[Lorian]

According to a search of our forums, Hypermiling is not a word that exists in the i30 community.

Not any longer!

Our cars are not hybrids, but there are a lot of things that can be of use from the Hypermiling community that can apply to i30 petrols and diesels.

So this thread is NOT to brag about how many MPG or LPK you get, it's to post advice and discussion on techniques that can help to attain these goals.

[Lorian]

So I'll kick off with a few. I know some are obvious  

Parking
Where possible try to park facing downhill, and in spaces where you don't have to reverse in or out.

Driving
Don't brake. Well of course you are going to have to brake, but every time you do you are wasting energy and increasing your fuel consumption. Think ahead, get your foot of the gas sooner.

Slowing down
Remember the fuel pump cut-off. If you don't have a scanguage this is not obvious, but then you are decelerating don't dip the clutch and coast, keep the car in gear because the ECU turns off the fuel pump.

[Mutley]

Parking
Where possible try to park facing downhill, and in spaces where you don't have to reverse in or out.

Why?

[bumpkin]

The petrol i30 can be driven extremely frugally around town.  It is possible to engage 5th gear from 30mph and the car will not shudder even as low as 25mph.  Change gear at 2-2500rpm in town also.

[whitbomb07]

Parking
Where possible try to park facing downhill, and in spaces where you don't have to reverse in or out.

Why?

So you don't have to fang the engine cold.

Not good for the engine, also when the engine's cold the engine uses more fuel.

If your facing down hill you can just coast (in gear) down, get a little bit of warmth and oil pressure up.

Regards

Daniel

[Mutley]

Parking
Where possible try to park facing downhill, and in spaces where you don't have to reverse in or out.

Why?

So you don't have to fang the engine cold.

Not good for the engine, also when the engine's cold the engine uses more fuel.

If your facing down hill you can just coast (in gear) down, get a little bit of warmth and oil pressure up.

Regards

Daniel

Ahhh that makes sense. Thanks!

Btw you shouldn't use 5th gear at such low speeds as it makes the engine work harder.

[bumpkin]

In 5th at 30mph the petrol i30 is quite happily sitting at 1500rpm, not a strain for the motor at all, unless you choose to try and floor it

In 4th gear at 30mph my car shows ~33mpg, in 5th this rises to ~38mpg.

So I'll kick off with a few. I know some are obvious  

Parking
Where possible try to park facing downhill, and in spaces where you don't have to reverse in or out.

Driving
Don't brake. Well of course you are going to have to brake, but every time you do you are wasting energy and increasing your fuel consumption. Think ahead, get your foot of the gas sooner.

Slowing down
Remember the fuel pump cut-off. If you don't have a scanguage this is not obvious, but then you are decelerating don't dip the clutch and coast, keep the car in gear because the ECU turns off the fuel pump.

Hey, great topic! Expect a lot of differing opinions...

I'll take exception to the idea that coasting (on the overrun) in gear is better than in neutral. Your point called: "Slowing down".

You need to consider whether the "engine braking" uses more energy than that saved from the zero fuel injection. I just love to coast down long hills in the reasonable belief that I'm saving fuel (apart from the quiet exhilaration ).

In practice, you need to evaluate (as best you can) which is the preferred way to progress WRT economy.

Given a very long descent I often observe a reduction of 0.1 l/100k before the bottom of the hill. I can't say I have repeated the experiment while maintaining 5th (top) gear.

If you really meant just while coasting to the lights. Then I take your point.

[eye30]

The best way to save fuel is ......................... don't turn the engine on 

Ask a mate for a lift

[Dazzler]

Hey Pip,

I get the same .1 improvement on descents maintaing 5th gear...

[Lorian]

Of course when I said decelerating I meant when you need to go slower, If driving down a very long hill it only applies at the bottom unless its steep enough that acceleration due to gravity is higher than the retardation caused by the engine breaking. We have some of those in my part of the world, but not on my regular commutes.

Here's another, I call it floating the throttle. If you are driving along at a constant-ish speed, conciously try varying the thottle. You will find you can often back-off the throttle a mm or two, and not actually go any slower. This is particularly usefull when getting a partial tow* from a larger vehicle in front of you on a motorway (highway,freeway). If you have a good tow the effect can be very noticeable in the fuel economy. A scangauge is SO usefull for seeing this effect.

*I say partial tow as you always need to maintain a safe distance to the vehicle in front of course. In the UK this is generally accepted as being a 2 second gap. I only ever use vehicles I can see through for even a partial tow.

[Dazzler]

All good advice thanks Lorian...

[ch0pst1x]

Slowing down
Remember the fuel pump cut-off. If you don't have a scanguage this is not obvious, but then you are decelerating don't dip the clutch and coast, keep the car in gear because the ECU turns off the fuel pump.

Unfortunately, i'm a noobie cake. As a result, I'm lost confused. This is apply only to slowing down from a hill or does this include slowing down into lights when you got your foot on the brake as well? Sorry, but could you explain this a bit more for me? =/ Sorry!

Slowing down
Remember the fuel pump cut-off. If you don't have a scanguage this is not obvious, but then you are decelerating don't dip the clutch and coast, keep the car in gear because the ECU turns off the fuel pump.

Unfortunately, i'm a noobie cake. As a result, I'm lost confused. This is apply only to slowing down from a hill or does this include slowing down into lights when you got your foot on the brake as well? Sorry, but could you explain this a bit more for me? =/ Sorry!

This refers to the ECU only feeding fuel to the engine when it requires it either to maintain idle or of course, when driving with accelerator pressed.

Whenever the car's motion is "pushing" the engine, no fuel will be used. This will occur when you fully release the accelerator whilst the car is in motion. No matter whether you are braking or not.

This will not occur when the car is in neutral (whether coasting or not) because it will then be idling.

[VatTas]

I wonder what is more efficient - driving in, e.g., 5th gear at ~1500rpm, or 4th gear at ~1900rpm (same speed).
In theory there shouldn't be any difference for fuel consumption, since in both cases you are moving the same mass having same overall resistance at the same speed.
But it's only when we do not take into account at what RPM engine is most effective.
If we are talking about 1.6 CRDI, I think that max torque is at ~1900. So it appears that it should be better to keep RPM close to this number (i.e. drive in 4th gear). But almost every "eco-driving" advice says "change gears as soon as possible". So I wonder if it's good advise...

[Lorian]

I'd say change gear as soon as the revs are high enough that when you have changed up you still have 1500rpm. That way you don't bog down.

When chaging down its most efficent to do so sufficiently soon for the FCO to kick in.

6th is more efficient in practice, but only just, there isn't really a lot in it. I can easily* drive on the motorway in 5th and get really good mileage, and I don't drive slowly.


*After 20 years of driving a 5 speed sometimes I still forget to change up 

I wonder what is more efficient - driving in, e.g., 5th gear at ~1500rpm, or 4th gear at ~1900rpm (same speed).
In theory there shouldn't be any difference for fuel consumption, since in both cases you are moving the same mass having same overall resistance at the same speed.
But it's only when we do not take into account at what RPM engine is most effective.
If we are talking about 1.6 CRDI, I think that max torque is at ~1900. So it appears that it should be better to keep RPM close to this number (i.e. drive in 4th gear). But almost every "eco-driving" advice says "change gears as soon as possible". So I wonder if it's good advise...

The RPM where the engine is most efficient will be masked by the turbo in the CRDi. You are correct that greatest efficiency occurs at max torque RPM but the "native" figure is being modified substantially by the feedback. So is the greatest efficiency at the final (system) max torque RPM or the original inherent figure?

That point aside, I suspect it is of lesser importance than your second point recommending running with the lowest revs (highest gear) for any given speed. Consider an extreme example of just how much extra accellerator, and therefore fuel, you need to rev the engine to say 4000RPM compared to idling, when the car is at a standstill. If this was not a consideration then most cars would not benefit from a 5th/6th gear because they usually can reach maximum speed in 4th anyway.

Lorian's advice to maintain the lower RPM at about 1500 when accellerating gently through the gears is sensible. This generally puts the change points between 2000 and 2500.

[VatTas]

Thats' what I usually do - let RPM climb to 2000-2500 then change gear.

Also, one more point - if you drive at low speed (e.g. 20km/h), overall resistance is rather small and there is very little difference in fuel consumption if you keep RPM at 1500 or at 2000 (not much power is required to move the car). But things change when speed goes up, as air resistance is function of speed v³. Much more power is required to move the car, so RPM starts to play bigger role - it becomes more efficient to drive at max torque RPM than below (i.e. you will consume more fuel driving 60km/h at 1500 than at 2000). With more gears it is easier to keep engine RPM in the optimal range, that's why 6-gear box is more fuel-efficient than 5.

[Surferdude]

For better fuel consumption, be careful where, when, how you use the Cruise Control.
CC doesn't think ahead for hills so it doddles along happily until the car starts to loose speed on the uphill and then slams down a gear or two in a mad dash to maintain the set speed.
I also suspect that the constant minor adjustments it makes on a straight flat road to maintain the speed would be causing throttle variances which would add to consumption.
I believe that a careful, forward thinking driver can operate much more fuel efficiently than a Cruise Control.

Having said all that, I am often happy to sacrifice any fuel saving for the benefits in staying under the speed limit and being able to devote my concentration to other things (like the idiots around me in the traffic and the road conditions).

Thats' what I usually do - let RPM climb to 2000-2500 then change gear.

Also, one more point - if you drive at low speed (e.g. 20km/h), overall resistance is rather small and there is very little difference in fuel consumption if you keep RPM at 1500 or at 2000 (not much power is required to move the car). But things change when speed goes up, as air resistance is function of speed v³. Much more power is required to move the car...

I think more correctly air-resistance varies with the square of the velocity, not cube. It is the power required to overcome that resistance that varies with the cube. So while air-resistance increases 4 times for a doubling of velocity, the power used increases 8 times. Why the power increase is double the air-resistance increase is because we will be covering the ground in half the time. Time is always in the power formula because power is the rate of doing work.

Not sure if I put that well but the bottom line is: If you double your cruising speed you use eight times the fuel all else being equal. Which does correspond to your V³ above.

Any physics teachers here? Feel free...

[VatTas]

I think more correctly air-resistance varies with the square of the velocity, not cube.

Of course you are right. I was looking at the power equation, when I wrote this. Should be rephrased a little bit.

[agentr31]

lol we have uber fuel efficent cars... i think we are doing enough!

lol we have uber fuel efficent cars... i think we are doing enough!

I remember thinking that in the 1960s when I was getting close to 30MPG out of a 1.6 litre Fiat!!

I'm glad we didn't stop there.

[diablo]

lol we have uber fuel efficent cars... i think we are doing enough!

My 1.4 petrol does a massive 31 around town, about the same as the cars I had 30 years ago.

My tip is not to slow down for bends.  8) Though it does wear out the tyres a bit.

[agentr31]

lol you guys would have cried if you had my old car... roughly to a tank i was getting 600km and it had a 100L tank in it... just before it went to the wreckers it was playing up, and i was getting 20L/100km it was terrible! especially parting with the $130 to fill it

[Edition]

Heres a question for you, when sitting in traffic, is it bad to just use the clutch to move along slowly? Does this put a lot of strain on the engine?

(Talking about the crdi here  )

[Shambles]

^-- that's what I do when needed, Eddy

Not sure whether anything is strained because of it tho

[Lorian]

If you are slipping the clutch then it will be (slowly) wearing. In traffic I quite often drive using the anti-stall only to accelerate in 1st or 2nd gears (even 3rd/4th), and no clutch, where possible.

You have to watch out the i30's CRDi's torque doesn't give the car in front a kiss, it can be a suprising surge on the anti-stall sometimes.

[Edition]

Yes I have noticed that Lorian, its a very powerful anti-stall! Did I read somewhere that you can get the garage to turn it off? (Not that I want to at the moment)

[Lorian]

I don't believe it can be turned off. You get used to it