[LM24] Nissan return to Le Mans (G56)

[skycafe]

Thanks, and certainly was not hanging around on that lap.

[deltawing]

The only way companies could justify multimillion dollars racing investment is if the technology they use could be related by layman to the everyday car production. It is why Audi is doing diesel entry and will fight to the end to keep it unequalized, so to have an edge. It is also why Toyota is not using a diesel regardless of how many LeMans they are going to lose - it does not make marketing case for them to use a diesel even if that could make them a winning team. It is also why Nissan HAD to use an electric-something, regardless of how irrelevant most people see it - it makes marketing sense to them as they are the leader in electric cars sales (at the moment). And in the case of Porsche, we have to wait another year to see where the marketing relevance is going to be, but there will be one. They are not spending millions on a car with random choice of architecture or ERS system....

[Machin]

Originally Posted by Articus

They were carrying around 120kg extra weight just to do 1 single electric lap. For the rest of the time they are running with the gasoline engine 400bhp only which makes for poor power to weight. To be even worse off, I've read that the engine doesn't actually make 400bhp in normal running. 400bhp is pushing it with all the dials turned up.

That is the beauty of my chart: you can use the chart to predict what performance you would expect from a Delta-shaped car running at different power:weight ratios. Below you can see what sort of lap time (based on the existing lap times), we should expect from a ZEOD with 120kg removed for the batteries... about LMP2 pace. interestingly the results, when looked at this way, show that the ZEOD if running to the same power:weight ratio as the original Deltawing, would've been slower than the original Deltawing, suggesting that it is an inferior design....

[deltawing]

Originally Posted by Machin

... suggesting that it is an inferior design....

And would you believe that? Or would you believe that the car is a lot heavier than what you read?

[Articus]

I thought I posted here last night but here so the 120kg is just the battery. There is a lot of other dead weight in the car for when it's just using the ICE. The electric motor, the battery management system, fuses, high voltage contacts, and so on. That adds up.

Any comparisons of the ICE car's potential relative to the Deltawing doesn't have enough information to be conclusive.

[Machin]

Originally Posted by deltawing

And would you believe that? Or would you believe that the car is a lot heavier than what you read?

I will say that if we add 100kg onto the ZEOD's declared weight it does make a much nicer curve on which the original Deltawing sits rather nicely, which does lend some credibility to the "overweight" claims

Any comparisons of the ICE car's potential relative to the Deltawing doesn't have enough information to be conclusive.

If we assume that the 100kg weight discrepancy is correct then we can make some really good estimates about the performance of a Delta shaped car or rectangular car with any power:weight ratio we desire.

Lets say we have a new category in which you're allowed a 400bhp engine and no weight limit. Lets assume that a "Super ZEOD" car, including driver and fuel, would weigh 620kg, and thus have a power:weight ratio of 645bhp/ton. We can predict it would lap at around 145mph average speed.

If we now took the same engine and put it in a rectangular car with a total weight of 670kg (i.e. 50kg more than the Delta-shaped car), it would result in a power to weight ratio of 597bhp/ton and we would predict a lap speed of 150mph. I.e. even though it weighs more and has the same engine, on the evidence we have so far you would predict it would be faster than the Super ZEOD. If we then add on the effect of ground effects bodywork (maybe 2-3 mph faster average speed?), and then a DRS system (another 2 or 3mph?) we see that the "Super LMP" would be lapping somewhere in the 155mph range: about 10mph faster than the Super ZEOD, despite having the same engine power. In fact we can then comfortably say that it would probably equal the Super ZEOD's performance even if it only had a power:weight ratio of only about 450 to 470bhp/ton, which, with a 400bhp engine, could be achieved with an all-up weight of 850kg.

Basically, what I'm saying is that from the evidence we have seen so far, a "heavy" rectangular LMP with the same engine as the ZEOD, and allowed the same aerodynamic freedoms, would still out perform it.. and that is why I'm not a big fan of this "innovative" wheel layout.



When we see the Delta-shaped car's curve higher than the rectangular curve, I will be impressed, and I too will call it "innovative"... until that day......

[joeb]

Originally Posted by Machin

Basically, what I'm saying is that from the evidence we have seen so far, a "heavy" rectangular LMP with the same engine as the ZEOD, and allowed the same aerodynamic freedoms, would still out perform it.. and that is why I'm not a big fan of this "innovative" wheel layout.

When we see the Delta-shaped car's curve higher than the rectangular curve, I will be impressed, and I too will call it "innovative"... until that day......

How much fuel would the rectangle LMP use compared to the Delta shape to achieve the same lap times?

[Flo aus N]

@macchin: thanks, very interesting. By thinking about the design of the Delta-Cars, it becomes obvious, why they perform so poor. The weight distribution ist ridicolous (yes, it is "okay" regarding tire loads, downforce, tire sizes) but that comes with a big priece: They drivers have to adopt their drving style dramaticly. The have to break before the turn, let the car roll through the turn and can only accelerate at the end of the turns. The cornering speeds of this car are at a level of a GTE car and that is quite ridicoulus, concerning that the car hast a DRS and a ground effect floor. So in terms of suspension design, tire loads, tire usage and therefor cornering speeds (and that matters a lot in terms of lap times, even at le mans) the cars are rubbish...

[miatanut]

Originally Posted by joeb

How much fuel would the rectangle LMP use compared to the Delta shape to achieve the same lap times?

Exactly.

When you throw away 1/3 of the car to make it lighter and also push less air around, even if it's not as ultra-optimized as the current rectangular cars, it's still using a lot less fuel to move that driver around.

[optica]

Originally Posted by Flo aus N

@macchin: thanks, very interesting. By thinking about the design of the Delta-Cars, it becomes obvious, why they perform so poor. The weight distribution ist ridicolous (yes, it is "okay" regarding tire loads, downforce, tire sizes) but that comes with a big priece: They drivers have to adopt their drving style dramaticly. The have to break before the turn, let the car roll through the turn and can only accelerate at the end of the turns. The cornering speeds of this car are at a level of a GTE car and that is quite ridicoulus, concerning that the car hast a DRS and a ground effect floor. So in terms of suspension design, tire loads, tire usage and therefor cornering speeds (and that matters a lot in terms of lap times, even at le mans) the cars are rubbish...

Before you dismiss the car as rubbish you might try researching the comments of every driver who has driven the various versions of the car since it first came into existence. It's quite a long list now.

[Maelochs]

The DWing cannot be dismissed as rubbish or haled as successful until it has been thoroughly developed.

No one knows what the car could do if it wever got proper development. From what it showed at Le Mans it could have easily run with P2 had ACO allowed it, even though it had so few miles of testing on it. It did well at Petit later that year as well.

Since then it has had no budget and a complete and completely underfunded redesign, drastically altering its properties and as far as I know has never gotten the differential it was designed for.

Also, without Ben Bowlby on the case ... the person who knows it best can't help, so whoever does work on it ... isn't Ben Bowlby.

Sadly the Zeod never got a good shot either. The DWing might be a great design, or it might be crap. No way to tell yet.

[optica]

If the Panoz crew could get the gearbox issues sorted it looks quite capable of ruffling a few feathers in TUSC. I hope that by Petit they have something that can go the distance. It will ultimately be judged by whether its efficiency produces a real advantage and it needs the longer races to prove its case.

[miatanut]

Originally Posted by optica

Before you dismiss the car as rubbish you might try researching the comments of every driver who has driven the various versions of the car since it first came into existence. It's quite a long list now.

Yes. I don't think anybody can say it hasn't been popular with the drivers who have driven it. They wind up grinning ear to ear.

[Maelochs]

"They wind up grinning ear to ear."

Maybe they're just happy to be out of the thing?

[skycafe]

Originally Posted by optica

Before you dismiss the car as rubbish you might try researching the comments of every driver who has driven the various versions of the car since it first came into existence. It's quite a long list now.

Yes, it seems to be normal to drive, or at least easy to adjust to. Bit of salt in granular form....I believe all the drivers got paid to drive it, and hoped to continue to get paid to drive...

[Machin]

Originally Posted by miatanut

Exactly.

When you throw away 1/3 of the car to make it lighter and also push less air around, even if it's not as ultra-optimized as the current rectangular cars, it's still using a lot less fuel to move that driver around.

Oh contraire; in my example I compared a 620kg 400bhp Deltawing with an 870kg 400bhp LMP. If they have the same engine producing the same power they will consume fuel at the same rate (400bhp requires about 75kg of petrol per hour if driven at full throttle). Now if one of those cars completes the race in a faster time it will actually be producing power (and hence consuming fuel) for a shorter time; it requires less fuel.

Now of course better aerodynamics and lower weight should make the car faster, and hence use less fuel, as described above, but better aerodynamics and lower weight don't help if the car corners so slowly that it is out on the track (consuming fuel at 75kg per hour) for longer.

Now if that sounds counterintuitive imagine an extreme example... lets say we have a 4bhp lawnmower engine in a go-kart consuming 0.75 kg of fuel per hour, and then stick the same engine in a tractor, will it consume more fuel per hour? Of course not.. it will still consume 0.75kg per hour, it is just that the tractor will go slower because of the weight. if it is slower it will take longer to complete the course and therefore it will consume more fuel; the faster car consumes less fuel, even though they consume fuel at the same RATE.

"But more aerodynamic road cars have better mpg's than big heavy unaerodynamic lorries" I hear you say... well that because you drive your road car and your lorry at the same speed (usually determined by the speed limit) in this case, the car will have less drag and hence a better mpg for the same speed.

Race cars don't have a speed limit, they have a power limit.

[miatanut]

Originally Posted by Machin

Oh contraire; ....

I don't know about your comparison, but on the track, the ZEOD didn't do enough laps to tell us squat, so we have to look at the DW.

The DW had 350 HP.

http://www.deltawingracing.com/tech-specs/

The P2's had 450 HP. The DW did 3:42.612. It had four P2's behind it. The DW got its driver around the track faster than those four P2 drivers, and did it with 78% of the peak HP. With your chart, you can say "IF the P2's weighed what the DW did, they would be faster." Great!

How are you going to get all that weight out of them? Without using unobtainium? The DW did it by not building 1/4 of the car.

[Machin]

How are you going to get all that weight out of them? Without using unobtainium? The DW did it by not building 1/4 of the car.

Because the rectangular wheel layout is more lap-time efficient it doesn't need to get down to the weight of the Deltawing in order to be faster than it, even with 350bhp, as my chart shows.

12 years ago we had the MG-LOLA EX257 which ran in the LMP675 class ("675" for 675kg, although the MG reportedly weighed 690kg).

http://en.wikipedia.org/wiki/MG-Lola_EX257

Or for a more up-to date example, how about the Wolf GB08S @ 550kg .

http://www.wolfracingcars.com/GB08S/TECHNICAL-SPECS

Throw in DRS for the rear wing, and full ground effects tunnels and we would have a very quick car indeed.

[nkoske]

Originally Posted by optica

Before you dismiss the car as rubbish you might try researching the comments of every driver who has driven the various versions of the car since it first came into existence. It's quite a long list now.

You do realize driver 101 says, "If you want a paying gig, you probably should s--t on the car in public if they're paying you to drive it or hope to get a paying gig. Exceptions exist for those drivers that are the top drivers in their field with long term contracts and/or other teams knocking on your door. Those drivers have the opportunity to s--t on cars."

Joking aside, How many drivers outside F1 s--t on any car.

[miatanut]

Originally Posted by Machin

Because the rectangular wheel layout is more lap-time efficient it doesn't need to get down to the weight of the Deltawing in order to be faster than it, even with 350bhp, as my chart shows.

12 years ago we had the MG-LOLA EX257 which ran in the LMP675 class ("675" for 675kg, although the MG reportedly weighed 690kg).

http://en.wikipedia.org/wiki/MG-Lola_EX257

Or for a more up-to date example, how about the Wolf GB08S @ 550kg .

http://www.wolfracingcars.com/GB08S/TECHNICAL-SPECS

Throw in DRS for the rear wing, and full ground effects tunnels and we would have a very quick car indeed.

To me, comparing this design at this time to a conventional car is about as useful as comparing a 1920's racing engine to a modern racing engine.

After a full season of two or three teams racing these against each other and getting a better idea of how to set the thing up, it might be possible to get a decent idea of what sort of lap time it could do. So far, there have been three different versions with frailties that have kept us from seeing what it would do if a driver actually wrung its neck.

What we need is a light weight/fuel efficient class where teams could bring their rectangular cars and other teams could bring their delta cars and other teams could bring their teardrop cars and we could see a proper battle of ideas.