Has anybody noticed that the electric motors will not work at very high speeds even in Sport Mode?

I think they shut down around 80-85. I don't know why this would be, necessarily, unless it is an attempt to avoid wild vectoring and a loss of control in the event a driver makes a sudden move at very high speed.

Or perhaps the electric motors aren't capable of the RPM necessary for very high speeds, so they're turned off so that they don't slow you down.

Regardless, the bad news is that the car does not keep up with other 400 HP cars at extremely high speeds. The top speed seems to be limited to what the J Motor can produce by itself, around 130 mph.

This means that relative to other cars with this kind HP, it will not be what you'd call quick around your typical 2.5 mile road course. The suspension's great at very high speeds, and on the way to when the electrics shut down it is capable of alarming alacrity.

And let's face it...you're not going to be doing much driving on North American roads at 100 mph. :-)

There's some good news in here, though. I'm going to go out on a limb and testify that this is below 5.0s to 60. It seems to be 4.5 to 4.8 range. I'm sorry I can't narrow it down more than that, but it's also hard to find a legal place to do this kind of thing, while having a reliable person and equipment to time. I just kind of squeezed into somebody else's time, and not being able to narrow it down more is due to this old man never being a very good drag racer, and having absolutely no experience with acceleration runs in an automatic shifting vehicle.

I'm afraid that I have raised some questions for myself about how the NSX is going to be performing.

Either they found some better motors and batteries for the NSX, or the twin turbo version of the NSX J Motor has more than enough HP to make up for the electrics turning off at higher speeds.

 

The rear electric motors shut down for propulsion and at 78 mph because above that speed they would be spinning above 11k rpm. They DO work for torque vectoring above 80 mph, however. When I get time, I'll post a link explaining the mechanism.

Back to work....

PS: how do you get around having to shift into first gear in Sport Mode? Will the car take over shifting after you manually select 1st for an acceleration run? Been working too hard lately to play much with it. Gotta pay that lease payment somehow.....

 

Yes

Agreed on numbers. Have been on the road a lot myself away from home and working to do the same...that is, finding time, equip, and place w/o going to track.


Actually the answer is what you stated PLUS simply the following...less weight, better gearing, and improved IPU (simply playing with better kw/h and Hp/TQ combined with tweaking the IPU) will result in fixing the design limitations you identify above. Drop the weight to an R8 level or below and you just shed between 300 lbs and 700 lbs. So if today's SH AWD Hybrid makes 80 hp for every 1000 lbs or so it would put the NSX at about 100 hp for every 1000 lbs by shedding weight and not doing anything to power unit. Raise the HQ/TQ with turbo and higher output batteries to let's say 500 and you have 140 hp for every 1000 lbs.

A 3500 lbs NSX with 500+ hp (eq TQ?) and that puppy will scoot to sub 4 easy approaching the low 3.

 

Here is some interesting forecast/speculation on the future of the Honda Hybrid SH AWD technology...as the following screen shot shows the last NSX-R was 2800 lbs and 276 hp...did 4.2 (to 4.5). It shows as the 197th best time at Hockenheim and it was a 2002 car. All approximate: at the time it had a ratio of about 110 hp per 1000 lbs. If you drop the existing Hybrid SH AWD unit in a 2800 lbs car you get 377+ hp to motivate the wheels. This would result in about 180 hp per 1000 lbs. This thing would SCOOOOT!

Clearly there is more to it than just a simple back of the envelope analysis...but it sounds like plenty of upside if the combination could be made to work....

 

Interesting information.

As I've pointed out in previous threads, the RLX Sport Hybrid really scoots; it is properly fast in Sport Mode. I just need to figure out the tricks around first gear.....

 

George,
As I read it...the rear engines disengage and stop adding net positive torque towards acceleration at 78mph....
they won't reengage until the speed drops to 75mph. While in the post 78mph and pre 75pmh mode, if (in a turn?), they do torque vectoring that is not net new power positive as it applies equal positive and negative left/right or right/left.

The reason it decouples is faster than 78mph it "produces too much voltage for the electric systems to handle reliably"
Here is the article:

The Acura RLX Sport Hybrid has the coolest all-wheel drive system

 

^^^^
beat me to it. That's the link I quoted in another thread.

 

Thank you! :-)

 

Wow. That article's been out since December 2013? I'd think that it'd feature more prominently in our discussions, because it has some very good information in it that I haven't seen anywhere else.

I had no idea that the 47 HP motor functioned as the alternator. I guess if I'd thought about it, I'd have realized it...but I didn't even think about it.

That is quite tricky!

Still a preproduction, then. :-)

 

That is why I see this Hybrid RLX SH AWD as an almost finished NSX with great seating for 4, almost all of the safety nannies, and mileage to boot. As many discussions in the forum have stated...this is a great car...it is Acura's finishing, QA, QC, and marketing that is failing.

 

Yes my thought / question in that thread about your milage is mathematically could that be one reason why somebody who goes over 78mph may get worse mpg, non linearly, than a person going say 71mph, 73mph or 75mph.... if after decouple the car is carrying the weight of the engines/systems plus lugging them and any friction without positive torque support from them. Also, if Acura/honda did not test or report on mpg over 78mph, could that explain low mpg rates attained for highway drivers, driving fast vs. mpg published on website for car.

 

Hybrids do not have any advantage at highway speed. Think about it, all the power still comes from gas unless you are regenerating elec through braking which would be more in city. Big advantage of hybrid is high low speed torque to get car moving - again a start and stop advantage


I'd guess that is part of the reason you don't see the battery charged tp 100% most of the time. They don't want to use gas engine to keep batteries charge, but rather leave room to soak up the regen. That would increase gas mileage compared to keeping battery charged by burning gas

 

It is not a major advantage, but the RLX Sport Hybrid's electric motors also allows the Variable Cylinder Management to be used more effectively on the highway. I say that because the extra "push" from the electric motors lets the RLX Sport Hybrid use the VCM more effectively and still maintain the driveability if you need sudden acceleration. To maximize fuel economy, highway cruising is in top gear and VCM using 3 cylinders. If you need sudden acceleration, the electric motor in the transmission can give a little boost of torque to the front wheels in the split second that it takes for the VCM to disengage and for the transmission to gear down. If you are below 78 mph, the rear motors also kick in that instant push to minimize/eliminate the momentary hesitation a non-hybrid car would experience when trying to accelerate from top-gear cruising.
Again, not a huge advantage, but a benefit on the highway of the Sport Hybrid RLX over a non-hybrid or a standard hybrid.

In addition, the torque of the electric motors CAN help to push the car down the road at highway speeds which could allow slightly lower RPM of the gas motor which enhances fuel economy slightly as well. This is particularily beneficial on a road that has stretches of braking (downhill twisty mountain road) so the batteries are being charged allowing the electric motors to be used more often to assist the gas motor. AGain, not a huge benefit but maybe 1-2 MPG worth???

 

^ so you are thinking that a gas engine running an alternator (electric motor)to charge batteries and then run electric motor and you think that is more efficient than just a gas engine powering the car at freeway speed

 

No, but a battery charged by regenerative braking running an electric motor to supplement a gas motor will make the gas motor more efficient. Apparently that is why the Sport Hybrid RLX is rated at 32 mpg highway and the substantially lighter non-hybrid RLX is rated at 31. I dont' dispute that the primary benefit of a hybrid is in city driving, but the electric motors help on the highway as well, just not as much because you are not braking as often.

 

no disrespect, but is the hybrid rated at 32?
it would surprise me - how do they do highway tests? would it include enough braking to make a difference?

 

According to Acura, the Sport Hybrid is rated at 32 highway. There is probably just enough braking during highway driving (when the car cuts you off going 30 mph slower that your cruising speed) to facilitate the necessary battery charging to allow the electric motors to make the small improvement in the mileage. Again, I'm not disputing the claim that the city mileage is by far the biggest benefit of a hybrid, but the EPA numbers (especially considering the extra weight the Sport Hybrid is carrying around) suggests that there is a small benefit on the highway as well. This may be unique to the Sport Hybrid's unique 3-motor design and I'm not sure that all hybrids see a small benefit in highway mileage over their non-hybrid models.

 

ok, I belive you - but I doubt its realized in real driving
just doesn't compute

I'd put up PAWS against SH at 75 on freeway for mpg any day of the week

city not so much

 

There must be just enough braking in the EPA tests to make the difference. That said, braking at highway speeds is probably the most efficient at recharging the batteries with regenerative braking.

 

My real world experience with highway gas mileage is that the highway EPA mileage is accurate. I just did a 250 mile freeway trip at 70-75 MPH and averaged 31.5 MPG, including 25% being stop and go traffic (ie a typical Southern California freeway ride). The electric motor was helpful during the stop and go traffic and it didn't really hurt my overall mileage any. I have had more difficulty getting the EPA City mileage of 28 MPG. So far my overall gas mileage for the 1,800 miles I have driven is approximately 27MPG with about 25% freeway driving.

Just to add one more time the rear electric motors assist in gas mileage is that in the 45 to 55 MPH speed range the gas engine will cut out and rely solely on the electric motors as long as the speed in constant and the terrain is flat or gently downhill. Any acceleration or uphill slope and the gas engine kicks in. It can also kick in to recharge the electric batteries when their charge gets down to 15% +/-.

 

I wonder if the 7 DCT has more to do with better highway mileage.

RPM at cruising speeds seems low.

 

Not sure what you are referring to, Bob. Doesn't Sport Mode automatically start you in 1st gear?

 

RPM built speed, people buy torque.

 

I bet you are right

 

I don't understand where you got this. The USDM RL is electronically governed to 135 mph, and the EUDM RL (along with some USDM TLs) is electronically goverened to 155 mph. The J35 has no issue surpassing 160 mph.

 

How much longer does the back straight at VIR need to be for me to be able to exceed the approximately 130 mph?

 

I can't tell if serious or not...

Are you saying you have reached 130 and the car resisted more speed? Were you near the rev limiter? How did the car behave?

 

The Car and Driver review of the Sport Hybrid RLX lists a top-speed of 130mph. This is surprisingly low for 377 HP. Maybe the legal team has managed to get their way with limiting top speeds as well?? 130mph is still WAY faster than anyone should be driving without being on a race track (and with proper training on said track), but I was expecting it to be higher... safety first I guess??

 

They don't do rev limiters any more. There's nothing as dramatic as a spark stutter.

You have pedal, but there's no point in trying to push it more because the car's systems don't allow it. If you push the pedal more, the car just doesn't do it.

No drama...the car just say, "No."

:-)

Acceleration past a certain point is more or less leisurely and more or less pointless. It's just not what the car's about.

It's about startling, Sterling mid level performance up to a logical point, and then it just stops.

Don't get me wrong. I love the car's performance, and it performs a lot better than people might expect judging from early reports with the preproduction cars.

Don't get me wrong either if it sounds like I'm pretending to be anything other than one dumb old man with just a little more track access than your average driver.

 

Interesting. I am willing to bet it is ECU limited. There is no reason why a DI J35 won't go over 130. Even the J32 in the 3G TL tops that.

 

Drove to the boonies yesterday and it went from 0 to 100 w/o skipping a beat and the 0 to 60 was less than 5 by my very unscientific measure (iphone - watch - timer). Also someone has posted 5.1 and quarter mile of 13.6 on 0 to 60 web site...not sure how accurate it is and (my opinion) I believe the car can do better...AND...this particular time post (still high based on my opinion) compares favorably to cars that are more expensive and in a class that Acura wants to compete against.

Gets back to marketing, communications, and sales pitch (or lack there of).

 

Missed this post. The link is:

Acura 0-60 Times & Acura Quarter Mile Times | New Acura TL 0-60, Integra, NSX T, MDX, TSX, RDX, Acura RSX and Legend 0 to 60 stats!

I wonder where they got that number? If true, pretty impressive.

 

I agree and I also believe that the car is capable of better numbers. Not quite M5 or S6 but dang for half the price when full loaded I can't complain with mileage to boot.

Jekyll and Hyde territory.

 

Did a few 0-60 runs on an empty Interstate on the way to work early this AM, using my old iPhone Dynolicious software. I did not shift myself so presumably as soon as I floored the pedal, I was in second gear. Further, traction was mildly challenging in 20-degree weather. . With those conditions, I can now hit a 5.8-5.9 0-60 fairly consistently.

No video this time, though listening to those crisp, short shifts might be entertaining for the masses. That can await my mastery of this car.

Next up is manually shifting into 1st. I'm worried that by manually moving into 1st, the car won't want to shift itself, leading to complications Ike the hung shifts I experienced the first time I tried this. Only way to know for sure is to try again. If a 1st gear start improves on 0-60 time

 

Try Sports mode manual shifts from 1 to 2 at low speeds and increase speed gradually as you get practice with the shifts. With the electric motor this car revs up fast. You may have to also play with accelerator a bit when shifting up.

 

best launch; AC off, VSA off, Sport Mode, hold left paddle for 1st gear, left foot on brake right foot on accelerator for a 1000 rpm - foot off brake and hard on accelerator - hold on

 

Pavement is too cold and salt covered with all season tires to get a good hook up by me. I am spinning almost constantly to around 55mph. Now if I roll into it from about 20 mph that is very cool, but I can't get into the throttle more than about 75% by my estimation without bringing in wheel spin in 2nd into 3rd gears. I have to wait to be in 3rd gear before I can "give it the full beans" based on traction limitations. That is nuts!

 

you are right. i should have added that you need dry clean and hot pavement to hook up good.

 

But if you click the paddle to manually shift into first gear, won't the car expect you to make the next shift? I.E. will you bounce off the rev limiter if you are expecting the car to take over automatic shifting after first gear?

It's been too icy and snowy here the last few weeks for me to try this again, so I shall have to live vicariously through those in warmer climes for about another six weeks.

 

set the HUD to show the RPM. although, i do the shifting myself i believe the 2nd will come on automatically. i hold the left paddle to make sure it does not shift before the red.
now you made me doubt myself. i'll verify and get back to you when i can. it is ice and very cold up here. when i tried it the first and only time, it was dry and maybe 50 F the car was one day old.
by the bye, the way i described my best launch is the way i always did it except for non-hybrid cars i get the RPM a bit higher.