Nissan LMP1 Discussion

[sssssssss]

no matter what program anybody ever ran at the lm test day, no competitive lmp1 team ever was among the lmp2s at the end of the test day, be it rainy or not.

the aco are not lying, their traps just aren't at the right point of the track to correctly measure the top speeds of the hybrids. until hybrid cars required longer braking distances, those speed traps were pretty much positioned at the top speed spot on the track (sometimes 3-4 km/h before that). but because, as you can see on the onboard videos, the higher the mj category, the more braking distance the car uses, the traps now catch the hybrids (not any other cars) while braking. that's the explanation for toyota's mostly under 300 km/h aco top speeds last year, as well as usually having the fastest sector 2 in laps that the cars weren't even hitting 300 km/h according to the aco data. now, since the nissan is in the 2mj class, its braking distance is shorter than that of its hybrid competitors, so it makes sense that they travel the fastest through aco's speed trap, and it's more than likely even they have already hit more than 336 km/h. but that doesn't nearly mean they have the real highest top speed of the pack.

[MitchZ06]

So they're not lying because the traps are in the wrong spot to measure top speeds by hybrid cars (uh....) but they are lying because the traps are in the wrong spot....makes sense.

Tell me then, how is the Nissan able to be going faster at the speed trap than the other cars (even if they're braking, IF) and be able to brake in a shorter distance? Surely higher speed = longer braking distance (the explanation you've tried to use above) so wouldn't the Nissan also be braking at that point? If Toyota was sub 300kmh at the same point the Nissan is 336kmh something isn't right with what you've tried to explain. MJ category should result in the cars being able to accelerate faster and achieve higher top speeds while also allowing deeper braking due to harder braking capability (when harvesting power).

If their race lap times are poor come the race then yes, sledge them to your hearts content. All I'm waiting for is the post race tech talk on RLM after Le Mans, not some test day before the race that is rather meaningless to anyone not involved with the teams participating.

[sssssssss]

the higher mj class cars need more braking distance to harvest more energy, that's why the toyota can already be under 300 km/h at the trap point while the nissan can be at 336 at the same point. of course, it depends on the lap and how early the driver did brake at that point. toyota did go 335 km/h through the trap this year and audi 333. it's not that toyota or porsche can't brake as late as the nissan, it's that they need to brake earlier if they want to harvest more energy. this is also why, on a number of occasions at spa, although the porsche was over 5 km/h faster than the audi in absolute top speed figures and it was clearly past the audi at the middle of the straight, sometimes at the end of the straight the audi could maintain it's position at the end of the straight because it could afford to brake later. and that's also why, at last year's le mans, you can see 340-350 km/h on the onboard data of the cars in laps that the aco speed traps say much less, sometimes even sub 300.

[ederss7]

Originally Posted by J Jay

This would be Gran Turismo 6, whose own in-game performance rating reckons a GT3 car is faster than both an LMP2 and a GT500? I'll take those figures with light sprinkling of salt

Still, it will get (more) people (more) interested, there's no doubting that.

Yes, lap times in the game are usually much faster than real life . So 3:25 seems impossible for Nissan . But no way a GT3 is faster than a LMP2 in the game.

[MitchZ06]

Sorry, but that sounds like someone's idea vs actual science....if they want to generate more power the faster they go and the harder they brake the more power they will generate, it's not as much about the time spent harvesting as it is about the velocity and forces involved.

[sssssssss]

well, fact is (and you can verify yourself if you compare onboard videos from the latter years with older ones) current hybrids do brake a lot earlier (well, lift and brake, actually) than what non-hybrid lmp1s did a couple of years ago. to me that means they do need that distance in order to harvest more energy, they really have no other reason to brake early. and it's also fact that the onboard telemetry, be it audi's official data or something else, shows a lot higher top speeds than the aco data. it's also highly improbable that porsche's top speeds are much lower this year than in 2014 and much lower than anybody else's, yet they still manage to achieve a record sector 2 with that. while nissan, with the supposedly highest top speed, are nowhere near any competitive times even in sector 2 alone.

[MitchZ06]

Lift and coast suggests fuel flow limitations (ie saving so as not to go over the per lap limit) vs having to spend longer on the binders to harvest power. It takes energy to make energy afterall....

[Gingers4Justice]

If only Nissan could harvest some of the nonsense in this thread. They'd make 8MJ easy.

[Bandicoot17]

I imagine they begin to recover energy in the same way that the Tesla road cars do. Lift fully off throttle and the car begins to slow as the regen kicks in, and only then will they hit the brakes. Nissan are having to harvest less (maybe not even the full 2MJ per lap) so they can just do the whole process a lot later.

[sssssssss]

exactly. i also recall rlm's spa commentary mentioning audi's shorter braking distance as compared to porsche's at the end of the straight.

[MitchZ06]

Instead of heresay is there any chance you can back up your claims with hard data (the juicy stuff like top speeds, sector times, braking points, rate of recharge, aerodynamic loads, track surface data) or are we sticking with "go look at some onboards"?

[Bandicoot17]

Originally Posted by sssssssss

exactly. i also recall rlm's spa commentary mentioning audi's shorter braking distance as compared to porsche's at the end of the straight.

This was clear at Silverstone too. Through Farm and into Village the brake lights on the Porsche began to flash (which suggests braking regen) a lot earlier than they did on the Audi.

[joeb]

Originally Posted by Gingers4Justice

If only Nissan could harvest some of the nonsense in this thread. They'd make 8MJ easy.

[Spyderman]

This might help : http://www.electric-vehiclenews.com/...bout-lmp1.html

[miatanut]

Originally Posted by Spyderman

This might help : http://www.electric-vehiclenews.com/...bout-lmp1.html

It's so refreshing having racing where teams take different technical approaches after years of all the cars being practically identical in top level professional racing.

[hcl123]

Originally Posted by sssssssss

well, fact is (and you can verify yourself if you compare onboard videos from the latter years with older ones) current hybrids do brake a lot earlier (well, lift and brake, actually) than what non-hybrid lmp1s did a couple of years ago. to me that means they do need that distance in order to harvest more energy, they really have no other reason to brake early. and it's also fact that the onboard telemetry, be it audi's official data or something else, shows a lot higher top speeds than the aco data. it's also highly improbable that porsche's top speeds are much lower this year than in 2014 and much lower than anybody else's, yet they still manage to achieve a record sector 2 with that. while nissan, with the supposedly highest top speed, are nowhere near any competitive times even in sector 2 alone.

Well its very hard to compare with 2 years ago... but if that theory of longer brake distances holds water, someone forgot to tell Treulyer lol ... the first minute of the video is illustrative, 3 GTs in a row the last for a dash almost on top of corner, and he sorted out of track 2 corners ahead...

https://www.youtube.com/watch?v=920KpqOiX0E

What LMP1-H doesn't seem to do is braking with the gearbox so much as in the pass, rapid succession of down gears for engine braking ... now they are sophisticated computer electronic fuel injected can achieve similar effects with higher gear ratios and save fuel in the process(engine is not forced to rev higher upon a down gear ratio)... perhaps there the sensation of lifting and coasting more than it really is, and besides they are hybrid, and the hybrid system is a *very* powerful braking element... not to mention the normal brakes that are for sure more powerful than in F1 ( they must the car is much heavier, its not a Moto4)... just superb braking ability those LMP1-H...

[Articus]

Originally Posted by Gingers4Justice

If only Nissan could harvest some of the nonsense in this thread. They'd make 8MJ easy.

[GTfour]

Look what Playstation gave us today!


[/IMG]

[wdave0]

Originally Posted by Articus

I think the issue(at least for me) is that this is following the pattern of the previous Bowlby/Nissan programs, delta and zeod,much innovation (or creative license) based on the same theme, much promise PR and no results so far. There seems no reason to expect a better result from this foraay into space than the other two.

[FormulaFox]

Originally Posted by wdave0

I think the issue(at least for me) is that this is following the pattern of the previous Bowlby/Nissan programs, delta and zeod,much innovation (or creative license) based on the same theme, much promise PR and no results so far. There seems no reason to expect a better result from this foraay into space than the other two.

The Zeod was killed by a bad choice of powerplant. The Delta Wing actually did very well, hitting the exact pace at Le Mans they were aiming for and ultimately getting a 5th place at the Petit Le Mans in only its second outing is no small feat, and it's added a 4th place PLM finish on top of that.

The Delta Wing, however, NEEDS the resources of a company like Nissan to develop it, and they no longer have it. I find it no coincidence that the car has had only ONE good run(the 4th place at PLM) since moving away from the version that was built with the assistance of Ben Bowlby and Nissan - of the car's four best runs, THREE of them(hitting all their performance targets at Le Mans, 5th overall at PLM, leading at Road America on pace) were done with the car which Bowlby himself oversaw the construction - two of them while it was still directly backed by Nissan. The third(leading Road America on pace alone) is IMO the least impressive of the three(as it didn't last long enough to matter and the car ended the race MANY laps down), and came without Nissan's backing.

As for the GTR-LM Nismo, it's right about where I expected it to be on test day. Sure, as has been pointed out, EVERYONE was doing testing programs at test day, but that doesn't actually say anything about relative performance at the limit. ALL of the P1 cars except the Kolles, Rebellions, and Nissan had been racing already this season, and all of the chassis except the Kolles and the Nissan had seen significant action in previous seasons.

The Kolles car also did not participate in the second session for reasons I have yet to see published - telling me it looks like the car has a serious flaw and that they may have LUCKED their way into that Nissan-beating time.

The point is, the Big Three had much more information on what their cars were like at the limit, and their testing programs were as a result closer to that limit. And don't doubt for a moment that the big three were running close to the limit; The fastest time of the test day was FASTER than last year's pole time.

Nissan still has a lot to figure out about exactly what the car wants in terms of ideal setup. They weren't anywhere near as close to pushing things as the teams with terabytes upon terabytes of past data were willing to go.

The only thing we can glean from this test with 100% certainty is that people who said the car couldn't outrun GTE cars were VERY wrong. Beyond that, we can be probably 90% certain that the car will be noticeably quicker come race week.

What we can't predict with any certainty whatsoever is how much quicker it will be. I suspect Darren Cox's prediction that they'll beat the LMP2 pole times will end up being correct, but the real question is by how much? 1/10th of a second isn't much at Le Mans, but it would still mean the car was quicker.

[haribo]

Originally Posted by FormulaFox

The Kolles car also did not participate in the second session for reasons I have yet to see published - telling me it looks like the car has a serious flaw and that they may have LUCKED their way into that Nissan-beating time.

They had a bad rear puncture early on in the first session which wrecked the rear bodywork, and they didn't have any spares.

[hcl123]

Originally Posted by wdave0

I think the issue(at least for me) is that this is following the pattern of the previous Bowlby/Nissan programs, delta and zeod,much innovation (or creative license) based on the same theme, much promise PR and no results so far. There seems no reason to expect a better result from this foraay into space than the other two.

I hope not... that will mean crawl until the end of next season (with luck) and leave when nobody is watching...enter with thunder leave in silence...

[Richard C]

Originally Posted by Spyderman

This might help : http://www.electric-vehiclenews.com/...bout-lmp1.html

Thank you. Nice article. My take away is that your braking distance may be impacted by the maximum harvest rate. With batteries giving you a slower rate.

IIRC, there was a thread here somewhere weeks ago when someone ask about the potential advantage of running multiple storage types as the same time. At the time I think nobody could come up with a benefit to that configuration. I wonder if a combination of battery + super capacitor might work well. In the scenario above you could potentially harvest into both at the same time with the super capacitor (smaller portion of total storage) taking the short term excess that the battery (larger portion of total storage) can't. I expect the reason why this would not work is the extra weight of the more complex electronics to manage both types in the same car?

Richard

[lne937s]

Originally Posted by Bandicoot17

I imagine they begin to recover energy in the same way that the Tesla road cars do. Lift fully off throttle and the car begins to slow as the regen kicks in, and only then will they hit the brakes. Nissan are having to harvest less (maybe not even the full 2MJ per lap) so they can just do the whole process a lot later.

Tesla goes into energy recovery on liftoff to make it feel like a "normal" car, where the engine slows the car on liftoff. It is not to make the car more efficient or faster.

In racing, I assume they really don't care if it feels "normal".

[hcl123]

Originally Posted by Richard Casto

Thank you. Nice article. My take away is that your braking distance may be impacted by the maximum harvest rate. With batteries giving you a slower rate.

IIRC, there was a thread here somewhere weeks ago when someone ask about the potential advantage of running multiple storage types as the same time. At the time I think nobody could come up with a benefit to that configuration. I wonder if a combination of battery + super capacitor might work well. In the scenario above you could potentially harvest into both at the same time with the super capacitor (smaller portion of total storage) taking the short term excess that the battery (larger portion of total storage) can't. I expect the reason why this would not work is the extra weight of the more complex electronics to manage both types in the same car?

Richard

Porsche above all i don't think they have to relay so much on recuperative braking for the 8 MJ, matter of fact i think for circuits like LeMans with long straights and so more time on full acceleration (when the wastegate is open and so the exhaust generator working) , the Exhaust Alternator (TIGERS) would be more than enough to harvest all the energy for the 8MJ release strategy... problem will be slower circuits with combinations of short straights slower curves and high acceleration zones...

Capacitor + Battery i suggest something you said, not only because it seemed proper but because is ( or at least was) foreseen in rules... only that battery is an *auxiliary battery* rated at 50V, which doesn’t impede of being a huge energy density device compared with a capacitor, and since both reside in the high voltage lines, a traction Energy Storage ( being capacitor, other battery or flywheel etc) and this Auxiliary Battery could 'spill' into each other and complement each other very nicely... and if harvesting is allowed for a lot of simultaneous (at least some) methods, it will be very handy for running all engine ancillary devices on electric means ( oil water pumps etc)... in the most simple config it would only need an additional electric motor instead of this devices being run by a pulley connected to the engine crankshaft ...

So that 'idea' is not that complex at all... some tests more focused on road cars have shown up to 7% more engine efficiency(electric ancillaries), motorsport could be more, which is a very considerable gain in efficiency... and the weight penalty!?..expect FIA/ACO to give a hand, 2016 could be again ~900kg, so instead of ballast...

[ the breaking distances between Porsche and Audi might be much more related with Audi running with much more downforce (they have a huge torque engine proper for this, which can also normaly break much heavier than a petrol engine without stalling(funny at Spa for Audi it seemed to have stalled twice one time for #7 another for #8)), which can help a lot upon breaking, than with braking issues related with hybrid harvesting needs]