NX350h Acceleration spec

[imgo]

I recently downloaded a wrong spec sheet for the 350h, noticed that all measurements were in inches, then realised it was for America. Duh.

But one spec stood out, the 0 to 60 mph acceleration was listed as 7.2 sec.

I know that the UK spec is 0 to 62 mph (100 km/h) but that is listed at 7.7 sec.

So I did some basic maths.

US: if 0 to 60 was 7.2 sec then 0 to 62 is approximately 62/60 * 7.2 = 7.44 sec, not the 7.7 UK spec, hmmm. Infact it would be quicker than 7.44 sec as I used the average acceleration of 0 to 60, ignoring the fact that at 60 mph the car would be accelerating faster than at say 10 mph.

UK: if 0 to 62 was 7.7 sec then 0 to 60 is approximately 7.7/62 *60 = 7.45 sec, not the 7.2 US spec, hmm hmmm. Again, it would be slightly slower than 7.45 sec for the oposite reasons I gave above.

So I pose the questions:-

Why is there such a big (aparrent) difference in the US and UK specs?

Exactly how quick is the NX350h 0 to 60mph?

Has anyone independently measured it?

It has just bugged me since I noticed the 'too big a difference' in the specs.

I guess that someone on here will tell me that a US mile is smaller that a UK mile, or something like that !

[ColinBarber]

1 hour ago, imgo said:

Infact it would be quicker than 7.44 sec as I used the average acceleration of 0 to 60, ignoring the fact that at 60 mph the car would be accelerating faster than at say 10 mph.

No, acceleration slows as the vehicle speed increases due to wind resistance. I'd expect to see at least a 0.4 second difference for identical cars with a 0-60 time of 7 seconds.

[imgo]

13 minutes ago, ColinBarber said:

No, acceleration slows as the vehicle speed increases due to wind resistance. I'd expect to see at least a 0.4 second difference for identical cars with a 0-60 time of 7 seconds.

Firstly I agree about the wind resistance is greater at 62 mph when compared to 60 mph, but i would suggest not significantly different for just 2 mph, but its been 34 years since I did fluid dynamics so I could be very wrong. But I do bow to your expert knowledge Colin.

The point I was trying to say is that when I put my foot down from a stop in my is300h, the initial acceleration is slower than say at 10mph as the ICE needs to kick in to full power, so the 60 to 62 time would (or should?) be much quicker than the 0 to 2 time, hence the average rate of acceleration to 62 is more than the average rate of acceleration to 60.

All that in mind, does that mean the NX350h 0-60 is infact 7.2 sec?

[Barry14UK]

To get a true comparison you would need everything identical for testing in the UK and USA including tyres, tyre pressures, fuel octane and ambient temperature and humidity.  Then some cars perform slightly better than others, so probably an average figure is given. In general use, such a small difference is academic, particularly in a car such as this.  

[ColinBarber]

1 hour ago, imgo said:

but i would suggest not significantly different for just 2 mph

you wouldn't think it would make that much of a difference but it does. If a car has a 0-60 time of 6 sec and acceleration was constant then each 1 mph would be 0.1 seconds, so that's 0.2 seconds between 60 and 62 mph, then factor in additional wind resistance and that the car is slower than 6 seconds and it all adds up.

This is a good example (I picked this just because the stats are easily accessible and the cars are identical): Tesla Model 3 RWD from UK and Ireland. Identical cars but just different units used for measurement. 

 

 

2 hours ago, imgo said:

All that in mind, does that mean the NX350h 0-60 is infact 7.2 sec?

Yes I would say so. The system output on the US and UK models is almost identical, with maybe a slight difference due to fuel grade. There could also be difference in wheels (weight makes a difference for acceleration) and possibly some rounding where the true 0-60 time could be as high as 7.24 and the 0-62 time as low as 7.66.

Historically Lexus US and European vehicles have been different - different power outputs, different emissions, different gearing but these days there isn't much variation between regions unless regulations get in the way.

[imgo]

Thank you Colin for your explanation, it all makes perfect sense. I can sleep well tonight!