Trail Braking/ Controlling Understeer

[BeQuietAndDrive]

Is this an effective technique for FWD cars? I had a LOT of understeer at the last Sunriders event. I feel this is due to:

1. My horrible stock Bridgestone Potenza RE92's.
2. No rear anti-sway.
3. Stock suspension which allows a good bit of body roll.
4. Me still learning how to drive fast properly.
I found myself often times in corners, coming out, having to get off the gas and work on unwinding the wheel slowly in order to overcome understeer.

Does trailbraking help to produce quicker lap times through getting rid of understeer, or would it make my slower through slower corner entry speed?

[Leonard]

To start with, you're fighting an uphill battle. All cars (in stock form) will understeer. They are designed that way because it's safer. Understeer leads to spins and complete loss of control. With understeer, you always have some amount of control of the car and the bonus that you can see where you're going.

I'm not really much of a FWD guy, so I can't really answer whether it would be beneficial for your car.
It was an absolute necessity in my mustang. Of course mustangs (pre05) can't turn to begin with. In that car, I could actually use trailbraking to rotate the back end on entry and power to rotate it on exit.
When I drove Jesse's MR2, I was coming into a turn way too hot and trailbraked out of pure instinct. It came around on me in a heartbeat.
The FFR doesn't react well to it either. I can get away with a VERY limited amount of trailbraking, but the even weight distribution and short wheel base make it very difficult to manage and in all reality thus far, I've found it faster to just slow down to a speed that I can take the turn at and accelerate out.

Back to the scion. I'd imagine it might be able to help a little, BUT I don't know that it'll buy enough corner speed to be worth it... As always, slow in, fast out works.

[mrf582]

Bridgestone Potenza RE92's.


There's your first major problem. when i switched from the re92s to azenis i went from top 50% to top 25%. pax wise i mean. i still have a lot to learn but just tires makes a HUGE difference. understeer went DOWN quite a bit for me with simply better tires. which means i was driving way too fast for the 92s before.

and seriously do this on your next event. whatever you set the front tire pressure to, make sure the rear is ATLEAST 10 psi MORE. so 40/50 45/55 etc. don't worry about the max pressure readings. they are written so max COLD pressure is 51 so hot can go up quite a bit. and even then there is a huge factor of safety built in. so you could run 60psi and not pop the tire at an autoX. just don't drive on the highway like that.

i'm speaking about these tires pressures from experience. you NEED crazy pressure like that for the shitty ass re92s.

[BeQuietAndDrive]

Ah, I see. I knew the stock WRX's ran the RE92's and I know the general concensus is how terrible they are.

At events I've been setting by tires to 32 front/36 rear. I was a tad worried to go over 40 psi, as that what was the stated max pressure.

And yeah, I guess I will just have to play around with my driving a bit. Maybe next event I'll have someone in another FWD car ride along with me to see how I'm doing. I know Loren has a lot of experience with FWD.

[mofugga]

2. No rear anti-sway
that is your main problem with understeer. slap a big bar back there & you'll see a significant reduction in understeer ;-) your tires suck, but no rear sway bar sucks worse!

[mrf582]

^^^i disagree. atleast for WRXs, a completely stock WRX with azenis will be faster than my car with spring/struts swaybar, camber plates on the RE-92s. how do i know this? b/c i've driven a friend car which is completely stock but with azenis.

[PseudoRealityX]

^^^i disagree. atleast for WRXs, a completely stock WRX with azenis will be faster than my car with spring/struts swaybar, camber plates on the RE-92s. how do i know this? b/c i've driven a friend car which is completely stock but with azenis.

agreed with mrf82. You can drive around understeer. You cannot drive around a lack of grip. Hence why STS allows so many more mods, and can only BARELY beat the Stock class equivalent with the same car.

[Muddy]

I used to drive a car with a similar setup. I would trail brake in and accelerate out. Of course, I did get a rear swaybar and some azenis. Both helped the car greatly. :D

[Boxy Rocket]

^^^i disagree. atleast for WRXs, a completely stock WRX with azenis will be faster than my car with spring/struts swaybar, camber plates on the RE-92s. how do i know this? b/c i've driven a friend car which is completely stock but with azenis.

Tires are probably the single biggest performance issue in Autocross. Suspension mods can and do provide great help, assuming one actually understands all the dynamics of suspension components they are trying to change (I sure don't). :dunno:

Plus with a lot of drivers (me included) its hard to tell if overdriving didn't cause a 'driver induced' understeer event. There isn't any car part that can prevent a driver from driving too fast and braking too late.

Actually I'm going to change my leading statement. Tires are the second biggest performance issue in Autocross. The loose nut behind the wheel is the first ....... :-P

[Loren]

I've driven this car. It's not just that you have crappy all-season tires, it's that you have NARROW crappy all-season tires. Get some rubber under the car!

A stiffer rear bar will definitely help a FWD car get around better. And don't forget alignment. Negative camber will always help... and if you want to loosen up the back end, you might experiment with small doses of rear toe out.

But get some tires first.

[kbmwm3]

In answer to your question about trail braking - it depends on the car and the track turn configuration whether it is a benefit or not. Like some other very fast people have said before - most people who trail brake use their brakes too much.
In tight manuevers - usually not a benefit - in open high speed turns - can work well.

First we must learn to drive the car at the limit - before we start modifying - then after we can turn laps back to back winthin a couple of tenths - then modify car to suit your driving style.

Yes - factory aligned car are set to understeer for safety. Get a performance alignment and go have fun.

Slow in - fast out is the golden rule
Do not fight the car - work with it

The biggest mistake people make driving is not using their brakes enough and early enough.
Slow in the slow sections and fast in the fast sections.
Easy to say - sometimes hard to learn.
Learn and you will be smoothe and fast.

Good luck,
Keith
JFF Racing

[RoadRacer]

...a lot of great information here. The only time I trailbrake is when i'm racing karts.

Here is my experience with fwd and understeer.
I ran a big rear bar on my Scirocco, no bar up front, race springs, Bilsteins, 3 deg neg camber up front, toyo ra-1's and seat time. I would not recommend that set-up on the street. The Scirocco was a track only car and I was very comfortable in that car.

In your case, I would recommend better tires, a rear anti-sway bar and seat time.

Patrick

[krekavhts]

Speaking from the side of an FWD guy I can say that yes tires can help, but only to a point. I have been through the whole deal of a stock car with shit tires, then good tires, then rear bar, then bigger better tires with lighter wheels then too real suspension, then to race tires. I have an Integra and that bastard understeered something fierce when I started. Granted I didn't know what I was doing, but once I learned I found that once I started understeering, even with a reinforced massive rear bar, I couldn't stop.

The wheel and tires didn't help that, I was simply over driving and the car couldn't rotate. However Springs and struts made all the difference. Understeer means you have over driven a corner and lost the capacity to decelerate and turn, however by significantly increasing the stiffness of the suspension I found that I was able to correct for this issue with a quick jab of the brakes. It would un-settle the rear end just enough to rotate. Many times this ended in a spin but once I got used to it the results were fantastic. Hell even RWD guys spun the shit out of the car, JIM, but regardlesss it made a much bigger difference in my opinion than tires.

However I would have never understood that without the long transition period of building up a car over 2.5 years. To be fair though its still not that competitive for STS. To damn heavy and not enough power.

[mrf582]

tires can help, but only to a point.

you mean tires are NOT the only things on the car that make a difference in handling?




:-D i keed i keed! :)



of course they only help to a point. otherwise nobody would bother with the suspension. they would just get the best tire and call it a day.

[krekavhts]

Think that up all by yourself :asshole:

[Chriskory]

if you got a set of azenis, you would not be restricted in entry speed
thats the most important thing you can do, it wont give the cool stance coilovers will
but if you plan on being faster, its the only thing that needs modification

the rest is driver

there is so much to learn on stock suspension, stick with it for a while
you'll appreciate the shift to a sports suspension later

[perdition79]

get some adjustable struts, set the front to full firmness, and pump them front tires up to 47 psi. my neon oversteers when you lift off the gas mid-corner. it can swing u-turns better than my camaro now.