Fuel Consumption In General

[BenIS]

Ok so the other night I was thinking, which uses more fuel, taking it easy and slow but obviously your engine will be running for longer OR going faster so that your engine is running for a shorter period? What do you think?

[noby76]

either way will use fuel. moving a car using a higher gear in low speeds will labour the engine and ecu will chuck in more fuel to compensate. also running a car in higher revs in lower gears for longer will also chuck in fuel. best way to drive any petrol powered car is always use the right gear for the right speed travelling and shift to next gear around 50% of the rev band which in most cases will be 3000 - 3250rpm whilst keeping a steady right foot. too slow on the accelerator and you will be holding up traffic behind you too fast on the accelerator and you be using a bit more fuel than the car needs to move then start to feather the throttle once the desired speed is reached to keep the moving momentum. all petrol powered cars will not run efficiently unless doing between say 60 -70mph in 5th or 6th gear so if your driving does not involve these speeds you will never reach the 29mpg quoted by Lexus for IS200 hence they have the town driving figure of 20mpg so if you are getting anything closer to this figure in town driving I wouldn't complain but if you are getting 10mpg then either the car needs servicing or you drive at 6000rpm everytime in each gear. things which could also make a car run efficiently or closer to its quoted mpg is using good clean oil and right viscocity, clean air filter, recommended spark plugs and good fuel.

[krisby1]

I think smoothness is the key, but I tend to use a mix of high revs and pootling, I'm happy to floor it up to 2nd then plop it into 5th, but I'm defo not a shortshifting **** that changes up at 1500 rpm in every gear, taking 500m to get to 30mph, the way I see it is that the quickest you get to your chosen speed the better, within reason of course, I mean, no point accelerating for 20 seconds, when you can do the same in 5 seconds and then just burble along. Plus, your engine will thank you for it, don't strangle the poor thing, I know my engine feels better now than it did 6 months ago because it gets a daily dose of the 5000s, and often the 6000s too.

Yet I average 27.2 at present, which ain't bad on a V5, and my daily commute into Shepherds Bush involves a fair proportion of stop start traffic.

EDIT: oops, thought I was on the Seatcupra forums, but then the same applies to the IS200 as well, atleast the way I drive it, not sure the wife is the same. Though I tend to drive slightly different in the IS as well, 1st gear is too short, and the clunk into 2nd more pronounced at high revs. Not sure what averaging in mpg at the moment as only had it 3 weeks, but I think about 26 if my maths is correct. I tend not to race it the same way from lights as my V5 as it makes a lot of noise for not much speed.

[BenIS]

haha I was gonna say a V5 IS200 never heard of one of them before!

[richardghia]

I heard 56mph was the optimum speed to travel the furthest on a set amount of fuel.

[ColinBarber]

I heard 56mph was the optimum speed to travel the furthest on a set amount of fuel.

a myth. It is just a figure used for economy testing. The most economical speed is different for every vehicle and dependant on gearing, engine mapping, cams etc.

However as a basic concept, slower is better. The power required to overcome wind resistance isn't linear so you waste more fuel the faster you go.

[peter97]

intresting points there guys! thanks.

[sjrainsford]

I've always found with my cars that it's a case of finding the cruising speed that the car 'likes' most. Normally the one that seems to require the least pedal pressure to achieve good pace.

My Prius was odd though as it had two. It would be really good at around 60mph. But at 90mph it was hardly any different to sitting at 70 in terms of fuel consumption. Almost as though it was an effort to hold 70mph.

Just hoping my Auto can average 30mpg on my A road runs when I pick it up and I'll be happy.

[BenIS]

My Prius was odd though as it had two.

A PRUIS! you should be ashamed of yourself lol

[sjrainsford]

My Prius was odd though as it had two.

A PRUIS! you should be ashamed of yourself lol

Hah! I loved it. One of the best cars I've ever owned. Such a nice day to day motor.

Picking up my IS later today, looking forward to it!

[gsdude]

I get maybe on average 380-400 miles to the tank with mixed city/motorway driving in my IS200 which has improved from the 350-360 I used to get before my full 60k service which was carried out recently. However I have developed a driving style since my first IS200 that I think goes quite easy on the petrol.

Its all about smooth and measured operation of throttle/braking and minimising the change in speed where possible ie anticipating the road ahead and holding a suitable speed to get you there without dancing on the pedals. Using the brakes is also technically wasting energy produced by the engine too so coasting at a steady speed and lifting the throttle in advance before junctions/roundabouts etc works far better than bombing it and then slamming the brakes right before a junction/roundabout etc.

On motorways I find cruising at around 60 seems to return the best mpg, I drove to Wolves and back last weekend and averaged 35mpg driving at roughly this speed.

Saying that though, using a similar driving style I used to get around 600 miles from a tank in my old astra 1.7 (probably the only good thing I experienced with that car!) and correct me if I'm wrong but I believe the IS200 has a larger fuel tank too!

[ridgersIS300]

My Prius was odd though as it had two.

A PRUIS! you should be ashamed of yourself lol

Hah! I loved it. One of the best cars I've ever owned. Such a nice day to day motor.

Picking up my IS later today, looking forward to it!

Agree. A Prius is a very good car. Forget the 'green' image, the technology behind it is amazing! People think Prius owners want to save the world etc but I know a couole that drive them just for the technology alone. I very nearly bought one. I wasn't bothered about mpg, lower emissions etc. I was tempted more by the practicality

[dave1]

Ok so the other night I was thinking, which uses more fuel, taking it easy and slow but obviously your engine will be running for longer OR going faster so that your engine is running for a shorter period? What do you think?

Was it a serious question Ben?

That reminds me of a joke from many many years ago.

A guy was stopped for speeding and gave the excuse that he was low on petrol so HAD to speed to get to the garage before he ran out.

[sjrainsford]

My Prius was odd though as it had two.

A PRUIS! you should be ashamed of yourself lol

Hah! I loved it. One of the best cars I've ever owned. Such a nice day to day motor.

Picking up my IS later today, looking forward to it!

Agree. A Prius is a very good car. Forget the 'green' image, the technology behind it is amazing! People think Prius owners want to save the world etc but I know a couole that drive them just for the technology alone. I very nearly bought one. I wasn't bothered about mpg, lower emissions etc. I was tempted more by the practicality

Exactly! I bought mine because I loved the technology. It was also quite practical, comfy and would never drop below 50mpg. Brakes last about 70k miles and services are fixed at Yaris prices. Cheap to run!

[noby76]

Exactly! I bought mine because I loved the technology. It was also quite practical, comfy and would never drop below 50mpg. Brakes last about 70k miles and services are fixed at Yaris prices. Cheap to run!

But wont stir the soul like an IS

[sjrainsford]

That's true. Only driven my IS a couple of times, and I really like it. Ok it's an Auto so not the enthusiasts type, but It cruises so nice at 80mph!

[ridgersIS300]

Exactly! I bought mine because I loved the technology. It was also quite practical, comfy and would never drop below 50mpg. Brakes last about 70k miles and services are fixed at Yaris prices. Cheap to run!

But wont stir the soul like an IS

Amen maverick

[BenIS]

Ok so the other night I was thinking, which uses more fuel, taking it easy and slow but obviously your engine will be running for longer OR going faster so that your engine is running for a shorter period? What do you think?

Was it a serious question Ben?

That reminds me of a joke from many many years ago.

A guy was stopped for speeding and gave the excuse that he was low on petrol so HAD to speed to get to the garage before he ran out.

Deadly serious lol I didnt get caught speeding haha! I only thought of it because there is a stretch if road on the A610 near where I live that is a 40 then 50 mph limit. 50% of drivers stick to it, yet the other 50% tank down it at 70+. It just got me thinking thats all.