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02-23-2012, 12:19 PM
#751
Former Vendor
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It looks east because in his car it IS easy when you have electronic assist on engine rpm during upshifts like all 997 Cups. This car also appears to have an auto blipper fitted for downshifts, so his right foot doesn't need to do any of the 2 pedal operation that you need to do in your 997 GT3.
Never mind heel on the floor, that car could use LFB all the time except for stopping.
I'll also come out in favor of NOT keeping your heel on the floor. Unless you have the sequential and auto-blipper.
Never mind heel on the floor, that car could use LFB all the time except for stopping.
I'll also come out in favor of NOT keeping your heel on the floor. Unless you have the sequential and auto-blipper.
No one ever said it was easy; it is not! It is, however, very doable if you focus on proper technique and what is really happening with the engine/transmission/speed/etc.
Last edited by Adam@Autometrics; 02-23-2012 at 12:48 PM.
02-23-2012, 01:00 PM
#752
Rennlist Member
Thread Starter
That is incorrect. There is NO auto-blipper on this car; you can see his right foot rolling to the throttle. There is a misconception that sequential boxes are "easy." Proper technique is even more important on sequential/dog tooth cars (without blippers), as there is no synchro to ease the transition between gears - they WILL engage right or wrong, and the 3-disc clutch is a switch, so you can't use that as a crutch either. Even if you do have a blipper, you must have proper timing of the clutch and shifter; things happen so much faster than in a H-pattern synchro box (especially one with a single disc clutch) that it is still not "easy."
No one ever said it was easy; it is not! It is, however, very doable if you focus on proper technique and what is really happening with the engine/transmission/speed/etc.
No one ever said it was easy; it is not! It is, however, very doable if you focus on proper technique and what is really happening with the engine/transmission/speed/etc.
02-23-2012, 02:27 PM
#753
Rennlist Member
It looks east because in his car it IS easy when you have electronic assist on engine rpm during upshifts like all 997 Cups. This car also appears to have an auto blipper fitted for downshifts, so his right foot doesn't need to do any of the 2 pedal operation that you need to do in your 997 GT3.
Never mind heel on the floor, that car could use LFB all the time except for stopping.
I'll also come out in favor of NOT keeping your heel on the floor. Unless you have the sequential and auto-blipper.
Never mind heel on the floor, that car could use LFB all the time except for stopping.
I'll also come out in favor of NOT keeping your heel on the floor. Unless you have the sequential and auto-blipper.
Is the question here concerning keeping your heel in one spot for both braking and throttle? Or pressing the brake with your heel off the floor?
The car in the video does in fact have an auto blipper.......its my size 12 right foot
02-23-2012, 10:57 PM
#754
Instructor
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I used the term "electronic assist" to cover both the ignition cut on upshift, and the autoblipper I believed was there. As I understand it, the sequential and ignition cut is standard 997 cup, auto blippers for downshifting are not standard but are available. Clearly in the video posted, your foot is blipping most of the time, but there are 2 shifts in rapid succession just at 1:40 in the video where I was doubtful about foot movement on the first downshift, and couldn't see any foot movement on the second downshift.
So I concluded that maybe there was an autoblipper. Evidently that isn't so. And so I also retract my comment about being able to LFB all the time.
Your video while interesting in its own right isn't (IMO) especially helpful in assisting with that question as applies to the H-pattern synchro box that I'm assuming (guardedlynow) that is in the OP's 997 GT3.
Any dog clutch box can (and should) be shifted much faster than a synchro box, so the synchro box doesn't need the fast blipping that the dog clutch box does, and the extra shifting time allows for less precision in the timing of the blip. Which should make avoiding brake modulation easier.
02-24-2012, 07:26 AM
#755
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For the life of me, I'm trying to remember what the hell a "dog clutch box" is...
I've seen a lot of clutch assys., but have yet to see or hear of one.
Not going to get into the precision thing.
I've seen a lot of clutch assys., but have yet to see or hear of one.
Not going to get into the precision thing.
02-24-2012, 09:31 AM
#756
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I would hazard a guess that he was talking about a dog ring transmission versus a box with synchros.
02-24-2012, 10:06 AM
#757
Nordschleife Master
Dog Boxes, a primer. Let me know if inappropriate here, or too long, and I will remove post.
Crash gearboxes or dog boxes.
... These are also known as crash boxes, or dog boxes, and use straight-cut gears instead of helical gears...
... the extra noise that is generated is reduced to a (pleasing?) whine by the sound-deadening effects of the oil...
... the brainchild of a racing mechanic who wanted to provide teams with a quick method of altering gear ratios in the pits without having to play "chase the syncro hub ball bearings" as they fell out on to the garage floor...
... rather than having an exact dog-tooth to dog-hole match, the dog teeth can have as much as 60° "free space" between them. This means that instead of needing an exact 1-to-1 match to get them to engage, you have up to 1/6th of a rotation to get the dog teeth pressed together before they touch each other and engage...
... So the combination of less, but larger dog teeth spaced further apart, and a slower spinning gearbox, allegedly make for an easier-to-engage crash box. In reality, it's still quite difficult to engage a crash box because you need exactly the right rpm for each gear or you'll just end up grinding the dog teeth together or having them bounce over each other. That results in metal filings in your transmission fluid, which ultimately results in an expensive and untimely gearbox rebuild.
But it is more mechanically reliable - it's stronger and able to deal with a lot more power and torque which is why it's used in racing...
... a dog box relies entirely on the driver to get the gearchange right. Well - sort of. Nowadays the gearboxes have ignition interrupters...
... Because of this, it is entirely possible to upshift and downshift without using the clutch (except from a standstill)...
Read more: http://www.carbibles.com/transmissio...#ixzz1nJ5gqQwU
... These are also known as crash boxes, or dog boxes, and use straight-cut gears instead of helical gears...
... the extra noise that is generated is reduced to a (pleasing?) whine by the sound-deadening effects of the oil...
... the brainchild of a racing mechanic who wanted to provide teams with a quick method of altering gear ratios in the pits without having to play "chase the syncro hub ball bearings" as they fell out on to the garage floor...
... rather than having an exact dog-tooth to dog-hole match, the dog teeth can have as much as 60° "free space" between them. This means that instead of needing an exact 1-to-1 match to get them to engage, you have up to 1/6th of a rotation to get the dog teeth pressed together before they touch each other and engage...
... So the combination of less, but larger dog teeth spaced further apart, and a slower spinning gearbox, allegedly make for an easier-to-engage crash box. In reality, it's still quite difficult to engage a crash box because you need exactly the right rpm for each gear or you'll just end up grinding the dog teeth together or having them bounce over each other. That results in metal filings in your transmission fluid, which ultimately results in an expensive and untimely gearbox rebuild.
But it is more mechanically reliable - it's stronger and able to deal with a lot more power and torque which is why it's used in racing...
... a dog box relies entirely on the driver to get the gearchange right. Well - sort of. Nowadays the gearboxes have ignition interrupters...
... Because of this, it is entirely possible to upshift and downshift without using the clutch (except from a standstill)...
Read more: http://www.carbibles.com/transmissio...#ixzz1nJ5gqQwU
02-25-2012, 03:55 AM
#758
Hi coaches
I've been fiddling with set-up changes to my car and am getting lost with the feedback.
How do you know when the car is really understeering? Oversteering?
I've been reading oversteer in my car for the longest time. But am really beginning to wonder if that is the case. Here is an example:
- Trail-brake heavily into a medium speed corner, nose is turning but a bit slowly, I get the car to the apex but am forced to keep more lock than I am happy with when getting back on the power. If I try to add more steering to rotate the car more @ apex the back steps out. Read: Oversteer
- Very fast, flat out right hander. Well, supposed to be flat out. I feel like I am forced to lift a bit on entry, but still can't really put the power down quickly enough, again too much lock on exit and a very slipperly exit curb waiting for me, had a huge moment and nearly put the car in the wall. Read: Oversteer
Is this actually understeer? Am I driving around the problem without realizing it?
I've been fiddling with set-up changes to my car and am getting lost with the feedback.
How do you know when the car is really understeering? Oversteering?
I've been reading oversteer in my car for the longest time. But am really beginning to wonder if that is the case. Here is an example:
- Trail-brake heavily into a medium speed corner, nose is turning but a bit slowly, I get the car to the apex but am forced to keep more lock than I am happy with when getting back on the power. If I try to add more steering to rotate the car more @ apex the back steps out. Read: Oversteer
- Very fast, flat out right hander. Well, supposed to be flat out. I feel like I am forced to lift a bit on entry, but still can't really put the power down quickly enough, again too much lock on exit and a very slipperly exit curb waiting for me, had a huge moment and nearly put the car in the wall. Read: Oversteer
Is this actually understeer? Am I driving around the problem without realizing it?
02-25-2012, 03:59 AM
#759
1st Gear
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hi, i just buy 1997 993 rs. i have problem with ABS/ABD system. when i hit my brake for
emergency stop my rear LH tyre lock. its look like the ABS not function correctly. i already replace the ABS hydraulic unit but same problem happend. anybody have this problem and can give me some info. ty.
emergency stop my rear LH tyre lock. its look like the ABS not function correctly. i already replace the ABS hydraulic unit but same problem happend. anybody have this problem and can give me some info. ty.
02-25-2012, 07:28 AM
#760
Rennlist Member
Thread Starter
Hi coaches
I've been fiddling with set-up changes to my car and am getting lost with the feedback.
How do you know when the car is really understeering? Oversteering?
I've been reading oversteer in my car for the longest time. But am really beginning to wonder if that is the case. Here is an example:
- Trail-brake heavily into a medium speed corner, nose is turning but a bit slowly, I get the car to the apex but am forced to keep more lock than I am happy with when getting back on the power. If I try to add more steering to rotate the car more @ apex the back steps out. Read: Oversteer
- Very fast, flat out right hander. Well, supposed to be flat out. I feel like I am forced to lift a bit on entry, but still can't really put the power down quickly enough, again too much lock on exit and a very slipperly exit curb waiting for me, had a huge moment and nearly put the car in the wall. Read: Oversteer
Is this actually understeer? Am I driving around the problem without realizing it?
I've been fiddling with set-up changes to my car and am getting lost with the feedback.
How do you know when the car is really understeering? Oversteering?
I've been reading oversteer in my car for the longest time. But am really beginning to wonder if that is the case. Here is an example:
- Trail-brake heavily into a medium speed corner, nose is turning but a bit slowly, I get the car to the apex but am forced to keep more lock than I am happy with when getting back on the power. If I try to add more steering to rotate the car more @ apex the back steps out. Read: Oversteer
- Very fast, flat out right hander. Well, supposed to be flat out. I feel like I am forced to lift a bit on entry, but still can't really put the power down quickly enough, again too much lock on exit and a very slipperly exit curb waiting for me, had a huge moment and nearly put the car in the wall. Read: Oversteer
Is this actually understeer? Am I driving around the problem without realizing it?
Seems, just from what you wrote, that yes you may be driving around understeer and/or a driving technique problem (i.e., perhaps not doing enough rotation early enough in the cornering sequence).
02-25-2012, 08:30 AM
#762
Understeer is when you hit the wall with your front end. Oversteer is when you hit the wall with your back end. Horsepower is how hard you hit the wall. Torque is how far you move the wall when you hit it.
Seems, just from what you wrote, that yes you may be driving around understeer and/or a driving technique problem (i.e., perhaps not doing enough rotation early enough in the cornering sequence).
Seems, just from what you wrote, that yes you may be driving around understeer and/or a driving technique problem (i.e., perhaps not doing enough rotation early enough in the cornering sequence).
I didn't have this problem before. I went to a more "rearwards" set up (lifted front end, more camber @ the rear) but limits always manifest as apparent oversteer. I'm chasing a "perfect" behavior where the car feels like its pivoting about the rear end, as opposed to the front. "Precision Understeer". Can't find it.
How do I know if I am driving around the understeer without realizing it?
02-25-2012, 08:45 AM
#763
Rennlist Member
Hi coaches
I've been fiddling with set-up changes to my car and am getting lost with the feedback.
How do you know when the car is really understeering? Oversteering?
I've been reading oversteer in my car for the longest time. But am really beginning to wonder if that is the case. Here is an example:
- Trail-brake heavily into a medium speed corner, nose is turning but a bit slowly, I get the car to the apex but am forced to keep more lock than I am happy with when getting back on the power. If I try to add more steering to rotate the car more @ apex the back steps out. Read: Oversteer
- Very fast, flat out right hander. Well, supposed to be flat out. I feel like I am forced to lift a bit on entry, but still can't really put the power down quickly enough, again too much lock on exit and a very slipperly exit curb waiting for me, had a huge moment and nearly put the car in the wall. Read: Oversteer
Is this actually understeer? Am I driving around the problem without realizing it?
I've been fiddling with set-up changes to my car and am getting lost with the feedback.
How do you know when the car is really understeering? Oversteering?
I've been reading oversteer in my car for the longest time. But am really beginning to wonder if that is the case. Here is an example:
- Trail-brake heavily into a medium speed corner, nose is turning but a bit slowly, I get the car to the apex but am forced to keep more lock than I am happy with when getting back on the power. If I try to add more steering to rotate the car more @ apex the back steps out. Read: Oversteer
- Very fast, flat out right hander. Well, supposed to be flat out. I feel like I am forced to lift a bit on entry, but still can't really put the power down quickly enough, again too much lock on exit and a very slipperly exit curb waiting for me, had a huge moment and nearly put the car in the wall. Read: Oversteer
Is this actually understeer? Am I driving around the problem without realizing it?
Similar thing in the fast corner. Say the car is pushing into and through the sweeper. The driver realizes he is going to run out of road, he lifts slightly which unloads the rear of the car and causes a slight over steer fade. This surprises the driver and he lifts more on instinct which just makes it worse. The best way to avoid that is if the car can't take it flat, then breath before going into the corner and power through it. If it can be done flat, then do it flat and don't upset the car with throttle lifts it doesn't need. I have seen a similar thing in this type of corner when guys aren't looking far enough ahead of the car. They focus too close to the front so when they are approaching the exit of the fast sweeper they all of a sudden get surprised when they realize they cant make it and over react with the inputs and cause bigger problems.
If you do realize it is an understeer induced over steer situation, than one thing to consider is the car and tires can only do so much. Don't try to force the car to carry more mid corner speed than it is capable of. Autox is great at teaching not to over drive the car.
This may not be what is going on in your situation but might be something to consider. Its hard to sort out a handling or driving issue over a key board.
I saw some post's over in the gt3 section with you guys discussing setup. Don't get too wrapped up in the fine details. (tenths of camber, mm of ride height ect..) If the car is not way out in any spec than it should be drive-able at the track. Endurance drivers have to drive around all sorts of problems during a long race when the car isnt "perfect". Just try to go as fast as the car is capable of and don't over think about set up. Focus on driving what you have. I would be willing to bet most of the guys couldnt tell a difference at all with setup changes like 5mm or .1 degree of camber. Unless the setup change is done correctly on a setup pad at the track and tested back to back on similar tires and similar conditions then there is no way to know really if there was any difference. If those guys say they noticed a difference while ignoring the fact they put on different tires, a day a month later and it was 20 degrees cooler outside ect...
A track like sebring could be 2 seconds faster in a morning session than in the afternoon. Sorry for the long post
Hopefully there is something in there that might help.
02-25-2012, 09:32 AM
#764
It sounds like it may be understeer induced oversteer. Basically the car is understeering more than the driver wants. He weights the nose by either trail braking more, (which if done too much itself can cause more under steer) or adding more steering angle (which if the car is pushing, turning the wheel more will not really do anything since the front tires are already at their friction circle limit). When the apex or mid corner speed is low enough, the front end starts to regain grip while the front wheels are turned too far or, because of the heavy trailbraking, the rear has started to over rotate which would be amplified by the front tires regaining grip. This cause the back end to step out and the car goes into an over steer. Basically the driver is trying too hard to drive around the under steer and causing a handling problem on exit.
Similar thing in the fast corner. Say the car is pushing into and through the sweeper. The driver realizes he is going to run out of road, he lifts slightly which unloads the rear of the car and causes a slight over steer fade. This surprises the driver and he lifts more on instinct which just makes it worse. The best way to avoid that is if the car can't take it flat, then breath before going into the corner and power through it. If it can be done flat, then do it flat and don't upset the car with throttle lifts it doesn't need. I have seen a similar thing in this type of corner when guys aren't looking far enough ahead of the car. They focus too close to the front so when they are approaching the exit of the fast sweeper they all of a sudden get surprised when they realize they cant make it and over react with the inputs and cause bigger problems.
If you do realize it is an understeer induced over steer situation, than one thing to consider is the car and tires can only do so much. Don't try to force the car to carry more mid corner speed than it is capable of. Autox is great at teaching not to over drive the car.
This may not be what is going on in your situation but might be something to consider. Its hard to sort out a handling or driving issue over a key board.
I saw some post's over in the gt3 section with you guys discussing setup. Don't get too wrapped up in the fine details. (tenths of camber, mm of ride height ect..) If the car is not way out in any spec than it should be drive-able at the track. Endurance drivers have to drive around all sorts of problems during a long race when the car isnt "perfect". Just try to go as fast as the car is capable of and don't over think about set up. Focus on driving what you have. I would be willing to bet most of the guys couldnt tell a difference at all with setup changes like 5mm or .1 degree of camber. Unless the setup change is done correctly on a setup pad at the track and tested back to back on similar tires and similar conditions then there is no way to know really if there was any difference. If those guys say they noticed a difference while ignoring the fact they put on different tires, a day a month later and it was 20 degrees cooler outside ect... A track like sebring could be 2 seconds faster in a morning session than in the afternoon.
Sorry for the long post Hopefully there is something in there that might help.
Similar thing in the fast corner. Say the car is pushing into and through the sweeper. The driver realizes he is going to run out of road, he lifts slightly which unloads the rear of the car and causes a slight over steer fade. This surprises the driver and he lifts more on instinct which just makes it worse. The best way to avoid that is if the car can't take it flat, then breath before going into the corner and power through it. If it can be done flat, then do it flat and don't upset the car with throttle lifts it doesn't need. I have seen a similar thing in this type of corner when guys aren't looking far enough ahead of the car. They focus too close to the front so when they are approaching the exit of the fast sweeper they all of a sudden get surprised when they realize they cant make it and over react with the inputs and cause bigger problems.
If you do realize it is an understeer induced over steer situation, than one thing to consider is the car and tires can only do so much. Don't try to force the car to carry more mid corner speed than it is capable of. Autox is great at teaching not to over drive the car.
This may not be what is going on in your situation but might be something to consider. Its hard to sort out a handling or driving issue over a key board.
I saw some post's over in the gt3 section with you guys discussing setup. Don't get too wrapped up in the fine details. (tenths of camber, mm of ride height ect..) If the car is not way out in any spec than it should be drive-able at the track. Endurance drivers have to drive around all sorts of problems during a long race when the car isnt "perfect". Just try to go as fast as the car is capable of and don't over think about set up. Focus on driving what you have. I would be willing to bet most of the guys couldnt tell a difference at all with setup changes like 5mm or .1 degree of camber. Unless the setup change is done correctly on a setup pad at the track and tested back to back on similar tires and similar conditions then there is no way to know really if there was any difference. If those guys say they noticed a difference while ignoring the fact they put on different tires, a day a month later and it was 20 degrees cooler outside ect...
A track like sebring could be 2 seconds faster in a morning session than in the afternoon. Sorry for the long post
Hopefully there is something in there that might help.I'm going to go to a "normal" set up and stick to it. Maybe not what I have now, but something I've had before. I'll leave set up to race cars with engineers.