How do you down shift in a sequential?
#1
How do you down shift in a sequential?
1. Brake, clutch, push lever forward, blip throttle, release clutch and repeat if multiple down shift
or
2. Brake, clutch+push lever forward+blip throttle all at the same time then release clutch
Video below looks like the driver do clutch+push lever forward+blip throttle all at the same time. I finally got used to push and release clutch with each gear change. Let's leave auto blipper out of the discussion for now ...
Cheers
Mike
or
2. Brake, clutch+push lever forward+blip throttle all at the same time then release clutch
Video below looks like the driver do clutch+push lever forward+blip throttle all at the same time. I finally got used to push and release clutch with each gear change. Let's leave auto blipper out of the discussion for now ...
Cheers
Mike
#3
#4
That's a video of me (left) and JvO (right) in my car (no auto-blipper), we're both shifting as described in #1-- clutch release on each gear downshifted. I just installed a dual chasecam setup in the car with 1 camera pointed at the pedals, I can post a video after I test the car on Sep 1st if it'll help.
-mike
-mike
#5
That's a video of me (left) and JvO (right) in my car (no auto-blipper), we're both shifting as described in #1-- clutch release on each gear downshifted. I just installed a dual chasecam setup in the car with 1 camera pointed at the pedals, I can post a video after I test the car on Sep 1st if it'll help.
-mike
-mike
Cheers
#6
If you blip after you hit the shifter, it won't help, too late. Should blip just before for best results. The auto blipper can't do that, works at the same time and seems ok but not quite as good as a perfect downshift. If you don't hear a grind, you did it just about perfectly. A good downshift will still grind a bit. Hope that helps!
#7
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dam, we got three mikes in this thread.
i am with analogmike. the sequence of movements should be same regardless of sequential or H pattern. brake as needed, clutch, blip and shifthing occur close to each other but NOT same time. the clutch should be on the floor and then blip, if clutch is not down, you can't blip. you are still in gear.
once you blipped, fraction of nanosecond later, you shift.
i am with analogmike. the sequence of movements should be same regardless of sequential or H pattern. brake as needed, clutch, blip and shifthing occur close to each other but NOT same time. the clutch should be on the floor and then blip, if clutch is not down, you can't blip. you are still in gear.
once you blipped, fraction of nanosecond later, you shift.
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#8
If you blip after you hit the shifter, it won't help, too late. Should blip just before for best results. The auto blipper can't do that, works at the same time and seems ok but not quite as good as a perfect downshift. If you don't hear a grind, you did it just about perfectly. A good downshift will still grind a bit. Hope that helps!
And autoblipper is not girls.
After 50 hours in my car without it, I had the tranny opened for rebuild and it was in perfect condition so I can say I didn't "need" a blipper. Got one installed this year just to do the downshifting sequence quicker (for multiple gears downshifts) and focus on braking at threshold. Couldn't use it much yet because of a recurring issue on the engine (resolved now !) but liked it a lot when I did.
#9
Another thing I've recently caught from looking at motec data from my 09 Cup is that timing of the downshifts is supremely important. If you downshift a little to late, you'll see your longitudinal G get closer to zero (car stops slowing down). I've been working on it, but it's really hard to get rite.. below is a screenshot of my personal best lap at TH (1:47.5) where all 3 of my downshifts into T14 are about 200-300rpm to late which causes the rear wheels to want to spin faster than the current speed when I let out the clutch. It also includes clutch pressure and gear force lever volts so you can see the timing of everything.
Mikymu, you should have the exact same motec system in your car so you should be able to compare your data to the screenshot...
ps: had a chance to test a grand-am/continental GS car last week.. if you can get the 997 cup braking rite, you can drive anything! :P
-mike
Mikymu, you should have the exact same motec system in your car so you should be able to compare your data to the screenshot...
ps: had a chance to test a grand-am/continental GS car last week.. if you can get the 997 cup braking rite, you can drive anything! :P
-mike
#10
I am not good at reading data but do you mean downshifting too late or blipping too hard for the wheels speed so the car feels like it wants to accelerate while you brake ? If I downshifted late I had to adjust the blip strenght to match the revs. With a blipper I guess you can't do that and timing is even more important ?
#11
I am not good at reading data but do you mean downshifting too late or blipping too hard for the wheels speed so the car feels like it wants to accelerate while you brake ? If I downshifted late I had to adjust the blip strenght to match the revs. With a blipper I guess you can't do that and timing is even more important ?
I like to downshift as early as possible in the braking zones to stabilize the rear of the car, my goal is to have the shift lights come on for 1-2 seconds on every downshift. On this lap the shift lights came on for all 3 downshifts, but just not long enough and it resulted in the loss of longitudinal G in the braking zone. These cars are very sensitive....
For ultimate lap time I don't think it hurts too much, but for passing under braking, etc.. you obviously want your braking zones as short as possible.
edit: this is just my opinion of course, i'm always open for advice/tips from others that do things differently!
-mike
Last edited by fleadh; 08-29-2011 at 03:07 PM.
#12
If you blip after you hit the shifter, it won't help, too late. Should blip just before for best results. The auto blipper can't do that, works at the same time and seems ok but not quite as good as a perfect downshift. If you don't hear a grind, you did it just about perfectly. A good downshift will still grind a bit. Hope that helps!
dam, we got three mikes in this thread.
i am with analogmike. the sequence of movements should be same regardless of sequential or H pattern. brake as needed, clutch, blip and shifthing occur close to each other but NOT same time. the clutch should be on the floor and then blip, if clutch is not down, you can't blip. you are still in gear.
once you blipped, fraction of nanosecond later, you shift.
i am with analogmike. the sequence of movements should be same regardless of sequential or H pattern. brake as needed, clutch, blip and shifthing occur close to each other but NOT same time. the clutch should be on the floor and then blip, if clutch is not down, you can't blip. you are still in gear.
once you blipped, fraction of nanosecond later, you shift.
Another thing I've recently caught from looking at motec data from my 09 Cup is that timing of the downshifts is supremely important. If you downshift a little to late, you'll see your longitudinal G get closer to zero (car stops slowing down). I've been working on it, but it's really hard to get rite.. below is a screenshot of my personal best lap at TH (1:47.5) where all 3 of my downshifts into T14 are about 200-300rpm to late which causes the rear wheels to want to spin faster than the current speed when I let out the clutch. It also includes clutch pressure and gear force lever volts so you can see the timing of everything.
Mikymu, you should have the exact same motec system in your car so you should be able to compare your data to the screenshot...
ps: had a chance to test a grand-am/continental GS car last week.. if you can get the 997 cup braking rite, you can drive anything! :P
-mike
Mikymu, you should have the exact same motec system in your car so you should be able to compare your data to the screenshot...
ps: had a chance to test a grand-am/continental GS car last week.. if you can get the 997 cup braking rite, you can drive anything! :P
-mike
#13
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#14
#15
Actually it's not really that it doesn't have synchros as much as the fact that it's sequential. If you had an H-pattern dog box there would still be some usefulness to double clutch rev-matching, though if your rpm drops are right, an argument could be made that it isn't required. But given how the internal function of a sequential works and the fact that it never really is in neutral, like an H-pattern box is, there's absolutely no need to double clutch. The blip is strictly to bring the engine up in speed a little bit to get it closer to the speed the gearbox shafts will be spinning to minimize the shockload on the driveline when you release the clutch.