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Thread: Nissan's new GT-R LM 1250hp prototype race car

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    http://www.trackhq.com/Banners/yellowsitesponsor.gif Blackbird's Avatar
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    You do realize that it's AWD, right?
    The ICE powers the fronts, but the rears are powered by elect motors.

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    A few of the LMP1 cars are already AWD. If a rear-engined AWD car can make front halfshafts last, this car shouldn't have any trouble either. And if the drag reductions and insane power succeed at making it faster than everything else on the grid, they might be able to afford the extra stops to keep fresh tires on the front. I'm not even sure they'll have tire issues, though. This isn't like comparing a Civic to a Miata. FWD didn't make sense before the hybrid systems came into play, but this is really an AWD car that's just biased toward FWD.

    Also, it has a flywheel-based KERS system, so no batteries or electric motors. Google "Flybrid KERS" to learn more about it. You can't see the rear driveshafts because they run through the upper bodywork and then into gearboxes at each corner, then out of the gearboxes into another set of super short driveshafts that go to the wheels. A lot of added complexity, but it keeps the driveshafts out of the air.

    I'll be surprised if they win this year, but it'll be a really cool car to follow through development. Way cooler than the deltawing lol. I bought my Le Mans tickets a month ago before I even knew about this thing. June can't come soon enough!
    Last edited by jpreston; 02-02-2015 at 10:34 PM.
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    From the racer.com article:

    Picture the loooooong driveshaft extending from the front of the car to the back of the car, terminating at the rear axle line. It connects to a differential housing that scales upward – high enough for driveshafts to reach across and over the through-flow aero tunnels. Those driveshafts connect to individual gearboxes that also sit in tall housings. With the high differential housing connected to the high outrigger gearboxes via driveshafts, the rear wheels are turned by short driveshafts from the base of the gearboxes.

    The entire exercise is done to prevent sticking driveshafts through the tunnels and reducing aero efficiency.
    Since you can't see them in any of the pictures, including this one, suspicion is that Nissan may not be using the AWD system yet.

    nissan_gt_r_lm_nismo_lmp1_by_marshall_pruett_30-4610-640-360-80-c.jpg

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    Rear engine AWD cars don't destroy half shafts because they're not putting 1,250 horsepower down through the same wheels they steer with. Again, out of the race by midnight.

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    The 1250-1500 HP figures are combined ICE + elect.
    ICE is probably making half that amount.

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    A few notes:
    The existing LMP1-H cars are all making +/- 500whp from the ICE's. This nissan is no different. Those cars also estimated to be making around 1000-1100 hp when all of the MGU's are active along with the ICE (estimated because the overall power isn't limited, just the amount they can store/expel). They are for the most part, throwing that MGU energy at a combination of the front wheels and back wheels. So it's safe to say that these cars are all throwing 200-400whp worth of electric power at the front wheels mid corner and corner exit and they are not having half shaft problems at this time.

    While I agree with brett that it will be interesting to see if the nissan can keep the front tires in the car, I'm not sure there will be half shaft problems. I feel like there could be a whole host of other issues with this car due to the insane packaging they've done. That being said, a hallmark of LM24 success over the last 5 years has been quadruple stinting the tires... they need to do that to have a chance.

    Regarding the rear drive component of the nissan. They are using a high mounted transfer case in the rear that keeps the rear drive axles very high in the knuckle and then uses a set of transfer gears to drop that power down to hub level. This is all obviously in an effort to not screw up the tunnel aero.

    So what I can't wrap my head around with this car is how it will deliver power compared to the existing hybrids. For the most part the other 3 cars are very similar in aero concepts (now that toyota's and audi's movable wings have been caught and deemed illegal) and power delivery (ICE rear, electric motors on the crank shaft and front wheels). The biggest distinguishing feature being how they generate and store electricity. EX, porsche using batteries, kinetic generation and heat generation, toyota using kinetic and capacitors etc etc.

    So what is nissans plan? Surely they will not be able to put power down coming out of the corners since the interviews suggest that their hybrid system is developed around being online all at once and at high speed/rpm instead of low speed/low end out of the corners. It would seem to me that is a huge gamble and that the musings from the team suggest they are planning on drag racing this car. IE super high straight away speeds and parking it in the corners.

    They better hope it doesn't rain at Le Mans. Yeah right.

    for those interested - most of my speculation comes from these links
    Le Mans/WEC - WEC: Q&A with Nissan's Darren Cox
    Le Mans/WEC - WEC: Nissan LMP1 tech talk with Ben Bowlby
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    If this design is as effective at drag reduction as it appears., it could afford to run a bunch more downforce that conventional designs, if anything about the Audi or Toyota can be described to as conventional. So I wouldn't expect this car to ineffective in the turns, quite the contrary. Note that some of the early leaked photos and rumors indicated a car with rear wing, which could presumably be it's ultra low drag Le Mans config. Weight on the nose means more torque can be applied there in a straight-ish line without as much tire wear penalty as a rear engined car. Like everyone else, I'm skeptical but also very eager to see how the concept will perform. The "there is no box" thinking by the design and engineering team is captivating to see in action.
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    Senior Member bellwilliam's Avatar
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    Quote Originally Posted by Blackbird View Post
    The 1250-1500 HP figures are combined ICE + elect.
    ICE is probably making half that amount.
    this is Trackhq in-house EV expert talking here:

    I doubt ICE (gas engine) is making 1/2, if front tires are significantly wider than rear tires. my guess would be more like 3/4.

    btw. This is what Honda / Acura does with their new hybrid system. ICE drives front wheel, electric motor drives rear wheels. Advantages:
    1. it is now AWD without the weight penalty (no drive shaft, diff....), so no more EV weight penalty.
    2. electric motors (with lots of torque) help the car on take off. where most weight transfer occurs. then ICE engine takes over after say 20-30mph.
    3. it eliminates use of 1 super low gear in transmission. electric motors can drive taller gear easily.
    4. it helps with engine shutoff during stops. ICE takes a while to kick in. in the mean time, electric motor drives rear wheel.
    5. recaptures energy while slowing.
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    Quote Originally Posted by emilio700 View Post
    If this design is as effective at drag reduction as it appears., it could afford to run a bunch more downforce that conventional designs, if anything about the Audi or Toyota can be described to as conventional. So I wouldn't expect this car to ineffective in the turns, quite the contrary. Note that some of the early leaked photos and rumors indicated a car with rear wing, which could presumably be it's ultra low drag Le Mans config. Weight on the nose means more torque can be applied there in a straight-ish line without as much tire wear penalty as a rear engined car. Like everyone else, I'm skeptical but also very eager to see how the concept will perform. The "there is no box" thinking by the design and engineering team is captivating to see in action.
    Absolutely agreed. It's really exciting to see a form of racing that is technically exciting in aero, mechanical, hybrid, driver battles, on track battles, tire tech etc. WEC is hitting every single portion of racing excitement for me at the moment with technology and team diversity.

    I'm really thankful that Nissan has showed up and been so open about their design and program. I suppose it's because it's such a radical design that they have little risk of people stealing their ideas (at this point). I am very excited to see how all of this will develop. I am very interested to see how this car responds to the drag reduction and aero balance vs mechanical grip balance that you reference as well. Totally radical stuff happening right now in endurance racing. The only other thing I could ask for is for the return of GT prototypes and GT3 spec cars taking the place of GTE AM.

    P.S. Another interesting thing about the nissan is the return of the flybrid style of electrical energy storage. I wonder how that is going to play out as they shoot for the 8mj energy class. Porsche had a lot of experience with that system with the GT3 R Hybrid and elected to go Li-Ion. The nissan however, supposedly has 2 of those things.

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    imo. This car is product of regulations. not of technical nature.
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    Quote Originally Posted by bellwilliam View Post
    imo. This car is product of regulations. not of technical nature.
    I quite disagree with that. WEC regulations are very open. To me this is really the last of the non spec series out there. IMO F1 might as well be a spec series.
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    William, compare the differences between the OEMs running WEC P1, now including Nissan, and you'll find more diversity than any other big buck racing series around the world these days.

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    Quote Originally Posted by Blackbird View Post
    William, compare the differences between the OEMs running WEC P1, now including Nissan, and you'll find more diversity than any other big buck racing series around the world these days.
    I was thinking LeMan, where regulation is everything. one year they favorite diesel, next year they favor hybrid. nothing is what they seem
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    Quote Originally Posted by ebruner View Post
    P.S. Another interesting thing about the nissan is the return of the flybrid style of electrical energy storage. I wonder how that is going to play out as they shoot for the 8mj energy class. Porsche had a lot of experience with that system with the GT3 R Hybrid and elected to go Li-Ion. The nissan however, supposedly has 2 of those things.
    Where are you guys seeing anything about this car having an electric hybrid system? I've read 6 or 8 articles now and they've all lead me to believe that this specific Flybrid KERS system is 100% mechanical. No batteries or electric motors.

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    Quote Originally Posted by jpreston View Post
    Where are you guys seeing anything about this car having an electric hybrid system? I've read 6 or 8 articles now and they've all lead me to believe that this specific Flybrid KERS system is 100% mechanical. No batteries or electric motors.
    the flybrid setups on these cars (porsche gt3 r hybrid included) have never been a kinetic storage device. They are simply a way of storing electric energy. There is no drive shaft that exits these flywheels with a clutch that acts on a drivetrain. They instead have a motor that spins up the flywheel which then turns the spinning flywheel back into electric energy when needed.

    Buuutttt.... this one may be different. "The device is mounted beneath the keel—just under the driver’s legs—and is driven by the 5-speed transmission that sits in front of the engine. It returns its energy to the front wheels through the same shaft that runs through the V6’s 60-degree engine V, and can send the rest, 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."

    It appears that this may be an actual kinetic only form of kers although the hybrid portion of this car, is the portion with the least information available.
    Last edited by ebruner; 02-03-2015 at 03:37 PM.
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    Yeah, that quote is the one I was talking about. I bet that's why they're talking about only using the KERS on the straights. Modulating power delivery with electric motors isn't that difficult. With a fully mechanical system, I imagine it's not much more than a simple clutch mechanism that engages/disengages the KERS flywheel. I bet it feels about like a 700hp shot of nitrous...



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    I agree with William. With enough regulations and power/fuel/etc... advantages, even a FWD P1 car can be competitive...

    I wouldn't call Audi/Porsche/Toyota as 'conventional' but rather there's an inherent balance and advantage to mid-engine, rear wheel drive/awd setups. There's a reason F1 cars aren't front engine fwd.
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    Dang

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    Quote Originally Posted by SDSUsnowboards View Post
    Beauty truly is in the eyes of the beholder.

    I can't get behind the FWD aspect.
    Hahaha! I see what you did there! behind & FWD? Sorry-being silly.

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