83rd Running Of The Le Mans 24 Hours - 13/14 June 2015.

[Furinkazen]

So by that logic you could take the data acquisition from Audi and swap it for Toyota's? They are both LMP's with 4 wheels and a cockpit after all. Surely you can't be serious. Track data and weather aren't exactly static entities either, these are primarily public roads we are talking about that get used year round and the weather...of course it will be exactly the same

No because different vehicles.

 

[Bo]

So by that logic you could take the data acquisition from Audi and swap it for Toyota's?

No, because they're entirely physically and mechanically different. The Nissan will remain the same, except the rest of it will actually function. Terrible logic.

Track data and weather aren't exactly static entities either,

But you get a range of data, and that's what's good about it - they've run the cars in all conditions imaginable. That's in no way worthless.

Surely you can't be serious.

I'm wondering if you're serious. Besides...

You have to think of their timescale - a large part of the team will never have done a Le Mans as part of a P1 team before. If you're aiming to win next year, time is against you completely - you have just one year for the entire team to be bulletproof. Letting up the one opportunity you're given to have the most realistic 24 hour race run possible would be extremely unprofessional of NISMO.

A dress rehearsal might go to pot and everyone forgets their lines and the stage falls down, but that's why it's a dress rehearsal. It means you know what can go wrong the next time.

 

[MustangManiac]

No, because they're entirely physically and mechanically different. The Nissan will remain the same, except the rest of it will actually function. Terrible logic.

But you get a range of data, and that's what's good about it - they've run the cars in all conditions imaginable. That's in no way worthless.

I'm wondering if you're serious. Besides...

A dress rehearsal might go to pot and everyone forgets their lines and the stage falls down, but that's why it's a dress rehearsal. It means you know what can go wrong the next time.

That's the thing, the car will be drastically different mechanically when they get it at it's designed specs. Physically Bowlby will have the aero worked out, I have no doubts about that.

As for the weather, yes it will add to the pool, especially if they run the rest of the season and the events leading up to Le Mans next year. I'll give you that, but you can get that data testing anywhere, anytime. I also never claimed that 100% of the data would be useless, just most of it.

As for being serious...yes. My grand father was an engineer, my father was an engineer and I have been an engineer for over 30 years. I stand by my statement that the majority of the data run in the current configuration will not transfer to the as designed specs. What qualifications do you have to back up your assertions?

As for the "dress rehearsal" true, but that's not data, that's experience and there is only one way to get it

 

[CodeRedR51]

You have to think of their timescale - a large part of the team will never have done a Le Mans as part of a P1 team before. If you're aiming to win next year, time is against you completely - you have just one year for the entire team to be bulletproof. Letting up the one opportunity you're given to have the most realistic 24 hour race run possible would be extremely unprofessional of NISMO.

I heard during the broadcast that some of the RJN team was helping out during the race since the LMP1 team was short on manpower.

 

[Holdenhsvgtsr]

 

[ROAD_DOGG33J]

 

[catamount39]

I just realized that this was the first win for the C7.R at Le Mans...AWESOME!

#Slow

 

[Holdenhsvgtsr]

My pics

Rest here
[URL]https://www.flickr.com/photos/42427406@N05/sets/72157654306083066[/url]

Best sounds of the weekend
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Best celebration
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Also best part of the weekend for me was getting to meet Marek Reichman.

I walked my mate down to his vantage GT3 then went to the fence to get some shots when a GT12 turned up and Marek got out and straight away asked for an autograph and he kinda shyed away saying he wasn't a famous race driver to which I replied I know you're Marek Reichman head of design who's designed cars such as then listed off my favourites and then his face lit up and was nothing but appreciative.

Beginning to wish I asked him to sketch me a design lol

 

[adam46]

Would it be possible to use that as a feature image in a race report?

 

[Holdenhsvgtsr]

Would it be possible to use that as a feature image in a race report?

it's not downforce radio is it?

 

[adam46]

it's not downforce radio is it?

I'll PM you.

 

[Exorcet]

Yes actually it will be useless. Not a single piece of data you mentioned will transfer over to the car when running in it's as designed specs, it will be too radically different to what they ran this year. I really don't see how this is so hard for people to see.

The usefulness of the data doesn't necessarily depend on the vehicle. Sure if they completely change the brakes and the cooling for the brakes the data for this car will not tell you what the brake temps on the new car will be. You would still have information on when and where peak loads occur though. The value of the data is not necessarily a binary 1 or 0, it depends on what you're looking for.

 

[niky]

Yes actually it will be useless. Not a single piece of data you mentioned will transfer over to the car when running in it's as designed specs, it will be too radically different to what they ran this year. I really don't see how this is so hard for people to see.

If you're counting it as data towards next year, when Bowlby will presumably have an entirely different hybrid system in the car, and possibly different brakes (personally, I think the latter will be rendered non-essential by the former), then maybe much of the data won't fly... but a lot of it will help design a better car.

And remember, the WEC isn't only Le Mans. There's still the rest of the year to run the car. And for that, the data will definitely be useful.

I see what you're saying about conditions, and definitely, as specific set-up data for racing, they won't be able to carry everything forward, because of the lack of rear wheel motivation. But the suspension and tire data are still useful, because Nissan still had to run minimum weight, with the same bodywork, engine and brakes designed around the non-functional hybrid system.

Think of it, even, as a torture test for the engine and gearbox, having to lug around corners where the hybrid system was supposed to fill in holes in the torque curve.

 

[mustafur]

Nissan Considering a potential Hybrid V8 Supercar for a future Garage 56 entry: http://carsales.mobi/editorial/details/ED-ITM-51885

 

[Sertsa]

Holdenhsvgtsr - Great images and sounds; thanks for sharing them. And very cool getting to meet Marek Reichman.

I'm still hoping to make it one year. Maybe next year, especially with Ford's returning, and maybe Toyota and Nissan will be more competitive in LMP1.

 

[redsoxboy80]

So I did a little investigating trying to figure out exactly how the GTR-LM team plans on adding a hybrid system next year. A few people in this forum have been talking about the plan for the car to have the hybrid driving the rear wheels next year (or having two different systems at the front and rear), and that makes sense because obviously the car is compromised by just being a FWD machine. The planned 'flybrid' system is interesting in itself, but I was curious as to exactly how Bowlby's team can incorporate the drivetrain components within the rear of the chassis without blocking the airflow, and therefore maintaining the car's low drag character.

These photos are widely available, and of course they are of the 2015 version of the car. Who knows what will be different next year. So this first is just a close up of the rear brake and suspension and there does not appear any sort of drive mechanism attached:

This photo clearly shows a halfshaft attached, suggesting that there was some plan to drive the rear wheels at some point. I believe this photo was taken before the AWD plans were abandoned this year:

Now this photo is much more interesting because, although no drivetrain components exist to drive the rear wheel, it might hint at the team's plan for mating the hybrid system and drivetrain component within the chassis:

The driveshaft in the middle of the chassis is obvious. I'm am still wondering exactly what they plan on doing with the halfshafts, gearbox, differentials, etc. There seems to be enough room in the middle to add a compact diff, but it seems impossible to keep the halfshafts out of the airflow. Still, any time lost from the drag created by a couple halfshafts will be greatly offset by the speed gained on corner exit from driving the rear wheels. The rotating halfshafts can always be covered with a small carbon cover to minimize any disturbance to the airflow.

I was also curious whether or not they plan on harvesting any energy from the rear under braking. I suppose the same driveshaft that transfers torque to the rear wheels could also be used to harvest energy. But that doesn't seem likely since the front end will have plenty of energy available to harvest anyway. And the additional hardware will create even more of a disturbance to the airflow. This is Audi's front MGU set up from 2012 to get an idea of the size of the components (the MGU, with the yellow caution sticker, is behind the power steering motor):

And finally an image many of you have probably already seen. A rear shot of a fully dressed GTR-LM looking forward. It's hard to imagine the same shot of next year's car, presumably with a working rear-drive system, having the same amount of free space within the tunnels. I'm sure the car will still have very attractive drag figures regardless exactly of what they do:

I can really only think of one thing that Bowlby and his team can do to keep the tunnels as open as they are now. The first is angle the driveshaft upwards or downwards, so the differential will rest either higher or lower than the rear-wheel centerline. The halfshafts then could be angled towards the wheel housings and less of their area would be exposed to free-flowing air. That's just an interesting idea I thought of. If I have any engineering background, it's mostly from karting and one year studying in an automotive mechanics program so please don't murder me if that's a stupid idea.

So anyway, this next year will be really interesting. This team have a lot of challenges ahead trying to make this car competitive.

Edit: Something I just thought of. Wouldn't they need a good amount of structural rigidity from the rear of the chassis if adding drive to the rear wheels?

 

[TenEightyOne]

If you're counting it as data towards next year, when Bowlby will presumably have an entirely different hybrid system in the car, and possibly different brakes (personally, I think the latter will be rendered non-essential by the former), then maybe much of the data won't fly... but a lot of it will help design a better car.

Yup, and sometimes field testing shows you that bits you thought were okay actually break/wear/plumb-don't-work. Sometimes you've just got to take one and break it to learn something.

The driveshaft in the middle of the chassis is obvious.

I'm not sure, I don't see why they'd carry a full-length driveshaft that led nowhere, it looks to me like an electrical bus that takes a plug on the end.

 

[niky]

If I recall right, the solution is to use individual driveshafts to each rear wheel, running longitudinally down the chassis at the sides. Neither has to be very big, as they're not meant to carry a crapload of power... just enough to provide corner exit traction and to balance the chassis on corner exit.

Or they could use hydraulic or electric motivation there. Or even portal axles... which would allow the driveshafts to run over the tunnel.

Either way, the rear aero is already designed with provisions for the rear drive built in... so it shouldn't change when the hybrid system is installed.

 

[CodeRedR51]

I thought it was common knowledge that the rear wheels have a sort of stepper gear system to avoid having half shafts disturbing air in the tunnel system. Or is that just something I learned and they never released info on?

Edit: http://www.roadandtrack.com/motorsports/a24903/nissan-gt-r-lm-nismo-tech-deep-dive-with-ben-bowlby/

...if the team decides to use AWD, to the rear through a long driveshaft beneath the tub that connects to a differential which then feeds the rear wheels through a complex system of secondary driveshafts and outboard gearboxes.

 

[Bo]

A few people in this forum have been talking about the plan for the car to have the hybrid driving the rear wheels next year (or having two different systems at the front and rear), and that makes sense because obviously the car is compromised by just being a FWD machine.

It never was a "just FWD" machine. It's not like they designed it as a FWD car and then planned to make it 4WD later - it is exactly the same as every P1-H.

Now this photo is much more interesting because, although no drivetrain components exist to drive the rear wheel, it might hint at the team's plan for mating the hybrid system and drivetrain component within the chassis:

Nope, they're the channels for air to flow from front to rear. That's not extra space, that's how it's designed. You're still ignoring the fact that all the hybrid systems are installed right now, as of regulations - they haven't butchered it out, there isn't anything left to add, it's all there now.

I was also curious whether or not they plan on harvesting any energy from the rear under braking. I suppose the same driveshaft that transfers torque to the rear wheels could also be used to harvest energy. But that doesn't seem likely since the front end will have plenty of energy available to harvest anyway.

The hybrid system is the only place these cars can perform regen. Rear braking power is largely what will slow the car down.

And finally an image many of you have probably already seen. A rear shot of a fully dressed GTR-LM looking forward. It's hard to imagine the same shot of next year's car, presumably with a working rear-drive system, having the same amount of free space within the tunnels.

It's all there - please understand this. They are not allowed to run the cars without any of the hybrid system installed - how you see it now is how it was designed, and it won't magically change layout when they manage to switch on the system.

 

[MustangManiac]

If I recall right, the solution is to use individual driveshafts to each rear wheel, running longitudinally down the chassis at the sides. Neither has to be very big, as they're not meant to carry a crapload of power... just enough to provide corner exit traction and to balance the chassis on corner exit.

Or they could use hydraulic or electric motivation there. Or even portal axles... which would allow the driveshafts to run over the tunnel.

Either way, the rear aero is already designed with provisions for the rear drive built in... so it shouldn't change when the hybrid system is installed.

I thought I saw somewhere that they explained that the plan was to go from a central shaft at the rear, up to a shaft heading towards the wheels and then back down to the wheels. I remember thinking " Why the 🤬 would they do that, it makes 4 points on each side, each one being a potential failure spot!" The explanation being to keep the shafts out of the tunnels of course. That just seems way to complicated to me, adding in so many failure spots.

I thought about angling the central shaft upwards as well and then to the wheels angle down. Yes, it would cut a bit through the tunnel, but would halve the potential failure points in the drive line. Two shafts down the sides as you suggest would also work, but at some point they would have to cross the tunnels to a central shaft wouldn't they?

I also heard someone say that you couldn't get 8MJ from a single flywheel and they intended to use two 4MJ's. You could then place the flywheels outboard the center, inline with the rear wheels and run the shaft as you mentioned. You are still going to run into one of two problems the way I see it. You either cut through a corner of the tunnels or you double the complexity (failure points) by going up and over them to tie into the central shaft on the engine. It will be interesting to see how they go about this.

 

[MatskiMonk]

failure points

I'm not sure they can beat Porsche or Audi if they shy away from that though. Replicate the system in the workshop, and test the crap out of it, identify the probabilities and risks, weigh them up against wind tunnel tested aero gains, and make a judgement.

 

[Bo]

Don't do a Lada Vesta and have a rocketship with wheels that break off if they hit a small piece of gravel.

 

[Famine]

I thought it was common knowledge that the rear wheels have a sort of stepper gear system to avoid having half shafts disturbing air in the tunnel system. Or is that just something I learned and they never released info on?

I heard pretty much on day 1 that they were using portal hubs.

 

[redsoxboy80]

I'm not sure, I don't see why they'd carry a full-length driveshaft that led nowhere, it looks to me like an electrical bus that takes a plug on the end.

Yeah when I first saw it I actually thought it looked more like a steering shaft. So yeah, I just assumed it's a driveshaft because of their intention for rear drive. But we don't even know if that middle tunnel is intended for rear drive components.

If I recall right, the solution is to use individual driveshafts to each rear wheel, running longitudinally down the chassis at the sides. Neither has to be very big, as they're not meant to carry a crapload of power... just enough to provide corner exit traction and to balance the chassis on corner exit.

Or they could use hydraulic or electric motivation there. Or even portal axles... which would allow the driveshafts to run over the tunnel.

Either way, the rear aero is already designed with provisions for the rear drive built in... so it shouldn't change when the hybrid system is installed.

Yeah the how part of the rear drive question is the intriguing part. If the rear aero doesn't change than it's safe to assume a conventional drivetrain won't be used. Hydraulic drivetrain ............ hmmmm that would be very innovative.

I thought I saw somewhere that they explained that the plan was to go from a central shaft at the rear, up to a shaft heading towards the wheels and then back down to the wheels. I remember thinking " Why the 🤬 would they do that, it makes 4 points on each side, each one being a potential failure spot!" The explanation being to keep the shafts out of the tunnels of course. That just seems way to complicated to me, adding in so many failure spots.

I thought about angling the central shaft upwards as well and then to the wheels angle down. Yes, it would cut a bit through the tunnel, but would halve the potential failure points in the drive line. Two shafts down the sides as you suggest would also work, but at some point they would have to cross the tunnels to a central shaft wouldn't they?

I also heard someone say that you couldn't get 8MJ from a single flywheel and they intended to use two 4MJ's. You could then place the flywheels outboard the center, inline with the rear wheels and run the shaft as you mentioned. You are still going to run into one of two problems the way I see it. You either cut through a corner of the tunnels or you double the complexity (failure points) by going up and over them to tie into the central shaft on the engine. It will be interesting to see how they go about this.

You pretty much summed up exactly what i was thinking. There's also the issue of the weight of everything too and how much will be left over for ballast, if any at all. With two separate hybrids I don't think there will be any chance of coming in under the minimum weight IMO.

Edit: Wouldn't any heavy components placed along the sides of the car would have a horrible effect on handling, especially if they're rotating too? Polar moment of inertia I believe. Correct me if I'm wrong on that.

 

[CodeRedR51]

It never was a "just FWD" machine. It's not like they designed it as a FWD car and then planned to make it 4WD later - it is exactly the same as every P1-H.

Exactly this, the car was designed for AWD from the start.

 

[Aloha62_2]

Edit: Wouldn't any heavy components placed along the sides of the car would have a horrible effect on handling, especially if they're rotating too? Polar moment of inertia I believe. Correct me if I'm wrong on that.

Just to address this one part as long as the mass is low in the body it has little effect and could even be beneficial to balance, there would be inertia from the gyroscopic effect but it would be incredible minor and driveshafts are very very light. You could easily pick up the propshaft assembly of say a BMW M5 with one hand and use the other to fit the mounting bolts, or have a cup of tea while waiting for the works experience kid to remember where he put said bolts.

The complicated shaft assembly was brought up by a lot of motoring press at the time but I remain sceptical, they would have to be very very thin parts to fit into the body panels we have seen and that doesn't go well with the mountains of torque electric systems produce, also all the converting gear whether its portal gears or chain would be heavy and inefficient.

I was personally expecting to see a motor system built into the rear hub and suspension packed away into the wheel arch.

 

[MatskiMonk]

@redsoxboy80 I know it's Hammond, but still relevant to your question

 

[MustangManiac]

Edit: Wouldn't any heavy components placed along the sides of the car would have a horrible effect on handling, especially if they're rotating too? Polar moment of inertia I believe. Correct me if I'm wrong on that.

As Aloha mentioned above it could even aid in stability, especially if you rotated them in opposite directions, the torque produced by one would negate the other. They do the same thing, for the same reason in duel engine aircraft by contra-rotating the props. It produces an incredibly stable platform.

 

[redsoxboy80]

@redsoxboy80 I know it's Hammond, but still relevant to your question

Ya know I saw that video a while back, and the fuel tank one lol. I was more concerned with the rotating aspect and the gearing needed to change the direction of the torque. But yeah it's crazy how strong CFRP can be.

As Aloha mentioned above it could even aid in stability, especially if you rotated them in opposite directions, the torque produced by one would negate the other. They do the same thing, for the same reason in duel engine aircraft by contra-rotating the props. It produces an incredibly stable platform.

That would be something new in a race car!

So we're definitely not short on possibilities or ideas for guessing how this car will send power to the back end. I figure it's the #1 challenge Bowlby and Co. need to figure out. Hopefully Nissan stays as transparent as they've been so far.