WINTER MPG

Juicedrinker · November 17, 2023

Hello everyone,

Bought a 2019 RC300H back in May and have had experience of Toyota hybrids before (also have a 2018 Yaris for past 3 years which my partner drives daily).

Whilst the Yaris typically loses 10-15% MPG during the colder days I've noticed the RC has dropped around 20-25% on the same types of temperature days.

I guess its because the hybrid Battery is less efficient due to the cold, the increased resistance on the tyres, size / weight of vehicle and large interior to heat up. It possibly also doesn't help because of the E10 fuel.

Out of interest has anyone tried Super unleaded during winter months and if so has the reduced Ethanol content increased MPG enough to more than offset the increased cost?

Thanks, Charlie

Jgtcracer · November 17, 2023

9 hours ago, Juicedrinker said:

Hello everyone,

Bought a 2019 RC300H back in May and have had experience of Toyota hybrids before (also have a 2018 Yaris for past 3 years which my partner drives daily).

Whilst the Yaris typically loses 10-15% MPG during the colder days I've noticed the RC has dropped around 20-25% on the same types of temperature days.

I guess its because the hybrid battery is less efficient due to the cold, the increased resistance on the tyres, size / weight of vehicle and large interior to heat up. It possibly also doesn't help because of the E10 fuel.

Out of interest has anyone tried Super unleaded during winter months and if so has the reduced Ethanol content increased MPG enough to more than offset the increased cost?

Thanks, Charlie

Not a hybrid but I get around 5-10% better mpg in my RCF using Tesco momentum in my car. Pays for itself…..

Also worth considering that it tends to drop for everyone, see below link

https://mag.toyota.co.uk/why-does-fuel-economy-drop-in-winter/

Bluemarlin · November 18, 2023

20 hours ago, Juicedrinker said:

Out of interest has anyone tried Super unleaded during winter months and if so has the reduced Ethanol content increased MPG enough to more than offset the increased cost?

Thanks, Charlie

I use super unleaded and get between 5-10% improvement in mpg. I used to use Esso E5 as that used to be ethanol free until a couple of months ago, but now any E5 will do.

DavidCM · November 18, 2023

Going off topic a little,but did you get your poor dipped beam resolved, Charlie?

Linas.P · November 18, 2023

To the question "if there is bigger difference between E5 and E10 on cold days", the answer is no. So if E10 is 5% less efficient in summer, it will be 5% less efficient in winter.

The difference is chemical, E10 simply has "less fuel" in it and it will have less fuel all year round.

Spark plug · November 18, 2023

The ethanol will absorb more water in winter ...I use E5 super all year round...

Linas.P · November 18, 2023

11 minutes ago, Spark plug said:

The ethanol will absorb more water in winter ...I use E5 super all year round...

Would not be relevant to anything in terms of MPG etc. E5 can have up-to 5% ethanol, E10 up-to 10%, in grand scheme of things - negligible difference. Water in fuel only becomes relevant if you planning to park the car for 6 months, maybe 12 months... then yes E10 will be worse. But if you finish that tank within a month then either will do and again difference will be negligible, whatever tiny amount of water would get absorbed would not make ad difference for MPG.

As well I doubt winter would make a different either. I guess one could argue that humidity is higher in winter, but in UK humidity is horrible all year round, besides lower temperature would slow down alcohol and water reaction, so in winter/lower temperatures ethanol would absorb water slower, not faster.

Spark plug · November 18, 2023

10% is double 5% which means E10 has double the amount of ethanol which is a big difference. if you do the maths...

Linas.P · November 18, 2023

Yes - double of negligible amount. Having some water in fuel as well does not affect your MPG, besides all fuel has some water in it. Pure petrol has trace amount of water, pure ethanol can handle about 5% before starting to separate, so E10 will have at most 0.5%. The discussion here is purely academical - there will be no impact to MPG either way.

Besides water in fuel in general does not reduce MPG, it could reduce power and slightly IMPROVE MPG, the problem with water in fuel is not that it hurts engine efficiency, but that fuel and water does not mix, causing separation and then when this water get's sucked into fuel system it could cause misfire and rough running. Again - will not be a problem for months!

Juicedrinker · November 20, 2023

On 11/18/2023 at 11:30 AM, DavidCM said:

Going off topic a little,but did you get your poor dipped beam resolved, Charlie?

Hiya, thanks for asking. No unfortunately it isn't and I am not able to get to a Lexus dealer anywhere near me. The nearest is Reading (and following how they dealt with me just over a year ago) I would never go there again. Swindon which is the dealer I like is not open on Saturdays and I am unable to have any time off work during the week until next year :sad: . I have just been told (after 6 months) that I should of had a Lexus Key Card with the car! So the dealer is going to try and get that to me and I will ask Swindon Lexus to programme it when I am in there.

DavidCM · November 20, 2023

Sorry to hear that Charlie.You've not had a good experience there.....these people often wonder why they lose business..

Juicedrinker · November 25, 2023

On 11/20/2023 at 7:36 PM, DavidCM said:

Sorry to hear that Charlie.You've not had a good experience there.....these people often wonder why they lose business..

Hi David, well I received the missing key card and a spare key fob last night!! So when I can get to Lexus Swindon they said they will pair them up and set up global opening and closing free of charge as I’ve used them for years!!! Now that’s really great service 😀

I took out the three year service plan with Lexus Swindon, I can’t fault them at all with every dealing that I’ve had with them.

I hope that you are getting good service / support with your chosen dealer

DavidCM · November 25, 2023

I had whittled it down to Hedge

End and Swindon, having had (mostly) negative reports about Reading...even though they are my nearest dealer(I live roughly midway between Newbury and Basingstoke).

I' m very happy with the service from Hedge End and what swung it for me was that they offered the Lexus Owner Club discount.

By the way,Reading didn't even answer their phone when I rang around looking at service costs.All I spoke to ,or was able to speak to,were the same price,but only Hedge End offered the discount.

I'm glad Swindon are performing properly for you....they get consistently good feedback.

andrey77 · December 3, 2023

How do you calculate that 5-10% difference guys at all? Is this small digits make you thinking to change the car for Ford Fiesta for example? lol. Just put the fuel and enjoy though

H3XME · February 27

On 12/3/2023 at 3:25 PM, andrey77 said:

How do you calculate that 5-10% difference guys at all? Is this small digits make you thinking to change the car for Ford Fiesta for example? lol. Just put the fuel and enjoy though

Well, if you've been using any old supermarket E10, and your Tank Average is 40mpg, then it's pretty easy to notice that your Tank average goes up to 42-44mpg by using E5... that's 5-10% increase. MPGs aside, Super Unleaded like Momentum99/Esso99+ (same fuel) has the best cleaning properties for the engine. Just because newer cars can take E10 doesn't mean they won't benefit from E5. Mind you, if you change cars every 2-3 years, you don't have to care about this as we're talking long-term benefits.