be confident before getting on the track. A couple things that I have learned and been instructed after getting my first few track days under my belt:

- Autocross has taught me a tremendous amount about car control, even when I get a little out of shape at the track, there is no panic just minor corrections to fix, this comes from many spins and saves in autox. Instructors are usually pretty surprised at how little track time I have considering my car control

- Throwing the car around - In autox I was used to very quick inputs (braking, throttle and steering), which is not good on the track. I have been working on smooth vs. throwing the car into corners like I do in autox. This is a work in progress for sure.

- Learning the track - one person recently told me this and I believe it to be true. Since you have to learn an autox course every time you go, learning a track is much eaiser, its almost like you train your brain how to learn new tracks. Now I get out on a new track and after a few runs, I feel like i pretty much have it down and can focus on perfecting rather than just learning the track.

- One of the biggest differences I found was you have to have big ones - going 60 on a fast autox is nothing like 110 and braking for a hard turn on the track. The thrill is different, you arent competeing like autox but, both are very challenging in their own way.

The differences are imence but skills certainly translate.

00r101

All the above is good. Nice ideas from nice people! Let me add that a big difference between the two is speed. The same car will act very differently near the limit of adhesion at 40mph compared to 80mph. Besides the fear of risk that speed might engender, there is a very different feel. Rarely does an autocrosser get into a 4 wheel drift whereas it happens more frequently in DE where the corners are long enough and the speeds high enough that a driver can gently approach the edge of adhesion and balance it at all 4 corners.

Another big difference is that autocross is a timed competition but DE should be a learning event only. I know some people time laps and compare their times. But DE is like fishing where you catch and release and don't take pictures. When you get home you can tell any damn story about how fast you were. In autocross the results are in black and white. I am not trying to put DEs down in any way but the thrill of competition is not there as it is in autocross. DEs have other compensating advantages and create a different sort of adrenaline rush, that's all.

utkinpol

thanks to everybody who contributed, great info.

I have done only 3 DE events so far, it is great fun and generally I have to work on same issues - primary one is throwing car into corner too aggressively, overly late braking with propagation of braking into corner itself and overall difficulties with selection of proper braking distances from different starting speeds - like how hard to brake after main straight going from redlined 4th gear into 2nd gear. they all preach 'slow in fast out' when my instincts really go 'fast as possible to limit of traction in and even faster out'. at least at auto-x you kinda need to be at that 'edge' in the first third of the corner. instructors at DEs do not seem to appreciate this approach at all.

plus on braking itself is is difficult to understand how it should be altered - at autox it is pretty much an immediate application of maximum pressure to pedal with gradual removal of pressure, at DE instructors insist on very gentle increase of pressure initially then going full hard but again, kinda 'smoothly'. 'smooth hard braking' - when I start thinking about all that in real time it usually results in over shooting my braking zone.

so it`s a lot of stuff to work on but it more or less comes together now.

genikz

This sums up my thoughts, with much less work, so thank you!

I've been autocrossing and attending DE's for 3 years now. I love the ever-changing course layout of the autocross, and it does help keep me sharp, but only to the extent that I can threshold brake without locking up, roll onto the throttle without breaking traction and get an overall comfort in the car while pushing.

However, when I get to the big tracks (Cal Speedway, Buttonwillow, Streets of Willow, Willow Springs) I usually spend the first couple sessions trying not to turn in too early and smoothing my steering inputs. The brake modulation is the same (for me anyway) and application of the throttle is usually close, but adapting to the later apex you tend to need for the proper line of many corners is tricky.

One other significant difference is when and how the car lets go. In an autocross, you'd be lucky to hold 60+ mph in any one corner, yet at many DEs you'll likely find many high speed corners. When my rear end steps out at an autocross, I typically countersteer in a quick snapping motion to get it back in line. That abrupt input is usually not what you need in a long sweeper should the back start to come around. You still need fast hands, but SMOOTH fast hands WITHOUT over correcting. Any mistake there is amplified as the speed increases. That has been a challange for me, but I'm slowing ramping up my speed at each DE and it's becoming easier to push closer to 9/10ths. I think I need a race scenario for the ***** to push 10/10ths...

Grantsfo

Im a firm believer that there are distinct differences in driving styles and lines taken in DE and AX.

DE you are carrying much higher speeds and have more room out of corners to maximize speed going into a straight. Well executed turn in DE will result in much higher speed at end of a straight. You are on straights with those slighly higher speeds as well that all add up to reduced lap times. Typical DE rewards very smooth and fast corner exits where you use lots of track to get that maximum exit from a turn.

AX the straights are much shorter or nonexistent and benefit from high corner exit speeds while important arent going benefit you quite as much as they do in DE. Often features are linked in rapid succession unlike anything you would encounter on a track. Often taking shortest route is the quickest route in AX. This does mean suboptimising lines you would typically take on the track. Its funny when you hear very expereinced track guys that may not have much AX seat time coach newbies while waling AX course. Talking about late apexes and getting wide just before turn entry. I usually do exact opposite. Early apex's where I can cut distance down. Rarely swinging out to get better angle of attack on turns.

Driving styles are differnt as well. On track i stay very focused on being very very smooth, Letting car take me out of turns with as little resistance on wheels as possible to maximise turn exit speeds. In AX it all about getting your car to turn. I find myself purposely unsetting balance of the car in AX to get rear end to rotate sometimes, Its only fastest of ax courses where I can use a little of track driving style.

Also AX speeds are much lower and your cars ability to maintain grip at slower speeds is much greater so taking suboptimum road race line isnt likely to impact you as much as it would at higher speeds where you truly will have hard time getting car to stick.

If I cut 20 feet off an AX course and can be close to your speeds I know who will win. Tough thing is knowing which corners will reward a early apex and which ones wont. I do hillblimbs as well and knocked huge amounts of time off my runs when I started to go against traditional wisdom of track lines. Learned this by closely watching top notch hillclimber and he would shoot up inside into certain slow turns where I would swing wide and shoot hard into apex and drift all the way out. He would fly into same turn almost at the apex slam on the brakes then come out just a little slower but he covered far less ground and speed differential wasnt enough to justify taking time to swing wide.

I think I explain it to my wife best while track is zen like, AX is like being in a fight.

NJ-GT

AutoX and DE are radically different, too much to explain.

AutoX, Time Trials, Club Racing, Pro Racing is the same, except sharing the track with other cars in Club and Pro Racing ( and some Time Trials formats).

Same dynamics, same approach, same lines. The pavement, road course and car determine the driving line.

There are autocross turns where one needs to add distance to keep the high speed, there are racetrack turns where the shortest distance works better than the DE line.

DE is nice for beginners, and slow drivers in slow or fast cars.

A very nice example of adding unnecessary distance (DE line) on a turn is on the NASCAR speedways, most cars can handle a tight line, because their lack of power don't require braking to enter the speedway turn, a DE driver would enter wide, hit apex and track out, slowww, that's 1 second lost (or more).

Then there is the pace, at autoX/TT/CR/Pro pace is good, DE pace is slowww everywhere.

porrsha

Horse pucky! There is one ideal line through a corner. That line is the quickest line that leaves you in the best position for your next corner.

whiskey52

i started DE's about 4 years ago and only started AX about 2. at first the thrill of the higher speeds kept me out of AX, but gradually i figured track time is track time. the AX has allowed me to understand the limits of my car regarding lateral adhesion, braking, (especially hard, late braking) an apply these findings to the DE track (with a heavy dose of respect for the speeds involved). one of my yardsticks in AX is the difference between my times (stock engine SC with suspension/brake mods) and the top cars (TT's). i figure the 1 sec diff in total time can be attributed to the quicker acceleration on the short straights. that means that our "time in the turns" is about equal. the extra hp of these cars isn't quite as significant as in the DE's. as i've moved up the ranks in DE, i'm on the track with some of these cars now, and find that i can hold my own in the corners, carrying more speed thru the section. once the course straightens out i just wave all the high hp cars by. i find benefits from both forms and have developed an better feel and understanding of the cars dynamics a little quicker than if i'd stayed with only one discipline. just mho

Grantsfo

Dont think we disagree on the quickest line. However think you are going to need to define "best position". LOL!

Joe Weinstein

For a given corner, the best line for car A may not be the best for car B.
This is especially true for autocross, where the speeds are low enough
that some more powerful cars can spin their tires at will anywhere
around the corner, while some weaker but lighter cars in the same
class, can't. Weak FWD cars have to maintain speed where moderately
powered AWD cars simply minimize distance, and powerful RWD cars
have to do whatever they can to get a late apex so they get straight and
on the gas ASAP out of the corner.