Rx300 03 onwards mpg...

[Spacewagon52]

44 minutes ago, Gbneil said:

Mpg no longer an issue as it will be Mrs car, she is urban commute so mpg will be dire, but she does about 50 miles a week so shouldn't be an issue. 

I would go for the RX300 then! Good luck with your search George!

[Gbneil]

On 21/09/2017 at 10:44 AM, Coxy said:

Hate to put a downer on things but honestly regardless of driving style if you're hoping for an average for 30mpg from the Rx300 then to be straight you are going to be dissapointed.

Go in wide eyes open, that's all. 

i think i may have caused some misunderstanding, i would not expect to average 30mpg in an rx300, i was initially asking if 30mpg would be available on long commutes sitting around 55mph as i am not a fast driver. i would expect an rx to average high teens/low twenties in daily use. my old ls400 used to return 34mpg on long runs, but averaged 24mpg weekly. i am aware there is a difference between a running average per trip and an overall average. many thanks for all the advice, gbn

[PCM]

At 56 I get, in theory... 28-30.

It might be optimistic, but aren't all cars?!

( And run through a few tanks of Shell V-Power ? )

Edited September 23, 2017 by PCM
Addition

[sorcerer]

4 hours ago, PCM said:

At 56 I get, in theory... 28-30.

It might be optimistic, but aren't all cars?!

( And run through a few tanks of Shell V-Power ? )

To get a true mileage figure just sign up to fuelly.com (click on my sig to take you there if you like or there's even an app for your phone if you want to do it 'at the pump') and enter the details of a few fill-ups; you'll soon see the 'real world' mpg as the pattern emerges.

And at the risk of igniting the age-old discussion, there's really no need to spend extra money on Shell V-Power or any other brand of 'super fuel' unless your engine is tuned to make use of it (and even then it's still very debatable as to whether there's any benefit or not).

[Coxy]

7 hours ago, sorcerer said:

 

And at the risk of igniting the age-old discussion, there's really no need to spend extra money on Shell V-Power or any other brand of 'super fuel' unless your engine is tuned to make use of it (and even then it's still very debatable as to whether there's any benefit or not).

My RX has returned a better mpg after running a few months on Shell Vpower. 

I previously only ran it on 'normal', I once filled up about £45 with higher octane v power from almost empty and noticed no difference at all, so reverted to normal.

However in the past 4 months I've done nothing but run it on higher octane v-power and my average mpg has now increased by 3. Same Commute, same roads, on average. 

I actually do not attribute this to the octane difference but more so the additional detergents they claim they put in it help clean the fuel system and touch point engine components. Which I feel is supported by the fact I had to run it on v-power consistently and it was a while before I started seeing postive results but those results have remained.

I otherwise agree on your assesment of octane vs vehicle requirements. I believe the RX manual advises 91 minimum which I believe most branded fuel is in the UK. 

[sorcerer]

You say "same commute, same roads" but that commute could be different every day, being affected by weather (especially wind speed and direction), minute differences in accelerator pressure and a whole host of other parameters.

As for detergents and cleaners in the 'super petrol', your theory may well be right. If they have actually cleaned the engine and its components then you should now be able to go back to 'normal' petrol and see an improvement in mpg over what you used to get on normal petrol, now that the engine is cleaner. If it holds true, maybe the same effect could be had by chucking some Redex or other engine cleaner in the tank every now and then, which may work out cheaper.

[Coxy]

On 23/09/2017 at 8:05 PM, sorcerer said:

You say "same commute, same roads" but that commute could be different every day, being affected by weather (especially wind speed and direction), minute differences in accelerator pressure and a whole host of other parameters.

As for detergents and cleaners in the 'super petrol', your theory may well be right. If they have actually cleaned the engine and its components then you should now be able to go back to 'normal' petrol and see an improvement in mpg over what you used to get on normal petrol, now that the engine is cleaner. If it holds true, maybe the same effect could be had by chucking some Redex or other engine cleaner in the tank every now and then, which may work out cheaper.

Actually if we're going down that route we'd also need to consider the fact that the months were getting colder from the start of the "project" and colder average also uses more fuel which further backs up my theory (because as it gets colder I should be seeing less MPG) and I have recently filled on normal for mpg to remain, 

[b4u2]

I must say now after seeing that the rx300 is very thirsty and not cheap on fuel!

[serbarry]

11 hours ago, b4u2 said:

I must say now after seeing that the rx300 is very thirsty and not cheap on fuel!

What would you expect from a 3.0cc V6 petrol?

[Spacewagon52]

13 hours ago, b4u2 said:

I must say now after seeing that the rx300 is very thirsty and not cheap on fuel!

Yes, they are thirsty - but you were aware of that before you bought your car.

[b4u2]

12 hours ago, serbarry said:

What would you expect from a 3.0cc V6 petrol?

I guess you have a point! 

[b4u2]

Thinking about converting it to LPG but only worthwhile if doing lots of driving

[b4u2]

Was shocked to only get 240 miles for a full tank on my rx300 

It costed me £80

[Spacewagon52]

31 minutes ago, b4u2 said:

Was shocked to only get 240 miles for a full tank on my rx300 

It costed me £80

You should not have been shocked, you were made well aware of the mpg figures before you bought the car. Your shock is the cost of fuel! I have just filled my LS400 - it was not empty - and it came to £84. The mpg for a vehicle is fairly constant depending on the journey. The only upside is if petrol is cheap. 

Over 250 miles you will be paying around £18 MORE than I am with a RX 400. Based on 22 mpg vs 30 mpg. 

Have you actually worked out the mpg?  I was generally getting 22 mpg overall. On a long run, the best I got was 28 mpg. If you convert your car to LPG then you can achieve over 30 mpg equivalent. look back on Sorcerers post.

I can't remember but I think it was Herbie or John who worked out the cost per mile:-

RX 300 petrol 23p

RX 400h petrol hybrid 18p

RX 300 LPG 13p

Not sure what the price of petrol was then but it gives you the difference. 

 

Wprk out how long it will take to save £2000 and that is around the cost of a good conversion. That is the break even point. after that you are in pocket. 

Answer this question: Will my RX 300 last that long?   PROBABLY! 90% sure if I stick my neck out!

I am sure Royoftherovers will chop it off!

[Herbie]

1 hour ago, b4u2 said:

Was shocked to only get 240 miles for a full tank on my rx300 It costed me £80

They are indeed thirsty beasts and that's why we had ours converted to LPG, but as said above, you asked the question a few times and were told the same answer every time, so it should not have come as a shock.

I have no idea why the cost of petrol is so high at the moment but hopefully it'll drop down a bit in the not too distant future.

Looking here shows the average for the RX300 is about 20mpg.

[m4rkw]

On 7/28/2021 at 12:04 AM, Herbie said:

They are indeed thirsty beasts and that's why we had ours converted to LPG

How long ago was that Herbie? Are you not worried about valve seat regression?

[Herbie]

32 minutes ago, m4rkw said:

How long ago was that Herbie? Are you not worried about valve seat regression?

It was a while ago now Mark but until I got my first hybrid about 3 or 4 years ago, all the cars we'd had for the previous 15, maybe 17 years had all been converted for LPG and no problems at all with valve seat regression or anything else for that matter.

LPG is better for the engine, better for the environment and definitely far better on the wallet and I would have it on this car now but I'm not brave enough. A hybrid can be converted but they are already extremely complex cars and I'm not brave enough to add another layer of complexity into the mix.

[m4rkw]

I looked into it for mine but came to the conclusion that my engine isn’t suited to it due to the soft valve seats. There are several reports of VSR even with flashlube systems fitted.