Tricky corners, how to know when to stay in 3rd and when to go into 2nd
12-05-2018, 01:39 PM
#31
Burning Brakes
My 2 cents from driving mainly sequential boxed / paddle shift race cars, but applies to whenever I drive H-pattern cars too:
Whenever I'm trying to figure out the optimal gear for a corner (which has been frequently since the last 3 cars I raced, I'd never driven and was at tracks I knew very well!) all I care about is car stability on entry and rotation by mid corner (direction car is pointed) which dictates how soon I can get back to power. Min speed is simply by product of those things and I almost never concern myself with it (unless it's a longer sweeper). The importance of the entry VS power down is dictated by the type of corner it is (onto a long straight, power down more important, otherwise entry).
Having said that, in my experience the gear has a huge effect on how the car enters the corner and how it rotates in the mid-corner. All of this depends on the differential type, setting and car type, but almost universally I approach it as:
* Taller gear (3rd vs 2nd for instance) gives me more understeer (which isn't always equal to rear end stability because the diff is generally more "open") which allows me to be more aggressive on entry. However, the by product of that is generally a little bit later back to power as it takes the car longer to get rotated enough for me to get back to power once and it tends to result in a smoother application of power as I try not to induce more power understeer on the exit.
* And conversely, if a corner is kind of between gears going down a gear (1st instead of 2nd for example) generally allows the car to rotate much faster after turn in and before the apex, allowing me to get back to power a little sooner -- eg: makes it "pointy". It's a good technique when the car setup isn't suited to a particular corner or you're diving down the inside of someone or trying to undercut them on the exit, but generally is more inconsistent (difficult to get perfect every time, and it's generally only faster if it's perfect).
Within reason the "RPM" of the car on exit has very little effect on the lap time (within reason) versus what can be lost on entry and mid-corner. And it's not because I tend to drive "high horsepower" cars, they're all about the same power wise in the classes I run.
And just as a couple data points:
* T3 at Laguna in the AMG GT3, I did all the practice sessions in 3rd gear and Dalziel was doing 2nd gear. I was using 3rd because it was "easier", but I was losing time (.15 overall, but gained on entry-mid) on corner exit because of the car "floating" through the apex and my delay going back to power. We talked about it a lot and studied the data for the first 2 days, but my head was having a hard time wrapping itself around going down to 2nd gear for turn 3 (all the other cars I'd driven it was an easy 3rd gear corner, but the AMG is geared very tall). I ended up trying it at the end of the final practice session and it made everything better. The car was "pointier" on entry so I could get it down to the apex and could rotate with power on exit to keep from understeering off over the exit curb, albeit a little harder to drive.
* T13 at COTA in the 488 GT3, I was using 2nd gear because the turbo hit at 5600 RPM in first gear was causing me lots of problems putting the power down on the exit. We were lucky enough to have a Pro's data lap in the 488 from the IMSA weekend and they were using 1st gear. However, my trace for that sector was about 1 tenth faster because my min speed was a tick higher (less engine breaking) but mostly because I was able to get back to initial power AND full power much sooner with the reduced torque of 2nd gear. It didn't feel very fast (I kept complaining to the engineer I felt like I was in a street car), but it was quicker and easier on the tires and more consistent.
If you don't have data to compare against, you're never really going to know which is better. Don't always trust your gut, trust the numbers and don't be afraid to try different gears at any time if it doesn't feel just rite (even mid-race or mid-session... things change).
-mike
Whenever I'm trying to figure out the optimal gear for a corner (which has been frequently since the last 3 cars I raced, I'd never driven and was at tracks I knew very well!) all I care about is car stability on entry and rotation by mid corner (direction car is pointed) which dictates how soon I can get back to power. Min speed is simply by product of those things and I almost never concern myself with it (unless it's a longer sweeper). The importance of the entry VS power down is dictated by the type of corner it is (onto a long straight, power down more important, otherwise entry).
Having said that, in my experience the gear has a huge effect on how the car enters the corner and how it rotates in the mid-corner. All of this depends on the differential type, setting and car type, but almost universally I approach it as:
* Taller gear (3rd vs 2nd for instance) gives me more understeer (which isn't always equal to rear end stability because the diff is generally more "open") which allows me to be more aggressive on entry. However, the by product of that is generally a little bit later back to power as it takes the car longer to get rotated enough for me to get back to power once and it tends to result in a smoother application of power as I try not to induce more power understeer on the exit.
* And conversely, if a corner is kind of between gears going down a gear (1st instead of 2nd for example) generally allows the car to rotate much faster after turn in and before the apex, allowing me to get back to power a little sooner -- eg: makes it "pointy". It's a good technique when the car setup isn't suited to a particular corner or you're diving down the inside of someone or trying to undercut them on the exit, but generally is more inconsistent (difficult to get perfect every time, and it's generally only faster if it's perfect).
Within reason the "RPM" of the car on exit has very little effect on the lap time (within reason) versus what can be lost on entry and mid-corner. And it's not because I tend to drive "high horsepower" cars, they're all about the same power wise in the classes I run.
And just as a couple data points:
* T3 at Laguna in the AMG GT3, I did all the practice sessions in 3rd gear and Dalziel was doing 2nd gear. I was using 3rd because it was "easier", but I was losing time (.15 overall, but gained on entry-mid) on corner exit because of the car "floating" through the apex and my delay going back to power. We talked about it a lot and studied the data for the first 2 days, but my head was having a hard time wrapping itself around going down to 2nd gear for turn 3 (all the other cars I'd driven it was an easy 3rd gear corner, but the AMG is geared very tall). I ended up trying it at the end of the final practice session and it made everything better. The car was "pointier" on entry so I could get it down to the apex and could rotate with power on exit to keep from understeering off over the exit curb, albeit a little harder to drive.
* T13 at COTA in the 488 GT3, I was using 2nd gear because the turbo hit at 5600 RPM in first gear was causing me lots of problems putting the power down on the exit. We were lucky enough to have a Pro's data lap in the 488 from the IMSA weekend and they were using 1st gear. However, my trace for that sector was about 1 tenth faster because my min speed was a tick higher (less engine breaking) but mostly because I was able to get back to initial power AND full power much sooner with the reduced torque of 2nd gear. It didn't feel very fast (I kept complaining to the engineer I felt like I was in a street car), but it was quicker and easier on the tires and more consistent.
If you don't have data to compare against, you're never really going to know which is better. Don't always trust your gut, trust the numbers and don't be afraid to try different gears at any time if it doesn't feel just rite (even mid-race or mid-session... things change).
-mike
12-05-2018, 10:18 PM
#32
Rennlist Member
My 2 cents from driving mainly sequential boxed / paddle shift race cars, but applies to whenever I drive H-pattern cars too:
Whenever I'm trying to figure out the optimal gear for a corner (which has been frequently since the last 3 cars I raced, I'd never driven and was at tracks I knew very well!) all I care about is car stability on entry and rotation by mid corner (direction car is pointed) which dictates how soon I can get back to power. Min speed is simply by product of those things and I almost never concern myself with it (unless it's a longer sweeper). The importance of the entry VS power down is dictated by the type of corner it is (onto a long straight, power down more important, otherwise entry).
Having said that, in my experience the gear has a huge effect on how the car enters the corner and how it rotates in the mid-corner. All of this depends on the differential type, setting and car type, but almost universally I approach it as:
* Taller gear (3rd vs 2nd for instance) gives me more understeer (which isn't always equal to rear end stability because the diff is generally more "open") which allows me to be more aggressive on entry. However, the by product of that is generally a little bit later back to power as it takes the car longer to get rotated enough for me to get back to power once and it tends to result in a smoother application of power as I try not to induce more power understeer on the exit.
* And conversely, if a corner is kind of between gears going down a gear (1st instead of 2nd for example) generally allows the car to rotate much faster after turn in and before the apex, allowing me to get back to power a little sooner -- eg: makes it "pointy". It's a good technique when the car setup isn't suited to a particular corner or you're diving down the inside of someone or trying to undercut them on the exit, but generally is more inconsistent (difficult to get perfect every time, and it's generally only faster if it's perfect).
Within reason the "RPM" of the car on exit has very little effect on the lap time (within reason) versus what can be lost on entry and mid-corner. And it's not because I tend to drive "high horsepower" cars, they're all about the same power wise in the classes I run.
And just as a couple data points:
* T3 at Laguna in the AMG GT3, I did all the practice sessions in 3rd gear and Dalziel was doing 2nd gear. I was using 3rd because it was "easier", but I was losing time (.15 overall, but gained on entry-mid) on corner exit because of the car "floating" through the apex and my delay going back to power. We talked about it a lot and studied the data for the first 2 days, but my head was having a hard time wrapping itself around going down to 2nd gear for turn 3 (all the other cars I'd driven it was an easy 3rd gear corner, but the AMG is geared very tall). I ended up trying it at the end of the final practice session and it made everything better. The car was "pointier" on entry so I could get it down to the apex and could rotate with power on exit to keep from understeering off over the exit curb, albeit a little harder to drive.
* T13 at COTA in the 488 GT3, I was using 2nd gear because the turbo hit at 5600 RPM in first gear was causing me lots of problems putting the power down on the exit. We were lucky enough to have a Pro's data lap in the 488 from the IMSA weekend and they were using 1st gear. However, my trace for that sector was about 1 tenth faster because my min speed was a tick higher (less engine breaking) but mostly because I was able to get back to initial power AND full power much sooner with the reduced torque of 2nd gear. It didn't feel very fast (I kept complaining to the engineer I felt like I was in a street car), but it was quicker and easier on the tires and more consistent.
If you don't have data to compare against, you're never really going to know which is better. Don't always trust your gut, trust the numbers and don't be afraid to try different gears at any time if it doesn't feel just rite (even mid-race or mid-session... things change).
-mike
Whenever I'm trying to figure out the optimal gear for a corner (which has been frequently since the last 3 cars I raced, I'd never driven and was at tracks I knew very well!) all I care about is car stability on entry and rotation by mid corner (direction car is pointed) which dictates how soon I can get back to power. Min speed is simply by product of those things and I almost never concern myself with it (unless it's a longer sweeper). The importance of the entry VS power down is dictated by the type of corner it is (onto a long straight, power down more important, otherwise entry).
Having said that, in my experience the gear has a huge effect on how the car enters the corner and how it rotates in the mid-corner. All of this depends on the differential type, setting and car type, but almost universally I approach it as:
* Taller gear (3rd vs 2nd for instance) gives me more understeer (which isn't always equal to rear end stability because the diff is generally more "open") which allows me to be more aggressive on entry. However, the by product of that is generally a little bit later back to power as it takes the car longer to get rotated enough for me to get back to power once and it tends to result in a smoother application of power as I try not to induce more power understeer on the exit.
* And conversely, if a corner is kind of between gears going down a gear (1st instead of 2nd for example) generally allows the car to rotate much faster after turn in and before the apex, allowing me to get back to power a little sooner -- eg: makes it "pointy". It's a good technique when the car setup isn't suited to a particular corner or you're diving down the inside of someone or trying to undercut them on the exit, but generally is more inconsistent (difficult to get perfect every time, and it's generally only faster if it's perfect).
Within reason the "RPM" of the car on exit has very little effect on the lap time (within reason) versus what can be lost on entry and mid-corner. And it's not because I tend to drive "high horsepower" cars, they're all about the same power wise in the classes I run.
And just as a couple data points:
* T3 at Laguna in the AMG GT3, I did all the practice sessions in 3rd gear and Dalziel was doing 2nd gear. I was using 3rd because it was "easier", but I was losing time (.15 overall, but gained on entry-mid) on corner exit because of the car "floating" through the apex and my delay going back to power. We talked about it a lot and studied the data for the first 2 days, but my head was having a hard time wrapping itself around going down to 2nd gear for turn 3 (all the other cars I'd driven it was an easy 3rd gear corner, but the AMG is geared very tall). I ended up trying it at the end of the final practice session and it made everything better. The car was "pointier" on entry so I could get it down to the apex and could rotate with power on exit to keep from understeering off over the exit curb, albeit a little harder to drive.
* T13 at COTA in the 488 GT3, I was using 2nd gear because the turbo hit at 5600 RPM in first gear was causing me lots of problems putting the power down on the exit. We were lucky enough to have a Pro's data lap in the 488 from the IMSA weekend and they were using 1st gear. However, my trace for that sector was about 1 tenth faster because my min speed was a tick higher (less engine breaking) but mostly because I was able to get back to initial power AND full power much sooner with the reduced torque of 2nd gear. It didn't feel very fast (I kept complaining to the engineer I felt like I was in a street car), but it was quicker and easier on the tires and more consistent.
If you don't have data to compare against, you're never really going to know which is better. Don't always trust your gut, trust the numbers and don't be afraid to try different gears at any time if it doesn't feel just rite (even mid-race or mid-session... things change).
-mike
"no" mostly , you are riight, but there are few times when you can get away with it. and some sometimes, there are long trail brake turn ins that can be a point where you can make that shift. (Before the actual turn starts)
12-05-2018, 10:21 PM
#33
Rennlist Member
Spec Boxsters dont have LSDs (well at least the legal cars dont), I have tried both ways.
Point being general advice is just that, general. Data wins, setup sectors, try different approaches, take the winner.
Point being general advice is just that, general. Data wins, setup sectors, try different approaches, take the winner.
12-06-2018, 10:00 AM
#34
Intermediate
Join Date: Jul 2013
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Discussions like this make me appreciate having to mix my own on the track. The challenge is fun and spurs more study, discussion and learning. I am sure I will cave and try a PDK one day due to peer pressure and my motor skills diminishing. Until then I will enjoy the excitement of anticipating a money shift that will result in a nice motor upgrade.
12-06-2018, 10:34 AM
#35
Discussions like this make me appreciate having to mix my own on the track. The challenge is fun and spurs more study, discussion and learning. I am sure I will cave and try a PDK one day due to peer pressure and my motor skills diminishing. Until then I will enjoy the excitement of anticipating a money shift that will result in a nice motor upgrade.
12-06-2018, 12:17 PM
#36
Rennlist Member
can you show me those turns in a video? i ran my car for many years with an open diff , so the same rules apply, for slightly different reasons.
i agree with your last sentence though... with one addition, compare different approaches (other drivers) , but also variations of those different approaches.
I rode at Sebring with a gentleman in a PDK Cayman S, and coming out of T3, T10, T13, T15, and maybe even T5 and that last bit of T17 (it has been a while so I don't remember exactly) the PDK would drop down to 2nd when he got back on power, and even though it was only in 2nd for a very brief period, it would absolutely launch the car out of the corner. One of these days I would like to try a PDK Cayman just for fun. A friend of mine has one and he offered for me to drive, but I wasn't on the track insurance policy so I declined. He said he is going to add me next time, I can't wait
being in the wrong gear, in cars in the 300hp range, you can be down near 50 hp vs a competitor for a second or two.... that is substantial. if you think you are slowing too much to be in that gear.........dont slow as much.. its really that simple.
12-06-2018, 03:55 PM
#38
Rennlist Member
most are... but, if you think about the extra force that more "horsepower" gives you when you put down the throttle, it makes sense to be in the right gear at exit. if you are not using fulll throttle due to grip (like down the exit of the corkscrew or turn 5 exit of thunderhill) then learn to do it, or continue to do as you have. its not a huge difference, but it is a little when you learn how to modulate the extra power, keep the car underneath you , and take advantage of the greater acceleration, even if it is for a second. over a race, those few feet, add up. Plus, for me, i just like shifting.
12-06-2018, 10:41 PM
#39
One coach I had with sport bikes had a pretty interesting approach to making these decisions: basically he looked at every corner as one of three:
-coming off a straight
-going into a straight
-blended
This seems like very basic stuff but- If you're coming off the straight you should carry more roll speed into the corner and drive deeper..sacrifice exit speed a bit.
If you're going into a straight you should brake earlier and get the bike/car turned early and get on the gas earlier to maximize your exit speed.
Blended is blended.
T12 at VIR is coming onto a big straight. So you should really be maximizing your exit speed. Every MPH more at the exit of that corner pays great dividends over the straight. Can you try a few different gear management approaches and check your exit speed for each?
-coming off a straight
-going into a straight
-blended
This seems like very basic stuff but- If you're coming off the straight you should carry more roll speed into the corner and drive deeper..sacrifice exit speed a bit.
If you're going into a straight you should brake earlier and get the bike/car turned early and get on the gas earlier to maximize your exit speed.
Blended is blended.
T12 at VIR is coming onto a big straight. So you should really be maximizing your exit speed. Every MPH more at the exit of that corner pays great dividends over the straight. Can you try a few different gear management approaches and check your exit speed for each?
12-07-2018, 08:01 AM
#40
Rennlist Member
Having said that, in my experience the gear has a huge effect on how the car enters the corner and how it rotates in the mid-corner. All of this depends on the differential type, setting and car type, but almost universally I approach it as:
* Taller gear (3rd vs 2nd for instance) gives me more understeer (which isn't always equal to rear end stability because the diff is generally more "open") which allows me to be more aggressive on entry. However, the by product of that is generally a little bit later back to power as it takes the car longer to get rotated enough for me to get back to power once and it tends to result in a smoother application of power as I try not to induce more power understeer on the exit.
* And conversely, if a corner is kind of between gears going down a gear (1st instead of 2nd for example) generally allows the car to rotate much faster after turn in and before the apex, allowing me to get back to power a little sooner -- eg: makes it "pointy".
-mike
12-07-2018, 02:40 PM
#41
Rennlist Member
^^^^^ Exactly. This has been my experience as well running a Cayman. The balance of the car is a important consideration with a car that understeers like most Porsches. 2nd can give you more control of the balance. Simply carrying a higher speed into certain corners can come with the penalty of not being able to rotate well - and therefore causing a delay getting back into the power. In the Cayman, when approaching slower entry turns, it almost always paid off to get down to 2nd gear, where coming off the throttle dropped the nose of the car more, allowing better rotation. The balance shift to front grip is more effective when you lift from 7,000 rpms in 2nd vs 4,500 rpms in 3rd.
