General Instantaneous Miles per Gallon

[306maxi]

I've bought a gopro just last weekend, if I'm not giving a lift tomorrow I'll take a video of one bit which just isn't good for economy

 

[mixwell]

as always the problem is that your roads and terrain differ to ours, there is a church near me which I could probably hit with a well thrown stone. The church is referenced in the Domesday book. That should give you an idea of what some of the roads around here were designed for *hint - it's not cars*

Would that church be just before the waterfall hill?

 

[306maxi]

Different one, but in the area

 

[UFI]

I've bought a gopro just last weekend, if I'm not giving a lift tomorrow I'll take a video of one bit which just isn't good for economy

Bearing in mind gradients don't show up from onboard video, and I never claimed that a really steep climb followed by an equally steep decent filled with switchbacks would be good for economy.

In you may be able to claim an exemption based on where you live, but modern roads are built to civil engineering standards that limit things like gradients. For much of the newer roads in the world the difference won't be that great.

It's not always about Maxi.

I also tow a light trailer occasionally, and have found no meaningful difference in my economy, believe it or not.

I've actually seen record numbers for a trip towing a fairly heavy trailer (note that I don't claim trailers help economy), but much like hills extra weight is stored as momentum, and used carefully, needn't be detrimental.

also cold weather really doesnt help things out = )

Vs 40 degrees in a car with a matt black crinkle finish roof (the three things you need for maximum sunlight absorption) with no headliner (which transfers all that directly to the interior) which means the A/C is on even on a sunny winter day, and I'd say cold weather/ hot weather basically cancel out.

I accept that cold weather can have a massive effect on economy, but there are hypermilers from all over the world, including the UK beating their official numbers. My main 'competition' is from a fellow in Belgium (neither hot nor flat), he's 39% over and my target :devil:

 

[UFI]

So at any rate, some general notes on economy.

I've personally never found acceleration at BSFC to improve economy (others have), but likewise, I've never seen a deficit either. Consumption being equal, I'd rather go faster than slower, and at least partially appease the tailgaters. Keep in mind today I was at BSFC in my 1.6 Renault and granny in her first gen Subaru Liberty/Legacy was accelerating faster.

I've designed an experiment to test the hypothesis that hills are energy neutral in the real world. If you can design a better experiment then please post it. So far all the other real world experiences are heresay. If you have a genuine interest in economy, by all means re-run my experiment on your own terrain.

I have 2,4,5 and 6 cylinder cars, petrol/diesel, NA/Turbo, tall geared/low geared, FWD/RWD/4x4, sub 1000kg to 2000kg, 0.9l to 4.0l, 0.33 cd to .45, LRR tyres to big fat all terrains. The each have their nuances and the only way to get the best out of them is by experimentation, even if that means using a little fuel in the process

 

[UFI]

What's more/less efficient though? A windmilling engine or an engine out of gear and having to burn fuel to spin itself round?

As JR's alluded to but not quite pointed out, if you need momentum, put it in neutral, if you need to stop or slow, put in in gear and cut that fuel.

 

[ahmett]

As JR's alluded to but not quite pointed out, if you need momentum, put it in neutral, if you need to stop or slow, put in in gear and cut that fuel.

not so easy in a dualogic = )

 

[306maxi]

oh believe me the gradients will show

 

[jrkitching]

As JR's alluded to but not quite pointed out, if you need momentum, put it in neutral, if you need to stop or slow, put in in gear and cut that fuel.

Exactly.

Just be careful not to do anything dangerous - you will not get much sympathy from officialdom if you have a prang whilst coasting in neutral.

That said, if you're pootling along in gear at ecodriving speeds and you do need to get out of the way in a hurry, you're going to have to downshift anyway; if you're already in neutral, you're halfway there .

 

[306maxi]

I've bought a gopro just last weekend, if I'm not giving a lift tomorrow I'll take a video of one bit which just isn't good for economy

If only I'd had it in the car tonight, you'd have seen two horses running down the road in front of me. Been a bonkers week for things happening on my drive home :/

 

[Sweetsixteen]

Old ideas are coming back.
I once owned an elderly Rover that had a free wheel, and it was common for cars of that era to have such a gadget.
I notice - totally off-thread - that automatic rad blinds are also coming back on some new cars.

 

[UFI]

Old ideas are coming back.
I once owned an elderly Rover that had a free wheel, and it was common for cars of that era to have such a gadget.
I notice - totally off-thread - that automatic rad blinds are also coming back on some new cars.

True. Toyota Hybrids don't have a neutral as such, but they have a freewheel mode where the engine is off. A few eco VAG cars have had freewheels put into their automatic drive trains. Bosch is developing a system for manual gearboxes that coasts in neutral and turns the engine off, supposed to be released on the next Golf.

Cooling air intakes used to be completely oversize. While many new cars still have an upper and lower grill, the upper is often there for brand identity alone.

 

[UFI]

Just be careful not to do anything dangerous - you will not get much sympathy from officialdom if you have a prang whilst coasting in neutral.

That said, if you're pootling along in gear at ecodriving speeds and you do need to get out of the way in a hurry, you're going to have to downshift anyway; if you're already in neutral, you're halfway there .

They'd have to somehow prove you were in neutral - and that you weren't just trying to grab another gear.

I can never once remember having to accelerate out of danger. Even if you're overtaking a truck and they decide to move into your lane, the brakes will always get you out of the situation faster.

Basically, the coast in neutral statutes are based on century old thinking, where the engine was required to supplement the friction brakes. The driving test here requires the driver to keep the car in first gear while stationary in traffic at all times. The explanation is that if you're rear ended your foot will slip off the clutch and the car will stall :bang:

But yes, not strictly legal and perhaps not always safe.

 

[UFI]

If only I'd had it in the car tonight, you'd have seen two horses running down the road in front of me. Been a bonkers week for things happening on my drive home :/

If you'd harnessed them, you'd have had two extra hp

 

[jrkitching]

I can never once remember having to accelerate out of danger.

Me neither, and I'm pleased to see this old wives tale being put to bed.

Even if you're overtaking a truck and they decide to move into your lane, the brakes will always get you out of the situation faster.

Absolutely, and if the worst happens, you'll at least be going much more slowly when you crash.

 

[logger]

I can never once remember having to accelerate out of danger. .

Me neither, and I'm pleased to see this old wives tale being put to bed.

Well I'll drag it out of bed.

I accelerated out of danger just last night, to avoid a Kangaroo on a gravel road. It was hopping out in my headlight dazzle from near abeam me. We were on a collision course, with insufficient time for me to stop. Had I done anything else, such as nothing or braked, it would have struck the forward side of the car. Flooring it allowed it to pass behind and I avoided the danger, but it was a close call.

Off Thread, sorry

 

[Sweetsixteen]

Me neither, and I'm pleased to see this old wives tale being put to bed.

Maybe it's time to put this wandering thread to bed also!

 

[Melanabb]

After reading this most riveting thread, I'd be surprised if even one poster turned out to be a woman! Just saying... Now, can we please go back to winter tyres?

 

[306maxi]

You do realise that if you drove more economically then you could afford more shoes and handbags you know

 

[Melanabb]

Now you talk in currency I understand! Still, I'd rather go without usual female fripperies and drive like a man - ... but wait, no- men are all driving like grannies! :doh: What is the world coming to!!