Clutch/Throttle See-Saw Motion

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MacAttack
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Clutch/Throttle See-Saw Motion

Post by MacAttack »

If I push the throttle down earlier than normal sometimes is that the equivalent of rev-matching?

For example if I'm accelerating in 3rd gear & just do everything normal I get a nice smooth shift to 4th.

If, on the other hand, I'm just cruising along slowly in 3rd gear & want to cruise in 4th instead, the shift is not
smooth going to 4th because the rpm's were never high enough in 3rd.

But if I start giving it gas much earlier than normal while just starting to let the clutch pedal out, it usually turns out pretty smooth. (as opposed to giving
it gas just as the clutch is almost released).

Does that question make any sense?
I'm giving it gas while letting the clutch pedal up as opposed to giving it gas just as the clutch pedal is fully released.
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Re: Clutch/Throttle See-Saw Motion

Post by LHOswald »

if your aim is to drive as smoothly as possible, more than likely your going to have to give a little bit of gas (even if its only a millimeter) while your releasing the clutch, to help the engine not drop revs so quickly. once you get a good enough feel with your car you can pretty much drop the gas, stab the clutch, drop it into the next gear and dump the clutch (albeit at the right time...this is the part that comes with experience) then add gas, and you'll never even feel a jolt.
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Re: Clutch/Throttle See-Saw Motion

Post by theholycow »

If something you did with the accelerator makes your shift smoother, then what you did was rev-matching.
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Re: Clutch/Throttle See-Saw Motion

Post by AHTOXA »

Just don't spend too much time throttling and engaging the clutch at the same time. You want some overlap but not too much when you are gassing through a slipping clutch.
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Re: Clutch/Throttle See-Saw Motion

Post by MacAttack »

AHTOXA wrote:Just don't spend too much time throttling and engaging the clutch at the same time. You want some overlap but not too much when you are gassing through a slipping clutch.
That's kind of what I was wondering about.

As The Holy Cow said I must be rev-matching since it smooths it out.
But I didn't know if the way I'm doing was better or worse than just working the pedals as normal but getting the jolt from everything not being matched up.

There are times when I want to shift & I know I'll get a jolt if I shift normal because the rpm's just aren't high enough for a smooth shift. So in those cases I'll start the throttle down what seems like a millisecond before starting the clutch pedal up, and it's very smooth.
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Re: Clutch/Throttle See-Saw Motion

Post by Reverence »

I categorise see-saw as 3 types of situations:

1) the perfect rev-match.
you don't feel any shock, all smooth

2) wheels catching up with motor. (you shifted too fast, or started adding too much gas before FP)
you feel the car accelerating faster than your initial acceleration, as you see-saw

3) motor catching up with the wheels (you shifted too slow and added too little gas to make up for it)
you feel car slowing down as you see-saw your way back to speed.

THC will add where I missed out (in a hurry)
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Re: Clutch/Throttle See-Saw Motion

Post by theholycow »

Reverence wrote:THC will add where I missed out (in a hurry)
Sounds about right to me.

Option number 2 can also be caused by rev hang.
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Re: Clutch/Throttle See-Saw Motion

Post by Rope-Pusher »

Image

Where have all the see-saws gone, long time passing?
Where have all the see-saws gone, long time ago?
Where have all the seesaws gone?
Insurance company lawyers have banned them everyone.
Oh, when will they ever learn?
Oh, when will they ever learn?

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Re: Clutch/Throttle See-Saw Motion

Post by bk7794 »

I hear that 1st to 2nd almost always needs to be rev matched to make it smooth correct? or will always have a shift shock. Can someone clarify?
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Re: Clutch/Throttle See-Saw Motion

Post by theholycow »

Most people just smooth that shift with the clutch.
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Re: Clutch/Throttle See-Saw Motion

Post by AHTOXA »

Yeah, because it's not practical to wait for revs to fall in range.
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Re: Clutch/Throttle See-Saw Motion

Post by bk7794 »

theholycow wrote:Most people just smooth that shift with the clutch.
And a bit of gas correct?
AHTOXA wrote:Yeah, because it's not practical to wait for revs to fall in range.
Is that why it is so jerky, cause you are waiting for the wheels to catch up for the engine right?
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Re: Clutch/Throttle See-Saw Motion

Post by theholycow »

bk7794 wrote:And a bit of gas correct?
Kinda. I suppose you could look at it that way. To me, the gas applied in that shift is the gas applied to accelerate the car, not as part of the shift. The engine is usually already revving higher than necessary in the 1->2 shift, which is why people have difficulty smoothing that shift until they learn to let the clutch smooth it...so you aren't really applying gas until you have enough clutch friction to accelerate the car.

Of course, if that doesn't work well for you, do experiment to find what works well.
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Re: Clutch/Throttle See-Saw Motion

Post by bk7794 »

theholycow wrote:
bk7794 wrote:And a bit of gas correct?
Kinda. I suppose you could look at it that way. To me, the gas applied in that shift is the gas applied to accelerate the car, not as part of the shift. The engine is usually already revving higher than necessary in the 1->2 shift, which is why people have difficulty smoothing that shift until they learn to let the clutch smooth it...so you aren't really applying gas until you have enough clutch friction to accelerate the car.

Of course, if that doesn't work well for you, do experiment to find what works well.
for some reason it seems like the car I drive wants gas a bit...not sure if the engine doesn't have rev hang, or if I am doing what you are talking about...I always seem to have to do something with the throttle to smooth it out..or maybe it is part of the acceleration...yeah I think your right cause sometimes for some reason my foot lets off the gas and I feel it bogging there.
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Re: Clutch/Throttle See-Saw Motion

Post by Reverence »

Problems with 1->2 shifts:

Initiating the shift:
1) too early off the gas before stepping on the clutch> car is already engine braking heavily (decelerating) and it jolts forward when you step on the clutch
***ease off the gas a little before stabbing the clutch pedal, don't just get off the gas.

2) too much on the gas while stepping on the clutch>> car is still accelerating heavily when you stab the clutch, there is a sudden deceleration and car jolts backward.
***ease off the gas a little before stabbing the clutch pedal

Completing the shift:
3) too early (quick) release of clutch pedal, car jolts forward
***wait longer before release clutch pedal, or controlled release of clutch (smooth it with the clutch). Car will be accelerating while clutch travels through Friction Point and you want to be back on the gas towards the end of that acceleration.

4) too late (quick) release of clutch pedal, car jolts backward.
***release the clutch earlier, or controlled release of clutch (smooth it with the clutch) as you are starting to add gas

5) just right (quick) release of clutch pedal, no jolts, you're not on the gas yet and you stab the gas pedal, car jolts forward (due to throttle lag)
***be back a tad on the gas as your release clutch pedal, or go easy on the gas pedal (feather it) to avoid surge of torque after the (throttle) lag.
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