Very poor fuel consumption corolla HB 2021 1.8. 33mpg. why. 120miles non stop with cruise on 110kmph

[ColinLimerick]

Thanks for all the advice folks. It is now running at 4.7l/100km (60mpg) happy with this

[2badmice]

I failed to reset mine when I bought my used Corolla.  (I did reset it the other day, but I haven't checked it) The best part for me, rather than looking for a number on the dashboard, has been how infrequent I've visited the petrol station, I usually visit once a month, with this car, but this is dependant on how often I see my side of the family and my daughter, as I work quite close to home so my journey is minimal.  It's a vast improvement when I am doing the family visits, then too, as I get more mileage for my money on those journey's compared to the VAG's I had in the past.

The worst part is since buying the car in October, it feels like fuel has jumped 60 pence per litre.

[Roy124]

On 6/28/2022 at 3:38 PM, RIbbotson said:

. I have never had to reset mine but it normally comes on if any tyre drops bellow 32psi.

I had one tyre at 27 psi and no warning light.  I think it was Frosty who said the tolerance was 20%.

[AisinW]

The warning light depends on the pressure when you reset it. I think 20% below is about right. It will not give any warning light if it is over pressure, if you accidentally put 44 psi but you feel how bumpy the ride will be. You can use any good OBD2 ELM327 compatible like Veepeak or Carista and use Tire Assistant apps. It also can read serial number of the TPMS. Don't buy random brand OBD2 that often are fake and cannot read complicated sensors. 

[Roy124]

Take the point about the make of OBD, but it is also App dependent.  What App do you suggest? 

[AisinW]

So far, I used reputable apps that does not rob your money.  Dr. Prius (free edition) is probably the most useful for hybrid. Torque lite (free) or pro.  Don't buy Carista apps, it cost too much because of monthly subscription type instead of permanent license. Tire Assistant app is free.  For Toyota, Carista app is not really helpful. We only need Dr. Prius and Torque Pro for complete scan and live data. 

https://priusapp.com/obd.html

I like Torque Pro and load it with Prius3 profile for Auris or Prius 4 for Corolla. https://priuschat.com/threads/geniii-prius-custom-pids-for-torque-app.98693/

[Tech429]

Still sounds low IMHO.

My Corolla seems to do an average of 56mpg but depending upon where you are driving it can go down or up - even had it at 80.6mpg after a short journey (3 miles) from my town, but the Hybrid motor was going more than usual due to my conservative driving.  It is all down to how you drive.

That said you should be getting an average of at least 50mpg surely be it on B roads, A roads, highway or in town driving?

Regarding tyres I would put in the loaded tyre pressures and not the normal (told by a Toyota guy to do this) as this is far better for equal tyre wear as if you run on standard 33 / 31psi you will wear out the edges of your tyres regardless.

[dee123456]

46 minutes ago, Tech429 said:

That said you should be getting an average of at least 50mpg surely be it on B roads, A roads, highway or in town driving?

 

OP updated the thread and said this.

On 6/29/2022 at 3:17 PM, ColinLimerick said:

Thanks for all the advice folks. It is now running at 4.7l/100km (60mpg) happy with this

 

[Roy124]

Just completed a long journey in one day but 5 stages in a 2020 1.8 Corolla. The journey was mixed motorway, dual carriage way, 2 Lane and some slower sections.  Overall the results were approximately :

318 miles, 65 mpg, 5 gallons and 42 mph average. 

High speed was ACC, 70 indicated 65 true.  Ordinary roads 60/55 indicated. 

We were very pleased and the whole journey took 9.5 hours and was not unduly tiring with Toyota sharing the workload. 

[DC_Ms]

On 6/28/2022 at 8:19 PM, AisinW said:

Yes, you are right, it is still more efficient than any comparable gasoline turbo engines. Diesel will win just because the internal energy of diesel fuel is 30% more and the compression ratio can be really high and can reach beyond 41% thermal efficiency.  Toyota still holds the record on most efficient gasoline engines at 41% thermal on 2.0 and 2.5L D4S. 

With Corolla Adaptive cruise control, you can follow semi trucks at 100 km/h at maximum adaptive distance and get 3.5L/100 km consistently in Motorway or Autobahn. 

Is there a sweetspot cruising speed on motorways where the 2.0 engine is the most efficient ? 

[AisinW]

1 hour ago, DC_Ms said:

Is there a sweetspot cruising speed on motorways where the 2.0 engine is the most efficient ? 

Almost all cars have optimum cruise speed close to 50mph/80kmh.  Basically lowest rpm too keep the speed against wind drag.  Following stream of traffict also reduce wind drag but always keep safe distance. I found adaptive cruise control is very effective and safe, especially behind bus or semi-truck.

I did an experiement and the drop at 100km/h is from 4L/100 km vs 3.5 L/100 km. I maintain 50-70m distance. 

[PRus]

2 hours stretch on the dreaded A34 from the south to the Midlands: 56.6 mpg(4.9L/100km for the Europeans including myself), adaptive set at around or over 70 on some stretches(was a passenger so I can't confirm or deny the actual speeds officer), and the boot was full with stuff including a heavy suitcase(20 kg), pram, beachbag, tent, 2 adults and a toddler, car seat. Not bad i suppose! 1.8 excel TS. Driving to Blackpool and back from the South Coast so I will be able to see how the car behaves on the motorways and long trips. 

[AisinW]

Tested in Autobahn, It increase significantly above  130km/h or 80mph, 6.5 L/100km (1.8L) and 7.2 L/100km (2.0L). Below 60mph or 100kph, we always get 4.5L/100 km or lower.

It makes sense because the wind drag increases by 69% from 100 to 130kmh and the consumption 60% increase. 

At max speed 180kph, 300% or 13.5 L/100km  consumption is to be expected.  

At higher RPM/ speed, the risk of engine oil consumption is much higher because the piston rings have certain limit to react and scrap the oil back to the crankcase. 

My old Altima 2.5L consumed 2L per 1000 miles at 70mph and drop to 1L per 1000 miles if I cruised at 60mph. 

I believe 40-60 mph is the best range for the engine to keep it clean and smallest wear per km. 

[TonyHSD]

60-65 mph perfect cruising speeds on any car 👍 This is how I drive and I am getting 60+mpg currently in old Auris hybrid 1.8, not bad at all. 

[Cyker]

Bizarrely, my Mk4 seems to have similar characteristics to my old Mk1 diesel - It likes being around 50-58mph for optimal consumption, which starts to drop as you go past it into the low-mid 60's, but as you get to 70-ish it weirdly goes up again?? (Not to better than at 50's, but more than I'd think compared to 60's!)

It can hold ~2000ish rpm at 70mph on a flat road (And can even go EV if going down hill!) which I suspect helps a lot...!

 

[AisinW]

Diesel is often more efficient on higher speed cruise than any gasoline engine with similar power. High torque at low rpm compensate win drag nicely. 

However, the hassle of emission system in Diesel is often offset all the gain of using diesel for pasanger cars.  Unless, it is older diesel without DPF nor Bluetec.

[Cyker]

Yeah, wouldn't touch a modern diesel - The emissions control stuff has destroyed their reliability. It's funny as lots of people on the forum say diesels are unreliable, which shows the only came across them well after all that started happening, as in my day diesels were considered the most bullet-proof and reliable engine! Easily cresting 100k miles when petrols needed a rebuild after maybe 60k  

I do find it impressive my Mk4 can hold the same or even less RPM at 70mph than my old Mk1 D4D tho' - The D4D'd be at maybe 2.5k IIRC whereas the Mk4 wobbles between 2 and 2.5k (If I squeeze the accelerator even a bit more tho' it does tend to jump straight to 3k+ and accelerate tho'  )

[50p]

3 hours ago, Cyker said:

Yeah, wouldn't touch a modern diesel - The emissions control stuff has destroyed their reliability.

 

Yup, 15,000 miles injector needed replacing. 15,137 another injector failed, different one this time. As still 2 original injectors remained I cut my losses and sold the car. Both failures were electronic apparently.

That's if you consider 2014 'modern'!

[AisinW]

After 2008, all diesel have DPF filter. Those consumable emission system cost more than hybrid Battery. This phenomenon cause market price  pre 2008 heavy duty diesel truck is more expensive than newer truck. 

Unfortunately we do not get super comfortable Sienna hybrid, a  42 UK mpg or 6.7L/100 km. An alternative to Transporter, Vito, or PSA/Opel/Fiat/ Proace diesel. 

[Roy124]

8 hours ago, TonyHSD said:

60-65 mph perfect cruising speeds on any car 👍 This is how I drive and I am getting 60+mpg currently in old Auris hybrid 1.8, not bad at all. 

True or indicated? 

[Roy124]

6 hours ago, AisinW said:

Diesel is often more efficient on higher speed cruise than any gasoline engine with similar power. High torque at low rpm compensate win drag nicely. 

However, the hassle of emission system in Diesel is often offset all the gain of using diesel for pasanger cars.  Unless, it is older diesel without DPF nor Bluetec.

Mercedes E220D (2005) at 70 true for much of the journey to Southampton would just touch 49 mpg.  Steady cruising at 100 however, whilst comfortable and satisfying did knock it back

My previous E200 was much thirstier and apart from the rust bug the engine was fine at 180k.  The E220 at 190k was said to be good for another 100+

 

[TonyHSD]

31 minutes ago, Roy124 said:

True or indicated? 

Sometimes indicated sometimes true, I usually keep speed between 65 and 70 indicated, which likely to be 60-65 true 

[MarcusWatson]

I saw a youtube video about these new solid bicycle tyres that are in development by a company called Gecko. It explained why air filled tyres are efficient (when properly inflated). Its because when you compress air it pushes back with very little energy lost i.e. think of a ball that almost bounces back to the same height as you dropped it from. Underinflated tyres lose a lot of energy, think about dropping an under inflated ball or trying to pedal with a flat tyre on a bike. I guess this explains the huge effect that underinflated car tyres can have! I was shocked at the consumption in the original post! I have only just got back from a 48.6 mile trip up the M40 from London to Oxford at 70mph where possible and got 64.9mpg in my 2020 1.8 Corolla Icon Tech HB, with 200kg of people aboard and air con blasting. Average speed was 45mph over the journey and EV distance 23%. As long as you keep the speed below I think 72mph you will generally see some EV only on the motorway and also don’t forget it will assist you even if its not shut the engine off. I am so glad I have this car now with costs going up and I’m keeping it when my PCP ends in September. Only my Dad is happier than me, his PHEV has had two tanks of diesel in the last year and everything else has been done on the 50 mile EV range 😎

[Roy124]

Marcus that consumption is near identical to my longer journey I detailed above. A woman in our club never betters 60 mpg.  She was no boy racer when I rode with her, so actually journey profile was probably the major factor.  She lives in town whereas I live 8 miles out. 

It really shows the importance of matching profile to model. I think we hit the sweet spot with a 1.8 Corolla and out of town use with more than half the journies on dual carriage way and over 20 miles. 

[AisinW]

Driving in stop and go traffict is always worse than any scenarios. 1.8 is more than enough for most people in mix Driving condition.  The 2.0L is ideal for hilly and mountain area where we can get higher torque at lower rpm from 2.0L engine and larger MG2. The 1.8L is still more efficient in relatively flat roads but can consume more with heavy loads and climbing.  Just like why Prius C or Aqua 1.5 L consumes more than Prius with 1.8L engine. Yaris is much smaller than Corolla and benefit from much lighter weight.