Ferrari LaFerrari vs Mclaren P1 vs Porsche 918

There are tracks where one is on the gas a lot more than off it - say Monza. The P1's power management will not allow the battery to discharge fully (not good for the battery longevity).

How then can the battery be recharged when there is a hardly any opportunity to do so? Either it forces recharging even when the throttle is open (in which case power output to the wheels is reduced) or it revs the engine really high during off throttle moments to "make up"'for lost ground (in which case you are wearing out the engine more than normal).

McLaren's decision not to use KERS doesn't make any engineering sense (efficiency) at all. Lack of KERS knowhow at Ricardo?

 

In the 918's test journos had to complete a recharging lap before going into hot lap mode. I'm sorry but you're wrong. I'm pretty confident the p1 as well as the 918 and the LaF, even if to a lesser extent, can't repeat their performances lap over lap until they find a balance between recharging and deploying battery power. And my guess is that that balance is further away from the p1's record lap times than it is for the others.

 

That doesn't mean I don't think 2 of the 3 are pretty.

......and I ask myself why a lot.




I will say all this battery talk makes me wonder which side is correct. I'd assume as all battery's that go bad the theory of non repeat laps makes the most sense.

If you've ever had a dying battery you all know the car stops eventually.

If the alternator or generators in the case of these 3 can't keep up the car would have to eventually just shut down.

I'd only wonder if it's fixable. If they will eventually add a charging unit that will keep up.

 

Right, I think for some of you to understand how this all works contrary to your early predictions you're going to need a powertrain engineer to explain the process in greater detail than I can. Even at the P1s top speed it can recharge the batteries as full engine power is not needed to maintain either 205 MPH in Race Mode or 217 MPH in Sport Mode.

More detail from fytl:

"The way the hybrid system runs, especially in race mode, is that it will try to always find a way to charge the battery. It is hard to show easy to understand examples, but there will be times the ICE can not speed up the car any faster than it currently is doing, it can not increase RPM quicker simply due to lag of something or another... if the ECU catches those times well, it can, even if its just for 2 seconds, overpower the ICE, take the extra torque out by power-inverting the e-motor to make it a generator instead, and not lose power to the wheels but power the e-motor."

Another future owner who drove the car at Dunsfold a few weeks back said that despite the car being driven at its maximum the battery meter never came close to being at zero. There were no recharging laps in order to bring the battery back to life either.

>8^)
ER

 

Well put! I too admire the fine art of watchmaking but let's be serious, cars are much more complex, exciting and insiring! If a watch fails you will miss an appointment, if a car fails you may lose your life! Also modern cars are so much better than 50 years ago that it isn't even funny comparing the two...

 

Anyone who has seen a car knows that high end sportscars are not about reliability.

 

I wonder why they limit the top speed in Race mode. Battery protection?

 

All of that makes absolutely no sense

 

Igor you realize brakes are used during a hot lap right? And, further, that you don't use the throttle while braking into the corner right?

Sent from my GT-I9505 using Tapatalk

 

^^ p1 doesnt recharge during braking, i believe.

@Realzeus, id assume the top speed is lowered bc the wing is fully deployed.

 

The wing is not up in the mode it will do 217? That has to be max rev not Wing related.

 

It does. Using the engine. Always the engine.

LaF and 918 both use retardation of forward momentum thru electric motor/generator braking - a system also known as KERS, to recharge the batteries. This is otherwise free energy that sadly the P1 does not take advantage of. By contrast, LaF and 918 will recharge using their engines, only when KERS recharge is not sufficient.

 

How hard is it for someone to understand that you'll only at moments need or use full engine power at the track??? The rest of the time the power not needed applied to the road will juice the batteries. Rocket science but not really. You've got more patience than me trying to explain this to people....

 

Igor, why you resist believing that a company like McLaren can make something work that you do not understand? The art of recharge is not limited to gradual depletion of power, there are many examples in the science of power regeneration where loss of charge does not equate to negative, i.e. less performance. Try to understand this simple fact: McLaren P1 will never have full battery depletion. How I know this? Simple. Do like me (and Erik?) - ask guru DPW if you ever have the wonderful opportunity to meet this genius. So this specific case can only happen if you are attempt drag racing at Bonneville Salt Flats in pure electric mode and the petrol engine is some way blocked from re-engaging activation. Now say "zio"…(uncle).

 

I for one am glad the P1 does not use regenerative braking. I don't care if this is lost energy. I realize the 918 is more efficient in this regard but who cares about efficiency, its a non-issue. If there is another way to recharge the batteries that doesn't sacrifice engine power and still have nice feeling brakes then I'm all for that. I think the 918 is an amazing car but every review so far has complained about the brake feel. A buddy of mine drove the 918 very recently and he said the same thing. I realize you could get used to it but brakes and steering are two things I don't want to have to get used to.

 

breaks on the 918 will be perfected before delivery. I was told by the engineers they hadn't finished calibration on the those test cars evo and co drove at Valencia.

 

Good explanation.

Makes the electric stuff seem kinda pointless though. Why all this fuss over hybrid tech if a supercar can't effectively deploy maximum power all the time anyway?

Just build a more efficient engine that delivers power more effectively. And make the car lighter.

Not saying that all of this isn't trick--it just suggests that all three of these cars would benefit more from the deletion of their electric systems than from any amount of "extra" power they might produce. If you can't effectively put down all engine power all of the time, then don't add more power--especially power that just needs to be reproduced.

 

I have heard that too; porsche is still working that out. There is another issue about the brakes that I didn't care for personally. The porsche engineers told me the way to drive it on the track is a long early brake, in order to charge the batteries. Thats not my preference. I can think of a few very long and very nice sweeper (public) roads in my area where I wouldn't brake at all, just lift and use engine braking. Theres no regen on engine braking.

 

Then you clearly don't understand how the P1 works and should probably stop making authoritative statements about what you believe is accurate in the face of ones from people who have either spent years of their life developing and testing it, or who have already spent time behind the wheel and have seen firsthand how it functions.

>8^)
ER

 

+1
Agreed.

 

One question: why, according to some reports, the 918 couldn´t reach max. speed at the end of its Nurburgring lap because the batteries were depleted? It should be able to recharge with remanent engine power. Plus, why the 918 needs a lap to recharge before a hot lap? It should be able to recharge during the hot lap.

 

Desoto, i havent heard that but in any case the 918s decouples the electric motor before vmax so it shouldn't have anything to do with batteries being depleted.

I can imagine a scenario whereas you drive with left foot on the brake while using throttle at the same time to charge the batteries. Probably only during a light cruise as that would normally confuse the hell out of the PASM system.

 

We'll see who's right if after record laps the P1 will still magically have 100% battery power. I feel confident ...

 

igor, I know you're skeptical about the p1's battery level and it seems to me you're still missing the point. After a record lap, the P1 will probably NOT have 100% battery power. It might even have 0% (I don't know). All that matters is the P1 can regen enough power during the lap to keep the motors running. It has enough efficiency and capacity to do that. That's why there are 220 lbs of batteries on board. Now if there were only 110lbs of batteries, I could see your concern, as there wouldn't be enough storage. The batteries act as a buffer. As long as they are kicking out whatever voltage is needed to power the motors it doesn't matter if they are at 10%, 20%, 30%, etc.

 

So I am basically right, and performance will drop. A lap started with 100% batteries won't be as fast as one started with 10% and the car will suck engine power and useful torque to keep batteries charged in a second lap. As I said I don't see keeping batteries always charged as a big achievement when done at the expense of performance. And BTW it matters, if batteries are at 100% they last a lap, at 10% they might not be enough for a long straight, before the engine is forced in recharging mode and speed will drop.