Is there a proper term for this on track behavior?

[Jamestl]

So I was at Autobahn outside of Chicago this past weekend and had a great time and learned a lot. One corner was a little baffling to me and I'm not sure what's the right term to describe it. On most of the corners, the car takes a set, and I can basically control the direction with changes in throttle, with more throttle mid turn = more track out, and less throttle with tucking in, which makes logical sense to me considering the physics of weight management. In this particular corner, however, the opposite is true. When I'm pretty far mid turn and heading for the second apex, more throttle equals more tuck in but in a very controlled and non-threatening manner, which was completely unexpected, and not what I've found at other corners.

Car is running 225 Direzza Z2's, and I have Bilstein B8/RCE Tarmacs with rear LCAs but otherwise pretty stock.

Is there a term for this behavior? It's not what I would normally equate with oversteer but maybe that's the correct descriptor? Does my description of it make sense? I can try to upload a video if helpful but not sure how clear it'll show that since it's not a dramatic shift in car direction.

[CSG David]

Depends on the corner. Is it banked? The grip may be different as well compared to other corners. Perhaps you are starting to learn about throttle steer.

[justinco]

On camber turn? Off camber turn? Different surface? Incline or decline?

The car is not going to behave exactly the same on every turn. Dynamics of the turn can make a big difference if dramatic enough.

[Jamestl]

Originally Posted by CSG David

Depends on the corner. Is it banked? The grip may be different as well compared to other corners. Perhaps you are starting to learn about throttle steer.

No banking, pretty flat, so not different vs. other corners in that regard. Grip may be different (not sure how to measure that aspect of it). Throttle steering is something I'm doing at the other corners so i don't think that's it. Again if the car is just more neutral rather than pushing a little bit when throttle is applied then I'd understand it easier since that may mean I have more grip and can push harder in that corner. But the fact that it's actually tucking the nose in by a couple of degrees that's confusing me because as I'm applying throttle more weight should shift rear and lowering grip on the front, but instead I somehow seem to have more grip.

[Shark_Bait88]

Which corner? I'm familiar with ABCC, and it might help to know which one you're talking about.

[Jamestl]

Originally Posted by Shark_Bait88

Which corner? I'm familiar with ABCC, and it might help to know which one you're talking about.

It's turn 13/14. I'm trying to crop a video so others can see it.

[TrqlessWonder]

Is the front end tucking, or is the rear end rotating? Also, what inputs are you putting in to get down to that second apex? Now contrast with how you get down and through the first apex.

[Jamestl]

Originally Posted by TrqlessWonder

Is the front end tucking, or is the rear end rotating? Also, what inputs are you putting in to get down to that second apex? Now contrast with how you get down and through the first apex.

I didn't think about it in those terms. I would say it's actually more the rear rotating than the front tucking, so that's a great clarification. Thank you.

On the first apex i'm more lifting, turning in to settle the car and as I'm between first and second apex I'm starting to apply throttle with same steering angle, and the rear rotates in a way that I'm not feeling in other corners where i'm doing the same thing (e.g., same steering angle and feeding throttle mid turn).

Here's the video of the corner:

[ame]https://www.youtube.com/watch?v=cMM0q7xRZGU[/ame]

And here's a video of the whole course to give you some sense. I already uploaded the entire thing and it seems to take forever to crop a little section so I'm just posting the entire thing for the sake of expediency rather than cutting one lap.

[ame]https://www.youtube.com/watch?v=KGuzuFbYnyI[/ame]

[Jamestl]

Originally Posted by justinco

On camber turn? Off camber turn? Different surface? Incline or decline?

The car is not going to behave exactly the same on every turn. Dynamics of the turn can make a big difference if dramatic enough.

I think the answer is no to every question. The vids are in the post above so it gives you some idea of the track and turn. Thanks.

[jvincent]

Originally Posted by Jamestl

I didn't think about it in those terms. I would say it's actually more the rear rotating than the front tucking, so that's a great clarification. Thank you.

On the first apex i'm more lifting, turning in to settle the car and as I'm between first and second apex I'm starting to apply throttle with same steering angle, and the rear rotates in a way that I'm not feeling in other corners where i'm doing the same thing (e.g., same steering angle and feeding throttle mid turn).

Sounds like classic throttle steer to me.

[Jamestl]

Originally Posted by jvincent

Sounds like classic throttle steer to me.

Thanks, Vincent. Since both you and @CSG_David mentioned it I'll assume it's the right term. I have two follow up questions:

1) How is "throttle steer" different from steering with the throttle? The latter, as I've been taught in the class and experienced on track, is bringing the car out or in with the throttle using the same steering angle (more throttle is wider turn, and inversely with less throttle). In this instance, the opposite is happening. So are they fundamentally two different concepts?

2) What's unique about this corner, based on what you can see, that causes this behavior? I understand that there are a lot of variations for each corner, but I literally have not felt this in another corner in any of the tracks I've been to, so I'm a little confused on what I'm doing that's unique. If I can apply this in other corners it'll be awesome but I have to know how to replicate...

Thanks much everyone!

[Icecreamtruk]

Forgive me if this sounds a bit raw, but all I see in the video is a car going around the track in a very tame manner. Maybe the tires are completly silent and video and sound dont tell the whole story, but your track out is still far off the edge of the track and your apex are a hit or miss. I see a little bit of the "tuck in" that you speak in the video, but that looks like what the car does when the stability control kicks in (brakes on rear wheels).

Maybe we have wildly different concepts of what throttle steering is, but throttle steering refers to steering the car by generating a rotation on the rear of the vehicule, by basically exceding the rear grip with throtle and getting a higher slip angle than the the front (or in other words, a very controlled and small drift thru the corner). I see none of that in the video.

[Stang70Fastback]

Originally Posted by Jamestl

1) How is "throttle steer" different from steering with the throttle? The latter, as I've been taught in the class and experienced on track, is bringing the car out or in with the throttle using the same steering angle (more throttle is wider turn, and inversely with less throttle). In this instance, the opposite is happening. So are they fundamentally two different concepts?

Keep in mind that throttle steering can occur in different ways. For example, if your car is set up to be a bit loose in the rear, you can get on the throttle, which causes greater rear slip angle ("oversteer") which can sometimes help the car turn in a bit better, or at least feel as though it is turning in better, and point you more towards the inside of the turn. That's one type of "steering with the throttle."

But depending on the track surface, tires, car setup, etc... it could instead just result in more understeer, since more throttle naturally shifts weight rearward, reducing front end grip. In that scenario, you would be pushed wide, to the outside of the corner. That's a different kind of "steering with the throttle." There are a lot of variables that affect what happens when you lean on the throttle mid-curve, and they will dictate how the vehicle responds. MOST of the time, it's safe to say that getting on the throttle widens your line through a corner, but sometimes you can take advantage of your setup to force a bit more rotation with the throttle.

I'm sure others can give better info, but that's a start anyway.

[Jamestl]

Originally Posted by Icecreamtruk

Forgive me if this sounds a bit raw, but all I see in the video is a car going around the track in a very tame manner. Maybe the tires are completly silent and video and sound dont tell the whole story, but your track out is still far off the edge of the track and your apex are a hit or miss. I see a little bit of the "tuck in" that you speak in the video, but that looks like what the car does when the stability control kicks in (brakes on rear wheels).

Maybe we have wildly different concepts of what throttle steering is, but throttle steering refers to steering the car by generating a rotation on the rear of the vehicule, by basically exceding the rear grip with throtle and getting a higher slip angle than the the front (or in other words, a very controlled and small drift thru the corner). I see none of that in the video.

Please don't apologize. You're using your time to provide advice and perspective, and that's helpful even if it's constructive criticism. I'm a fairly novice driver, and certainly have a lot to learn, hence my question on this as it's a foreign feeling for me.

On to your points.
- Circling in a tamer manner -- as mentioned, definitely have lots of room to improve as a novice, but certainly didn't feel tame in the driver's seat! The sound on the video recorder isn't great so you do have to turn it up a bit to hear well.

- Track out -- are there particular corners where you feel I didn't track out enough? There's one corner in particular where I'm definitely guilty and it's something I need to work on, and in general I'm probably a foot off the edge just because I'm not comfortable enough to be that close yet, but my instructors did not feel I'm far off the edge on the other corners. Not challenging your assertion, just want to better understand if there's any particular corner(s) you're referring to.

- Apex -- Again, specific corner commentary would be helpful.

- Stability control -- everything was off.

- Throttle steer -- got it. Your explanation makes perfect sense and that was the sensation going through that corner. Is that a term of art and when I say throttle steer everyone knows that it's different than steering with the throttle?