Auto X techniques

[mojoyaris]

I was at a Test n Tune recently over the weekend. It had a few of the basic elements, Slalom was one of them. This slalom was about 38 paces in between cones so it was a long slalom with about 5 cones.

By the time I got to the 4th cone my brake pedal went hard and wouldn't press down. (Left foot braking technique).

Has anyone had this problem with the throttle on and using the left foot braking technique to balance the car around the cones?

When I took my foot off the brake the pedal went back to normal. The brake would only go hard if I had the throttle on and after a few cones into the slalom.

My other cars wouldn't do this, just the Yaris.

I was wondering if it was something that is built into the car or if it was something to do with my master cylinder or brake lines.

[blueskana]

PM VK about the brake work he's doing on his car, might help out.

[mojoyaris]

Found out that on some of the new cars like the Mazda's when you do left foot braking the throttle cuts off after a couple of pumps on the brake. This is to prevent the average driver from hitting the brakes and throttle at the same time causing and accident when the car lurches forward. For the Toyota, it's the brake that goes hard. Something I hear has to do with the ECU.

There's got to be a way to override this.

[kurokoma-kun]

Originally Posted by mojoyaris

Found out that on some of the new cars like the Mazda's when you do left foot braking the throttle cuts off after a couple of pumps on the brake. This is to prevent the average driver from hitting the brakes and throttle at the same time causing and accident when the car lurches forward. For the Toyota, it's the brake that goes hard. Something I hear has to do with the ECU.

There's got to be a way to override this.

You have got to be shitting me! This sux!

I have been left foot braking on an uphill corner on mountain road I know well--got to maintain momentum cuz if you let it bog there, or worse, puss out and brake, the Yaris will take a looooong time building revs again.

But I don't think I wanna try it on auto-x course now! Though I don't pump, more like slowly apply til I get just enough traction, then let off pretty gradually too...

[whoguy]

Hi..... it's probably something to do with the Vacuum assist on the brake system. If you open the throttle, vacuum behind the butterfly decreases which causes the Vacuum assist to work less effectively.

Normally when you hit the brakes, you would normally release the throttle allowing full vacuum to assist braking.

[mojoyaris]

Originally Posted by whoguy

Hi..... it's probably something to do with the Vacuum assist on the brake system. If you open the throttle, vacuum behind the butterfly decreases which causes the Vacuum assist to work less effectively.

Normally when you hit the brakes, you would normally release the throttle allowing full vacuum to assist braking.

aha! Now that is starting to make sense.

[cali yaris]

I don't use left braking technique, and I keep up with pretty much everyone.

I would suggest, with all due respect, considering the advantages and disadvantages of the technique?

[mojoyaris]

20 years ago when I got into Autox we used to use left foot braking alot in the old Datsun 510s and Corolla's running about 150 hp (alot back then). It worked keeping the throttle on. I've timed it in my Yaris which after using the coilovers I just accelerate through the slalom instead of steering with the throttle. By the time I get to the last cone (lets say it's a 5 cone slalom) I get enough oversteer the rear just tucks around and it gets me to the next element. I never use left foot braking competitively. (besides, I can't get it to work on this car).

In my rally days. I used to left foot brake alot. My favourite usage was getting the car over railroad tracks or bridges where I'd tap the brakes just before the bridge or or tracks. This would unweight the front end and save it from being bashed to hard. This way, it would hopefully last for another stage. Another method for this we used to use it to get it to unbalance the car to get it around a longer sweeper but had to scrub off some speed. Yank the steering wheel from left to right (or vice versa) and make the turn with slight opposite lock and playing the throttle to steer it around (I used this technique for the 710 and 510's which were both rear wheel drive).

I have tried various laps at our last test n tune with and without the left foot technique. (I can use it about 3 times before the pedal jams up.). The difference was mixed. So if it works or doesn't work in getting a better time I'll never know until I can get more runs with experiments. It does do one thing. For times when you want to keep up the revs, need to slow down a bit but not enough to change into first gear.

Another technique I use for tighter turns like a hairpin. I'll use the ole heel and toe technique to gear down and brake for the turn while keeping the revs up for another launch out of the turn. (If you have an LSD this is better, otherwise you're just spinning your right tire!!).

It might work for some, maybe not for others.
I'm old school. Was taught to double clutch and do clutchless gear shifts etc.

So any tips would be helpful with these new cars.

[mojoyaris]

Hi Cali Yaris. I have megan gauges installed just like yours. I installed the oil temp, pressure and water temp. They match the stock dashboard lights perfectly.

[kurokoma-kun]

Originally Posted by mojoyaris

I'll use the ole heel and toe technique...clutchless gear shifts etc.

Clutchless shift works great in the Yaris! But you can heel-toe in it? I have tried and can't do it, pedals are too different of heights...

[nqd]

^ +1
i used to heel toe in my civic all the time...but this car..... its just difficult

[mojoyaris]

get some of those bolt on pedals. they help out alot and make the gas pedal larger so you can put your heel on it.

[cali yaris]

yep, that works, but put the add-on to the gas only, not the brake too!

[nqd]

what would u recommend for pedals?

[reznunt]

Originally Posted by nqd

^ +1
i used to heel toe in my civic all the time...but this car..... its just difficult

not difficult if you have double-jointed ankles and can touch your big toe to your shin

[kurokoma-kun]

Originally Posted by reznunt

not difficult if you have double-jointed ankles and can touch your big toe to your shin

owie

[mojoyaris]

Sparco has nice pedals. but pretty much any set you can get will work.