George Knighton

I am having difficulty reconciling the 377 HP stated by Acura with the 0-60 times of 4.8-5.0 that we seem to be able to achieve even with 19" wheels and all season tyres.

I suspect that we are probably really looking at 410-425 HP.

hondamore

I happened upon a website www.060calculatorcom which takes horsepower numbers, curb weight, drive type (fwd, rwd, awd) and transmission (manual, auto, dct) and calculates an estimated 0-60 time based on that information. When I enter 377HP, 4400 lbs, AWD and DCT, the calculator estimates a 0-60 time of 4.77 seconds. Apparently, according to this algorithm anyway, the 377HP number is close.

There are a lot more factors than those 4 pieces of information but if you click "The science behind the calculator" there is a good explanation of the rational behind choosing those four pieces of information.

Maybe the RLX's All-season tires aren't so bad after all? Maybe the low-end torque of the electric motors combined with the J35 are the perfect marriage to get a huge car moving faster than you'd think you could?

When I changed ONLY the drive type from AWD to FWD, the number jumped to 5.388 seconds. When I changed ONLY the transmission type to Auto, it changed to 5.432 seconds. So, it appears that the combination of AWD, electric motors, Vtec, and that sweet DCT are the secret behind the Sport Hybrid RLX's amazing performance out of only 377HP.

Obviously nothing scientific here, but just food for discussion.

hondamore

Here is the explanation of the 0-60 calculator's reasoning/rational for predictions:

0-60 mph Calculator for cars

The Science Behind the Calculator

September 25, 2008 by Steve Wortham

Introduction

I created the 0-60 calculator back in 2004. At the time I couldn't find anything quite like it so I built my own. It's a bit of a toy that I still use to this day. Since I created it, it's been linked to from hundreds of websites and I figure it's about time to explain how it works, why it works, and just what you can and can't expect from it.

How it works

It's a rather simple Javascript calculator that works off of power/weight ratios and rating factors. The idea is this: take sample data from the 4 most important points of analysis (horsepower, weight, drive wheels, transmission type) and then write a formula to best fit the 0-60 calculations based off of that data. So when I started out I tried to make the calculator work for everything from a Ford GT to a Subaru WRX to a Hyundai Elantra. It didn't take me long to come up with a formula that fit quite well for all of these cars. And to my surprise, it only required a small amount of fine tuning after that as I continued to test other cars. And every "normal" production car I tested from that point on was quite accurate according to their published 0-60 times.

Why it works

It's my belief that horsepower, weight, drive wheels, and transmission type are the most important factors.

Some have asked me, "What about torque?" Well, torque is a factor and obviously torque is needed to move the car. But the peak torque number really doesn't tell you much. You'd really need the full torque curve to get much benefit and that would add to the complexity of the calculator. The peak horsepower number, however, tells you a lot. That's because horsepower is derived from torque and RPM, hence the formula: HP = Torque x RPM / 5252.

I'll give you a couple of examples to illustrate my point. A '99 Honda Civic SI is famous for it's high-revving motor but also infamous for its lack of torque. As you may have picked up by now, high-revving motors tend to have more horsepower than torque. In this case the Civic has 160 hp and 111 ft-lbs torque. But, because the motor revs so high, Honda has the freedom to change the gearing accordingly which almost makes up for its lack of torque. In just the opposite fashion, there's the '97 3.8L V6 Mustang I used to have. It had 215 ft-lbs of torque but only 150 hp. It was not a high-revving motor by any means. Those two cars are examples of very different approaches for affordable sporty cars of their time. Sadly though, even though my Mustang was RWD and had much more torque than the Civic, the Civic was actually faster since it had 10 more horsepower and weighed less.

When is it inaccurate?

There are plenty of scenarios where you can find inaccuracies. Gear ratios are a big factor, of course. Some cars can get to 60 mph in one shift, some in two shifts, or there's some like the Ford GT that can get to 60 in 1st gear. But grip is perhaps the biggest issue. The calculator isn't going to do so well with extremely high-horsepower cars or high-horsepower cars with skinny tires. The old Corvette Sting Ray is a good example of that. Back when they had the 427 in that car, its puny tires were so over-powered it was ridiculous. So if you put the parameters for that car into the calculator I'm sure you'll find the result a bit optimistic.

But as I said, it is a toy. I find it helpful to get a vague idea of how fast my project car ideas would be if I ever built one, or how much faster my Subaru will be after shedding 100 pounds. I hope you can find a similar use for it yourself. Enjoy.

RLX-Sport Hybrid

My testing with a V-Box and an app on my phone (which I would expect to be less accurate but it wasn't), posted a best time to 60mph of 4.89 seconds. My assumption is that with sticky tires and ideal traction, we could see 4.6-7 seconds, but who cares anyway. It is a blast to drive, gets ridiculous gas mileage, has tons of interior room and luxury, an awesome sound system, and is a sleeper.

JM2010 SH-AWD

^^ Great car. Most underappreciated vehicle on the road today.

krava

Maybe we can get a supercharger for the RLX? Before I "jumped ship" and got the RLX they were talking about a stillen supercharger for a GS4. If they make that and don't make one for the RLX that ...

Ken1997TL

The low-end and immediate torque is what makes the RLX so quick in a 0-60 mph measurement.

If you measure say 0-100 mph, it will be more like a 300 hp car since the electric motors are not assisting at the higher speeds.

In summary, the hybrid system makes the car feel AND perform even faster than it would seem on paper.

George Knighton

If you peruse the 4G TL Forum, you'll find that somebody made a supercharger kit for the J37 6-6 SH-AWD.

It's possible that these people could be persuaded to adapt their kit for the J35, but they might be stymied by the different fuel management system on the RLX (direct injection on the RLX).

All of the J Motors of whatever ilk are under stressed and could handle more horsepower than we give them.

Fitting a supercharger under the front lid of a FWD RLX is going to take some fidgeting and shoehorning, but I can see how it might happen.

But one thing always leads to another. You've got some bottlenecks that are going to prove restricting unless you've also willing to attack some things to do with the head design (the exhaust ports) and the rest of the exhaust system.

Remember, too, that the J37 6-6 SH-AWD has the advantage of a clutch pack on the rear.

With the FWD J35, you're asking for a hell of a lot of horsepower to go through the front differential, which is an open differential, and I have no idea if the Torsen axles used on earlier FWD 6-6 cars would even fit into the differential of the new 6-speed automatics.

One thing always leads to another, leads to another.

George Knighton

Somebody else told me that just a couple of days ago, and I'm still not sure about whether I agree.

In Sport Mode, sure, or with a FWD RLX, sure.

I do *not* think that the Sport Hybrid does that well off the line unless you are in Sport Mode. It's nice that unlike other stop-start systems we have torque immediately available, but it's only going to do what you really want if you're in town traffic or creeping through a parking lot.

Mind you, I agree that in daily life this is a really big deal and a significant contributor to overall efficiency.

But I keep hearing people talk like the total 74 HP on the rear wheels more than makes up for the ¼ second it takes for the 250-volt starter motor to get the J Motor running...and my personal experience tells me that it doesn't make up for it and that there are many times that, if you know you'll need the performance, reaching down and going into Sport Mode ahead of time is a huge help, and settles all doubt.

:-)

It doesn't exactly poop out but you're right that it sort of hits a little wall below 100 mph.

What we really enjoy and what really enhances our lives is the startling mid-range performance the Sport Hybrid provides, say, when you need to move quickly from 35 mph to 75 mph.

Yes. Exactly.

The car's set up for what we would normally have to do.

RLX-Sport Hybrid

Trying to get 300+ hp to the wheels on any FWD car without any type of LSD, will result in a never ending inside wheel spin and not acceleration. I would NOT mess with the RLX as it is not a 1967 Corvette.

RLX-Sport Hybrid

Respectfully, the EV motor is always active on the front wheels.

George Knighton

Over 90 mph, then, you're saying that we have basically 424 HP available to the two front wheels.

The car sort of hits a wall somewhere in the 80-90 range if you're accelerating.

I'm sure you wouldn't have said that so definitively if it weren't true, but it makes me wonder why the car slows its momentum over 90 if the 47 HP motor on the front is active all the way up to the 132 mph limit.

iutodd

Here's a quote from a R&T article about the RLX Sport Hybrid:

"Part of the beauty of the system is that the motors are fairly small, made possible by gearing them down. A planetary gearset couples the motors to their
respective wheels at a 10.38:1 ratio. The problem with that is that at about 78 mph, as the motors reach 11,000 rpm, they begin to produce too much voltage
for the electric systems to handle reliably."

However, as it goes on to explain later, the system can still vector torque above 78 mph, it just doesn't power the wheels.

RLX-Sport Hybrid

My understanding from Acura directly when I called soon after buying the car was the following: the front EV motor stays connected and producing 100% power to vmax and the rear EV motors decouple at 78 mph but still provide vectoring above that speed. It is possible I am incorrect, but that was and is my interpretation as the power delivery seems suspiciously robust above 78 mph for a 4400 lbs car with only an ICE motor running.

George Knighton

And vmax [sic] occurs at what speed?

:-)

Allowing a car going 90 miles per hour to suddenly realize the instant torque available from a 47 HP electric motor seems somehow unwise if somebody floors it.

There's no LSD on the nose. We rely on the the vectoring provided by the rear motors to point the nose when needed, but it seems like it's a little too much to expect.

If you know how to explain this to me so that a dumb old man can understand it...I'd appreciate it. It's not your responsibility to explain it to me, but I don't know how it would be used in a wise way.

George Knighton

I wonder if those people who visited us from Torrance would still answer if we emailed them and asked.

RLX-Sport Hybrid

When I averaged the data that came from the V-Box and the one dyno run I completed during the winter on winter gas mind you, I got a peak 389 wheel hp and peak and 419 peak ft/lbs of torque, but more importantly with 400+ ft/lbs of torque from idle to 4,000 rpm.