M4cs Power output analysis - This S55 variant is quite potent

[CanAutM3]

Originally Posted by melvyn

Wouldn't shifting at 6000 keep it above 5500 and in the torque plateau.After 6k it falls off fast and is very noticeable, although it will still hit the redline in 4th, can't say if it will in 5th

Shifting 3rd at 6000RPM drops the RPM to ~4500RPM in 4th, well below the power plateau that starts at ~5500RPM. Even if the engine makes less torque, it still makes more power. Getting a car to accelerate at its best is all about maximizing power throughout the acceleration run.

There are likely other contributing factors that got you to get your best time and speed on that specific run. I can only assume that you would have been slightly faster had you shifted 3rd at a higher RPM (I reckon ~7200RPM).

[M3GymNut]

Originally Posted by CanAutM3

Truth hurts chief. I'm also not the only person on this thread that shares the same view point. Let me guess, they're trolls too?

[CanAutM3]

Originally Posted by M3GymNut

Truth hurts chief. I'm also not the only person on this thread that shares the same view point. Let me guess, they're trolls too?

Your comments just prove your ignorance .

Have you even bothered to

[M3GymNut]

Originally Posted by CanAutM3

Your comments just prove your ignorance .

Have you even bothered to

Listen man, if someone either doesn't agree or is just simply asking a question towards you, it's either they're a troll, ignorant, or they come off as hostile(which I am quoting to you as saying to me on quite a few counts). What's the deal? When you post opinions or let alone create a thread you have to be open minded and at least courteous in your responses. It's always a negativity with you. I don't mean no harm man, I'm pretty sure we love the same cars so let's just take a chill pill.

[Wills2]

Originally Posted by melvyn

BM put a software update into the early cars for better traction as can be seen below.
CS has huge mid range pulling power over the CP.

I can feel that difference on my 2016 M3 after I'd had the 2017 SW flashed, not sure it was the best idea to be honest.

[CanAutM3]

Originally Posted by M3GymNut

Listen man, if someone either doesn't agree or is just simply asking a question towards you, it's either they're a troll, ignorant, or they come off as hostile(which I am quoting to you as saying to me on quite a few counts). What's the deal? When you post opinions or let alone create a thread you have to be open minded and at least courteous in your responses. It's always a negativity with you. I don't mean no harm man, I'm pretty sure we love the same cars so let's just take a chill pill.

When pot meets kettle...

Who's being negative here . You don't think that you coming into a thread without even reading it and posting that "it is worthless" is trollish, ignorant or hostile?

I don't mind constructive debates at all. I actually seek them and do have an open mind towards them since they improve collective knowledge. However, making blanket negative comments without substance adds zero value to the forum community.

[melvyn]

Originally Posted by CanAutM3

Shifting 3rd at 6000RPM drops the RPM to ~4500RPM in 4th, well below the power plateau that starts at ~5500RPM. Even if the engine makes less torque, it still makes more power. Getting a car to accelerate at its best is all about maximizing power throughout the acceleration run.

There are likely other contributing factors that got you to get your best time and speed on that specific run. I can only assume that you would have been slightly faster had you shifted 3rd at a higher RPM (I reckon ~7200RPM).

It hits the limiter at 7600 rpm , the torque plateau finishes and levels out at 5500, 4500 revs is right on the mark to pick the next gear up.You may as well say redline it in each gear, which won't give you the best speed in your car as you will find out when you've ran it in

The power plateau starts at 3k revs

[CanAutM3]

Originally Posted by melvyn

It hits the limiter at 7600 rpm , the torque plateau finishes and levels out at 5500, 4500 revs is right on the mark to pick the next gear up.You may as well say redline it in each gear, which won't give you the best speed in your car as you will find out when you've ran it in

6 years of applied and science and engineering will have me disagree here. Torque at the crank is irrelevant to establish acceleration potential without considering gear ratios. To maximize acceleration at any given road speed, you need to maximize power at that speed. The formula is "a = P/mv" where "a" is acceleration, "P" is power, "m" is vehicle mass and "v" is vehicle speed. Lowering the revs below the power plateau (below 5500RPM) will not yield optimal acceleration, it's physics.

In the same way, redlining every gear is also not optimal (1st and 2nd need to be redlined, but not the others), as the power drops off past 7200RPM to a point the the engine make more power in the higher gear.

[melvyn]

Originally Posted by Wills2

I can feel that difference on my 2016 M3 after I'd had the 2017 SW flashed, not sure it was the best idea to be honest.

Yes, I had the first 2014 model , I can remember overtaking another car and had to keep coming off the throttle along side them to get the tyres to bite.Having said that , after a couple of weeks getting to know the car and using mdm and making sure the tyres were warmed up solved that issue.
I think I agree with you .

[CanAutM3]

Originally Posted by Wills2

I can feel that difference on my 2016 M3 after I'd had the 2017 SW flashed, not sure it was the best idea to be honest.

Originally Posted by melvyn

Yes, I had the first 2014 model , I can remember overtaking another car and had to keep coming off the throttle along side them to get the tyres to bite.Having said that , after a couple of weeks getting to know the car and using mdm and making sure the tyres were warmed up solved that issue.
I think I agree with you .

Same here. I miss that low RPM rush in the CS. I guess I have to re-learn to downshift

[melvyn]

Originally Posted by CanAutM3

6 years of applied and science and engineering will have me disagree here. Torque at the crank is irrelevant to establish acceleration potential without considering gear ratios. To maximize acceleration at any given road speed, you need to maximize power at that speed. The formula is a = P/mv where a is acceleration, P is power, m is mass and v is vehicle speed. Lowering the revs below the power plateau (below 5500RPM) will not yield optimal acceleration, it's physics.

In the same way, redlining every gear is also not optimal (1st and 2nd need to be redlined, but not the others), as the power drops off past 7200RPM to a point the the engine make more power in the higher gear.

Well your in for a treat

This car you have will kick your view out of the door.Your out of the plateau at 5500 as the graph quite clearly shows.You will feel the power drop abruptly at 6000rpm, to a point where you will think your previous M4 was more powerful to the redline.
That's your enjoyment to find out though, I will be more interested in your view on suspension, especially on your back roads and high speed on the road.

[CanAutM3]

Originally Posted by melvyn

Well your in for a treat

This car you have will kick your view out of the door.

I seriously doubt it will. Science is science

Originally Posted by melvyn

Your out of the plateau at 5500 as the graph quite clearly shows.You will feel the power drop abruptly at 6000rpm, to a point where you will think your previous M4 was more powerful to the redline.
That's your enjoyment to find out though, I will be more interested in your view on suspension, especially on your back roads and high speed on the road.

That's where you are getting confused, the torque plateau is irrelevent without considering the gear ratios. In a given gear, yes, the car will accelerate most at the torque peak. However, across gears, the gear that provides the most power for a given road speed will provide the best acceleration. There is no way around this.

I am completely confident I will experience exactly this when I have my car on track on the 24th

[melvyn]

Originally Posted by CanAutM3

I seriously doubt it will. Science is science



That's where you are getting confused, the torque plateau is irrelevent without considering the gear ratios. In a given gear, yes, the car will accelerate most on the torque plateau. However, across gears, the gear that provides the most power for a given road speed will provide the best acceleration. There is no way around this.

I am completely confident I will experience exactly this when I have my car on track on the 24th

Pick one of your long straights and do it your way to the braking point and then try shifting at 6k to the same braking point , see what speed you hit:
In third and fourth

[melvyn]

Just to add , the above graphs are in fourth gear

[CanAutM3]

Originally Posted by melvyn

Pick one of your long straights and do it your way to the braking point and then try shifting at 6k to the same braking point , see what speed you hit:
In third and fourth

Will do and will report back

[CanAutM3]

Originally Posted by melvyn

Just to add , the above graphs are in fourth gear

Not sure how that is relevant ?

[melvyn]

Originally Posted by CanAutM3

Not sure how that is relevant ?

Different tune with the CS, look at the way the CP gains on it at 5500

[Wills2]

Originally Posted by melvyn

Yes, I had the first 2014 model , I can remember overtaking another car and had to keep coming off the throttle along side them to get the tyres to bite.Having said that , after a couple of weeks getting to know the car and using mdm and making sure the tyres were warmed up solved that issue.
I think I agree with you .

That's exactly how I used to overtake!

Now it's more confidence inspiring but less fun and feels less of a monster.

[shortseller]

With all this talk about optimal shift points, is it safe to assume the car is at its optimal performance when the dct is in auto mode set on 3 bars and in sport+ mode across the board?

[melvyn]

Originally Posted by shortseller

With all this talk about optimal shift points, is it safe to assume the car is at its optimal performance when the dct is in auto mode set on 3 bars and in sport+ mode across the board?

That is a great mode to use on open roads as it really holds on to the gears, will hold the speed in third and fourth from approx 70-128, but won't redline.Still convinced changing at 6k in third gives more speed.
Changing at 7300 in third auto drops the revs to 6100 in fourth , out of the torque band.

[CanAutM3]

Originally Posted by melvyn

That is a great mode to use on open roads as it really holds on to the gears, will hold the speed in third and fourth from approx 70-128, but won't redline.Still convinced changing at 6k in third gives more speed.
Changing at 7300 in third auto drops the revs to 6100 in fourth , out of the torque band.

More like 5500RPM

1.277 / 1.701 x 7300 = 5480

[melvyn]

Originally Posted by CanAutM3

More like 5500RPM

1.277 / 1.701 x 7300 = 5480

Yep maybe a little more in auto, 6kish in manual