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

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ship69

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Hi

I had a weird experience driving about 40 miles on the motorway today. After driving about 10 miles to warm up the engine I reset the computer to zero. I then found that driving at a constant 80 MPH (on the speedo) (using Cruise Contro) my Honda Accord Tourer (2007 i-CDTi 2.2L Ex Estate) claimed to be delivering a mere 42 MPG, over c.10 miles.

Thoroughly depressed not to say alarmed, I then slowed down to 70 MPH and I found after about 15 miles it seemed to have been delivering 54 MPG - i.e. 10 MPG more!

Now, anything over 50 MPG is fine by me and in any case 70MPH is dangerously slow(!) IMHO for motorway driving, so I sped up to 75MPH and it stayed at about 51 to 21 MPG. Then I thought well, maybe the engine needed all that time to warm up and I took it up to 80 MPH... I ran out of road before I could get a meaningful reading (plus the road wasnt flat enough) but the MPG certainly did appear to plummetted again. The strange thing is that when I occassionally driver "seriously" fast say 85-90, the MPG is normally about 42-44 MPG in any case.

I am now wondering if 80 MPH a *terrible* speed to drive a Tourer at ! Some weird aerodynamic black hole at that speed?? And could it be that I get *more* MPG by going at say 85MPH than by going at 80MPH??

Have any if you built a graph of MPH versus MPG for the Tourer?

J
 
My Tourer 2.0 has the worst gearing I could imagine for cruising. It's revving it's nuts off (4K ish) at just under 80mph which isn;t good at all. Need a 6th gear.
 
wouldnt have thought this was a very sensible place to post about breaking the speed limit dude...as for the fuel,sounds about right,although it would probably level off a bit if you covered a larger distance.
 
Of course you were doing all this on a private test track John ;)

I've said before, I'll say it again.. 1900RPM is the magic number on the Accord's (mapped or otherwise) for optimum speed/efficiency. On a 6 speed facelift, that should give you around 70mph.

On the 5 speed pre facelift cars its closer to 65mph - but seriously it makes all the difference to economy.
 
accordster said:
wouldnt have thought this was a very sensible place to post about breaking the speed limit dude...
Click to expand...

Technically you are correct BUT:

1. My speedo is exaggerates wildly according to my TomTom
2. Almost *everyone* on the motorway breaks the speed limit.
3. The police dont seem to bother if you are going less than about 85MPH
4. I am a pragmatist. And sometimes the law is an ***. Going (a bit) fast in itself is not necessarily dangerous. What is dangerous are other things such as:
   a. Driving too close to the car in front (almost every driver on the roads)
   b. Not spotting what is about to happen (e.g. the car ahead will need to pull out when it gets to that 60MPH lorry)
   c. Being half asleep because your driving is too dull
5. I always make sure there is some other sucker driving faster than me (to dimminish my chances of being the one they stop)
6. When the fuzz hammer on my door I shall say I was making it up.
7. In any case, I was talking about my recent trip to Germany where is no speed limit on the motorway. [ahem]
8. I'm not using my real name on this forum

J
 
F6HAD said:
On a 6 speed facelift, that should give you around 70mph.
Click to expand...

In 6th gear on mine it says about 69 MPH on the speedo - although the Sat Nav says less (I'll need to check - I'm guessing 66 or 67 MPH [?])

J
 
Not exactly a wild exaggeration though is it Mr Smith ?

You don't seem to like your car very much at the moment?
 
Wish i could get 40+ mpg :lol: :lol: :lol: :lol:
 
1900 RPM is the golden ticket. Stay in that region as much as possible and see how slowly the fuel gauge moves. i've learned this simply through trial and error, but basically I find cruising anywhere between 50 and 65mph in 6th gear (pre facelift 2.4 manual) and the car is happy as larry. I've no desire to push it to 70 or over. The only time I do motorway driving I have the family in the car, and frankly that's when it comes into it's own. Sit in the slow or middle lane (traffic depending) at 60-65mph with cruise control, get great fuel economy, the car's quiet and smooth and I can have silly conversations with my 2 year old son about the trucks we're driving past and Peppa Pig and other silly nonsense. Happy times, and 400+ miles from a tank in 2.4 ltr. Quite sophisticated for a modestly priced car of it's ilk.

:)
 
Peppa Pig and other silly nonsense
Click to expand...

You need an iPod adapter and start teaching them some proper tunes matey :lol: Mine requests all-sorts of bizarre stuff... X-Japan, Rammstein and Kate Ryan are his favourites. Must be the water round 'ere.
 
on my last tank (even in the cooler conditions) i managed to adverage 52.3mpg :D i would say thats with 60%town driving and 40% motorway.

yes i was driving like a granny :ph34r:
 
> Not exactly a wild exaggeration though is it Mr Smith ?
Which bit - the MPG?

> You don't seem to like your car very much at the moment?
I ought to hate my car being as it has cost me SO much money already. I mentally I am looking it as part of the purchase costs, and am planning to drive the car into the ground over the next 100K miles or so. Nonetheless perhaps irrationally I do still quite like my car. It's a fairly comfortable ride on motorways (where I am spending a lot of time), MPG is reasonable, cornering is OK... all-in-all not bad. The most irritating thing at present is trying to make out-bound phone calls using the bluetooth to connect to the HFT - which is proving very, VERY flakey when dialing from the phone. So although I am starting to lose patience I do still quite like my car. (But ask me again in 1 months-1 year... when we'll start to find out just how reliable these Accords REALLY are!)
 
Dan Robinson said:
You need an iPod adapter
Click to expand...

Can you tell us any more about this? Is this an expensive item & how does it work?

I have a 2007 Honda Accord Tourer Ex with Sat Nav and HFT. I was told that I would need to spend something insane like £200 just to get my iPod to connect directly to the radio (which isnt all that good in any case) so probably not worth it.

I am currently using a:
"Belkin TuneBase FM with Handsfree In-car Mobile Phone/Digital Player Charger and Holder"
http://www.amazon.co.uk/Belkin-TuneBase-Handsfree-Digital-Charger/dp/B0048JTTII/ref=sr_1_cc_2?s=automotive&ie=UTF8&qid=1324639897&sr=1-2-catcorr

It works and is definitely better than nothing... but I dont like it.
There is quite a lot of radio interference - particularly from local radio stations and as you drive around the country they change, and this require you to find yet another FM radio frequency to use... :[

J

P.S. Back to my original question - surely someone somewhere has built an MPH vs MPG graph for a Diesel Accord Tourer, no?
 
well ive just bought an ice device which is a portable hands free kit which plugs into the lighter socket and also plays your music through the speakers and i can honestly say its brill no interference from radio £17 from Groupon
 
Have a look for the xcarlink bud..... easy DIY, will be a lot less than £200 :D
 
rhinogolf said:
well ive just bought an ice device which is a portable hands free kit which plugs into the lighter socket and also plays your music through the speakers and i can honestly say its brill no interference from radio £17 from Groupon
Click to expand...

The Ice Device (from Bluetooth World) looks quite interesting.
However it's not clear how it really work in practice.
- Is there any dock for you iPhone so that you can see the iPod whilst driving (e.g. when making an outbound phone call)?
- How useful is the remote in practice (particularly if you cant remember someone's full phone number...)?


Yes, xcarlink looks slightly promising - does it allow you to connect to the HFT? Either way I think I'll need to wait until I have more money in the bank for all this. (My long term plan would be to completely replace the (crappy) SatNav and perhaps put a better Radio in and put decent speakers in too... but God alone knows what all that would cost! And I would need to put a bit more sound-proofing in to make it worth it. £££ ! )

J
 
Back to the original question(s):
A) HAS anyone build an MPH vs MPG graph (for the Tourer) ?

B) And is 80MPH a terrible speed?

I am concerned about the impact of weather (esp even gentle wind) but so far I am finding I get about about 45MPG at 80 (on the speedo) and about 49-50MPG at 75.
i.e. 4 or 5 extra MPG for an going 5MPH slower.
The strange thing is that going at 90 does seem to be much worse than 80. Hence my original questions... (!)

(I have to be careful with these ***ertions as they are only the fruit of fairly short tests... but I would be interested to know if others were finding similar things.)

J
 
The resistance caused by wind and the air you're pushing through will not increase at a linear rate.

Also the obc is not accurate.

Incline is also impossible to control.


You will need constant states of too many variables to make a graph work I'm afraid.
 
Dan Robinson said:
You will need constant states of too many variables to make a graph work I'm afraid.
Click to expand...
Or otherwise LOTS of data all from different sources.
If everyone on here got their MPG figure over at least 10 mins at a set cruise control speed - we could put them all in a spreadsheet and plot the results - some would no doubt be out but the average of 50 x MPG figures at 65MPH would be relatively accurate.
 
Is it better on fuel doing 70 by your foot or by cruise control? Good tip about the 2k revs. Im really heavy footed and get 280 miles to a tank of 70quid
 
There's debate. It depends how you drive I think. If you're very smooth and don't mind slowing down uphill and speeding up downhill then you save fuel on the foot. Basic principle is to keep your throttle pedal in exactly the same place at all times - cruise control definitely doesn't do this!
 
True, but it doesn't use the brake and does fine tune the fuel very accurately. For those of is on relatively flat areas its great.
 
Hate to be so new and point out something not right. Ive an 03 6 speed 2.4 type-s. Fahad mentioned that 19k revs is optimal and is69mph. But it just 48 mph. And 70mph in 6th is 2600 .
 
> Or otherwise LOTS of data all from different sources.
Such as where?
I did try Google I couldn't find any directly relevant graphs.

> If everyone on here got their MPG figure over at least 10 mins at a set cruise control speed -
> we could put them all in a spreadsheet and plot the results - some would no doubt be out
> but the average of 50 x MPG figures at 65MPH would be relatively accurate.

Although I would be interested to see the numbers, in my experience even a very slight, barely perceptible incline seems to make a HUGE difference according to the MPG machine in the car (which I understand cant be trusted, but which nonetheless is all that I have).

Likewise even a 5 or 10 MPH headwind makes a massive difference (perhaps as much as 5 MPG?)
The headwind makes MPG results even over very long journeys somewhat unreliable.

Nonetheless, personally I do almost all my miles at pretty much steady speed on motorways, so over say 200 - 1000 miles the numbers would start to become statistically very significant.
e.g. I suppose I could try driving at one target speed for one month and a different target speed for another month and then see what the difference in MPG is.
(I would need to find a way of ignoring those times when I was in a tearing hurry though!)

J
 
how are you lot getting your mpg figures?
is there a function on the car? and if there is an average mpg screen, how on earth do i get that up?
 
John, are you talking about the real time bar doo dah or the avg MPG screen?

The only thing I can think of is that you use software such as Proscan, and an obd reader and use the fuel flow readings and try and log them in relation to speed.

I am struggling somewhat with the need for all this when surely keeping a log based on fuel receipts would be more useful.

Just keep the car under 2k revs if you're concerned about economy.?

How is your wind proofing going?
 
Dont forget the Physics behind this lot guys.

la_te_xi_t_1_24.jpg

In that model:

A is the cross sectional area of the car.
ρ is the density of the air.
C is the drag coefficient that depends on the shape of the car.
v is theVelocity of the car

in the equation you can see velocity is actually squared, so the change in your cars speed has a squared effect to the energy needed to move the car forwards.
 
Big difference every 1mph then really. Is there a mpg function in the accord?
 
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