New Owner Advice... petrol and updates

[b33rdy]

Hi,

Just got a 67 plate IS300h, and I was wondering if it's worth using high octane petrol?

 

Also, can I do the firmware updates myself? For things like sat nav... there's no dealer even remotely close to where I am.

 

Thanks!

[zippyone]

Hi Kieron,

My word, Ampshire, no dealer remotely close?  How about Snows, at Hedge End. I think there's another dealer at Chichester.

Just normal petrol will do, as there is no real gain from high octane all the time, accept for the tax man of course. However, a tank of high octane every now and then won't go amiss.

Look through the site there is a lot about using/not using high octane.

Best wishes.

Michael.  . 

[route66]

Firmware updates are doable by yourself if you have premium navigation - You can purchase these yourself from the Lexus website.

 

If you have regular Navigation (or, no Nav), in theory, this is a dealer-only option.

 

An alternative is to look around eBay for independent suppliers whose solutions work with either Nav system. A quick search will give you details.

[b33rdy]

Thanks Chaps,

 

Route66: How do I know if I have premium navigation?

 

You're right Zippyone, Snows in Hedge End is the closest, but it's still a £50 to £100 boat ticket to get there /:

[ColinBarber]

14 minutes ago, b33rdy said:

How do I know if I have premium navigation?

 

You would have the remote touch controller (mouse like interface). The rotary controller operates the standard Nav system.

[b33rdy]

Ah, ok - so it's just the standard nav for me.

Thanks Colin!

[rayaans]

5 hours ago, b33rdy said:

Ah, ok - so it's just the standard nav for me.

Thanks Colin!

I dont think you can update the standard nav by yourself. Could be wrong though, not really had much experience with those. 

No point in using high octane fuel in this one though

[Mr Vlad]

There are those who say it''s a waste etc to use a high octain fuel. They have their opinion but they are so wrong. My experience tells me I get an extra 3-5 mpg. My car runs better. I use the stuff every 3rd fill up. The extra expense is worth it. However it is up to the individual. 

[rayaans]

3 hours ago, Mr Vlad said:

There are those who say it''s a waste etc to use a high octain fuel. They have their opinion but they are so wrong. My experience tells me I get an extra 3-5 mpg. My car runs better. I use the stuff every 3rd fill up. The extra expense is worth it. However it is up to the individual. 

Its impossible to measure fuel economy of different fuels. Too many variables. 

[ColinBarber]

10 hours ago, Mr Vlad said:

There are those who say it''s a waste etc to use a high octain fuel. They have their opinion but they are so wrong. My experience tells me I get an extra 3-5 mpg. My car runs better. I use the stuff every 3rd fill up. The extra expense is worth it. However it is up to the individual. 

If you find it makes that much of a difference and worth the expense then why not use it all the time?

How much difference is the fuel cost in your area? For me it is an extra 10p per litre, around 9%, but makes less than 5% difference in usage.

[JeffL]

honestjohn.co.uk is always pushing Shell V-Power with fuel system cleaning additives to improve the performance and fuel ecomomy of all engines, both petrol and diesel. I use Tesco regular unleaded and never had a problem with my 10 year old GS300. Often wonder though, should I try the Tesco Super Unleaded. Might it clean the engine? Does it need cleaning? Will I get better performance and more MPG? Not tried it yet though.

[zippyone]

Hi Kieron, and members,

Sorry, I had forgotten the I.O.W. Mmmm! expensive trip these days, I used to pay 2-3 quid. Next time I'm sat at Lee on the Solent and my wife suggests we go to the island, i shall have to ask her for extra pocket money first.

Fuel economy is an individual thing, especially in a hybrid, it boils down in the main to how heavy your right foot is, and how you use it - like some other things i am aware of:) There is much good advise given here, but it always boils down to the same thing,  'you.'

Mr. Jingles is a bog standard 17" IS 300h,  has just had his 3rd annual service and has clocked 50,000 km (31,068 m). I fill him about once a month to the brim and most of the time drive in 'normal.' I do not use cruise control, as there is never the room for it to function properly.

In Italy the standard petrol is 'EN228 green' it is 95 RON. In the Uk it is called 'Regular,' I believe, Germany 'E10.' I use this most of the time, however, i give Mr jingles a treat twice a year and fill him up with 98 RON. Just to clear his throat you understand.

I generally travel at the speed limit (+ - a bit ). Mr. Jingles appreciates the TLC that i give him and in return rewards me with  5.4 - 5.3 L/100km ( 52-53 mpg). There ain't many folk can beat that. I removed my go faster stripes many years ago, after grew up and i'd learned how to drive. - Just in case you think the  good mpg are  because of where i live, don't believe it, in February early March it was rarely above zero, the lowest about -10°c. 

Lexus is a good car, an expensive good car, but very comfy and reliable, it is not a racer, more like a mobile home, yes, sometimes you will wish you could live in it. Just treat and drive it well and you will have a friend for life. There are too many 'chimps' buying  Lexus now and i feel, destroying its image, but life goes on. Anyway, whatever juice you put in it, 95, 98 or even orange! it is your money paying for it, learn to drive it properly and it will reward you. You can find me on 'Spritmonitor and Fuelly,' why not check me out.

Sadly, i am going to retire 'Mr. Jingles.'  In June or July i shall take delivery of a new, 'IS 300h Executive,' with all the bells and whistles. It will have 18" wheels, but i expect the comfort to be better and the economy to be about the same, the latter being up to me mainly. Despite the heavier wheels, it seems to have the same overall weight.

I now need a new name for it, because it is an 'it' for the moment. I was thinking of 'Rupert,' - it was the name of my teddy bear when i was young and indeed, before many of you were born i suspect. Any suggestions would be welcome, please send them along.

Best wishes.

Michael.   

  

 

 

[wharfhouse]

Haven't tried super unleaded in my 300h but in my previous BMW (3.0 litre petrol) when I used it I found two things:

1. The engine was a tad quieter and smoother - however I have found this can also happen between different petrol suppliers anyway - but the super unleaded always delivered this

2. The petrol consumption was on average about 5% better over a tankful on super unleaded (based on using the same petrol provider and petrol station) - appreciate that this is difficult to measure accurately given the constant changes in real world driving but I did the comparison quite a number of times on the same long runs so I am pretty sure that I was seeing a small increase. However, given the increased cost of super unleaded then I would say any cost benefits were awash

3. There may have been a slight gain in performance on super unleaded - I never actually measured this so it was only perceived and again very negligible, if at all, and may well be linked to the engine running a bit quieter / smoother

I ran the previous BMW on super unleaded pretty much constantly however - not for any financial gain but it just seemed to run slightly better. Haven't bothered with the 300h though as it seems to run so smoothly and quietly on regular unleaded anyway!

[MONTIMAR]

I am an avid follower of Honest John and I have always used Shell V Power from new. As a low mileage driver the extra cost is is nothing to bother about. I keep a record of all my fill ups and the car has averaged 55.3 MPG over 4000 miles.

[Mr Vlad]

Rayaans there are not too many variables to asertain the better running and economy in using super unleaded.

Colin. I don't use it all the time because it's not needed. There is always a quantity of the good stuff left in the tank to boost the normal stuff.

I've been using the good stuff for years in both petrol and diesel and my cars have always run better for it. Oh and my previous cars have either been the top of the range or the sport derivative.

As has been stated the difference in price between the two isn't worth bothering with. Looking after ones pride and joy is worth bothering with. And as I've stated its an individual's choice.

[Guest]

A small amount of fuel with 98% octane rating isn't really going to effect 95% much ... even if you have 1/3 rd of a tank left you end up with 96 at best. Anything lower than a 3rd of a tank and you get closer and closer to 95. If you want to use random Octane ratings then this is the way to go. Only using one or the other do you know what you actually have.

For engine cleaning you could use Toyota's fuel system treatment and add that once in a while.

I have dyno charts for bikes showing where owners have tried 95 versus 100+ octane fuels and lost as much as 30% power in the mid-range with high octane fuel and the power eventually catches back up right at peak. To use the higher octane properties effectively you need certain properties of engine design and ignition programming.

I would never argue about it being your personal choice to use it or not. You can put lemon juice in there if you like  I'm not trying to prove you wrong, or me right. It's your money and if it makes you feel good go ahead and use it. 

........The Atkinson cycle modifies that process by leaving the intake valves open for the first moments of the compression stroke, as the piston travels toward top dead centre, which effectively lowers the compression ratio of, say, 10:1 to something more like 8:1, or so. That adjustment reduces the force on the piston on the power stroke.

 

 

 

[paulrnx]

Tesco super unleaded doesn't have all of the additives and clever stuff that BP and Shell have in their 'super' unleaded fuels. I'm sure I've read somewhere that Tesco just adds something their standard fuel to increase the octane rating to 99. Nothing like the stuff that BP and Shell do to their Ultimate and V-Power fuels with all the cleaning additives aimed at keeping engines cleaner and healthier.

I found no difference in my NX300h between standard unleaded and Ultimate/V-Power. Initially I thought there was a difference but over time I felt that there was no difference in terms of economy or response. The 300h engine just isn't geared towards performance and I suspect the ECO doesn't use a different map for higher octane fuel because it's all about economy and efficiency rather than power and response. In fact, I was convinced that my NX300h ran better on standard unleaded.

[Thackeray]

On 14/03/2018 at 1:27 PM, Comedian said:

The Atkinson cycle modifies that process by leaving the intake valves open for the first moments of the compression stroke, as the piston travels toward top dead centre, which effectively lowers the compression ratio of, say, 10:1 to something more like 8:1, or so. That adjustment reduces the force on the piston on the power stroke.

Could you explain a bit more what this means? Lexus quotes the compression ratio as 13.0:1 on the IS300h engine. Is that just a hypothetical figure for a non-Atkinson cycle and in reality the compression ratio is lower than that?

[Guest]

15 minutes ago, Thackeray said:

Could you explain a bit more what this means? Lexus quotes the compression ratio as 13.0:1 on the IS300h engine. Is that just a hypothetical figure for a non-Atkinson cycle and in reality the compression ratio is lower than that?

Imagine the volume of a cylinder. If you compress a 100% of the volume into 10% of the volume you have a compression ratio of 10:1 - that's how the figure is arrived at.

However if we have a valve at the top that lets air out for 50% of the piston travel we only compress the second half giving us 5:1 in reality. So the piston does less work and that's how the engine is made more efficient. Less pumping losses. Runs cooler so more thermally efficient.

Doing that process just on air in a tube raises the temperature hugely - it's that heat that diesels spray fuel into for ignition. Petrol has an octane rating so it doesn't burn in that heat and it is there while compression is happening. You also don't want it igniting on hot surfaces. So if you have a hot high compression engine you use a higher octane, 13:1 would suggest you need super but the manual says 95 even though the compression figure is higher than an RCF which has to run super. So with higher octane being more resistant it also burns more slowly so your max cylinder pressure comes at a different time. That's where ignition advance comes in. You could potentially actually lose power using 98 over 95. 

I don't know the valve duration of the Atkinson cycle so can't give exact figures. But if the manual says to use 95 then 98 is potentially a waste of money. 

[paulrnx]

Interesting. I was convinced by NX ran better on 95 rather than 97/98. I doubted that the engine was able to make use of the better knock resistance of higher octane fuel by altering the map to accommodate this

[Thackeray]

2 hours ago, Comedian said:

However if we have a valve at the top that lets air out for 50% of the piston travel we only compress the second half giving us 5:1 in reality. So the piston does less work and that's how the engine is made more efficient. Less pumping losses. Runs cooler so more thermally efficient.

Thanks for the detailed explanation - that's very helpful. So I'm guessing that you're not saying that the compression is actually reduced. Just that the 13:1 compression ratio would be even higher if the valve were designed to close as soon as the piston began its compression stroke. 

[Guest]

No, I'm saying 13:1 is if the valve was closed (the physical dimensions). The fact it is open probably gives you 10:1 or 9:1 in actual compression. 

 

I don't know these numbers are factual - it's an assumption based on the fact your manual says "Use 95"

 

 

 

 

[Thackeray]

5 minutes ago, Comedian said:

No, I'm saying 13:1 is if the valve was closed (the physical dimensions). The fact it is open probably gives you 10:1 or 9:1 in actual compression. 

 

I don't know these numbers are factual - it's an assumption based on the fact your manual says "Use 95"

 

 

 

 

Ah, that's interesting. Seems to make sense based on the octane rating. I wonder if there's any way to confirm it.

[ColinBarber]

On the Prius the static compression ratio is 13:1,  effective compression ratio is 8:1 but the expansion ratio remains at 13:1. The IS will be similar. 

I believe the new UX250h will have an engine with a compression ratio of 14:1.

[Guest]

Thanks colin

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