2011 Endurance news

[Formula None]

Another example of a flattened leaf:

I hope it does, it looks incredibly cool

I agree! Looks like it's designed to meet GT300 specs.

[wesley123]

indeed, that is in no way a car that meets the ACO GT specs.

But what I dont get, does it run 100% on batteries? if so, how are you going to reload them that quickly?

[Formula None]

Yeah, it's all electric. No idea about changing batteries, doesn't look to be quick change since they're fixed between chassis and motor subframe.

R18 crash photos courtesy Allan McNish:















Note the 120deg cylinder bank, central exhaust (which I envision F1 doing if they go with V6 turbos instead of I4s), cockpit fed gearbox cooling ducts (?), rear CF subframe and the very long frame tubes that join with the front monocoque. Also, what is the flat plate above the gearbox? Just a heat shield for the central exhaust?

[machin]

An I6 would have more torque, because a V6 .....

If every other aspect of the engine were the same, why would the Inline arrangement create more torque? A cylinder doesn't know if its got one buddy infront of it and one behind it, or instead one to the side of it so why would it create more torque in one arrangement compared to the other?

Engines bad for revving (naturally unbalanced)
60 and 90 degrees V6
I4

The Yamaha YZF-R6 (inline 4 cylinder) revs past 15,000rpm in standard form... so it may be theoretically "worse", but it can still be made to work rather well....

[wesley123]

Engines bad for revving (naturally unbalanced)
60 and 90 degrees V6
I4

The Yamaha YZF-R6 (inline 4 cylinder) revs past 15,000rpm in standard form... so it may be theoretically "worse", but it can still be made to work rather well....

Well it needs to rev high, it is simply to overcome the power deficit they have compared to the diesels. A diesel has way more torque compared to gasoline powered cars. This torque comes in quite handy while accelerating. To overcome this deficit you just need to generate more pwoer out of your gasoline engine, you are just showing up with a knife in a gunfight, the only way you will win it is when the gun fails.

[machin]

People can get in all sorts of a muddle when they use power and torque in the same sentance... One thing I can guarantee is that if the Diesels out accelerate the petrol cars it is for one reason; their average POWER is higher than the petrol engine cars POWER across the rev range they use during that acceleration. The reason? The rules favour the Diesels and allow them to make more POWER. Simple as that.

[Muulka]

The Toyota already returned this year, being the powerplant in the Rebellion Lola. For next year anyone can get these Toyota engines, if they drive a Lola

No, they're planning a full-blown works LMP1 car, not just an engine- they've been testing it for over a year:
http://www.autosport.com/news/report.php/id/92396

[wesley123]

People can get in all sorts of a muddle when they use power and torque in the same sentance... One thing I can guarantee is that if the Diesels out accelerate the petrol cars it is for one reason; their average POWER is higher than the petrol engine cars POWER across the rev range they use during that acceleration. The reason? The rules favour the Diesels and allow them to make more POWER. Simple as that.

I am talking horsepower and Torque here, quite different. The Diesels are just having the advantage of the enormous torque they are having compared to the gasoline cars. If im correct the Engine in the R15 had around 1100Nm torque, compared to a gasloline car that has 500Nm, you wont tell me such an torque advantage wont do anything.

Mulsannescorner on this;

Yesterday brought a bevy of interesting emails into our inbox. Seems a few of you have been reading our series that is stepping through the methodology of predicting engine power outputs. Now, power is one thing, and as we've been showing, the outputs between the gasoline powered cars and the diesels aren't too dissimilar. At least it seems to be much closer than in years past. So how can the large performance deficit between the two "categories" be explained? Simple, torque. As one of our Industry Experts let's on, "I have done a lot of simulation work for Le Mans...torque is way more relevant than anything else. By a big bunch." Le Mans has what amounts to five long straights; from Tertre Rouge to the first chicane, from the L'Arche Chicane (first chicane) to the La Florandiere Chicane (second chicane), from the La Florandiere Chicane to Mulsanne Corner, from Mulsanne to Indianapolis, and from Arnage to the Porsche Curves. Think of these as five drag strips. What's more important on the drag strip, power or acceleration from torque? So check this out, our Expert tells us a 10% increase in torque can amount to, wait for it...upwards of a 3.7 second decrease in lap time. A similar percentage increase in power only drops lap times at Le Mans by around 2.6 seconds. Furthermore, a 10% increase in downforce is only good for a 1 second drop in lap time. So of course the manufacturers have gone the technical route that leads to the easiest way to decrease lap time. They aren't stupid after all and they have a lot of Boffins running the numbers. Says said Expert, "Two mph faster out of the chicanes is 10-12 mph faster at the end of the straight--even gas turbos can't make up for the 22 to 26:1 compression ratio of a diesel. All that BMEP just shoves the car down the track, out of each corner." And it does that five times with consequences each lap. Stephen Knight, "knighty" on the 10-10ths forum, relevantly relays, "I remember Peter Elleray once said that during the Bentley LMP900 development they actually realized, via many track simulations, that torque was of more importance than power at Le Mans...hence they increased the 3.6 liter Audi engine to 4.0 liters, the net result being slightly less power but a lot more torque, which gave them a significant acceleration advantage, much like the diesels have..."

[machin]

I am talking horsepower and Torque here, quite different.

...

As one of our Industry Experts ....

That's part of the problem; the "experts" fall into the same trap and mix torque and power and get all muddled up as a result. That guy from Mulsanne corner really does make a mess of thing -its no wonder people get confused!

The output of an engine (and its ability to accelerate a car) can be expressed either in terms of forces (using the engine's torque curve), or in terms of energy (using the engine's power curve)... the thing is they describe the same output, but they do it in two different "languages". Mixing the two "languages" gets you into all sorts of confusion. However you can easily convert from one language to another since BHP=(lbft/5252)*RPM. It doesn't matter if you use power or torque to calculate the acceleration -you'll get the same answer, as long as you apply the right maths!

What's important for working out a car's performance is the power or torque at the car's driven wheels. The nice thing about power is that the power at the wheels equals the power at the engine flywheel, minus a bit due to heat loss in the tranmission, so its easy to compare one engine installation to another. The problem with torque is that the torque at the wheels can be very different to that at the flywheel, making direct comparisons between different engine installations a bit more difficult. The thing to remember here is that if two cars have the same sized tyres on their driven wheels then if they have the same torque at those driven wheels they will also have the same power. We have the laws of pyshics to thank for that. However, they may have vastly different torque outputs at the engine flywheel, but it doesn't matter, because its the power or the torque at the driven wheels that matters.

Lets take two engines, one with 200bhp @10,500rpm (that's equivalent to about 100lbft @10,500rpm) and another with 200bhp at 5,250rpm (that's equivalent to about 200lbt @ 5,250rpm) -all figures at the engine flywheels.

Lets assume that the tyre sizes are such that at 40mph the driven wheels turn at 525rpm... that means the first engine needs a 20:1 overall gear ratio to turn the 10,500rpm at the flywheel to 525rpm at the driven wheels, and that means the torque at the flywheel is multiplied by 20 to get 2,000 lbft at the driven wheels. The second engine can only use a gear ratio of 10:1 to turn 5250rpm into 525rpm, and that means its 200lbft at the flywheel is multiplied by 10 to get the torque at the driven wheels... and therefore the torque at the driven wheels is.... also 2,000lbft! So one engine has twice the torque of the other (at the flywheel), and yet since they have the same power they also have EXAcTLY the same capability to produce torque at the driven wheels, and therefore (everything else being equal) will cause the cars to accelerate at the same rate.

Its important to remember that its not peak power that is important, but power at all the RPM points which are used during acceleration (typically the top 40 to 30% of the rev range for a car with normally spaced gears).

[747heavy]

the quoted 22-26:1 compression ratio, should make you wonder what the guy really knows about modern turbocharged diesel engines.

~16:1 is probably closer to the truth, these aren´t Golf Mk.2 diesels anymore

[wesley123]

I am talking horsepower and Torque here, quite different.

...

As one of our Industry Experts ....

Text

Thanks for the explaination. I uderstand that the real power output wouldnt be much different to each other, but what causes the Diesles to be that much faster? sure they are favoured, but that can tbe that much. I still do believe the Diesels have the power advantage and also have the power available sooner, the Peugeot and Audi showed higher trap speeds but were also faster in corners. I think we can say that this cant be all higher df and less drag then the other runners. And certainly not from the Peugeot.

[machin]

I think you're right; the peak power output may be similar, but the power output at lower RPM on the Diesels is higher... all other factors (aero, weight, etc) will be similar.

Remember peak power only determines the acceleration at 6 road speeds on a six speed gearbox... say 50mph, 75mph, 100mph, 125mph 150mph and 175mph, with the same gear ratios the power developed at 75% peak revs would only determine the acceleration at 38mph, 56mph, 75mph, 94mph, 113mph and 131mph, the power at 80% peak revs would only determine the acceleration at 40mph, 60mph...etc, etc, etc...

When people say "this engine has more torque than that engine, even though they have the same Power" I think what they actually mean is "this engine has more power at mid-range revs than that engine even though they have the same peak power".

[747heavy]

maybe the following graphic will compliment machin´s exellent post.
it´s fom different BMW road car engines, so not 100% relevant to the topic, but perhaps it helps to visualize the underlying problem.



if you compare the "power curve" of the old V12 engine with the "power curve" of the V8 twin turbo you will see two interesting things. The old V12 has a higher peakpower and both have app. the same max torque (600Nm) output.
The difference is that the V8 twinturbo has his torque over a much wider rpm range and therefore has also more "power" from 1500-3500 rpm, then from ~3800-4500rpm both angine produce app. the same power, as they make app. the same torque in this rpm range.
From ~5000 rpm onwards the V12 would have the upper hand, making more "torque" and therefor "power" until ~6500rpm.

This example is a bit simplified, to the matter at hand, as both engines operate in the same rpm range (band). Under this condition, the engine which produces for "torque" for a give rpm, will also produce more power.

But I hope it goes some way, to explain the basics of the discussion.
Expressions like "more power" or "more torque" are a bit vague to desribe a dynamic process. As you see in above example, both engines make the same " max. torque", but the turbo engine will do so for much longer, therefor it has an advantge when operated in the 1500-2500 rpm range.
Which engine is better on the track, will depend from the track characteristic and the gearing (assuming for the moment, we talk about the same car in terms of aerodynamics (drag) and weigth).

In this specific case if we see the "power output" over a range from 1500-6500 rpm, both engines are quite evenly matched (app. same area under the power curve in the range from 1500-6500 rpm), so it will come down to, which engine spends how long at which rpm (gearing & track characteristics) to see, which car maybe has an advantage overall.

Just as a side note:
Looking at topspeeds, is maybe not conclusive as well, because two cars could have the same topspeed, but on could be much quicker down the straigth, if it reaches his topspeed much earlier.

As an extreme example lets consider two cars on a straight which is 6km long, both reach an ultimate speed of 320km/h but one reaches the speed after 3.8km the other after 5.8km.
You can calculate for yourself, how much quicker(laptime wise) one car is over the other.

At the moment it seems, that the Diesels have an advantage in LeMans, but to say it´s all down to there higher "torque" jumps maybe a bit short, to get the overall picture.

[747heavy]

maybe this two engines, are a better illustration to see, that there are different means to an end. Again, there are both road car engines from the same manufactuer (Audi).
Both produce similar power ~5000hp (the V10 n/a is a tad more powerful), but in an complete different way.
The funny/interesting thing is that one produces his peak power at exactly twice the rpm.
Not surprisingly, both achieve similar performance in the same car, with an slight advantage for the V10 n/a engine.

claimed figures by Audi:

R8 V10 FSI:
0-100 km/h: 3.9sec
v max: 316 km/h

R8 V12 TDI
0-100 km/h: 4.2 sec
v max: 325 km/h

As the R8 V12 TDI is a prototype/study this figures are maybe not 100% correct, aslo I think that the V12 TDI is probably heavier, but I could not find a weight for it. The V10 FSI is said to weight 1620kg.
But it perhaps goes some way to show, that you can achieve similar results with completely different engines, and that "torque" is not the be all/end all, and can´t (or should not) beseen in isolation.

To have a "better" picture, one would need to calculate "thrust" (a force) at the driven wheels over the needed speed range, to see which car/engine has an advantage around a given track.
This would need to include the gear ratios and tire diameters as well.

[machin]

Excellent find there 747. Those Audi curves illustrate the discussion nicely. Twice the torque, but still only the same peak power since the revs are half as much. The same power at the flywheel means they'll have the same capability to produce power OR torque at the road wheels (where it counts).