Fuel Efficiency EX 2.2 auto diesel, what is the cruising sweet spot?

Discussion in '8th Generation (2008-2015) [Acura TSX]' started by ballisma, Friday 18th Apr, 2014.

  1. ballisma Club Member ★ ☆ ☆ ☆ ☆

    Hi guys
    Enjoying my new EX 2.2 diesel auto
    Just wondering at what speed is the the car is the car most efficient on the motorway?
    Should I set cruise control on 60?65?70?....
  2. FirstHonda Premium Member Club Supporter

    I do 90% of my miles on the motorway (c15k per year) in an EX I-DTEC Auto.

    After 2 years, I reckon 70mph suits it very well if you aren't in too much of a hurry. I get about 45-47 MPG on a run at that speed, although I've moved away from using cruise in the past few months as I can get the economy higher without it, and I like to see the MPG average going up!! Sad I know...

    It is a VERY refined and relaxed motorway cruiser though. An excellent choice :Thumbup:
  3. ballisma Club Member ★ ☆ ☆ ☆ ☆

    Hi FirstHonda,
    Thanks for your reply, I'm glad someone else agrees with my auto gearbox choice and it is achieving high MPGS
    I do 75% motorways and feel great when I see the MPG going up (not sad at all!)
    Coming from a 535d its an improvement but not as much as I imagined
    I seem to get 43 average so far
    The reason I ask is cruising at 60 with my BMW seemed to lower revs and achieve better MPG than 70, being a bigger engine seemed to put less of an effort cruising at that speed
    What do you mean you can get better economy without cruise control? Do you put in manual to achieve lower revs? Would that work?
    I'm very pleased with how refined and composed it is compared to my previous eager BMW
  4. FirstHonda Premium Member Club Supporter

    ^^ Re : cruise control.

    I had always thought using cruise control would optimise economy, but not using it and being careful with acceleration I find works bettter (when I can be bothered). As an example, on sections of the M1, you can coast on downhill sections, then increase speed towards the "bottom" which makes the uphill section easier on the car.

    Using cruise in that sort of situation it has to increase revs to maintain the speed on the uphill stretch. Hope that makes sense?!:Smile:
  5. ballisma Club Member ★ ☆ ☆ ☆ ☆

    Mmmm interesting, I'll give it a go
    Thanks again
  6. Doc Expert Advisor ★ ★ ★ ★ ★

    Matt Peterborough
    Cruise control can't anticipate the road ahead. As mentioned when going down hill you can allow the car to increase speed without depressing the accelerator more, or reduce the acccelerator to maintain the same speed. In cruise control the engine will retard to employ engine braking to maintain the preset speed on the down hill sections. Going up hill you can slowly increase speed on the approach to carry momentum up the hill. In cruise control the car will not anticipate the hill then will have to accelerate to get up the hill once it's already started loosing momentum.
  7. ballisma Club Member ★ ☆ ☆ ☆ ☆

    Thanks Doc, I'm going to trial it for a week
  8. mikey77 Club Member ★ ☆ ☆ ☆ ☆

    I find 120kph (74mph) using adaptive cruise control on French autoroutes - which are rarely very busy - gives 45mpg equivalent and more on a long run. It's an excellent cruiser and the best auto transmission I've ever had, even better than the GM400 in my 6 litre XJS.
    FirstHonda likes this.
  9. FirstHonda Premium Member Club Supporter

    ^^Have to agree about the autobox.

    Have read in the motoring press criticism that it is outdated, and only five speed...but IMHO the ratios are beautifully matched to the engine.

    Isn't it nice when things, just, work? :Smile: