Rx450h gen3 pulling power at speed

[Stefan213]

Hi guys, i have a rx450h from 2011 and i notice at speeds over 70mph the power os not there, i can see the engine reving but the pullimg power is not there, it feels like a car with less then 100bhp. 

At low speed you can feel the 295bhp... is that usual ? 

 

Thanks

Radu

[Barry14UK]

I don't know what you are comparing with but as you go faster the aerodynamics play an increasing part so you need disproportionately increasing bhp to achieve every additional mph.  Put another way the car is going to take longer as it moves towards it's maximum speed, appearing to be short of BHP to overcome resistance.  Of course it's not just a matter of power but also of appropriate gearing.  A graph showing time taken to achieve various speeds on the flat would be interesting if available.

[Stefan213]

3 hours ago, Barry14UK said:

I don't know what you are comparing with but as you go faster the aerodynamics play an increasing part so you need disproportionately increasing bhp to achieve every additional mph.  Put another way the car is going to take longer as it moves towards it's maximum speed, appearing to be short of BHP to overcome resistance.  Of course it's not just a matter of power but also of appropriate gearing.  A graph showing time taken to achieve various speeds on the flat would be interesting if available.

Thanks for the replay, well i compare it woth various cars i had in the past and the last one was a skoda superb.

Today on motorway a nx300h was accelerating faster and i was flat out 😅 

Sorry for my spelling mistakes

Radu

[Barry14UK]

OK, you only questioned acceleration at 70+mph in your previous post.  Don't know which model of the Superb  you are comparing with but the fasted with a top speed of 155.3mph and 0-62 time of 5.6secs well out performs the RX450h with respective figures of 124.3  and 7.7.

However, the top speed of the NX300h is 112mph with 0-62sec time of 9.3. So if working well this should be comfortably beaten by your RX.

There are many things that could contribute to a loss of performance and maybe the first thing to check is whether a fault code can be seen.  Maybe an idea to discuss with technician where your car is serviced.

.

[Lager shandy]

Just one more thing to add if your car is ok at lower speeds power wise ,Was your main Battery low when you tried out dragging a nx300h with 100bhp less as that will be your power loss .the nx300h is lighter and less of a drag through air .

[Herbie]

How long have you had the car? Are you new to Toyota/Lexus hybrids or have you driven one before?

If you're new to it, what you're describing could be the eCVT in operation and if so, it's nothing to worry about, it's just the way they work.

The eCVT (Electronic Continuously Variable Transmission) uses just one continuously-meshed gear so you don't get the 'steps' of a standard transmission. There's also the 'drive-by-wire' throttle, which means that the accelerator pedal is an electronic device instead of operating a physical steel cable that pulls on a lever or whatever.

All in all, it combines to make a system where the engine speed bears no relationship to the actual road speed and under certain conditions the engine can sound like it's racing but in reality the car isn't moving as quickly as you would expect it to for that particular engine sound.

There's a website that explains it all and even has a great animation that you can play with and adjust - I'll try to find it again and link it for you.

[Stefan213]

Thanks for the help

Barry14UK i scaned for the fault cods using a Teachstream and its all clear. 

I will need to take to a test drive my brothers in law RX and see if it is the same.

Lager shandy the Battery was charged and yes the nx is lighter but you have extra power and 2 more cylinders on the rx

Herbie this is my first Lexus but i have it for allmost 1 year and i am a motor/motorcycle guy.

What i want to see if the rest of rx's feels the same, if on motorway i give it full gas its like a slipping cluch but if you use 3/4 of acceleration you can feel the power been used better. 

Maybe it's just me and i was expecting to get the same feeling from low speed and at the moment i think its not safe to overtake. 

I love the car under 60/70 mph 

[Barry14UK]

Well if you can borrow your brother in Law's car you can make a more direct comparison.  It would also be an idea to log by video against speedo stop watch times to reach several reference points from standing start. If the results are similar you don't have to spend time and money investigating a problem that isn't there.  If there is a significant difference you have to start checking the many things that could individually or collectively cause this.

Herbie makes a good point about the unusual nature of the transmission.  On hard acceleration the engine revs increase  sounding rather like clutch slip.

Really, the RX excels  as a very comfortable cruiser for 50 - 70mph.  I might have gone a little faster than this at times (say I carefully choosing my words, because it's easy to gradually increase speed with little perception).  However, demand immediate heavy acceleration and the aforementioned revs will rise intrusively until you reach the desired speed and will then drop right back as you ease off the gas to maintain that speed.

Having said all that, there is no reason why a standard NX300, though a lighter car, should be able to out accelerate an RX450h as the acceleration times and top speeds I gave illustrate.  

[Stefan213]

Thanks Barry14UK, i checked again today and i notice that on a flat road acceleration is fine but as soon as you go uphill things change and i think its to do with the Atkinson cycle engine and weight.

Will check my brother in law car tomorrow and update 

Thanks 

Radu

[flookyk]

30 minutes ago, Stefan213 said:

Thanks Barry14UK, i checked again today and i notice that on a flat road acceleration is fine but as soon as you go uphill things change and i think its to do with the Atkinson cycle engine and weight.

Will check my brother in law car tomorrow and update 

Thanks 

Radu

My route to and from work and home is on motorway with a stretch each way that goes from two lanes to three uphill both ways ... i usually take things steady until reach these uphill 3 lanes then have a bit of fun accelerating up the hill... 

...all I can say is it is not sluggish in the least and can quickly go from 50mph to ... err... let's just say license loosing speed ... uphill.

[Lager shandy]

Maybe clutch slip ? 

[Barry14UK]

• Take a look at this, different model Lexus but same sort of transmission.  It supports what has been said.  https://www.honestjohn.co.uk/our-cars/lexus-gs450h/the-cvt-gearbox-a-love-hate-relationship/