Menu
What's new
By:
Advanced search...

Anyone build an MPH vs MPG graph for the Tourer? (And is 80MPH a terrible speed?)

Yes, I am using the *average* MPG function that is built into the car (a 2007 Honda Accord 2.2Litre Diesel Exec Tourer estate).
Clue: It's on one of the buttoms the stearing wheel - at the bottom when wheel is pointing straight ahead.

I know several people on this thread say that the built in MPG figure is it pretty inaccurate, but it's all I have (other than VERY long term figures using my fuel receipts).

My new working theory is that the MPG at 75-80MPH (on the speedo) is actually WORSE than at c.85 MPH... It certainly feels like it ! This may sound bonkers but there may be some weird aerodynamic effect at play at certain speeds on the Tourer.
At about 68 MPH the MPG is suddenly excellent (I would hope for over 50MPG).

However the trouble is that personally I find it extremely dangerous on the motorways to go this speed because
a) Almost all car want to overtake you AND
B) You still need to overtake all lorries.
And this is a very bad combination! In fact I would argue long and hard that staying in the fast lane, at normal fast lane speeds (albeit with a pretty large gap between you and the car ahead) is actually much safer.

J
 
I wouldn't advise staying in the fast lane to anyone....... cos it's illegal.
 
:lol: Very true. It is for passing only.

There will be no strange aerodynamic effect - maybe a something to do with turbo/fuel/throttle interaction... Remember the road will undulate and have a marked effect. The faster you go, the less you might notice it as momentum will absorb some of the immediate throttle response you need to compensate.

Ship, from what you said about the miles you cover, it shouldn't take long to accumulate a decent sample of MPG figures from receipts.
 
this thread is getting a bit silly....
i will do some research tonight and see what calculations i can do.

the most economical speed on the motorway is probably 40 where the car is near 1.2k rpm.
but obviously thats dangerous, you can sit at 50 mph and that returns amazing economey, but you cant be in a rush and dint mind being overtaken by lorries.

the faster you go, the force / energy required to move the car increases dramatically. 70mph will get better economey than 80, isnt that common sense?
 
I've been thinking about CC / Right foot in regards to mpg for a long time - too long frankly, but MPG is the new performance to me ha ha.

To me the key to great MPG isn't a set speed, but a constant speed.

Every morning I drive the same 13 miles of motorway, and of course the same back. I'm lucky enough to be going against the flow of traffic so it's reasonably free flowing, but not empty.

Like most UK motorways there's virtually no one in lane 1 bar the odd truck, a rag-tag group of half-asleeps in lane 2 following the car ahead and a long queue of people in lane 3 all trying to psuh past the guy in front.

If I set my cruse at 60 sit in lane 1 and only venture into the 'cattle lane' when I've got to pass a truck, it takes me 13 mins to get to work and I get 600 miles from a tank c50mpg, not bad for a big estate! If I let my competitive nature take over and I join lane 3, contstantly braking from 85 to 70, back up again, fighting to not be cut up from people in lane 2 etc - it takes 10 mins to get to work, but I get as low as 35mpg! and I arrive in work stressed and angry.

But when I drove down to Loire in the summer on the virtually empty French Autoroutes I set it at 82mph - 130kph (their limit) could travel 100miles without having to touch the brakes at time and even though we sat in stop-start traffic through Paris (THANK YOU NOT VERY MUCH SAT-NAV!!) we still managed 600 miles, which meant we did the whole trip without having to stop for fuel.

That's my take on it anyway.
 
TheHole said:
after a bit of digging i found this.
http://www.pumaracing.co.uk/TOPSPEED.htm

good link and table that shows you how badly speed effectly your MPG
Click to expand...

Perhaps some people here are missing my point. Yes, clearly the SLOWER you go, the lower the wind-resistance and so the BETTER will be the fuel consumption. No question. And yes, wind resistance goes up non-linearly (i.e. give or take with the square [or even cube] of velocity). And no, I am not claiming to get a greater MPG at 85 compared to say 70-75, it's just that it certainly feels like it ! I am probably getting almost exactly the same MPG at 85 as at 70-75.

I now suspect that something strange is going with the engine running at different speeds. Perhaps the turbo charger is particularly inefficient at certain revs (?)

And so what I am claiming is that something rather surprising happens between the speeds of 70-75 and 85 MPH with means that the MPG does not fall off anything like as fast a rate due to that last 10-15MPH at 85 MPH as one might reasonably expect.

Simply put, the MPG at 65 is remarkably good, the MPG at 70-75MPH is surprisingly poor, and the MPG at 85 MPH is suprisingly good.

J

P.S. Back to my original question, I was wondering if anyone had produced some graph-able data (similar to TheHole's link) but for the 2.2L Diesel Tourer (Accord)
 
You must log in or register to reply here.
Top