Being that i've taken quite a few long motorway journeys in the last few months, Liverpool, Wales, Derby, Manchester, Northampton etc. I was wondering on a 1.6 petrol engine where the 'sweet spot' was for the best MPG returns is. As cruising at 70 doesnt give the best desired results, though having just had a recent trip to Derby along the A38 (which is pretty much straight and flat), i believe it maybe around the 60 mph mark. Giving good journey time and decent economy. Admittedly the CN+ Trip computer states 41.8 mpg, on occassion 42, though rarely seen above that. However having just browsed the forum, i stumbled upon the Panda section, which seems to indicate that the on board trip computer is extremely optimistic, and can be out by 2/3 MPG which is worrying.

Also, would i see a significant return in MPG if sitting behind an articulated Lorry on long journeys sitting at around the 60 mark?

Just put your foot down. Do 110 in the right hand lane all the way and youll get there much quicker and use the same amount of petrol as if you ****ed around behind lorries and such. Simple

(This is a joke)




But not really.

pensuke said:

Being that i've taken quite a few long motorway journeys in the last few months, Liverpool, Wales, Derby, Manchester, Northampton etc. I was wondering on a 1.6 petrol engine where the 'sweet spot' was for the best MPG returns is. As cruising at 70 doesnt give the best desired results, though having just had a recent trip to Derby along the A38 (which is pretty much straight and flat), i believe it maybe around the 60 mph mark. Giving good journey time and decent economy. Admittedly the CN+ Trip computer states 41.8 mpg, on occassion 42, though rarely seen above that. However having just browsed the forum, i stumbled upon the Panda section, which seems to indicate that the on board trip computer is extremely optimistic, and can be out by 2/3 MPG which is worrying.

Also, would i see a significant return in MPG if sitting behind an articulated Lorry on long journeys sitting at around the 60 mark?

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Great topic! I have a 1.6 too but I have been driving my sons 1.2 for the past couple of weeks while I raise the cash for a new gearbox for mine. The difference in fuel consumption is HUGE. I dont know if its because my gearbox was dying and that uses more fuel perhaps? I drive the same in both of them.

We have a couple of trips to Wales coming up soon, probably in the 1.2 so any tips for better fuel consumption would be great.

Want good MPG, buy a JTD.

Shadeyman said:

Want good MPG, buy a JTD.

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Have no idea where I am going to find £700 for a gearbox and clutch right now so not an option sadly lol. Besides, I love Petunia and want to keep her

Shadeyman said:

Want good MPG, buy a JTD.

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Well, when i bought my Stilo way back in 06, i wasn't even using my car to commute to and from work, and was more of a weekend/social thing so could not justify the purchase of a JTD (not to mention prices back then were 4-5k+). Since then, my circumstances have changed and i commute and do alot longer journeys and i'm just trying to make the best with what i currently have.

There must be a certain spot whereby it's at its best and returning the best MPG. When i had my Nissan, it was around 56mph, which was nice to know on long journeys or when entering fuel reserves and calculating your next pit stops yadda yadda. Surely this equilibrium between speed and mpg exists?

My 1.8 currently turns about 14 MPG on this wonderful capital we call Bucharest. Streets are crowded from 7am to 8 pm, virtually not going anywhere any time fast.

A trip of about 2.8 miles takes around an hour to complete. Yuppyy I love Romania!

Anyway, I found that on it, the best way to drive on long distances (not that more 200 km of motorways in Romania to start with), but when it does happen, the most economic speed is 65 MPH (105 km/h). If you let it reach its own speed and keep the accelerator steady, it will do 38 MPG (6.1 l/100km) which is kind of the best you every get, unless you want to keep it steady in 5th gear doing 35MPH (55km/h), in which you turn out 41 MPG.

I know people with JTD Stilos that only turn 34 MPG in Bucharest.

pensuke said:

There must be a certain spot whereby it's at its best and returning the best MPG. When i had my Nissan, it was around 56mph, which was nice to know on long journeys or when entering fuel reserves and calculating your next pit stops yadda yadda. Surely this equilibrium between speed and mpg exists?

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It's when the engine is at the revs of peak torque (check in your car manual) and of course in top gear.

You'll get even better mpg at lower speeds still but the journey can get a might bit boring . One absolute rule is ALWAYS climb hills at max torque as that way you'll get the best return from petrol/diesel that you've burnt getting up the hill.


....and going down the other side - don't use your brakes

I do believe it's also down to how much you actually press the accelerator. Torque peak on the 1.8 is 3500 RPM, and if I do that I am going 80ish. Consumption is higher, at least in my case.

vladof said:

I do believe it's also down to how much you actually press the accelerator. Torque peak on the 1.8 is 3500 RPM, and if I do that I am going 80ish. Consumption is higher, at least in my case.

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Yes; but it's still most efficient in terms of distance/time etc.

You will always get better mpg at lower speeds as this is just a reflection of the laws of physics

I agree.

So Argonought, i wouldnt suppose you have that information, in regards to the peak values in 5th, as i was never blessed with a car manual when i purchased my stilo. Also, do these values fluctuate as the car gets lighter due to consumption, weather etc.

Also, i've had a new exhaust put in with a big bore. My dad recons it's running rich due the residue inside the exhaust. If, my car is running rich, i assume that would have a detrimental effect to my MPG even IF im driving economically, is that correct to assume?

doing a few trips to reading from north London in my 1.8 i return 32mpg....doing 90mph on cruise controll.....that is on optimax though....

mzhussein said:

doing a few trips to reading from north London in my 1.8 i return 32mpg....doing 90mph on cruise controll.....that is on optimax though....

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See my car is happy sit at 80mph all day, though on my recent journey to Liverpool, (89 miles from my house) it took more than half a tank, which doesn't seem reasonable from that tank. Don't get me wrong i got there in 1hr 9 mins, which i was impressed with, but the pinch to the pocket wasn't nice.

And i thought premium fuels burnt quicker from my understanding? would perhaps a mixture of premium and regular advisable for better results?

You will burn more fuel if you put regular instead of premium. Premium burns faster thus giving more power for less gas.

Just put your foot down V. All the time, everywhere. Even through towns with lots of small children.

maybe take that statement with a pinch of salt....or some dutch courage lol

You know that did cross my mind, when we spoke about my sons car, and my mechanic seems to be under the impression that the gearbox is the same on the 1.2 as the 1.6 which is why the 1.6 is prone to fail as the engine is too big for the gearbox ( maybe someone here will say otherwise?), so if that is the case, the 1.4 is most likely the same too?

My worry here, and perhaps someone can help, (sorry to go off topic), is that its a big job and a lot of the cost involved is labour so if I show up at my mechanic with a salvage gearbox, and he fits it, am I going to void any warranty for the work? If he supplies and fits then its covered for a year, but if I supply and HE fits where do I stand?

I would love to save some money here and right now its the cost thats preventing me from doing it, but I dont want to end up spending more in a few months? I think perhaps a mod may want to move this to a new thread?


My son was going to lend me the money until he saw some wheels he wanted for his car

Ok I started another thread to see if a 1.4 gearbox will fit my car. I was going to get a recon one anyway but Ill ask my mechanic how much he was going to pay for that and get back to you. Thanks.

Argonought said:

It's when the engine is at the revs of peak torque (check in your car manual) and of course in top gear.

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As i'm another person without the car manual.... have you any idea of what my 1.6 peak torque is??

On topic, I drive weekly up and down england from Kent to the West Midlands.
As i always drive at 80mph it's always giving me 37.9mpg taking the tank of fuel to empty from just over half way.
If i drive at 90mph it depends if im driving north or driving south to whether I save fuel or not. I have experienced driving 85mph burns less fuel than 80mph going up north... coming down south is 80mph all the way as it burns the same if not less than 85mph.

I think my 80mph sits at 3,500rpm and my 90mph sits at 4,000rpm