Ferrari LaFerrari vs Mclaren P1 vs Porsche 918

I no more believe a Ferrari sub 7.00 claim than I do any other manufacturer including Mclaren. Neither have proven a thing so far.

Claims are easy to make.

 

No one said the P1 was going to be the most fuel efficient hybrid. Why is it hard to believe that they just burn a lot of extra fuel to keep the battery charged?

 

True.

 

It's not but unless they contravene the laws of thermodynamics the power they use to do that reduces the total power available to run a race lap. Race laps are run at 100%TP and 100%BP. That is why the 918 is so fast. It harvests "free" energy (KERS) which does not reduce total energy. La Ferrari does as well. McLaren doesn't. That is fact.

 

True. True.

 

What is TP and BP? Throttle and brake position?

 

To Mclaren: video, or it didn't happen

 

If a lap at the ring requires full throttle less than 50% of the time, it should be able to keep the batteries charged as any time it's not at full throttle, it will be charging the batteries. That includes any time that the TC is working, which you'd imagine would be quite often with the amount of power that thing has. It's not just under braking, it's any time you aren't at full throttle.

Also, wouldn't it be harvesting 'free' energy any time you're braking? I'd imagine it will be used to 'engine' brake and the brake system tuned to account for it as you would in any car that would have a large amount of engine braking. Indeed, I can't see how it wouldn't be used to harvest that 'free' energy as they'd have to decouple it from the drivetrain or keep the throttle partially on the IC engine during braking, which wouldn't make much sense.

 

Here's an on-board lap from Friday at Dunsfold in the P1 courtesy of andy c on McLife. Tires said to not the least bit fresh (certainly not fresh cut slicks ) an unknown quantity of fuel and of course a passenger was on board. From line to line I've timed the lap at about 1:13.2 for those so absorbed by numbers.

[ame]http://www.youtube.com/watch?v=6KZdM8WSiQY[/ame]

He added "By comparison, my similar pro lap nearly 3 years ago in the 12c was around 1.23, and then look what the Stig did on his own."

Doubt we will see 7 seconds of improvement with the P1 on newer tires, low fuel and with a lone driver, but I've heard the expected time is sub-1:10. No need to worry about McLaren telling us though, as Top Gear UK are sure to handle this.

>8^)
ER

 

Mclaren sucks at any levels. Anys.

 

So informative.

 

Doesn't make sense why P1 wasn't designed to harvest energy during braking since that is free kinetic energy converted to electricity. All other manner of harvesting energy is parasitic - produced by the engine thru fuel burning. I mean why bother with all that extra weight, all that complication and cost if at the end of the day, all that power comes from the engine anyway? Why not just build a 903-hp engine and be done with it?

From a thermodynamics point of view, the P1 as designed ain't energy efficient.

 

Sorry. Should have I softened the blow? (Purple tongued face)

 

The P1 recovers tremendous amounts of power under braking, it just doesn't use the brakes to do so.

>8^)
ER

 

Jim clearly disagrees >
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Very good Mark! I like we have you here!

James, you are so full of facts! That is in-credible and it amazes me! How are you able to know so much knowlege like this? Please I ask you again, why is the Pagani, as you say, so much superior to 918, P1 and LaFerrari in sense of quality, fit/finish and other things? Is it only your opinion or is it fact to? I am very sure you must know this answer because very few people are in a fortunate position like you to make this answer. I try very hard to understand you but I donot understand you specifically on this point.
What i do understand very well is thermodynamics and I must correct you because it is my expert subject. For others reading, what you are describing in you intellectual manner with the formula in earlier post is all about entropy as I think I know that you know and the direction of any system to thermal equilibreum, mean there is no possibility of continuos motion system. But you realise also that a decrease of entropy only is applicable of a system that is NOT in isolation yes? If you study the system that P1 using, you will so see that this is the variable they are using for their technology, that is to say, they use an ISOLATED entropy system. The system they employ, contrary to your equation, IS in equilibrium. You know about Bolzmann yes? I must say you are in-credible if you believe you can't "win" energy and you MUST lose. There are new technology development from very clever engineers capable of coming at this impossible problem from a new angle, you must open your mind to the future James because nothing is impossible. The human has not found yet the limits of physics, but they are always finding ways to smash obstacles.

 

Which type of lithium batteries are the three cars using?

Cobalt oxide? Phosphate?

 

Lithium-ion phosphate are the battery type in all three cars.

>8^)
ER

 

I think there's a bit of misunderstanding here with regards to how regenerative braking works. The brakes on the LaF or the 918 have nothing to do with generating current to recharge the batteries.

It's the electric motor (or motors in the case of the 918) changing function from motor to generator during braking that provides the the current used to recharge the battery. How does this work?

Functioning as a motor, the battery provides current to the motor's stator, creating a magnetic field which cause the motor's rotor to spin, which thru gears provide extra torque to the wheels.

Functioning as a generator, current goes in the reverse direction. The wheels which previously were recipients of torque from the motor, are now the sources of torque which is now transmitted thru drive gears to the motor. In effect the wheels spin the motor's rotor, cutting the magnetic field from the stator and generating current which is used to recharge the battery.

It's called regenerative braking because the wheels sees the motor as a load. The motor functioning as a generator provides a braking effect to the wheels.

It's elegant engineering with efficiency as ultimate goal and is it true the P1 doesn't use it?

 

It's not nor can it contravene the laws of Thermodynamics by doing anything but convert petrol into electricity. When it does it is turning chemical energy into electrical energy and the machine to do that (it's engine) is using it's power to do that instead of providing maximum output to move the car. The inefficiency of that operation creates heat which is LOST not HARVESTED as it is in a car with a KERS system.

Harvesting energy and turning that harvested energy (KERS) into electrical energy by a separate from the petrol motor system NOT driven by the petrol motor (Engine driven generator) but by a machine (KERS) hooked directly to the source producing kinetic energy (The car through it's wheels) does add otherwise lost energy to the system. IT DOESN'T CREATE ENERGY. IT ADDS OTHERWISE LOST KINETIC ENERGY TO THE CAR. The system in
918 does this. The system in La Ferrari does this. The system in P1 does not.

 

Direct braking kinetic energy regeneration is not employed in the P1 to maintain a consistent feel during braking. The car generates up to 0.25G of drag on brake regen, but it does not harvest the wasted kinetic energy from the brakes, unlike the 918 and the Laferrari.

Interestingly, a few P1 owners who were test driving the car at Dunsfold 2 days ago were told that the car will never deplete its battery, unless in E-mode. Their goal was to be able to lap the 'Ring, lap after lap without running out of juice. The car should run out of fuel before battery power.

 

Eric

McLaren clearly told me they were going to build 500 P1's, they told me that at the factory. The demand for 500 P1's weren't there so they cut the number to 375.

At Pebble in their tent while you were there FS told me that they had beaten P1 and were below us. (6:51) and were going for an even faster lap and would announce that very soon.

BTG reported a 7:04.

They went back to the Ring. Mark Antar and others on McLaren Chat clearly stated that he/they (A german Customer) had been told that P1 had run an incredible time and it would be reported soon. It wasn't. It wasn't reported soon after that either.

The EVO note came out. I believe that once again this a total PR disaster for McLaren. You admire them for not releasing a Ring Time and don't feel it is. I do. (P1's Ring time, not sure how you feel about "McCheeter")

As an aside on Lambo Chat a poster is stating that P1 is not sold out and there are 2 slots available at The Collection should anyone who still want one but thinks they are sold out.

Best to you and Cheers to Mark

 

Mark

I have driven a car with "Direct braking kinetic energy regeneration".

The brake feel is excellent.

If you want to confirm this simply rent one of the many "regular" hybrid passenger cars and SUV's that do and try the brakes.

Cheers

 

One interesting thing .
I was also told at mclaren that they would be making "around500" cars and my understanding was they would be "just over half a million pounds ". A lot of is did say 500 was too high (to be fair ) but to me what's interesting is once they cut the numbers the price magically nearly doubled .
Call me paranoid if you like but I just prefer to think of myself as smart around a pound note .

 

I believe Mclaren, regardless of what they say, have not released a time simply because they are waiting to see what ferrari will do. I believe a lot of us are underestimatg what ferrari can really do besides mclaren. I believe ferarri will destroy the 918. Then when that sick time drops, mclaren will defend themselves.