Evo_Someday

I'm hooked on Autocross and Solo. I know some basics but have some comments / questions which should make for an interesting discussion. I'm going to cover a few concepts as far as I understand them and then lets discuss your thoughts or corrections.

Throttle steer, as I've read and been taught, is when you change the direction of a vehicle in a turn through the use of the throttle instead of the steering wheel. The idea is that throttle steer can be used to keep the vehicle on the correct line without upsetting the vehicle’s stability as much as a steering input (or possibly used in conjunction with slight steering inputs to aid in keeping the right line).

The way I understand it, for throttle steering to be effective in a turn, you must enter the turn at the correct speed. The correct speed being the speed just before the front wheels plow through the turn (understeer). So the idea here is to have all the braking completed as you enter the turn - enough but not too much. Right?

Now, if you’re in mid-turn and you realize your vehicle is too close to the inside of the turn, increasing the throttle slightly will move the weight off the front tires and push the car to the outside of the turn. Conversely, if the vehicle is outside of the line, releasing the throttle a little will force more weight onto the front tires, and the vehicle will steer closer to the center of the turn. AS we all know, too much of a change in throttle could cause the vehicle to spin or slide off the track. Throttle steering inputs are slight and should never be abrupt.

You can further enhance throttle steering with trail braking. The concept of trail braking is that by applying partial brakes in the turn as needed, you will transfer more weight and traction to the front tire as they are forced into the pavement.

To me, this just sounds like a variation on throttle steering. Instead of letting off the gas you just give it brake. The results should be the same should they not?

I have started applying this method by left-foot-braking in the turn as needed to help counter act the understeer and pull the car in tighter and keeping it in line while still being able to keep boost up with my right foot. This sounds to me like the best solution. I need experienced input on this concept.

I haven't masterd these methods yet but my using them I am definately noticing an improvement in handeling and a definite reduction in understeer by left-foot-braking in the turns.

On a side note: a more advanced application of the throttle steering is the throttle lift in a slalom which, when properly modulated, should help to rotate the car around the cone nice and tight. I've not been able to pull this off properly but I would like to hear some opinions and inputs on these techniques and whether they work for you.

Oviously the biggest trick to autocross and solo is getting through the turns quickly. So proper turn entry speed, taking the proper line (late apexing usually faster?), and using the best throttle, steer, and brake technique to get around the turns are key elements I would like to learn more about.

Thanks for any thoughts.

bulletman815

i race karts alot, which are on slicks and throttle steer is very usefull. especially when it is wet becasue the karts do not turn at all with the steering wheel. u have the idea, its all about weight distribuion. you use oversteer to get the car to turn more, but if you use too much of course you will lose speed. the idea is that you unweight the back so that it comes around, this can be done by hard braking or throttle lift depending on speed of course. also if you do not have understeer and you have the front of the car pointing in the direction you want to go, you can give it more throttle so that the back will come around as well. hope that helps but you pretty much have the whole idea.

interms of late apexing, it all depends on the corner, you sometimes have to sacrifice your line in a corner or two in order to set up for a turn leading to a straightaway.

Evo_Someday

I've done some parking lot practices to see if I can get it to rotate under hard throttle. The only thing that happens when I punch it is the turn radius becomes even larger as the Evo's front end pushes out. So that's not the right answer. Maybe it's an AWD thing or maybe just my car's specific setup.

The best way I have found so far to make the turns tight is to brake like a **** before the turn, turn in, then left foot brake to keep it tight then hit the gas and push out through the exit. It doesn't feel like the fastest way around and my times show it.

Now maybe if I get some coilovers and anti-sway bars I can keep it flat enough to slide it around a bit. That would be nice.

fastkevin

iTrader: (11)

The way your car reacts to throttle/brake/lifting is directly correlated to how it's set up. Pitching the car to square off a turn can definitely decrease lap times if used correctly in the correct place. It's not always the quickest way around(even though it can be more fun ).
If you're just getting into driving around a track, IMO, you should concentrate on proper line selection, getting your braking done before the turn, and getting your corner entry/mid corner speed/exit speed down. Kinda like learning to walk before you run, and there's no way you're gonna get quick lap times unless you get the basics down first. Heck, I don't think you ever get to the point where you get the basics down perfect. I've been trying for 13 years or so, and I know I don't. On top of that, the "basic" line isn't always the fastest around, and trying out alternate lines is pretty fun, and when you find one that works, it's also pretty rewarding(just remember not to show your hand until it's go time, and you have no choice)
FWIW, I find pitching the car is beneficial in quick, low-speed right-lefts (or vice versa). Squaring a turn off can also help if you're dealing with a turn that allows deep braking, which is leading to a long straight. You'll sacrifice mid-corner, sometimes even exit speed(pretty rare) to gain speed down the straight. Tons of variables with this, as if it's in a race and you're using it to get around someone, simply stealing the apex from the guy in front of you sometimes works best(although if he's a wriley SOB, he could brake-check you and your screwed). Although you blow the turn by doing it, you blow the other guy's turn even worse as he's gotta lift and steer outta the way
In reference to you writing that picking up the throttle to rotate your car mid-turn if you find you're too inside. Firstly, I would think rotating the car around would be the last thing you'd want if you're too inside. Secondly. you'd have to pick up the throttle a lot to get the back end to break loose. More than likely, you'll just plow the front. I think I might have misunderstood what you wrote. I'll go back and re-read it.
If I'm coming into a turn that I wanna pitch the car out in, I try to get it loose going in. Depending on your car's set up, this can be done by steering wheel inputs, or picking up the throttle early (harder than usual). In a rear engine car (911) you can also get the car rotating by lifting, but I haven't had enough time in an Evo to try it with this car. I know suspension tuners try to get the Evo more tail happy than it comes from the factory(which is a plow)
Edit: You wrote about increasing throttle to take weight off the front to allow it to drift outside. .You're taking weight off the front, which would just plow it even more, correct? Even so, if you're trying to get the car outside, pushing the front would do it. Lighting up the rear, and getting it stepped out is just gonna decrease your turning arc, which in the scenario you describe, is not what you want

MitsuJDM

iTrader: (6)

I love to use trail braking and throttle steering. My Evo loves to oversteer. I come from drive FWD and I'm still used to FWD driving habits which includ many techniques to induce an oversteer situation. Not nessacerly oversteer, but a nice rotation.

I have no issues going full throttle and understeering out of a turn, jst due to my driving habits. I'm not going to say I've never understeered, but it's fairly rare. Evo's love weight distribution. They seem to be very sensative to it.

shuttlegoose

iTrader: (17)

i just got into autox as well and i have been having a lot of trouble with my times. this seems like it could be a pretty good thread, one thing i learned from my instructor was that he said be smooth. i was doing a lot of throttle on throttle off type stuff instead of letting off slowly and getting on slowly and things like that.

fastkevin

iTrader: (11)

He's absolutely right. Learning to be smooth is critical to fast lap times. When you're herky-jerky, you upset the chassis, which makes you slower entering, and exiting corners. You're more likely to spin as well.

Evo_Someday

I'm not sure how you're doing that. Maybe a lot of front camber, low rear camber, rear toe out, stiff rear sway? Maybe it's your springs?

Like I said before, When I try to nail the gas in the turn, it pushes out even more. I changed my front camber bolt from -1 to the -2 position and that has helped a lot but the front still isn't holding like I want it to.

I have a feeling a lot of this is related to my tires. My next step will be to change tires from bridgestone 235/45 to Dunlop Star Spec 245/40 to get better grip and less sidewall roll. I'm hoping that will improve the situation dramatically.

I'll update the thread with my findings when I do so.