Recommendations for best fuel economy in an XC90 T8

[sk546]

Originally Posted by 100K+

Think I can use "B mode" in power and AWD modes only. In Hybrid and pure modes gearbox defaults to "D mode". What I have noticed is in D mode the engine revs in a higher gear than I would drive, so I select "B mode" in power and manually change up the box. A great feature is when slowing down for roundabouts / junctions the gearbox auto changes down for you, so you just need to change up to maintain progress. I have found you can "double change" by pushing the lever x2 in rapid succession. I don't notice any retard when in B (unless i'm in too low a gear) and don't use "recharge" function as the recharge costs more in lost MPG than recovered via recharge.
Also as others state running in pure mode is almost as expensive as petrol, as i don't have cheap electric and thus pay full wack.
Cheers
Bob

Selecting B mode does nothing at all to the change programs of the ICE gearbox. The only thing that changes the gearbox shift logics is changing the Drive mode.
When you put the car in Power mode, this changes the gearshift logic to hold the gears longer and have a higher rpm when cruising as this gives the car a more sporty response i.e. Power...........
B mode is selectable in any driving mode and you will only feel the regen effect when you take your foot off the accelerator. When the ICE is running, you will not get instant regen effect like you will when just the electric motor is running, it kicks in a bit more gradually but should be very noticeable when it does.
As you have a newer Recharge model, have you tried using the one pedal drive? In the setting page, you have to deactivate the 'Creep' mode and have B selected on the gearbox. With these engaged, you can do pretty much all of your driving without ever touching the brake pedal. Its odd (very odd) to get used to it to start with but once you do, its really good. I only use 1 pedal drive now and it feels really odd when getting into our other car that you have to use the brake pedal.

[sk546]

Originally Posted by pjm84

I have a 3 litre petrol PHEV SUV that weighs in at 2.5tonnes. I've yet to get below 30mpg with a flat battery even with spirited driving. With a flat battery its about 32 (at 80mph) to 37mpg (at 65mph). I'm sure with the right road and conditions I could probably nudge 40mpg.

A less highly strung modern 3 litre 6 cylinder is always going to be more economic at pushing a big heavy car along than a highly strung 2 litre 4 cylinder. Its not really comparing apples with apples is it.
If you have the X5 PHEV, its 3 litre output is quite a lot less (both power and torque) than the Volvo 2 litre and if you have the VW group V6 then its similar power but again, less torque.

Engine downsizing dosent always work like it should and I would have been a happier person had Volvo not used the 2 litre 4 cylinder for the Recharge models but it is what it is.
I was close to getting either an X5 45e or a Porsche Cayenne E-Hybrid but neither drove as good as the XC60 PE unless you threw another £20K of options on them (Rear Wheel Steer, Active Anti Roll bars etc) putting their list price's at nearly £90k and neither engine felt as sharp response wise. Saying that, both sounded way better and that alone almost swung me!!

[S90]

6 pots are at the end of their time. More and more manufacturers are killing anything bigger than 4 pot in the scramble for the emission and cost trophy!!

I must say, the engine in my 4 pot v90 sounds a hell of a lot better at full pelt than the last car, almost 6 potish

[pjm84]

And the cost........ Defender was introduced with a 4 pot and its was a no, so not suprised when they ditched the engine and replaced them with a 6 pot.

Yep its the X545e. Didnt realise that VW also had an hybrid option with a 3.0l / 6 pot

Heavier than the T8 and this T8 seems tuned, so I dont think it did too bad, if you look at the comparable numbers and an even start. That said plenty of tuning option for the X545e for 500hp plus (as the 3litre is detuned for longevitiy in hybrid)

https://www.youtube.com/watch?v=sxTBo60_3d8

[sandys]

Here is the old xc90 with small battery being driven with an empty battery and still managing a decent fuel economy, it very much comes down to style and where you drive from the looks of it

https://www.youtube.com/watch?v=Fej1TBTIEOE

[100K+]

Originally Posted by sk546

B mode is selectable in any driving mode and you will only feel the regen effect when you take your foot off the accelerator. When the ICE is running, you will not get instant regen effect like you will when just the electric motor is running, it kicks in a bit more gradually but should be very noticeable when it does.
As you have a newer Recharge model, have you tried using the one pedal drive? In the setting page, you have to deactivate the 'Creep' mode and have B selected on the gearbox. With these engaged, you can do pretty much all of your driving without ever touching the brake pedal. Its odd (very odd) to get used to it to start with but once you do, its really good. I only use 1 pedal drive now and it feels really odd when getting into our other car that you have to use the brake pedal.

I do indeed have newer recharge and I'm pretty sure B mode offers a manual selection of gears. I use this in power mode as this is the only method I can get the ICE to constantly run, without the EM. I have heard about one pedal operation and will give it a try. Thanks for advice.

Cheers Bob

[sk546]

Originally Posted by 100K+

I do indeed have newer recharge and I'm pretty sure B mode offers a manual selection of gears. I use this in power mode as this is the only method I can get the ICE to constantly run, without the EM. I have heard about one pedal operation and will give it a try. Thanks for advice.

Cheers Bob

If you want the ICE to run and not use any battery, use the battery hold option but why you don't want any electrical assistance is beyond me.
Just for info, in power mode, the car deploys both electric and ICE to give the best performance so if you don't want to use any battery charge, you should still select the Battery Hold function but again, I'm unsure why you would want to.

As far as manual selection of the gears go, you can change gears manually at any stage by pushing the gear selector left or right and the current gear selected shows. When in D, the manual selection reverts back to being run by the drive mode pretty quickly. Selecting B holds the manual selection so it doesn't revert back to auto gear shift but B itself does nothing to the software running the auto gear selection logic, as I mentioned before the only thing that does that is the drive mode.
If you want to be able to drive about in auto gear selection but want the car to run a much lower rpm when driving about normally, select Hybrid drive mode and put battery hold on. this will essentially give you a non plug in hybrid car that will do slow speed manoeuvring in electric and kick the ICE in when going any faster than 10-15 mph. The gear change logic also changes gear earlier and holds a higher gear when cruising meaning a lower rpm. You will, however, notice quite a difference in performance and response levels but you should be rewarded by better fuel economy mostly due to the ICE not continuously running when its not needed.

[marky4]

I've just come across this thread a few days ago after buying a T8 just before xmas. I wasn't sure what to expect. This is my 19th Volvo and 4th XC90 with 1 very short lived stop gap Merc 320 coupe. to date. I wasn't sure if it would be the best option but i couldn't be happier with it. The mpg figures i read about in this thread were better than i was getting but i have got to grips with how best to drive it and my short commute to work early morning and back in rush hour leaves me around 8 miles left each night. We have changed our electricity tariff to a cheaper overnight rate and i charge it from 12.15 every night. I run it on pure electric all week and it is proving very economical. This is the best Volvo i have owned over the last 35 years. I use it in hybrid mode at weekends as it isn't viable to use in pure electric on motorways .The only thing i would say is the petrol engine is a bit thirsty , i wish Volvo had made a diesel version of the T8 .Reading some posts on this thread regarding the small engine powering a big heavy car well Volvo Trucks when they were still one company with the car division broke into the British market in 1967 with a 30/32 tonner lorry powered by a 6.7 litre turbocharged engine and it was a huge success and 1 of the reasons the British commercial vehicle manufactuers disappeared. Back to my car and yesterday morning i reset the mpg on the console and the figure coming up is 150 mpg , now i'm not daft enough to believe that figure but that's what it says. Sorry to bore you with my ramblings

[Philip Fisher]

150mpg is the equivalent of infinity. It never goes above 150mpg.

[marky4]

Yeah i noticed that this morning when the engine cut in going up my steep drive , the mpg quickly dropped tp 109 mpg ( i could live with that ) but soon went back up to 150mpg when the electric took over .