Jenson Button's view on noise and torque of the turbo 6 vs NA V8...

[Boss330]

Originally Posted by SoFlo335

Actually, those GP3 cars ran NA 3.5L V6 engines in 2013. But from 2010-2012 they ran 2.0L turbo engines.

I do agree with everything else you have said. Although, it is common sometimes to short shift coming out of slow corners, but it has nothing to do with the amount of low end tq the engine creates. Instead, the short shift has more to do with traction, short shifting will help you not break traction, and still get a good exit.

Hahaha... Major faux pas on my side...

Let's try this GTR then... (just imagine how much faster they could have gone if the driver had known that turbo engines is faster if you short shift )

[solstice]

Originally Posted by SoFlo335

Actually, those GP3 cars ran NA 3.5L V6 engines in 2013. But from 2010-2012 they ran 2.0L turbo engines.

I do agree with everything else you have said. Although, it is common sometimes to short shift coming out of slow corners, but it has nothing to do with the amount of low end tq the engine creates. Instead, the short shift has more to do with traction, short shifting will help you not break traction, and still get a good exit.

Nice someone else joins. I'm curious about the thought behind this. I think this works well with a NA engine were you have a lot less power at low rpms and can choose to shift instead of throttle modulate to limit excessive power and going sideways. With a turbo engine I would be more inclined to not shift and get the gear multiplication jolt and similar power which seem to be a larger risk to lose traction?

[Boss330]

Originally Posted by solstice

Nice someone else joins. I'm curious about the thought behind this. I think this works well with a NA engine were you have a lot less power at low rpms and can choose to shift instead of throttle modulate to limit excessive power and going sideways. With a turbo engine I would be more inclined to not shift and get the gear multiplication jolt and similar power which seem to be a larger risk to lose traction?

Take a look at the GTR videos, not a lot of short shifting to be seen as they set the Nurburgring time

The idea behind short shifting is that if you change up to a higher gear, you get less torque to the driving wheels. This is where the torque to the wheels calculations come into play. One cannot look at the engines torque curve alone. What matters is torque to the rear wheels!

Even though the engine makes more torque lower down (like a turbo engine usually does), what matters is how much torque the rear wheels get. Which is why it's better, for maximum acceleration, to go to the redline since you, even with a falling torque curve, see more torque to the rear wheels at redline than you do at, say 5500rpm, in the next higher gear.

Just look at the very simplified torque after the transmission calculation attached to my post (not taking into account inertia and drivetrain losses).

Say you are in 2nd gear and are coming out of a corner and don't have great traction. No matter where in the rev range you are in 2nd gear, you will see that changing up to 3rd gear will give you less torque to the rear wheels and hence less force available to break the traction between rear wheels and tarmac. That is why short shifting is beneficial in low traction situations

Notice that, for best acceleration, you also see that in 3rd in this example it's better to shift to 4th (depending on at what RPM 4th will start at) slightly before 7500rpm, since the torque after the transmission is higher at 5000rpm in 4th than it is at 7500rpm in 3rd. But if the gear ratio in 4th will only bring the rpm down to 5500rpm, then it's better to go to the redline in 3rd.

[SoFlo335]

Originally Posted by solstice

Nice someone else joins. I'm curious about the thought behind this. I think this works well with a NA engine were you have a lot less power at low rpms and can choose to shift instead of throttle modulate to limit excessive power and going sideways. With a turbo engine I would be more inclined to not shift and get the gear multiplication jolt and similar power which seem to be a larger risk to lose traction?

Well, I'm guessing that this F1 engine will drive more like a NA engine with a lot of tq, rather than a conventional turbo engine. I think they will be using the HERS to wind up the turbo to avoid turbo lag.

In the turbo GP3 car, there was a lot of lag, so as a driver, you would have to apply the power much earlier than normal to spool the turbo up, once the turbo was spooled up, the driver would then hold the throttle there (prob 50% or so), until they were ready to go to full power and exit the corner.

Being in a low gear coming out of a hairpin (for example), you can't be too aggressive with the throttle application, if you are, then you will light up the rears. That's where short shifting comes in. If you short shift to the next gear, you will have less tq to deal with, and you can be more aggressive going back to power, maximizing your exit.

[solstice]

Originally Posted by Boss330

Take a look at the GTR videos, not a lot of short shifting to be seen as they set the Nurburgring time

The idea behind short shifting is that if you change up to a higher gear, you get less torque to the driving wheels. This is where the torque to the wheels calculations come into play.

Even though the engine makes more torque lower down (like a turbo engine usually does), what matters is how much torque the rear wheels get. Which is why it's better to go to the redline since you, even with a falling torque curve, see more torque to the rear wheels at redline than you do at, say 55000rpm, in the next higher gear.

Just look at the very simplified torque after the transmission calculation attached to my post (not taking into account inertia and drivetrain losses).

Say you are in 2nd gear and are coming out of a corner and don't have great traction. No matter where in the rev range you are in 2nd gear, you will see that changing up to 3rd gear will give you less torque to the rear wheels and hence less force available to break the traction between rear wheels and tarmac. That is why short shifting is beneficial in low traction situations

Sorry, but I'd like to hear SoFlo335's thoughts. I'm done with you eposs , hundreds of videos, twists and turns and focus on the wrong details. We're mainly talking about difference to a NA engine here and why short shifting the turbo engine in this situation make more sense than the NA engine. In my opinion , the opposite is true.

[Boss330]

Originally Posted by solstice

Sorry, no offense but I'd like to hear SoFlo335's thoughts. I'm done with you eposs , hundreds of videos, twists and turns and focus on the wrong details. We're mainly talking about difference to a NA engine here and why short shifting the turbo engine in this situation make more sense than the NA engine. In my opinion , the opposite is true.

Don't understand how the concept of torque to the rear wheels doesn't make sense

Focus "on the wrong details" care to provide me an example of which "wrong details" I have focused on?

That concept is the same both on a NA and turbo engine... If you get less torque to the wheels when changing up, you have less force acting on the wheels and hence less acceleration, or chance of tire slip.

But no prob that you want to hear it from someone else

BTW, the calculations was based on the S55 torque curve, and the DCT gear ratios

And, shouldn't those "hundreds of videos" showing high performance turbo cars being driven the way I have tried to explain to you tell you something? That perhaps short shifting isn't the quickest way to drive these cars...

You say that in your opinion it's not better to short shift a turbo engined car out of a corner if traction is a problem. Can you explain why you believe that short shifting gives no traction advantage in that situation?

[solstice]

Originally Posted by Boss330

Focus "on the wrong details" care to provide me an example of which "wrong details" I have focused on?

That concept is the same both on a NA and turbo engine... If you get less torque to the wheels when changing up, you have less force acting on the wheels and hence less acceleration, or chance of tire slip.

The little detail that this was all about the difference to last years NA cars. That is the whole context. When you say you expect more short shifting coming out of corners with the new engine that implies that this is now more beneficial vs the NA engine. Lecturing about something I already know is not doing anything but sounding patronizing and trying to score cheap points counter to the original argument. This really is the last time I'm going to reply to you in any matter. There the last word is yours make it count.

[Boss330]

Originally Posted by solstice

The little detail that this was all about the difference to last years NA cars. That is the whole context. When you say you expect more short shifting coming out of corners with the new engine that implies that this is now more beneficial vs the NA engine. Lecturing about something I already know is not doing anything but sounding patronizing and trying to score cheap points counter to the original argument. This really is the last time I'm going to reply to you in any matter. There the last word is yours make it count.

The turbo engines have a broader rev range to play with, which is why I believe there might be more shortshifting than before. And that the much larger torque of the turbo engines means traction will be a problem, and then short shifting out of corners might be better for traction as changing up decreases the torque to the rear wheels. So IMHO short shifting might be seen more often out of corners for traction reasons, NOT for best acceleration down the straights where I believe we will still see redline shifting. So, more short shifting since the torque is so much higher and traction out of corners might be an issue. Not short shifting as a way to get quicker acceleration when traction isn't limited. AND, this year they have 8 fixed gear ratios (to be decided by the team before the start of the season), meaning that at some circuits the ratios won't be optimal for the track and that we might see some odd gear changes.

We have allready seen the Ferrari's struggling with traction out of corners, short shifting might be necessary to get traction

And I really think you are over reacting a bit here. I have tried to explain some facts, using examples such as videos in a way to illustrate my points (to show that it isn't just me, but also how these cars are driven in real life). The torque to the wheels concept is not a matter of view that can be dismissed as not relevant.. It's fact that cannot be ignored in understanding where the optimal shift points are for best acceleration or to understand why short shifting actually is better coming out of a corner with low traction (both in a NA engine and in a Turbo engine, such as the S55).

And I don't see that I have been lecturing you in things you allready knew? You wrote (before editing it) that my torque to the wheels post didn't make any sense to you. And you claim that it will be better for traction not to short shift out of a corner in a turbo engine (probably as you are just looking at the engines torque curve and see that if you short shift you get right back in that fat mid range torque again and therefore also should get more torque breaking the rear wheels loose). Understandable mistake, but what the wheels get is the torque multiplied by the gear and final drive ratio. And if you look at that you will see that torque to the rear wheels are lower if you change up, even if you are at 7500rpm in 2nd (where engine torque is at it's lowest) and change up to 3rd and start at 5500rpm (where the engine torque is at it's highest). So as long as changing up results in lower torque to the rear wheels, then short shifting is better for traction

In 2nd you have 1037Nm coming out of the trans at 7500rpm, but only 400Nm on the crank
In 3rd you have 935Nm coming out of the trans at 5000rpm, but 550Nm on the crank

So, even where you "only" have 400Nm at the crank, the torque multiplication through the transmission in 2nd sends 1037Nm to the rear axle. Changing up to a higher gear (3rd) and starting at 5000rpm where you have 550Nm at the crank, the torque multiplication through the transmission in 3rd ends up with "only" 935Nm to the rear axle, even though you have 150Nm more at the crank at 5000rpm than you had at 7500rpm.

All of the calculations are done without taking account for inertial losses and drivetrain losses, which might alter the crossover rpm's by a few %

Torque to the wheel calculations is a mathematical way to find optimum shiftpoints for best acceleration, and also illustrates why short shifting gives less torque to the driving wheels. And therefore, why it's beneficial to short shift if traction is limited. For best acceleration it's better to stay in the same gear as long as that gear has more torque to the wheels than the next gear. When torque to the wheels is lower in the gear you are in than in the next higher gear, then it's time to change up

[swamp2]

Originally Posted by Boss330

All of the calculations are done without taking account for inertial losses and drivetrain losses, which might alter the crossover rpm's by a few %

Making up random guesses off the top of your head?

Well when you have on the order of the same torque loss as power loss, ~15% from crank to wheels, the changes to shift points can be well more than a few % (of course heavily dependent on the shape of the torque curve). They too can be in the 10-15% range. Wost case scenario in the M-DCT M4 is for the 5-6 shift, that will change by about 13% in rpm taking or not taking losses into account.

[Boss330]

Originally Posted by swamp2

Making up random guesses off the top of your head?

Well when you have on the order of the same torque loss as power loss, ~15% from crank to wheels, the changes to shift points can be well more than a few % (of course heavily dependent on the shape of the torque curve). They too can be in the 10-15% range. Wost case scenario in the M-DCT M4 is for the 5-6 shift, that will change by about 13% in rpm taking or not taking losses into account.

Still doing the personal insults I see...

No, I was going by what you and CanAutM3 discussed So, a worst case 13% and the rest below that. Sounds like a few % isn't that far off...
(at least that isn't far off in my native tongue, but perhaps "a few" means something else in English (have to take that into account as swamp2 has commented on my sloppy English before...)

And after reading up on the definition in English of "a few" or "few", I agree that I should probably have chosen a different wording than "a few %" as it seems that "a few" usually implies anywhere between 3 to 7 (but varies according to the context it is used in).

[swamp2]

Originally Posted by Boss330

Still doing the personal insults I see...

No, I was going by what you and CanAutM3 discussed So, a worst case 13% and the rest below that. Sounds like a few % isn't that far off...
(at least that isn't far off in my native tongue, but perhaps "a few" means something else in English (have to take that into account as swamp2 has commented on my sloppy English before...)

Nope, sorry again, there was ZERO insult there. Hypersensitive much?

Comparing fact to your number indicates you basically made it up. Perhaps also you misunderstood the limited scope of that discussion. Run the real numbers yourself if you have any idea how to do so.

If you call a few close the 13, we will continue to be able to effectively communicate on anything even loosely technical.

[Jockey]

Jesus Christ, you two really need to start your own thread bitching back and forth.

[Boss330]

Originally Posted by swamp2

Nope, sorry again, there was ZERO insult there.

Comparing fact to your number indicates you basically made it up. Run the real numbers yourself if you have any idea how to do so.

If you call a few close the 13, we will continue to be able to effectively communicate on anything even loosely technical

Read my edited post above that perhaps explains my use of the phrase "a few". And that after reading up on the definition of that phrase in English I understand that it was the wrong phrase to use...

There was probably no insults directed towards me in that post either...


So how am I supposed to understand these comments from you:

"Making up random guesses on the top off your head"
"basically made it up"
"Run the real numbers yourself if you have any idea how to do so."

That is personal attacks and insulting...

And since you are nit picking my English, what does this mean:

Originally Posted by swamp2

If you call a few close the 13, we will continue to be able to effectively communicate on anything even loosely technical

[Boss330]

Originally Posted by Jockey

Jesus Christ, you two really need to start your own thread bitching back and forth.

We have had good discussions, but it now seems that instead of discussing the issues he is doing personal insults instead

[swamp2]

Originally Posted by Boss330

We have had good discussions, but it now seems that instead of discussing the issues he is doing personal insults instead

Well nothing like correcting gross errors of fact. I suppose that is not worthy of an ego-stroking "discussion"...



Seriously.

Of course I do fully agree on many good prior discussions.

[Boss330]

Originally Posted by swamp2

Well nothing like correcting gross errors of fact. I suppose that is not worthy of an ego-stroking "discussion"...



Seriously.

Of course I do fully agree on many good prior discussions.

As a consequence of your comment on "a few" I did have to look up the dictionary to see what that phrase meant in English, and I agree that the phrase "a few" was the wrong phrase to use...

The sentence I would have used in my native tongue has a word/phrase that I was sure meant the same as "a few" in English. However I realize that "a few" is a more limited amount than the native phrase I would have used...

And I admit that I thought it perhaps wasn't more than 10% at most.

BTW, do you agree with Solstice's view that there isn't any point in short shifting a turbo engine like the S55 if traction is a problem (like accelerating out of a corner)? It seems he doesn't agree with my take on torque at the rear wheels, and that even though engine torque is higher at 5000rpm than 7500rpm, it can still yield less torque to the wheels to short shift. And hence be better to short shift if traction is a problem.

[Boss330]

Originally Posted by swamp2

If you call a few close the 13, we will continue to be able to effectively communicate on anything even loosely technical.

Not entirely sure what that means

But I interpret your sentence above to mean that as long as a I mean that "a few" can be as much as 13%, then we won't be able to communicate on anything even loosely technical.

As I wrote previously, I agree that the term "a few" is usually limited to a lower number than 13, and I have since read the dictionary to see that in English that phrase wasn't appropriate.

But, since you have so strong opinions on my use of the phrase "a few" in that context and how we won't be able to "communicate on anything even loosely technical" based on that...

Let me remind you of how you, as an example, described the jerk in the F8x as 0,2G per 0,2second. Let me also remind you that a jerk of 0,2G per 0,2second is the same as a full on emergency brake situation...

"Making up random guesses off the top of your head?" possibly back then... And I tried correcting your "gross errors of fact" on the magnitude of the jerk not possibly being that large, but I never once saw a mathematical calculation of the real jerk (apart from your "emergency brake jerk" example ).

As you used an example that was such a "gross error of fact" I should have understood that we wouldn't be able to "communicate on anything even loosely technical"...

In fact "comparing fact to your number indicates you basically made it up" and that you really had NO idea on the real magnitude of the jerk. You had just looked at a curve and hadn't done any calculations to verify wether the jerk was on a scale that was beyound or below the treshold of human detection. Or wether it was far beyond the treshold, or just around the treshold, of human detection.

How can we discuss anything "even loosely technical" when you are "making up random guesses off the top of your head" which when, "comparing fact to your number indicates you basically made it up" and was a "gross error of fact"...

See, I can reply the same way you do

[swamp2]

Originally Posted by Boss330

Not entirely sure what that means

But I interpret your sentence above to mean that as long as a I mean that "a few" can be as much as 13%, then we won't be able to communicate on anything even loosely technical.

As I wrote previously, I agree that the term "a few" is usually limited to a lower number than 13, and I have since read the dictionary to see that in English that phrase wasn't appropriate.

But, since you have so strong opinions on my use of the phrase "a few" in that context and how we won't be able to "communicate on anything even loosely technical" based on that...

Let me remind you of how you, as an example, described the jerk in the F8x as 0,2G per 0,2second. Let me also remind you that a jerk of 0,2G per 0,2second is the same as a full on emergency brake situation...

"Making up random guesses off the top of your head?" possibly back then... And I tried correcting your "gross errors of fact" on the magnitude of the jerk not possibly being that large, but I never once saw a mathematical calculation of the real jerk (apart from your "emergency brake jerk" example ).

As you used an example that was such a "gross error of fact" I should have understood that we wouldn't be able to "communicate on anything even loosely technical"...

In fact "comparing fact to your number indicates you basically made it up" and that you really had NO idea on the real magnitude of the jerk. You had just looked at a curve and hadn't done any calculations to verify wether the jerk was on a scale that was beyound or below the treshold of human detection. Or wether it was far beyond the treshold, or just around the treshold, of human detection.

How can we discuss anything "even loosely technical" when you are "making up random guesses off the top of your head" which when, "comparing fact to your number indicates you basically made it up" and was a "gross error of fact"...

See, I can reply the same way you do

Keep up the f*&%ing misrepresentations... Much like you very often do, ONE of my replies on the jerk topic used some very crude approximate numbers just to make a point. Later, at your insistence, I corrected the numbers to be exact as per the simulations and guess what, the exact numbers indicated the exact same GENERAL PRINCIPLE I was making with the approximate numbers. Wow what a full on tragedy, get your head screwed on straight, really.

Glad you now understand a few vs. 13. If you couldn't acknowledge that, indeed we could not expect to have really any fruitful discussions with technical content.

Finally let me also remind you that your use of the e-brake analogy with jerk is entirely wrong. Jerk under braking is NOT how much deceleration an e-brake can provide. Jerk in the context of an e-brake is basically how rapidly the acceleration will go from zero (assuming constant velocity at the time of brake application) to the peak of deceleration under full lock up conditions. The factors affecting jerk in that case are: how long it takes the pads to go from just touching the rotor to fully locked, how much time the pad slides in the caliper body, caliper flex, wheel and tire flex, etc. You still just don't get it and I'd be willing to let that go but you just want to keep beating the dead horse and making yourself look sillier.

I can barely believe I have the patience to respond to such drivel...

[Boss330]

Originally Posted by swamp2

Keep up the f*&%ing misrepresentations... Much like you very often do, ONE of my replies on the jerk topic used some very crude approximate numbers just to make a point. Later, at your insistence, I corrected the numbers to be exact as per the simulations and guess what, the exact numbers indicated the exact same GENERAL PRINCIPLE I was making with the approximate numbers. Wow what a full on tragedy, get your head screwed on straight, really.

Glad you now understand a few vs. 13. If you couldn't acknowledge that, indeed we could not expect to have really any fruitful discussions with technical content.

Finally let me also remind you that your use of the e-brake analogy with jerk is entirely wrong. Jerk under braking is NOT how much deceleration an e-brake can provide. Jerk in the context of an e-brake is basically how rapidly the acceleration will go from zero (assuming constant velocity at the time of brake application) to the peak of deceleration under full lock up conditions. The factors affecting jerk in that case are: how long it takes the pads to go from just touching the rotor to fully locked, how much time the pad slides in the caliper body, caliper flex, wheel and tire flex, etc. You still just don't get it and I'd be willing to let that go but you just want to keep beating the dead horse and making yourself look sillier.

I can barely believe I have the patience to respond to such drivel...

I now you did correct your numbers, just like I allmost immediately did when it was pointed out that in English "a few" wasn't the appropriate term

I'm sorry, but in the above post you misrepresent my post. I said YOU used an example of 0,2G/0,2s to illustrate jerk in the F8x, not that i thought that was a representation of jerk. NOR that I believe that a emergency brake (from start to finish) situation is the same as jerk. That is a statement you cannot find in my above post, I just used YOUR example and explained that 0,2G/0,2s is the same deceleration as a emergency brake situation (remember it wasn't MY example, it was yours)...

And by that, it seems that your reply above is directed towards yourselves and your own 0,2G/0,2s example on jerk.
At least you aren't holding back when commenting on your own drivel

My understanding on jerk has been that it's a sudden jolt or change in acceleration. Like going from a 0 acceleration situation to a full on emergency brake situation over a short period of time. When you have achieved maximum deceleration, you don't have jerk anymore, you are decelerating at a steady rate. Unless you hit a spot of better friction and deceleration changes, which would again be jerk. And you usually have a jerk situation just as the car stops because of the change from gliding friction to static friction and the weight transfer as the car grinds to a halt. Basically, a simplistic way of describing jerk is that every time acceleration/deceleration changes from a steady rate, you have jerk. If you, from point B-C (discounting the acceleration from A-B and deceleration from C-D) have a continous steady acceleration or a steady speed with 0 acceleration, then you don't have jerk. If you change the velocity, either up or down, there will be jerk.


What I have asked you about is a quantification on the jerk on a scale that tells us wether it's "noticeable jerk" or not. Yes, you have compared it to the jerk in the E9x M3 and shown that it's larger. But if I understand you correctly there isn't any noticeable jerk in the E9x M3? If the jerk in the E9x M3 is undetectable to the human body, then it doesn't really help saying that the jerk is x times larger in the F8x. Because we still don't have a number that says if "x times larger jerk than in the E9x M3", is above or below the treshold of human detection

But really, the topic of "noticeable jerk" isn't of any interest to discuss further for either of us I would think. For me, the test drive will be the deciding factor. If it feels good and pulls hard to the redline, then that is what matters If it feels like it "runs out of breath" towards the redline, then that will be a disappointment (both because of the character of a M engine shouldn't be like that and because that would mean I have been wrong all the time... )

(BTW, I happen to deal with brake calculations and application time quite regularly. Not that I'm an expert, but I do know the basic principles and know that application time is a factor that needs to be adressed in a calculation on brake distance or speed from brake distance calculations. For instance on a truck it might take 1 second in older systems to apply the brakes. Modern cars actually have EBS systems that pre sets the brake pads if an emergency situation is detected. This is to avoid loosing time in moving the brake pads from a 0 friction situation to a low friction setting, when the driver applies the brakes. That first movement of the pads is allready taken care of by the electronics. Same thing is done on some cars as a way of keeping the brake disc/rotor free from water/moisture, the brake pads are frequently applied just enough to warm up the disc/rotor so that it keeps dry, and has optimum friction should the driver need to brake).


BTW, I also had to look up the English dictionary on the meaning of the phrase "sloping curve". Again I see that it doesn't mean what I thought it meant. I thought that in English "sloping curve" was a description of for instance how the torque on the S55 is represented after 5500rpm, but that obviously is a negatively sloping line, not curve...