6000rpm

[LordByronUK]

Has anyone ever been able to reach 6000rpm in their IS? I've tried hard, it goes up to about 4800rpm fairly quickly but then it massively slows down after about 5000rpm in the long climb to 6000. So slowly in fact that I've never been able to reach 6000rpm. In my partners NX300h however I can reach 5800rpm fairly quickly and predictably. I know the gearbox is tuned slightly differently in the NX, but I do find it strange how seemingly impossible it is to redline in the IS.

Thoughts?

[Linas.P]

It has CVT, so it always going to find most economical transfer rate. Reaching red-line is never economical nor unnecessary, meaning you will never reach it unless you getting to top speed of I believe 114MPH.

If you really just want to see it hitting redline momentary, then "down-shifting" and engine braking is your best bet. Other option is to drive at tops speed, which I guess cannot be achieved on British roads.

[wharfhouse]

1 hour ago, LordByronUK said:

Has anyone ever been able to reach 6000rpm in their IS? I've tried hard, it goes up to about 4800rpm fairly quickly but then it massively slows down after about 5000rpm in the long climb to 6000. So slowly in fact that I've never been able to reach 6000rpm. In my partners NX300h however I can reach 5800rpm fairly quickly and predictably. I know the gearbox is tuned slightly differently in the NX, but I do find it strange how seemingly impossible it is to redline in the IS.

Thoughts?

Not sure if the 6 pseudo gears allow this - switch to Sport mode and move the gear lever to S and then use the paddles (or gear lever) to shift up or down. Try selecting a lowish gear and keep on the accelerator and it may red line - although it may choose to change up before. Never tried it to the red line myself though in lower gears I've found the revs do rise quickly. 

[sheamus]

Slightly off topic but I've noticed that in auto mode (D) at motorway cruise speed, the engine revs are higher (by about 500) than switching to manual and paddle shifting to 6th gear - now what's that all about?

[LordByronUK]

Yeah I've tried it in manual mode and been very aggressive with it, but it always downshifts and same result. Even using the kickdown switch, same! I think you're right, it's the way the CVT has been programmed for efficiency, and I imagine if I floored it for long enough from a motorway speed then the computer would be more inclined to rev all the way to the redline (as seen in the the NX). You're right in that it's programmed to quickly give peak torque between 4200-5000ish RPM, and won't give full power unless you really really need it for efficiency reasons, the eCVT way I guess...

[Thackeray]

4 hours ago, LordByronUK said:

Has anyone ever been able to reach 6000rpm in their IS? I've tried hard, it goes up to about 4800rpm fairly quickly but then it massively slows down after about 5000rpm in the long climb to 6000. So slowly in fact that I've never been able to reach 6000rpm.

My guess would be that it's limited by the maximum permitted speed of Motor Generator 1 (MG1). There's a direct ratio between the engine and MG1 of 3.6:1 so if the car is stationary and the engine is spinning at 1,000 rpm, then MG1 is spinning at 3,600 rpm. There's a software limit set for MG1 to avoid damage to the electric motor/generator. I don't know what the limit is but the first Prius had a limit of around 10,000 rpm. I'm pretty sure the IS300h is a couple of thousand higher than this but if the car was stationary 6,000 rpm for the engine would equate to 21,600. The engine might cope but the motor/generator probably wouldn't survive.

But when the road wheels start to turn (along with MG2), the direct linkage through the planetary gearset means that as MG2 speeds up, MG1 slows down. And if MG1 slows down, the limit for the petrol engine gets higher.

You can see the effect of this in the following video:

The engine revs pretty quickly to around 4,000 rpm but then only rises more slowly in line with the rise in the speed of the car.

This is also why there's a software limit of 200 kph (125 mph).

 

[Linas.P]

12 hours ago, Thackeray said:

The engine revs pretty quickly to around 4,000 rpm but then only rises more slowly in line with the rise in the speed of the car.

Well, the engine spins quite quickly because eCVT changes ratio to get you in the most efficient power-band. So it isn't really comparable with normal gearbox acceleration in the same gear.

[Maxz]

Hi, came back to this post because in my haste to get out and pick up a takeaway, I unwittingly knocked the shifter into “S” (paddle) mode. With the radio on fairly loud and not paying attention, I noticed the car was a bit sluggish but didn’t hear the higher reviving engine (given it is typically so quiet and refined anyway). Part way through the journey noticed the “S” instead of “D” on the dash and rectified my error. Question is per Thackeray’s response, other than ruining my average mpg, am I safe to assume the software will have prevented me from doing any damage (I.e. overevving the engine)?

All seems fine after my little oversight to be honest. I also now have the tachometer permanently on so any future mishaps are noticed earlier (plus not blaring the music so loud anymore!).🙉

[Linas.P]

12 hours ago, Maxz said:

Question is per Thackeray’s response, other than ruining my average mpg, am I safe to assume the software will have prevented me from doing any damage (I.e. overevving the engine)?

Yes - the eCVT will upshift and downshift regardless, you could not cause any damage even if you wanted to. S - sort of keeps the chosen ratio for a bit longer, but still switches gear well below redline, or under optimal RPM i.e. you could not stall. 

[Mr Vlad]

This thread has got my head thinking. I'm pretty damn sure I redlined my is300h when I had it. From a standing start with the switch set to power and traction Battery at least on half and foot buried into the carpet. This by the way on a motorway slip road. Every day on the way home from work I'd rag it from those traffic lights and I'm certain I hit 6k revs. Made a lovely noise lol (not as good as my is250 tho 😗)

[Maxz]

20 hours ago, Linas.P said:

Yes - the eCVT will upshift and downshift regardless, you could not cause any damage even if you wanted to. S - sort of keeps the chosen ratio for a bit longer, but still switches gear well below redline, or under optimal RPM i.e. you could not stall. 

Thanks that is reassuring to know. I did wonder why when I came to shift from S to D, why it was in 2nd and not 1st, which it would have been when I first set off. Good to know they build these things to be idiot proof!!🤪

[Linas.P]

15 hours ago, Mr Vlad said:

Made a lovely noise lol 

Wasn't it from speakers? 

From my memory - you could certainly hit 6000rpm or thereabout, but you can actually "redline" it, eCVT changes like 500 or 1000 rpm short even if you keep it in manual and set it to particular ratio etc. To be honest that makes sense as these engines are not "rev happy" - by which I mean they don't get more powerful the more you rev them and there isn't much point to go past ~4500. By contrast IS250 is quite rev happy, anywhere above 3000RPM it just starts shining.

[Mr Vlad]

Don't think the engine noise was coming from the speakers (always had the ML loud lol)