Let’s Talk Traction

Dannyvandelft

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I learned this first hand the first couple of pulls with TCS off and then on. I definitely bury my foot into the firewall since I’m so used to driving low Hp/ Tq cars. I am very guilty of that :lol:. I guess I better practice restraint and learn how to modulate.
Yup! We have peak torque at 1600 RPM so if you just mash the throttle the tires will lose traction quickly.

Pretend if there's strings going from your steering wheel to your throttle pedal. As you turn the wheel, it pulls the throttle pedal up. As you straighten out, the pedal goes down.

A tire has a certain grip limit. Viewed from above it looks like a circle with a cross in it. Kinda like a compass.. Forwards is acceleration, backwards braking, left and right turning. Of you ask a 100% grip for acceleration, any sideways movement loses traction. If you steer full left and ask 100% grip, any throttle or braking input loses traction. If you ask 50% steering grip, you have 50% left to accelerate or decelerate. You steer or accelerate/decelerate past 50%, you lose traction. That's why as you reduce steering input, you can accelerate harder, and vice versa.

That's what makes the best racing drivers. They can "feel" the limit of the tires and coordinate inputs on the edge of the grip levels.
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Escapist

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Just to be clear, a single push of the TCS button turns off VSC, right? And a 3 second push shuts off the entire system. I've been driving with a single push TCS off assuming it disables VSC cause that crap creates too much brake dust.
 

piper1

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Yup! We have peak torque at 1600 RPM so if you just mash the throttle the tires will lose traction quickly.

Pretend if there's strings going from your steering wheel to your throttle pedal. As you turn the wheel, it pulls the throttle pedal up. As you straighten out, the pedal goes down.

A tire has a certain grip limit. Viewed from above it looks like a circle with a cross in it. Kinda like a compass.. Forwards is acceleration, backwards braking, left and right turning. Of you ask a 100% grip for acceleration, any sideways movement loses traction. If you steer full left and ask 100% grip, any throttle or braking input loses traction. If you ask 50% steering grip, you have 50% left to accelerate or decelerate. You steer or accelerate/decelerate past 50%, you lose traction. That's why as you reduce steering input, you can accelerate harder, and vice versa.

That's what makes the best racing drivers. They can "feel" the limit of the tires and coordinate inputs on the edge of the grip levels.
I know this is really for a topic in a different section but does go along with what you're talking about here. Have you left foot braked in your supra yet? It's something I started when I had my MK3 and continued through the years in my z4. There was an auto crosser article I read a long time ago that made the comment in an auto since there's no clutch why not put your left foot to better use than mashing the kick plate. During my test drive in a 2020 mkv around January / February I had left foot braked the whole time, of course never pushing the car but when I made the comment towards the end of the drive about it to the sales person riding shot gun they had no idea and said the ride felt so smooth.
 

Dannyvandelft

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I know this is really for a topic in a different section but does go along with what you're talking about here. Have you left foot braked in your supra yet? It's something I started when I had my MK3 and continued through the years in my z4. There was an auto crosser article I read a long time ago that made the comment in an auto since there's no clutch why not put your left foot to better use than mashing the kick plate. During my test drive in a 2020 mkv around January / February I had left foot braked the whole time, of course never pushing the car but when I made the comment towards the end of the drive about it to the sales person riding shot gun they had no idea and said the ride felt so smooth.
I've always heel/toed since I've always autocrossed/tracked manuals and used my left foot for clutch operation. I haven't tracked my Supra yet since I only got it in October.
 

65sohc

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My car has an e50 tune. R888R's in the rear are a huge improvement over the stock tires. They definitely "sing" and I wouldn't put them in the front for that reason, though you quickly get used to the sound from the rear. Adding "road-hugging weight" went out with the Pinto. Also bear in mind that none of these tires is rated for sub 60 degrees.
 

MA617M

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Just to be clear, a single push of the TCS button turns off VSC, right? And a 3 second push shuts off the entire system. I've been driving with a single push TCS off assuming it disables VSC cause that crap creates too much brake dust.
No, it just raises the threshold. VSC is still there, but it allows greater slip angles and a bit of wheelspin
 

Escapist

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No, it just raises the threshold. VSC is still there, but it allows greater slip angles and a bit of wheelspin
Ahh, thank you for clearing that up. Going to see how the car feels with everything turned all the way off. Will update assuming I don't crash it.
 

65sohc

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Toyo R888R 305/35-19 works much better than stockers.
 

underdonk

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My '21 3.0 is stock. Maybe my expectations are too high, but I have been quite disappointed at the performance of the stock tires Toyota/BMW decided to put on this car given the amount of power it's putting down. Especially so in a short wheelbase vehicle that has a good bit of body roll upon cornering (all factors for consideration when attempting to put power down with the suspension loaded up). This is amplified when the tires aren't up to temperature. Even in a straight line with cold(ish) tires the amount of wheelspin you can get with the electronics off is surprising. I'm lucky that my car is just a toy so I don't have to worry about streetability, but tires are at the top of my list of upgrades. I imagine better shoes - especially when combined with a set of swaybars - will fix any number of issues.

EDIT: This will be critically important for someone who is planning on autocrossing and hoping to be competitive in any manner, as you're not going to be able to get these things up to anywhere close to optimal temperature prior to a run.
 

Evolution

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EDIT: This will be critically important for someone who is planning on autocrossing and hoping to be competitive in any manner, as you're not going to be able to get these things up to anywhere close to optimal temperature prior to a run.
My auto-x experience with stock tires is this. I get 3 laps per session.

1st lap - feels like you are on ice
2nd lap - tires are warm enough to halfway hook up
3rd lap - tires overheated and back to feeling like driving on ice
4th lap - normally a non timed fun run - full drift mode

Actual track wheels and tires are on order but who knows when they will arrive. Doing another race this weekend and another one in 3 weeks, all on stock tires and not planning on setting any records...
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