Missing HP

[NSX-SA]

Am i missing something the spec's on the HP of the new NSX is:

Twin turbo v6 - 500hp
Rear direct drive motor - 47hp
Front twin motor unit - 36 + 36hp

Total - 619hp not the widely advertised 573hp.

Or is this rpm limited/average hp as the max hp is at:

TTV6 - 6500rpm
RDDM - 3000rpm
FTMU - 4000rpm

 

[2015 NSX]

As you noted, the gas engine and electric motors don't operate at the same rpms or make max HP at the same speed.

 

[Gadgetman]

Just my Two Cents

As you noted, the gas engine and electric motors don't operate at the same rpms or make max HP at the same speed.

Agreed
I suspect it is a combination of balancing limitations of the electrics vs RPMs, particularly with the fronts since they are direct wheel drivers vs via transmission like at rear. Plus some writings indicate the rear electric is typically/frequently maintaining battery charge... more so than fronts which are doing more torque vectoring and regen. braking. Rear can't generate and provide power at same time so after some power input (and battery depletion) it shifts to gen mode taking power away from the ICE.
I also suspect they could quote a short term power with qualifiers (time based... say even if just in XX? minutes) based on boosted (full elec power use) level within the front RPMs limits (or car equivalent speed) and with rear providing full assist vs any generation.
All in all it is probably difficult to provide us realistic and useful power numbers like ones we're used to with ICEs w/o some new qualifiers like speed and/or time.

But since they don't wish to quote a lot of specs like Cd etc, we'll probably not know.
Eventually it should get on someone's AWD Dyno and we'll have at the wheels numbers (post losses) which is what really matters. But again, what ever is found is under certain (new for us) limiting qualifiers.

 

[chrisn]

I actually think it is beneficial to charge the battery and drive the car at the same time and, apart from WOT situations, this would not be problematic at all. With throttle-by-wire, in a cruising situation, the car could automagically increase throttle to exactly compensate for the extra load from charging. This would be a smart way to charge the battery in situations where you don't care about fuel efficiency but want to maximize the performance envelope.

The data point that I am eager to hear is if the battery will run out of juice at any point around a racing circuit with repeated lapping at 10/10ths. From a physics perspective, it should be able to recover enough energy from braking to dump back into acceleration, but the real world issue us bounded by maximum regen rate, battery capacity and any heat related limitations. I assume the engineers made this a design goal (never run out of breath under WOT on any popular road course). Recharging under partial throttle could help a lot here.

Obviously in "WOT Forever" situations (Texas Mile, or long straights on Nurburgring), the hybrid system will run out of juice and become useless deadweight, but hopefully this won't be the case for typical HPDE events.

 

[JD Cross]

I actually think it is beneficial to charge the battery and drive the car at the same time and, apart from WOT situations, this would not be problematic at all. With throttle-by-wire, in a cruising situation, the car could automagically increase throttle to exactly compensate for the extra load from charging. This would be a smart way to charge the battery in situations where you don't care about fuel efficiency but want to maximize the performance envelope.

The data point that I am eager to hear is if the battery will run out of juice at any point around a racing circuit with repeated lapping at 10/10ths. From a physics perspective, it should be able to recover enough energy from braking to dump back into acceleration, but the real world issue us bounded by maximum regen rate, battery capacity and any heat related limitations. I assume the engineers made this a design goal (never run out of breath under WOT on any popular road course). Recharging under partial throttle could help a lot here.

Obviously in "WOT Forever" situations (Texas Mile, or long straights on Nurburgring), the hybrid system will run out of juice and become useless deadweight, but hopefully this won't be the case for typical HPDE events.

I think you're right.
Usually the amount of time you're at WOT on a circuit is not all that long and there's lots of time when you're at partial throttle or braking.
I view the electric motors as equivalent to a supercharger/turbo add-on.
The front wheels can regenerate under braking and cornering and the main electric motor can charge when full power is not needed.
I'd expect the ICE would make adequate power under high rpm/high speed conditions when the electric motor torque is greatly reduced anyway.
I'm hoping the key to performance will be the amount of torque available under all conditions and the switching back and forth between various combinations of ICE and electric will be seamless.

 

[goldNSX]

The available hp of hybrids car is generally lower than the sum of all systems (this has been discussed before).

Keeping the battery cool is the most critical part on the track. With so many charge and discharge cycles within a short period it will have to cope with a lot heat. That's why the car has 10 radiators or so. On a normal hybrid like a Gen1 Insight with an air cooled battery you can't charge the battery with max current for a longer time. After 10 seconds the electronics detects a battery being to hot and will cut the battery charge. On a normal drive you're always a little bit on the discharged side of the equilibrium. Honda will make sure that you don't have to pass on torque vectoring after a longer time on the race track. As torque vectoring gets a higher priority (I guess) and given the physical laws you might have to pass on straightline performance on the race track in favor for torque vectoring.

The hybrid system is pretty much different from a turbo or supercharged system.

Interesting enough because it reveals a wide area for tuning the system.

 

[chrisn]

As torque vectoring gets a higher priority (I guess) and given the physical laws you might have to pass on straightline performance on the race track in favor for torque vectoring.

Interesting enough because it reveals a wide area for tuning the system.

In any situation that I can imagine where you'd want torque vectoring, you would have just finished braking or at least been out of WOT for a couple of seconds, which should build enough juice for the torque vectoring to feather you around the next bend. Frankly, it should be possible to get regen from rear wheels WHILE SIMULTANEOUSLY powering the front wheels with that regen juice (e.g., as you were reaching for the apex and rolling on the throttle on the way out). The time where you would be at WOT at same time you would benefit from torque vectoring would be VERY brief indeed (just as you were tracking out from a corner).

I think the bigger challenge would be straight-line WOT for 6-7 seconds (a la "Overboost"). At least you'd be getting good airflow to cool things down a bit.

Agree on tuning potential. In theory, in repeated lapping the system should be able to dynamically optimize the use of the battery on a track-specific basis. Unless the baseline performance envelope is such that you never run out of juice under any expected scenario, which would also be awesome.

 

[docjohn]

The early track videos show the car pushing badly.....most of the discussion was centered around the tire choice...but I also suspect overtaxed and useless front motors, as essentially dead weight, and possibly creating mechanical drag...

 

[goldNSX]

In any car the braking capabilities are factor >2x higher than its acceleration capabilities. So you have at most only 1/2 of the time of recuperation of the energy you've just drawn. That's the Achilles heel of the battery. If you don't want to run out of juice you have to restrict power consumption of the hybrid system. On the track you might have the anti-turbo-lag functionality and torque-vectoring but you won't have additional power I guess. In the case of the rear wheels powering the fronts on a straight you even have a power loss but benefit in the next corner due to torque vectoring. It would be a very unpredictional car if you have it in one turn but not in the next.

Interesting that the journalists were not allowed to use the track mode. I guess it was not finished due the high demanding task.

Overheating was the cause no. 1 in F1 of McLaren Honda F1 during the last season. The components were too small (zero size concept) and the cooling of them so problematic that they always lost the hybrid system after a few laps (Alonso's GP2 engine). Renault had the same problems in the second half of the race with a hybrid system getting weak. The opponents just had to wait for this to happen so they could overtake them.

Generally a battery doesn't like to operate at its max termperature. I could imagine that it will be a 'consumable' for the track guys like tires or brake pads.

 

[chrisn]

In any car the braking capabilities are factor >2x higher than its acceleration capabilities. So you have at most only 1/2 of the time of recuperation of the energy you've just drawn. That's the Achilles heel of the battery.

But it's not really a time-bound problem if you can recover a lot of that braking energy in bursts.

Also, I think the problem is best characterized by looking at how much time is spent at WOT on a lap. AT EVERY OTHER INSTANT, the surplus power from the ICE is (at least in theory) available to recharge the battery. On top of this, you get the "bursts" of recharging from heavy braking. It's not just braking zones versus the rest of the track. Extra load on the ICE to compensate for parasitic load of recharging could be made transparent to the driver (unless he had very sensitive hearing).

100% agree with you that the system MUST be predictable, at least in turns. This is why the system might cut off the juice early on long straights to make sure it can be available for a potential turn--- this is an area where the car could adapt dynamically in repeated lapping (e.g., "I'm gonna lets this guy run the battery dry on this straight, because I know I can regain enough while he dives for the apex in order to get him around the corner with torque vectoring). Similarly, the car could choose to NOT overtax the ICE to recharge the battery if it knows that a braking zone is coming. You get the idea.

 

[goldNSX]

But it's not really a time-bound problem if you can recover a lot of that braking energy in bursts.

We have to agree that the problem is in the IF clause. If you want the same energy in a fraction of the time you have higher losses of conversion which builds up in heat mainly in the battery. The hybrid system can only take in a fraction of the energy during hard braking. That's why it has some serious carbon brake discs. In short burst you can overheat the battery and have to wait until it cooled down (punish yourself). I fully agree with you that the recuperation period will be / must be distributed along the whole track. From this I conclude that you won't have the extra battery punch like you have on a street drive. If it would be in the braking phase only you overheat the battery or don't get enough energy back in the pack. That's what a normal hybrid car also does even on a normal road drive. Ok, this car will have an exceptional good cooling for the battery but the principles are basically the same.

I'm pretty sure that we'll see several steps of improvements in the system, comparable to the ALB of v1. So the first batch of the cars are not the best ones.

 

[chrisn]

We have to agree that the problem is in the IF clause.

Touche.

I hope you're wrong about no bonus punch at all on straights. That would be disappointing. If there was a dramatic fall-off in EV boost on straights, I think the Sonoma/Infineon reviewers would have noted it. Perhaps the nannies (electronic and human) made them drive 7/10ths or whatever so maybe they wouldn't have exposed this. I guess we'll all see.

I will say that the internal resistance / round-trip efficiency of LiPo batteries is very good in the "meaty middle" of the State of Charge range, which translates into lower temps if you design and size the pack with a view toward optimizing performance versus other factors. Although I suppose this might come at some weight penalty, for a car that is already fat for the track.

I'm due to put a deposit down in a couple of weeks and wish I had more answers. I am betting that he Acura execs are smart enough to know that you don't put out a $200K "Halo car" with a "Track mode" that goes into limp mode after a couple of laps....

 

[goldNSX]

I guess that all the added engineering took so long. My second guess is that the car at the Nurburgring burnt down because of heat problems in the battery pack. But I could be wrong. I'm pretty sure they won't disappoint anyone out there but I also think that even more will follow after the first edition...

 

[Gadgetman]

It wasn't the Battery on fire at the Ring

I guess that all the added engineering took so long. My second guess is that the car at the Nurburgring burnt down because of heat problems in the battery pack. But I could be wrong. I'm pretty sure they won't disappoint anyone out there but I also think that even more will follow after the first edition...

I learned a few things today from a reliable source.
#1
Ring fire was due to one of the front motors which caused the fire. Though not sure if from overheat under load/regen/ or just inadequate overall cooling. Maybe a combo of it all? Good thing they have been doing a lot of testing before release and corrected for findings

#2
Plus I learned that Oil changes are going to be ridiculous. If given correct info, there are two reasons. Numerous interlocking panels need to be removed in proper sequences to enable access to 7 (YES SEVEN) separate Oil drains. Was told it was ~ 3 1/2 + hr job requiring more than one tech (though not sure why more than one... panel breakage perhaps?).

#3
And on the only brakes available now... OMG
especially if the car is tracked.
numerous details like Heat up drive, cleaning, removal off car, more cleaning and close up inspection for flaws (micro cracks). Then baked to 250 in an oven (more cleaning?). Then finally weighed for for min specs/tolerances and comparisons between sides etc, If one side no good (for any reason) both sides need replacing (~ $4k a pop) Weight will be more critical than thickness (which should not vary much).

#4
Also, not sure if optional interwoven or the high priced accessory wheels... but one of them is not able to be tracked!

#5
Good news on ICE
They have beat up a lot of them and given them numerous repeat tear downs to inspect and mic components/parts. Findings so far (or lack of that is) suggest it is built like a TANK! and will take a lot of abuse w/o failure or degradation. Something We all expect from HONDA! Not sure the other guys (high end brands F,P,Mc, etc) running in this field can say that.

I have good faith in my source, but who knows.
time will tell.

 

[chrisn]

Great info. Would be nice, ahem, to know pre-ordering which of the wheels is not supported for tracking...... I was going to get the interwoven ones. Maybe stick with the default.

I *HATE* that you are forced to buy the Carbon Ceramic brakes (for now)--- I consider this akin to an extortionate mark-up / early adopter premium. I see no upside for those brakes for track use.

 

[goldNSX]

#2 underbody aero panels and several motors/gearboxes add up to the complexity of an oil change. It won't be as 'cheap' to maintain as ist precedator as expected.

#3 in a hybrid car for the street the brakes are one or two sizes smaller. In a true sportscar I guess it won't be the case.

#4 If that is the case then I guess that the wheels fitted with the semislicks are the one for the track, the wheels you can't get with the slicks are not.

 

[Gadgetman]

My initial guess on wheels that are at issue (non track use) is the ~ $10k accessory set. Those claim to being CNC machined (maybe from Billet block?) where as the choice wheels ... Y's (and Interwoven?) are Forged (so much stronger).
Note, I heard that when you buy those CNC'd ones, (most likely as source was not totally sure) you get them in addition to standard ones chosen... because they are an accessory like mats etc.. So I'm guess you buy the accessory ones for show. I don't care for those , but they are at least are built as asymmetrical sets. Really bummed that interwoven s are not.


Dealers GM's should know more after next weeks Town Hall meeting in Ohio... if (newest) Air bag Flim Flam doesn't continue to steal bulk of the event time.