Question about "sport shifting"

[Skawttey]

Originally posted by: gopunk

Originally posted by: notfred
You can't feather the clutch from a 3000 rpm launch in an auto, regardless of whether you tell it when to shift or the computer does. With no clutch, the tranny is either in gear, or it's not. With a clutch you get to take advantage of the in between space where the transmission is partially connected to the engine. It's also a lot more useable for revving the car w/o the wheels engaged than momentarily dropping the car to neutral like you'd have to do in an auto.

Note that this doesn't mean a manual tranny is necessarily going to launch better than an auto.

is feathering another term for making it so that the transmission is only partially connected to the engine? and all i know about clutches is from that link posted earlier, but wouldn't doing that wear down your clutch?

yes, that is correct. And yes, it will wear down on the clutch. All clutches will wear out eventually though, it is just the nature of the beast. How much you ride on it though will determine how quickly it will wear

 

[mugs]

Originally posted by: ElFenix

Originally posted by: mugsywwiii

Originally posted by: gopunk

could you elaborate on exactly how the clutch gives you control in layman's terms... what's rev-matching?

Learn to drive a manual transmission and all will become clear to you.

Edit: Woah... automatic transmission that doesn't shift until 6000 rpm? I thought they shifted way lower than that

umm... any regular auto will shift at the engine's redline if you floor it...

My bad, I thought he meant it shifted at 6000 normally, not with the pedal to the floor. I misread it.

 

[Mill]

Originally posted by: gopunk

Originally posted by: Millennium
Pretty basic idea of how a clutch works and why it is needed.

thanks for the link.... i still have a few questions though.... where does the gear changing come into play? is the amount of slippage based on how fast you push the clutch down? and what is rev-matching?

Let me think of a simple way to explain. Imagine you are going through a curve, you don't brake through curves you accelerate through them. You break before the curve and rely on acceleration to bring you through it. In most automatics, the transmission is not going to downshift you the meat of the powerband as easily as you can with a manual. When you rev-match you make the clutch and the engine spin at similar speeds. You basically rev while downshifting to keep the clutch and engine in harmony.

 

[Rainsford]

Originally posted by: Millennium

Originally posted by: gopunk

Originally posted by: Millennium
Pretty basic idea of how a clutch works and why it is needed.

thanks for the link.... i still have a few questions though.... where does the gear changing come into play? is the amount of slippage based on how fast you push the clutch down? and what is rev-matching?

Let me think of a simple way to explain. Imagine you are going through a curve, you don't brake through curves you accelerate through them. You break before the curve and rely on acceleration to bring you through it. In most automatics, the transmission is not going to downshift you the meat of the powerband as easily as you can with a manual. When you rev-match you make the clutch and the engine spin at similar speeds. You basically rev while downshifting to keep the clutch and engine in harmony.

That's one of the better explanations I've heard of that. Now how about an explanation of why all this is worthwhile driving around city streets? It's like overclocking your computer to surf the internet. Now I don't mind coolness for the sake of coolness (especially since I am doing exactly what I suggested in the last sentence), but at least admit it has no real value what so ever

 

[Desslok]

SMG.....................DROOOOOOOOOOOOOOOOOOOOOOOL

 

[gopunk]

ah thanks guys, i think have a much better understanding of how a standard transmission works

Originally posted by: ElFenix
sport shift is merely a computer controlled automatic transmission that lets you pick from a couple of gears, but the computer still has full control over the transmission and you still get the slushbox power loss, which is generally more than a manual.

there is such a thing as a sequential manual, aka semiautomatic, which is a manual transmission that has a computer operated clutch that allows it to shift in thousandths of a second instead of tenths like a regular manual.

hmm... so what happens when you select a gear...? in my car it tells you you're in 1-5... so is it lying to me...? i guess the one thing i'm not understanding is what is the point of moving the stick up or down if it's still auto...

 

[notfred]

Originally posted by: Cyberian

Originally posted by: notfred
You can't feather the clutch from a 3000 rpm launch in an auto, regardless of whether you tell it when to shift or the computer does. With no clutch, the tranny is either in gear, or it's not. With a clutch you get to take advantage of the in between space where the transmission is partially connected to the engine. It's also a lot more useable for revving the car w/o the wheels engaged than momentarily dropping the car to neutral like you'd have to do in an auto.

Note that this doesn't mean a manual tranny is necessarily going to launch better than an auto.

You may find this hard to believe, but not everyone is bustin' their ass trying to get 0-60 times under 6 seconds.

I realize. Did you notice the words "sport shifting" in the thread title? Did you misread that as "commute shifting" or something?

 

[notfred]

Originally posted by: gopunk
ah thanks guys, i think have a much better understanding of how a standard transmission works

Originally posted by: ElFenix
sport shift is merely a computer controlled automatic transmission that lets you pick from a couple of gears, but the computer still has full control over the transmission and you still get the slushbox power loss, which is generally more than a manual.

there is such a thing as a sequential manual, aka semiautomatic, which is a manual transmission that has a computer operated clutch that allows it to shift in thousandths of a second instead of tenths like a regular manual.

hmm... so what happens when you select a gear...? in my car it tells you you're in 1-5... so is it lying to me...? i guess the one thing i'm not understanding is what is the point of moving the stick up or down if it's still auto...

When you move the shifter to whichever gear, the car still shifts to that gear. It's an auto, but when you put it in "sport shift mode" it tells the car not to shift except when you tell it.

 

[atom]

hmm... so what happens when you select a gear...? in my car it tells you you're in 1-5... so is it lying to me...? i guess the one thing i'm not understanding is what is the point of moving the stick up or down if it's still auto...

Think of it like this, say you are driving around. What would you rather be doing, driving in 3rd gear while reving the engine higher or be in 4th gear with the engine at a low RPM? With a sport shift, you get to pick, not the ECU.

 

[Mill]

Originally posted by: Rainsford

Originally posted by: Millennium

Originally posted by: gopunk

Originally posted by: Millennium
Pretty basic idea of how a clutch works and why it is needed.

thanks for the link.... i still have a few questions though.... where does the gear changing come into play? is the amount of slippage based on how fast you push the clutch down? and what is rev-matching?

Let me think of a simple way to explain. Imagine you are going through a curve, you don't brake through curves you accelerate through them. You break before the curve and rely on acceleration to bring you through it. In most automatics, the transmission is not going to downshift you the meat of the powerband as easily as you can with a manual. When you rev-match you make the clutch and the engine spin at similar speeds. You basically rev while downshifting to keep the clutch and engine in harmony.

That's one of the better explanations I've heard of that. Now how about an explanation of why all this is worthwhile driving around city streets? It's like overclocking your computer to surf the internet. Now I don't mind coolness for the sake of coolness (especially since I am doing exactly what I suggested in the last sentence), but at least admit it has no real value what so ever

The city streets around here are curvy enough that you have fun no matter what.

 

[gopunk]

Originally posted by: notfred

Originally posted by: gopunk
ah thanks guys, i think have a much better understanding of how a standard transmission works

Originally posted by: ElFenix
sport shift is merely a computer controlled automatic transmission that lets you pick from a couple of gears, but the computer still has full control over the transmission and you still get the slushbox power loss, which is generally more than a manual.

there is such a thing as a sequential manual, aka semiautomatic, which is a manual transmission that has a computer operated clutch that allows it to shift in thousandths of a second instead of tenths like a regular manual.

hmm... so what happens when you select a gear...? in my car it tells you you're in 1-5... so is it lying to me...? i guess the one thing i'm not understanding is what is the point of moving the stick up or down if it's still auto...

When you move the shifter to whichever gear, the car still shifts to that gear. It's an auto, but when you put it in "sport shift mode" it tells the car not to shift except when you tell it.

hmmm ok... so basically the difference in control between stick shift and sport shift is that with sport shift, you can't control the feathering of the clutch and you can't disengage the engine easily... is that about right?

 

[gopunk]

Originally posted by: atom

hmm... so what happens when you select a gear...? in my car it tells you you're in 1-5... so is it lying to me...? i guess the one thing i'm not understanding is what is the point of moving the stick up or down if it's still auto...

Think of it like this, say you are driving around. What would you rather be doing, driving in 3rd gear while reving the engine higher or be in 4th gear with the engine at a low RPM? With a sport shift, you get to pick, not the ECU.

eh i don't know.... you're talking to a n00b here

 

[notfred]

Originally posted by: gopunk
hmmm ok... so basically the difference in control between stick shift and sport shift is that with sport shift, you can't control the feathering of the clutch and you can't disengage the engine easily... is that about right?

Well, from a standpoint of using it, that's most of it. From a standpoint of how it works, an automatic transmission (with or without sport shift) is COMPLETELY different from a manual.

 

[gopunk]

Originally posted by: notfred

Originally posted by: gopunk
hmmm ok... so basically the difference in control between stick shift and sport shift is that with sport shift, you can't control the feathering of the clutch and you can't disengage the engine easily... is that about right?

Well, from a standpoint of using it, that's most of it. From a standpoint of how it works, an automatic transmission (with or without sport shift) is COMPLETELY different from a manual.

alrighty, well thanks for everyone clearing things up!

 

[ElFenix]

Originally posted by: gopunk

Originally posted by: notfred

When you move the shifter to whichever gear, the car still shifts to that gear. It's an auto, but when you put it in "sport shift mode" it tells the car not to shift except when you tell it.

hmmm ok... so basically the difference in control between stick shift and sport shift is that with sport shift, you can't control the feathering of the clutch and you can't disengage the engine easily... is that about right?

the computer will still override and shift if you hit the redline or if your speed drops too low for the gear you're in. if you use sportshift mode you can leave it in sportshift mode and come to a complete stop and it will go all the way down to 1st from whatever gear you were in, say, 4th. you're in 5th at 75 and try to go to 2nd and it will let you go down to 3rd, but not second. the computer still has ultimate control. with a real manual, you have the ultimate control. you want to go above redline, you got it. you want to drive around in 2nd gear on the freeway at 6000 rpm, you got it. you want to do what that guy did with his RSX and downshift from 5th to 2nd instead of 4th and blow your engine? you got it. the most useful thing i've found for sportshift modes is dropping a gear before passing someone on the highway, which isn't any different than pressing the overdrive button on a regular automatic. sportshift is actually neither, when you think about it.

 

[erikiksaz]

hmmm ok... so basically the difference in control between stick shift and sport shift is that with sport shift, you can't control the feathering of the clutch and you can't disengage the engine easily... is that about right?

If i'm reading your question right, the answer is yes. Anyways, i don't think anyone's brought i up so far, but here's why i think stick is mucho useful:

1) You get to choose to keep the rpms high or low. Higher gas mileage depending on how you wanna do it.

2) From what i know, i don't believe automatics downshift (nm, forgot about the "gears" on an auto). When you're driving and want to accelerate quickly, you would drop down to the next gear (or the 2nd lowest, depending on your speed and how much ass you wanna haul). For the most part, this isn't needed in city driving, unless you like to make close cuts often!

3) You get to choose WHEN the car shifts gears. This is pretty much tied to #2.

 

[Mill]

Originally posted by: erikiksaz

hmmm ok... so basically the difference in control between stick shift and sport shift is that with sport shift, you can't control the feathering of the clutch and you can't disengage the engine easily... is that about right?

If i'm reading your question right, the answer is yes. Anyways, i don't think anyone's brought i up so far, but here's why i think stick is mucho useful:

1) You get to choose to keep the rpms high or low. Higher gas mileage depending on how you wanna do it.

2) From what i know, i don't believe automatics downshift. When you're driving and want to accelerate quickly, you would drop down to the next gear (or the 2nd lowest, depending on your speed and how much ass you wanna haul). For the most part, this isn't needed in city driving, unless you like to make close cuts often!

3) You get to choose WHEN the car shifts gears. This is pretty much tied to #2.

Go ahead and throw your opinion out the window, because automatics do downshift.

 

[xEDIT409]

So let me get this straight, When one downshifts, the gas pedal is pressed the entire time while shifting?

 

[PeeluckyDuckee]

taking a wild guess at the question posted by atom, would it be more efficient to run it at 4th gear with lower RPM? But if the torque is with the higher end RPMs and you want better response, then 3rd gear at high RPM would be the preferred choice I would think?

Interesting topic

 

[mAdD INDIAN]

Originally posted by: gopunk
some cars have this "sport shift" thing where it's automatic transmission, but you can still put the car in different gears. is the only difference between this and stick shift, the lack of a clutch? it seems to me this would offer the same amount of control as a stick shift...

thanks!

those have the torque converter. Its the same thing has manually shifting your auto tranny from D into 2 or 1 (or D1/D2/D3).

 

[Eli]

Originally posted by: xEDIT409
So let me get this straight, When one downshifts, the gas pedal is pressed the entire time while shifting?

Yes.

Haven't you ever ridden in a car with an automatic when the driver passes some slowpoke?

 

[idNut]

My car is slap stick, it's kinda cool.

 

[xEDIT409]

Originally posted by: Eli

Originally posted by: xEDIT409
So let me get this straight, When one downshifts, the gas pedal is pressed the entire time while shifting?

Yes.

Haven't you ever ridden in a car with an automatic when the driver passes some slowpoke?

I didn't know this... I've had a stick for a year now, and whenever I downshifted, I let off the gas, and when i shift down, I apply gas again... damn i'm stupid...

 

[Goosemaster]

Lets say that traffic is moving @ 30mph on I-95 and you see a nice little gap that you can slide into in the next lane

AUTO: Reagardless of sport or regular, the car DOES NOT anticipate this manuver, so even if you floor it, it will start in its current gear and progress there after......if it is in 4th gear for example, the gear can certainly keep the car moving at its present speed, so you'll really have to floor it so the trans will sense that it is in a weak section of the power curve and it will finally shift.

MANUAL: Keep in mind this is done in a matter of seconds or in a split second.

1. You gauge your speed.
MYCAR: 1st gear tops off noramlly around 20, 2nd @ 40mph and 3rd @ 60...these are reasonable...i can push the car if i want to.

Basically, since I am going 40mph in 4th gear, i gauge that if i need a lot of speed quickly i will shift to neutral, rev up( as the lower gear will be spinning faster and so i don't wear out the clutch), and shift into second

KEY INFO: because the revolutions will be a lot higher at the same speed, a lower gear will spin faster and it will be at the maximum point in the powercurve....basically gas-engines reach peak-power @ higher revs(diesel doesn't have to)

So although 4th gear will keep the car moving @ around 2000-3000rpm, if i floor it it will not immediate accelerate because i will be in a weak section of the engine;s powercurve.

In 2nd however, I will be at a high point, so if i floor it, i will FLY.

That is why sport shifters aren't as handy as they seem.

Keep in mind, racing sown a staright away is another story.


I am talking about shifting the car in neutral and letting it glide while you rev up the engine(applying the gas) and then letting out the clutch so that whne it makes contact with the flywheel the amount of time in which they sping at different speed while in contact is decreased or elimninated.....


Hopefully i didn't just confuse the hell out of you.

 

[gopunk]

Originally posted by: Goosemaster
Lets say that traffic is moving @ 30mph on I-95 and you see a nice little gap that you can slide into in the next lane

AUTO: Reagardless of sport or regular, the car DOES NOT anticipate this manuver, so even if you floor it, it will start in its current gear and progress there after......if it is in 4th gear for example, the gear can certainly keep the car moving at its present speed, so you'll really have to floor it so the trans will sense that it is in a weak section of the power curve and it will finally shift.

MANUAL: Keep in mind this is done in a matter of seconds or in a split second.

1. You gauge your speed.
MYCAR: 1st gear tops off noramlly around 20, 2nd @ 40mph and 3rd @ 60...these are reasonable...i can push the car if i want to.

Basically, since I am going 40mph in 4th gear, i gauge that if i need a lot of speed quickly i will shift to neutral, rev up( as the lower gear will be spinning faster and so i don't wear out the clutch), and shift into second

KEY INFO: because the revolutions will be a lot higher at the same speed, a lower gear will spin faster and it will be at the maximum point in the powercurve....basically gas-engines reach peak-power @ higher revs(diesel doesn't have to)

So although 4th gear will keep the car moving @ around 2000-3000rpm, if i floor it it will not immediate accelerate because i will be in a weak section of the engine;s powercurve.

In 2nd however, I will be at a high point, so if i floor it, i will FLY.

That is why sport shifters aren't as handy as they seem.

Keep in mind, racing sown a staright away is another story.


I am talking about shifting the car in neutral and letting it glide while you rev up the engine(applying the gas) and then letting out the clutch so that whne it makes contact with the flywheel the amount of time in which they sping at different speed while in contact is decreased or elimninated.....


Hopefully i didn't just confuse the hell out of you.

no not at all... that was a really good explanation of things to be a n00b but if you have sport shift, couldn't you hit the gas, then downshift? i see why the stick has an advantage over normal automatic transmission tho.