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      11-26-2011, 04:51 PM   #1
Ateam
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Best place to shift-dct

So I realized I am just not good at being able to take it all the way to 8400 without having fuel cutoff engage. I try to shift around when the needle passes 8k and usually that works but sometimes it is a bit to late and its hard to guess how much before 8400 to shift, in order for it to actually hit 8400 in manual mode? Same with the shift lights-sometimes I get it sometimes not. I am probably just inept but any tips may help!
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      11-26-2011, 05:09 PM   #2
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So I realized I am just not good at being able to take it all the way to 8400 without having fuel cutoff engage. I try to shift around when the needle passes 8k and usually that works but sometimes it is a bit to late and its hard to guess how much before 8400 to shift, in order for it to actually hit 8400 in manual mode? Same with the shift lights-sometimes I get it sometimes not. I am probably just inept but any tips may help!
I'm going to be that smartass and say the bet place to shift the DCT is from inside of the car.

Don't the shift lights help with this issue at all? Maybe shift while it's amber?
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      11-26-2011, 05:43 PM   #3
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its all about feel and practice...i can shift at 8400 without looking
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      11-26-2011, 05:50 PM   #4
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its all about feel and practice...i can shift at 8400 without looking
How do you know your shifting at 8400 if your not looking?
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      11-26-2011, 05:54 PM   #5
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How do you know your shifting at 8400 if your not looking?
I have seen videos and my friends have told me.
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      11-26-2011, 06:05 PM   #6
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Except as a purely academic exercise, I'm not sure I understand the focus on shifting at 8400. If you look at the hp/torque characteristics of the engine, it just doesn't make much practical difference. On the typical road course, you're usually much more appropriately focused on what you should be doing with the other controls, in order to have the car where it needs to be at about the time it needs to be there.
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      11-26-2011, 06:12 PM   #7
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Originally Posted by elh0102 View Post
Except as a purely academic exercise, I'm not sure I understand the focus on shifting at 8400. If you look at the hp/torque characteristics of the engine, it just doesn't make much practical difference. On the typical road course, you're usually much more appropriately focused on what you should be doing with the other controls, in order to have the car where it needs to be at about the time it needs to be there.
+1. I would focus on shifting at around 8k rpm, if you are at the track/WOT. As you have probably realized, this is easier in higher gears than lower gears, in part due to how short 1st and 2nd are, and due to how quickly the engine revs.
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      11-26-2011, 06:18 PM   #8
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good advice. Shifting at 8k or so sounds like a good goal and then you are likely to truly shift around 8200-8400 by the time it shifts. That is a good target to shoot for thanks
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      11-30-2011, 06:24 AM   #9
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Isn't this what the Shift Lights are for?
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      11-30-2011, 06:41 AM   #10
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Quote:
Originally Posted by elh0102 View Post
Except as a purely academic exercise, I'm not sure I understand the focus on shifting at 8400. If you look at the hp/torque characteristics of the engine, it just doesn't make much practical difference. On the typical road course, you're usually much more appropriately focused on what you should be doing with the other controls, in order to have the car where it needs to be at about the time it needs to be there.
1... At the track I'm just too busy to be looking at the speed and RPMs, so I do my best to "feel" the car and shift when it needs it.
I make mistakes, but I'm getting there.
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      11-30-2011, 08:55 AM   #11
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Isn't this what the Shift Lights are for?
Yes.
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      11-30-2011, 09:08 AM   #12
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This car revs so freely and quickly it's easy to just bounce off the limiter. Also, I believe you can adjust the sensitivity of the shift lights, ie. they come on earlier or later in the rev range. Don't think bouncing off the limiter is going to kill this car, at least hasn't killed mine yet I think you'll find seat time will cure all problems. The more I drive the more I love it
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      11-30-2011, 09:22 AM   #13
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Why would you want to take it all the way to 8400? By the time the engine has spooled up to that level, the torque has basically long been acheived, and waiting to shift will likely have the negative effect you are attempting to avoid. Try and use your other senses (not smarts) to determine when to shift. Feel and sound should be key, and use your lights to assist in your alert to shift. As the christmas tree begins to light up, shift. Don't wait until it reaches the end, if you do, you have missed your shifting point.
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      11-30-2011, 09:44 AM   #14
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Why would you want to take it all the way to 8400? By the time the engine has spooled up to that level, the torque has basically long been acheived, and waiting to shift will likely have the negative effect you are attempting to avoid.
Well, D5 will shift at red, and if you do the math (or search the forum - its been posted before as I recall) you will see the car is fastest when shifted at max RPM.
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      11-30-2011, 10:34 AM   #15
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Quote:
Originally Posted by von_zoom View Post
Why would you want to take it all the way to 8400? By the time the engine has spooled up to that level, the torque has basically long been acheived, and waiting to shift will likely have the negative effect you are attempting to avoid. Try and use your other senses (not smarts) to determine when to shift. Feel and sound should be key, and use your lights to assist in your alert to shift. As the christmas tree begins to light up, shift. Don't wait until it reaches the end, if you do, you have missed your shifting point.
vz
This has been my experience. The evidence is in how you're pushed back into your seat when you shift.
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      11-30-2011, 01:47 PM   #16
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This has been my experience. The evidence is in how you're pushed back into your seat when you shift.
No. mkoesel is correct on this. The best shift point for this car is exactly at the rev limiter. Not one rpm shy of it. Of course, that's not practical, but closer is better, and closest is best.

You're pushed back in your seat at the shift not by power or torque, but by rotational inertia. The engine is forced to slow down in an instant by, say, 3000 rpm or more on the one-two shift (less as you go up through the gears), and that energy is transferred through the driveline to the rear tires.

If the auto has a setting that will shift at the rev limiter, that's the one to use. Otherwise, use the one that shifts at red line.

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      11-30-2011, 05:28 PM   #17
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Guys, the simplest way to think about this is when an engine has a very linear power curve like the M3 the power you are producing is directly proportional to the rpm. Shift always at 8k instead of 8400 and you are only using

8000/8400 x 414 hp = 394 hp

This is a very rough calculation but shows even an 8k shift is leaving about 20 hp off the table! Not a huge difference (5%) but if you are counting 10th's or simply want to be insured you are moving out as best a possible you have to shift at redline.
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      11-30-2011, 05:57 PM   #18
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Originally Posted by swamp2 View Post
Guys, the simplest way to think about this is when an engine has a very linear power curve like the M3 the power you are producing is directly proportional to the rpm. Shift always at 8k instead of 8400 and you are only using

8000/8400 x 414 hp = 394 hp

This is a very rough calculation but shows even an 8k shift is leaving about 20 hp off the table! Not a huge difference (5%) but if you are counting 10th's or simply want to be insured you are moving out as best a possible you have to shift at redline.
Not only that, after every shift you'll end up at a higher rev if shifted at 8400rpm compared to 8000rpm hence more power again.
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      11-30-2011, 07:29 PM   #19
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High revving V8 FTMFW
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      11-30-2011, 07:37 PM   #20
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That's what's great about raising the rev limiter to 8600rpm. I did this with the ESS tune and now I can shift at 8400 RPM without hitting the limiter. I don't even have to look at the rev gauge, just shift when the lights turn red and I get a perfect shift every time.
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      11-30-2011, 07:48 PM   #21
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That's what's great about raising the rev limiter to 8600rpm. I did this with the ESS tune and now I can shift at 8400 RPM without hitting the limiter. I don't even have to look at the rev gauge, just shift when the lights turn red and I get a perfect shift every time.
Easy for me to say since it's not my car, but you will definitely be quicker if you shift it at 8599 rpm instead of 8400. In fact, shifting at close to 9000 rpm would be best - even with a dead stock power curve.

Of course, it might blow up, but that's a small price to pay for another tenth or two, isn't it?

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      11-30-2011, 08:01 PM   #22
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Easy for me to say since it's not my car, but you will definitely be quicker if you shift it at 8599 rpm instead of 8400. In fact, shifting at close to 9000 rpm would be best - even with a dead stock power curve.

Of course, it might blow up, but that's a small price to pay for another tenth or two, isn't it?

Bruce
I don't get it. Are you saying my engine is going to blow up if I shift at 8600 rpm?
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