Upshifting mid-corner in S6 ?

[CanAutM3]

Originally Posted by LiM3y

[There may have been some writer bias expressed in the above message]

Really ??

Originally Posted by LiM3y

As a 6MT user, shouldn't you have the correct gear selected for the track-out before you reach the apex, either by "handbag-holding" flippy-flappy paddles or "hairy-chested" heel-toe shifts, during straight-line or trail braking?

In most cases this is also what is done with DCT, you essentially downshift while braking to be in the right gear to accelerate out of the turn. However, in some corners (as gearhead mentions), it is beneficial to upshift during track out to maximize the power band. DCT makes it easy, so why not use it. On the specific example I mention in this thread, some corners are taken flat out (no braking at entry). In these cases the cornering speed is lot limited by lateral grip but rather by entry speed. In this case, it is very beneficial to maximize the power band by shifting mid-turn rather than short shifting before turn-in.

Originally Posted by LiM3y

Is this about down shifting during turn-in?

This is another benefit of DCT. I can think of a very specific turn where I use it. It is at Temptation at Calabogie. It is a 180deg decreasing radius turn with an entry speed of about 85mph and an exit of 45mph. So with an entry speed of 85mph it is not wise to downshift in 2nd and 3rd is not the best gear to pull at 45mph. With DCT I can trail brake through most of the turn, downshift in 2nd at the apex (which is very late apex) and be in the power band to accelerate out.

Originally Posted by LiM3y

I am confused about DCT throttle sensitivity and gear change abruptness in cornering with DCT.

This is the beauty of the smarts behind DCT. It does a harsh power shift in a straight line and a butter smooth shift when the car is under lateral load. The original question of this thread was if that smart logic was also programmed in S6.

[saeedg48]

might snap the back end out.. but that could just be fun

[Gearhead999s]

Apparently we all have been doing Temptation wrong at Calabogie
Watch Scott Maxwell in the factory Boss 302 R Grand Am Cup car.

[CanAutM3]

Originally Posted by Gearhead999s

Apparently we all have been doing Temptation wrong at Calabogie
Watch Scott Maxwell in the factory Boss 302 R Grand Am Cup car.

There are so many ways to do Temptation, difficult to figure which one is right

My line is very similar to the one in the video (albeit not as fast ). I personaly don't like the "rim shot". Interestng to notice in the vid how he downshifts after the initial turn-in, even with a MT.

He also seems to be closer to the "racing" line, to protect against an inside pass...

[Gearhead999s]

Originally Posted by CanAutM3

There are so many ways to do Temptation, difficult to figure which one is right

My line is very similar to the one in the video (albeit not as fast ). I personaly don't like the "rim shot". Interestng to notice in the vid how he downshifts after the initial turn-in, even with a MT.

He also seems to be closer to the "racing" line, to protect against an inside pass...

My line through Temptation has been to go straight across to about 1/2 track and use a late apex to clip at the apex.There are so many lines that seem to be OK at that corner.CMP is a track where late apex's are King!I have about 1000 laps there on my old bike!



Coming out of Temptation.

[Gearhead999s]

Here is a video from last fall at Calabogie.Fast forward through the 1st 4 minutes.

[CanAutM3]

UPDATE:

With all the recent posts about shifting mid turn with DCT, I decided to update my old thread.

So I tried it this year and I can confirm that there is no issue shifting mid turn using S6. The DCT ECU has been very smartly programmed and when it senses a shift while the car is laterally loaded, it will execute a very smooth shift (no surge). The power delivery remains constant and the chassis doesn't budge. Very convenient .

I have attached vids to show me shifting mid turn in S6 (twice in each vid) and as you can attest, the car remains absolutely stable.

[4sevens.com]

I would beg to differ - my experience is different. If you're truly at the limit of mechanical grip (at peak slip angle) any change in throttle will indeed upset the car. The shifts for me are quick but just the slightly 1/10s drop in power will indeed upset your car if you're at the limit. In my experience if I'm not at the edge of the limit, it'll do fine, but if I'm at the cornering limit the shift will cause me to have to counter steer to correct additional yaw. So sometimes I'll anticipate it and relax the wheel just a tiny bit before I shift and then add steering right back after the shift - it all happens in less than 1/2s.

[CanAutM3]

Originally Posted by 4sevens.com

I would beg to differ - my experience is different. If you're truly at the limit of mechanical grip (at peak slip angle) any change in throttle will indeed upset the car. The shifts for me are quick but just the slightly 1/10s drop in power will indeed upset your car if you're at the limit. In my experience if I'm not at the edge of the limit, it'll do fine, but if I'm at the cornering limit the shift will cause me to have to counter steer to correct additional yaw. So sometimes I'll anticipate it and relax the wheel just a tiny bit before I shift and then add steering right back after the shift - it all happens in less than 1/2s.

What drop in power? You have two clutches slipping against each other with both providing tractive force, there should not be any drop in propulsive force.

What I do notice though, is as you upshift, the propulsive force is less in the higher gear. This slightly changes the front/rear weight distribution. So on high speed sweepers, the car balance changes slightly towards oversteer (or less understeer) after the upshift since there is less weight on the rear wheels. But it is all very manageable.

I did however experience what you mention. At CMP, there is crest in the middle of a corner and I need to upshift right when I hit the crest. I do as you say and slightly open up the steering wheel just before I upshift.

[bigjae1976]

I've had the back end come out a tad with an S5 upshift from 2nd to 3rd. Caught it and not a big deal. It was mentioned earlier, never had an issue from 3rd to 5th going up or down.

Its those certain places where you take advantage of the DCT to drop down into 2nd. So I just leave it in S4 and I have been happy. And your expensive and non-replacable gears take less of a pounding.

[4sevens.com]

Originally Posted by CanAutM3

What drop in power? You have two clutches slipping against each other with both providing tractive force, there should not be any drop in propulsive force.

What I do notice though, is as you upshift, the propulsive force is less in the higher gear. This slightly changes the front/rear weight distribution. So on high speed sweepers, the car balance changes slightly towards oversteer (or less understeer) after the upshift since there is less weight on the rear wheels. But it is all very manageable.

I did however experience what you mention. At CMP, there is crest in the middle of a corner and I need to upshift right when I hit the crest. I do as you say and slightly open up the steering wheel just before I upshift.

Sorry - I meant change in power. plus or minus will affect the cars yaw at the edge.

[CanAutM3]

Originally Posted by 4sevens.com

Sorry - I meant change in power. plus or minus will affect the cars yaw at the edge.

We agree

[4sevens.com]

Originally Posted by CanAutM3

We agree

Awesome! And the closer to the edge the smallest amount of power change requires exponentially quicker reflexes to fix the problem or it's spin time. Especially if you're on slicks

[Gearhead999s]

Originally Posted by 4sevens.com

Awesome! And the closer to the edge the smallest amount of power change requires exponentially quicker reflexes to fix the problem or it's spin time. Especially if you're on slicks

That is when it starts to be fun

[CanAutM3]

Originally Posted by 4sevens.com

Awesome! And the closer to the edge the smallest amount of power change requires exponentially quicker reflexes to fix the problem or it's spin time. Especially if you're on slicks

I guess it all depends on how a specific car is setup and balanced.

As you reduce the propulsive force due to the higher gear, some of the rear leteral grip is lost due to the shift in weight towards the front. However, since less of the rear tire grip is used for longitudinal acceleration, more lateral grip becomes available (think friction circle).

For a given setup when upshifting, I guess it could be possible that the lost grip at the rear due to the weight transfer outweighs the gained grip from the friction circle. In this instance it could probably lead to a spin...

However, it is not the case in my car. I do feel the change in yaw, but no instability.

[Jaypod]

Coming out of MT M3 and recently into a DCT, I have played with the transmission upshifting and downshifting in and out of turns etc. While I wouldn't say it upsets the car much you still have to pay attention and make minor corrections etc. I still do believe trying to maintain good habits and tell my students to always brake and change gears in a straight line. After all we are lapping and not racing.

[CanAutM3]

Originally Posted by Jaypod

Coming out of MT M3 and recently into a DCT, I have played with the transmission upshifting and downshifting in and out of turns etc. While I wouldn't say it upsets the car much you still have to pay attention and make minor corrections etc. I still do believe trying to maintain good habits and tell my students to always brake and change gears in a straight line. After all we are lapping and not racing.

Agreed, I do the same with my Novice and Intermediate students. You are busy enough working on much more fundamental elements of performance driving.

However with some advanced students that want to improve their skill and lap times, it is something I do work with them. BTW, shifting mid corner can also be applied to MT cars, it just requires much more skill to execute.

[Jaypod]

Originally Posted by CanAutM3

Agreed, I do the same with my Novice and Intermediate students. You are busy enough working on much more fundamental elements of performance driving.

However with some advanced students that want to improve their skill and lap times, it is something I do work with them. BTW, shifting mid corner can also be applied to MT cars, it just requires much more skill to execute.

Agree on advanced students trying to improve skills or lap times. In my MT car I used to shift in corners to help get the car rotated when required or just to get a better launch out of the corner as downshifting before the turn was not an option. Doesn't seem to have the same result with DCT however so the pedals are your friends.

[4sevens.com]

Originally Posted by CanAutM3

I guess it all depends on how a specific car is setup and balanced.

As you reduce the propulsive force due to the higher gear, some of the rear leteral grip is lost due to the shift in weight towards the front. However, since less of the rear tire grip is used for longitudinal acceleration, more lateral grip becomes available (think friction circle).

For a given setup when upshifting, I guess it could be possible that the lost grip at the rear due to the weight transfer outweighs the gained grip from the friction circle. In this instance it could probably lead to a spin...

However, it is not the case in my car. I do feel the change in yaw, but no instability.

True - but also depends on how you're loading your outside front and rears. If you're truly at your limit on both front and rear, maximizing your grip mid corner, any power change will cause bad problems. If not, then you're probably not at your grip limit - in fact thats how I usually detect how well I'm loading both fronts and rears... if theres more room to wiggle the wheel or play with the throttle then I'm not at the limit. The absolute limit mid corner it a beautiful and delicate thing

[CanAutM3]

Originally Posted by 4sevens.com

True - but also depends on how you're loading your outside front and rears. If you're truly at your limit on both front and rear, maximizing your grip mid corner, any power change will cause bad problems. If not, then you're probably not at your grip limit - in fact thats how I usually detect how well I'm loading both fronts and rears... if theres more room to wiggle the wheel or play with the throttle then I'm not at the limit. The absolute limit mid corner it a beautiful and delicate thing

I agree that balancing a car near the limits with plenty of slip angle is a delightful experience

However I am not sure I am on board with your entire statement.

From my understanding, the limit of adhesion is not a clear cut black and white thing. Tires need to slip to generate grip, hence the harder you push the more slip you will have. There is no hard limit per say, only increased slip. Even as you feel the tires are sliding away, the still are generating lateral force.

Further, I don't believe that there is a single car out there that is perfectly neutral in every driving condition. Hence, you will never be at the "limit" (read same slip angle) of the front and rear tires simultaneously in every condition.

As long as the changes to inputs are smooth, the change in slip level remains predictable and the driver is able to compensate. What concerns me more is abrupt changes in inputs that would suddenly and drastically alter the slip level of the tires where the driver is not able to react fast enough to correct it.

[bigjae1976]

If you exceed the grip limits from an up or down shift it should be managable even if it does upset the car. Not like it should surprise you.

[4sevens.com]

Originally Posted by CanAutM3

I agree that balancing a car near the limits with plenty of slip angle is a delightful experience

However I am not sure I am on board with your entire statement.

From my understanding, the limit of adhesion is not a clear cut black and white thing. Tires need to slip to generate grip, hence the harder you push the more slip you will have. There is no hard limit per say, only increased slip. Even as you feel the tires are sliding away, the still are generating lateral force.

Further, I don't believe that there is a single car out there that is perfectly neutral in every driving condition. Hence, you will never be at the "limit" (read same slip angle) of the front and rear tires simultaneously in every condition.

With every tire there is an optimum slip angle with produces maximum grip. Before and after this "peak" grip falls off. With slicks that peak is really sharp with the greater angle falling off really fast. What I'm describing is loading both outside front and rears right at the peak - that is the fastest you'll ever go in a corner. Loading both is not so much the "perfectly netural setup" but rather how you drive the car. With any car anywhere near close to neutral a skillful driver can load front and rears evening - trust me, I've worked up to this point. I take student's cars to this limit all the time. (there are lots of little advanced tips I can tell you but thats beyond the scope of this thread)

It is at this point, where you are at peak grip (optimum slip angle) that the car is basically at it "limit." The limit of the fastest you'll go around a corner. It is at this limit that tiny tiny changes in power will cause your car to exit the corner less than optimal (over/under steer) requiring correction. And if you're on slicks the tiniest big of power change can throw you into a wild goose chase after your wheel.

hehe I like describing these experiences

bottom line. I don't shift mid-corner if I'm driving race pace. If I can actually shift mid corner (even though the shift is very very fast) then I'm leaving more on the table and need to go faster through the corner lol