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Discussion Starter · #21 ·
CarMeister, I am neither joking, nor does it matter to me if you said that.. Your post makes it sound like it is somehow "bad" that the P1 has no hot lap mode. But my post is clarifying that it does not matter at all since a hot lap mode is not needed and would add nothing.

So again, I am honestly not sure what you are trying to claim.

You are correct, the porsche needs a "hot lap mode" for some reason to achieve a faster time on the ring. This makes little sense and the P1 does not need it. A "hot lap mode" would add nothing because the P1's ECU does not make the car slower in hybrid mode.
 

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CarMeister, I am neither joking, nor does it matter to me if you said that.. Your post makes it sound like it is somehow "bad" that the P1 has no hot lap mode. But my post is clarifying that it does not matter at all since a hot lap mode is not needed and would add nothing.

So again, I am honestly not sure what you are trying to claim.

You are correct, the porsche needs a "hot lap mode" for some reason to achieve a faster time on the ring. This makes little sense and the P1 does not need it. A "hot lap mode" would add nothing because the P1's ECU does not make the car slower in hybrid mode.
With all due respect. I think you're confused, and didn't read/understand what I was responding to. And I'm to lazy to re-read ISV's question. But quite frankly, I think you're overreacting. "Hot lap" came up; cause ISV mentioned the 918 running out of charge, and speculated why, what it would to on it's further laps (while mentioning the P1 as well)? That was the entire premise for my response.

FYI/According to Porsche: The 918 could to 7-7:02 on the Ring in "Race Hybrid mode" where it regenerates the battery constantly via engine and brake regeneration. As you know, this time is currently faster than anything we know of the P 1. This is a time it should do over and over again as well. As I said in my response: the 918 has ran on various tracks for owners, writers and drivers alike in Race Hybrid, while keeping a steady charge. So what you're implying ("the 918 needs a hot lap mode") is not an issue.

I repeat. It's just the 918's battery is so big, it can practically do the entire ring with out engine regeneration. That's a bonus (and really so hard to understand)!? Though in reality, the overwhelming majority of owners would never need to use it ("Hot Lap"). And it certainly does fine by itself in Race Hybrid. But of course the big battery, has it's benefits on the track and the real world (performance, cabin conveniences, etc.), besides "Hot Lap" mode. It just makes the 918 a versatile vehicle. I was only addressing a question regarding battery depletion, additional laps with the 918. There is/was no "fanboyism".

The P1 was never criticized. That was your interpretation? I was just answering, addressing the two vehicles, regarding the 918's recent Ring Video with Lieb at the helm, in lieu of ISV's comments. "Hot Lap" on the Ring, essentially means the 918 has a bigger battery, which we already knew.

I hope that helps (for good)? Whew! :)
 

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Discussion Starter · #23 ·
CarMeister...

you are right, we know nothing about the P1's ring time. And this whole thread has nothing to do with the time either. It is an explanation of the tech in the P1 that was discussed many times.

Just since you keep bringing up the 918... the battery in the 918 has 6.8kWh. Even ignoring the front engine, taking only the one connected to the gearbox, 115kW. Will only power for 212 seconds. Less than half the time it takes around the lap. Explain to me how it uses "all the power" the whole lap using a "hot lap" feature?!

None of this makes sense. But more importantly, this is a P1 thread about its tech, can we stop discussing 918 tech please?
 

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CarMeister...

you are right, we know nothing about the P1's ring time. And this whole thread has nothing to do with the time either. It is an explanation of the tech in the P1 that was discussed many times.

Just since you keep bringing up the 918... the battery in the 918 has 6.8kWh. Even ignoring the front engine, taking only the one connected to the gearbox, 115kW. Will only power for 212 seconds. Less than half the time it takes around the lap. Explain to me how it uses "all the power" the whole lap using a "hot lap" feature?!

None of this makes sense. But more importantly, this is a P1 thread about its tech, can we stop discussing 918 tech please?
HOT Lap uses selective regeneration compared to Race Hybrid and it's other modes. Generalizations are used (Porsche included) to avoid confusing nomenclature, technical terms, electrical, battery charge, dissipation figures, etc... You know that.

Yes, it's a P1 thread. And I never criticized the P1, or offered a wanton, unprompted opinion on the vehicle. I answered a posters question, in regards to the 918. And I thought I gave a good answer at that, concerning what he was seeking Some how you took offense?

There was never any disrespect to the P1. And I ONLY brought up the 918's Ring Times in "Race Hybrid" mode, cause you kept repeating 'The 918 needs HOT LAP to record and repeat fast laps', thus alleging it was inferior to McLaren's Hybrid set up (not that it matters). That's all.

This was really never a comparison, competition between the two vehicles in my eyes. And I would be happy to end it right now.
 

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@ftyl
Thanks for your post. It really cleared up a lot of the confusion for me.

I suspect the P1 will be much faster then most people think it is considering how much more advanced it aerodynamics are (seem to be) compared to the other two. They may have had to sacrifice a little in terms of aesthetics (subjective, of course) for the sake of aerodynamics but given their stated goals for the P1, they've done the right thing.
I imagine the P1 will be devastating around places like Suzuka, Silverstone or Spa.
 

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Great post ftyl, that's the most complete information on the P1 drive train I've read anywhere, thanks for posting.

I suspect the P1 will be much faster then most people think it is considering how much more advanced it aerodynamics are (seem to be) compared to the other two.
I looked up the numbers and the difference is much greater than I anticipated for most cars:

2009 GTR - 176 pounds of downforce at 186 mph
2011 Porsche 911 GT3 RS 4.0 - 426 lbs of downforce at 193 mph
Enzo Ferrari - 1709 lbs of downforce 185 mph (note: it reduces downforce above 186 mph to achieve a higher top speed)

McLaren P1 - 600 kg ( ~ 1323 lbs ) of downforce at 161 mph

They may have had to sacrifice a little in terms of aesthetics (subjective, of course) for the sake of aerodynamics but given their stated goals for the P1, they've done the right thing.
Sacrifice? The P1 is perfect. It's so good it's hard to find the right adjectives to describe it really.
 

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Great post ftyl, that's the most complete information on the P1 drive train I've read anywhere, thanks for posting.



I looked up the numbers and the difference is much greater than I anticipated for most cars:

2009 GTR - 176 pounds of downforce at 186 mph
2011 Porsche 911 GT3 RS 4.0 - 426 lbs of downforce at 193 mph
Enzo Ferrari - 1709 lbs of downforce 185 mph (note: it reduces downforce above 186 mph to achieve a higher top speed)

McLaren P1 - 600 kg ( ~ 1323 lbs ) of downforce at 161 mph



Sacrifice? The P1 is perfect. It's so good it's hard to find the right adjectives to describe it really.
I'm a little suspicious of those downforce figures of the Enzo. It sounds really high. Are those figures from Ferrari? If it's true, that seems pretty impressive even at that high speed.

I understand that you think the P1 looks perfect but a lot of people think it's not so great. That's why I was careful to write "subjective" in my post. Regardless, my point was I have no reason to doubt the P1 will be much faster then any other roadcar on most tracks.
 

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ftyl - great write up, thanks for sharing. I like to clarify one detail on the battery charging bit - what you describe

1) The ECU applies negative torque to the motor, unless the battery is full, when you are off throttle.

This is in fact KERS - right? i.e. the energy in this mode is converted kinetic energy?
 

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Discussion Starter · #32 ·
ftyl - great write up, thanks for sharing. I like to clarify one detail on the battery charging bit - what you describe

1) The ECU applies negative torque to the motor, unless the battery is full, when you are off throttle.

This is in fact KERS - right? i.e. the energy in this mode is converted kinetic energy?
No, it is not KERS as far as I understand the rules of F1. KERS is only allowed while braking I think? It is the same basic tech though, just that the P1 does not modulate the torque based on braking...
 

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I think you answered my question, in the broadest sense it is a KERS, as long as we don't get hung up in the braking part, i.e. by definition KERS will 'brake' forward momentum/kinetic energy:

What is KERS?
The acronym KERS stands for Kinetic Energy Recovery System. The device recovers the kinetic energy that is present in the waste heat created by the car’s braking process. It stores that energy and converts it into power that can be called upon to boost acceleration.

How does it work?
There are principally two types of system - battery (electrical) and flywheel (mechanical), although F1 teams have so far all opted for the battery system. Electrical systems use a motor-generator incorporated in the car’s transmission which converts mechanical energy into electrical energy and vice versa. Once the energy has been harnessed, it is stored in a battery and released when required.

For many reasons explained in posts above, this is an excellent energy recovery system.


No, it is not KERS as far as I understand the rules of F1. KERS is only allowed while braking I think? It is the same basic tech though, just that the P1 does not modulate the torque based on braking...
 

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I'll take a stab at this.

The P1 may not have enough charge from it's battery alone (i.e. no active regeneration, all out mode) to run a "Hot lap" ala the 918 Spyder on The Ring. That's my guess? So when they say it doesn't run out (unless I'm mistaken), that's in their "race" mode, applying regeneration from the engine of the batteries.

The 918 Spyder can run the ring, and practically any other track in "race hybrid" mode and never run out of juice (due to engine and brake regeneration). This has already been established by prospective owners, drivers, media alike on a variety of tracks. FWIW: Race Hybrid mode is supposed to be 3-5 secs behind "hot lap mode" on the ring. However, the battery [in the 918] is so big, they can run the ring with no regeneration, for practically the entire thing. Towards the end, on the straights, Lieb was probably placing it in "Race Hybrid" mode to regenerate the batteries at that point.

This wouldn't be an issue for the overwhelming majority of owners, who would rarely ever have the need to place the 918 in "Hot Lap Mode", and drive it near 10/10's on a track as long as the Nurburgring to begin with. I'm sure most (unless they were race car drivers), could never drive it 8-10/10th in Race Hybrid mode. Remember, all the 918's performance stats (0-60, etc.) are in Race Hybrid Mode, which regenerates the batteries via the brakes, and/or engine.

I hope that helps??
Makes sense (i think) .. thanks. Had better leave it at that as it seems going out of topic wrt to a certain car is unacceptable but all kinds of other topics on other threads are alright...

Would be intersting to see what the p1 onboard lap is like when Mclaren finally do get a time done to see how it looks compared to the car that cannot be mentioned.
 

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It regenerates in _two_ ways:
1) The ECU applies negative torque to the motor, unless the battery is full, when you are off throttle. Some people call this "regenerative braking" but it is NOT! Because it does not depend on BRAKING. It simply depends on NO THROTTLE. To the driver, this simply feels like more engine braking than just the petrol engine would bring. The power taken depends on the motor speed, the gear and the power train mode the P1 is in. I did not ask for details but I guess the negative torque applied changes depending on power train mode, thus together with speed and gear it generates more or less power.
2) If you drive steady speed, the ECU will also, to regen, turn off the motor, then increase the engine torque and subtract that torque via negative torque applied to the motor, which will in turn generate energy stored in the battery. While driving the car you will notice this since the motor will rev higher without you asking for more power or the car speeding up.

The P1 DOES NOT however use REGENERATIVE BRAKING. What this means is, the negative torque applied to the motor does NOT CHANGE when you brake in order to keep brake-feel 100% based on mechanical braking instead of a mix of the two! They DID consider increasing negative torque when braking, but were concerned with brake feel so stepped away from the idea.
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What you've described is regenerative braking, the same principle as applied to locomotive DC motors or oil rig drawworks AC motors for example.

What occurs during regenerative braking is a current flow reversal as the motors stop providing drive and instead become driven (by momentum or inertia), thus becoming power generators. The power generated is either dissipated into resistor banks as heat or, as in the case of these hyper cars, stored in batteries. The spinning drive shafts sees the generator as a load that is trying to impart a braking effect on their rotation, thus the term regenerative braking.

Obviously this form of recharging, being free, is much preferred over the other one which requires engine torque (more fuel) which is parasitic.
 

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Makes sense (i think) .. thanks. Had better leave it at that as it seems going out of topic wrt to a certain car is unacceptable but all kinds of other topics on other threads are alright...

Would be intersting to see what the p1 onboard lap is like when Mclaren finally do get a time done to see how it looks compared to the car that cannot be mentioned.
Gotcha!! ;) :D ;)

Interestingly enough: That car that cannot be mentioned, was criticized strongly, by many (on that brand that cannot be mentioned websites). However, no one was severely criticized for it, or threatened to leave. It was just considered their opinion (whether "Right, Wrong, Strong or Indifferent").

Now, some naysayers [apparently] disappeared on their own--off those websites, once that car [that cannot be mentioned] Ring Times were announced, and people were able to see the finished interior, exterior, and sound, realizing how much they liked it. However, like you; I'll leave it at that for previously stated, potential safety reasons :)

I would like to add, McLaren Life is a fine, informative website [of course] in it's Damn Self. ;)
 

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Discussion Starter · #38 ·
Can the P1 run 100% on petrol engine without any electric motor?
Yes. In BOOST mode, it turns off electric motor and you choose via the IPAS button when you want it added for extra accel.
 

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Great thread. I'm fascinated by how it can seamlessly switch between petrol/electric/both (as well as recharging) all through one gearbox - and all while retaining the same drive characteristics. Clever stuff!
 

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I postulate that the folks at McLaren probably have some people better suited than us forum goers to determine how many miles on track / laps on track the P1 can stay at top performance, and I would further postulate that they probably thought of this ahead of time. :)

Thought in 3 steps:

1. Lets say that somewhere on some bend at the 'ring the driver lifts to keep a steady speed. In this moment, the amount of power that the engine develops drops hugely. From full throttle to partial throttle to maintain speed not accelerate.

2. In a car like the P1, the electric motor can add its torque/power to the transmission input, powering the rear wheels.

3. If you were doing a hot lap, as in 1. above, and the driver lifted, and the petrol engine was simply left at wide open throttle, the electric motor could then reverse and DELETE torque from the transmission input and use that torque to power the battery. (edit, poor typing earlier)

Thats how I picture this system working. The engine just runs, in its track/max mode, at a higher level of throttle overall for the course of the lap than it would without the hybrid system. Think of two curves

a) throttle setting without the hybrid system (from zero or near zero to full throttle)
b) throttle setting at WOT the whole lap

The area in between these two curves should be available for battery recharging. And that should be enough to charge an electric system that is generating less than 20% of the total power.

I'm not an engineer, but if this is how the system works one should be able to tell because when braking for turns in those videos the engine would still sound like it was under some strain. Its speed would be changing (with the changing transmission input shaft speed, related to gear and wheel speed), but it would stay under strain when braking for a corner.

Who has good ears? And if a very technically versed person is among us ... is this close to accurate?
 
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