Cruise Control

[Linas.P]

2 hours ago, ColinBarber said:

The smaller hybrids are about economy and emissions. Why you would use an engine that is inherently heavier and less economical, and doesn't actual produce any more power.

On first part I agree .. kind of. Lexus wanted to make an engine which has smaller emissions on paper and faulty test methodology. Indeed 2AR-FSE seems to be more economical engine will lover emissions that 4GR-FSE. But I would like to emphasise the part on paper and in test methodology - this does not translate into real-life

Both engines are 2.5L, but 4GR-FSE is 37hp more powerful (212hp vs 175hp in most powerful versions of either engine). The quoted 223HP on 2AR-FSE is with hybrid engine and this figure is highly misleading as it is simply adding HP of ICE and HP of electric engine, whereas in reality they reach they maximum HP at different times so at no point IS300h makes 223hp, the other figure sometimes seen on adverts is 181hp and that is closer to reality. Besides whole hybrid system is far heavier than just ICE. So saying that 4GR-FSE is heavier is wrong and saying that it is less powerful is also wrong. Even if we just look to dry weight of both ICE engines 4GR-FSE would not be much heavier, because it does not require as many counterbalances as 4L.

Now indeed it is less economical, but that is because it does not have Atkinson cycle and because it is ICE only, a lot of economy on hybrid is achieve by combining it with batter and electric engine. Just look at economy of the engine when it runs on its own e.g. just cruising on motorway at 70MPH - what is the result - basically the same fuel economy. Besides, I didn't say take 4GR-FSE as is any just attach hybrid to it... I said they should have updated it to be more economical and more powerful. 

No if we just assume electric engine makes 48hp (difference between claimed total power and ICE power), then 300h based on 4GR-FSE (or after upgrades FXE) should have had at least 260hp and theoretically should have had similar economy. Now granted it would not match fake emissions on paper, but I reckon real emissions on road would have been similar if not better.

And as well, this is not even that far fetched. 450h is literally 350 (2GR-FSE) mated to hybrid system and with added Atkinson cycle (2GR-FXE)... and it is great system.

Finally, this is just hypothetical scenarios invented by type expert on the forum, Toyota engineers obviously had better understanding and didn't just decided to waste billion developing new engine if they had perfect one on the shelf. The only problem is that their goals may not be something generally considered to be a good thing my actual drivers e.g. maybe goals were to make engine cheaper, emissions smaller.. and that is at the cost of nice sounding, more responsive and more powerful engine. 

[paulrnx]

10 hours ago, ColinBarber said:

The smaller hybrids are about economy and emissions. Why you would use an engine that is inherently heavier and less economical, and doesn't actual produce any more power.

But if you had driving modes that covered all the bases the car could be everything for everyone. The car is sold as a sports saloon after all.

Have a genuine ECO mode that does save fuel and gives the economy minded people what they need.

Have a genuine Sport mode that maximises electric assistance and includes an aggressive ICE map, again to give performance minded people what they need.

Then something in between for a Normal mode which in my book should be something similar to the current Sport mode. Not having to mash the accelerator every time you need a bit of performance would I think lead to better real world fuel economy.

They are lovely cars no doubt about it but I think they could be so much better.

[ColinBarber]

8 hours ago, Linas.P said:

Both engines are 2.5L, but 4GR-FSE is 37hp more powerful (212hp vs 175hp in most powerful versions of either engine).

True but it isn't a fair comparison. To convert the 4GR-FSE into something suitable for a hybrid vehicle (a 4GE-FXE if you will) it would be detuned to around 180 hp, as it is done with the 2GR-FSE and 2GR-FXE, so the difference is very small.

It's moot really though. Both the GR and AR engine designs are now old and out of development. The A25A series take over as the 2.5l engines now being developed with similar power levels, 210 bhp for NA and 180 bhp for hybrid.

[Linas.P]

7 hours ago, paulrnx said:

The car is sold as a sports saloon after all.

Well... on that one I have made few threads in the past 😄

I think simply not using "sport" anywhere near these cars would already be good start, just to manage the the expectations of potential buyers.

And I agree with rest of your points - for massive company with best engineers in the world it should have been possible to design something better, both performing better, sounding better and more economical at the same time. Overall, 300h for me always looked like a little bit lazy attempt - they just made on the basis of "good enough".

@ColinBarber - yes it is mute point, always been. And indeed making 4GR more efficient/suitable for hybrid would make it less powerful. I would still prefer V6 any day over L4. And as per above - marketing car more realistically would help as well. Having better choices in UK would help, having plug-in hybrid version would help etc. Overall, I am not sure what Lexus tried to achieve this mk3 IS - the range just never been really competitive, especially in UK. Competitors certainly delivered more diverse range, both more powerful cars for those who wants power and more economical cars for those who wants economy... and competitors took advantage of government taxation as well (we can see sharp decline in 300h sales as soon as emission were reduced to 75g for company cars) - because they didn't introduce plug-in hybrid. Being only reliable sadly does not sell cars, especially new ones - it becomes more relevant on used market.