RobinJI
Posted a lot
"Driven by the irony that only being shackled to the road could ever I be free"
Posts: 2,995
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Apr 23, 2012 19:36:51 GMT
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golf balls and cars arn't the same thing so it doesn't naturally hold to be true that what applies to one does to another..... ....What matters is how fuel is metered and theres a whole pile of sciencey stuff I won't pretend to understand well enough to explain which says heat, barometric pressure and altitude are not going to affect the actual fuel dispensation or use.... I was always under the impression that the dimples in golf balls were to aid stability, not range. If it worked at reducing wind resistance then the aerospace and motorsport industries would have cottoned on a long time ago. As for the second part, there's theory behind it, but it's a little simplistic. In theory, the calorific value of fuel will never change, so the amount of it used to generate a set amount of energy/power will always be the same. However the engines ability to release that energy from the fuel, and then convert it into movement will definitely be changed by external factors as its efficiency's effected.
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Last Edit: Apr 23, 2012 19:38:46 GMT by RobinJI
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Raoul Duke
Part of things
Posts: 990
Club RR Member Number: 117
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Apr 23, 2012 19:42:42 GMT
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The fuel tank on mine is black plastic, and if the sun's on the side of the vehicle, it's shone on right through the rear wheel arch. It gets too hot to touch, and is a sealed system. It emits a fair PFSSSSSSssssss if I crack it open during the day too. But, I'll hush now Well, clearly a sun-baked tank is an issue that'll never concern anyone in the UK anyway
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...a redder shade of neck on a whiter shade of trash...
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Apr 23, 2012 19:55:58 GMT
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Staying in too high of a gear makes quite a differenced in my dads Mondeo. Ive been driving it to work the last 3 weeks and its a 6 speed diesel, so i found myself sticking it in 6th when i hit 50-60 on the journey. Its all A-B roads, bendy and a hilly, so even though i was keeping it at, say, 200 revs lower, i was using a little more throttle for the same pace i would have kept in 5th. This week however i've kept it in 4th,5th on the drive and noticed around 5-10mpg increase in economy and a quieter car basicly, higher revs and a 1/4 throttle was cheaper than lower revs and 1/2 throttle on my drive Hope that helps and makes sense!
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Too many projects, not enough time.
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RobinJI
Posted a lot
"Driven by the irony that only being shackled to the road could ever I be free"
Posts: 2,995
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Apr 23, 2012 19:57:14 GMT
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If you do this, you can get quite good economy - but you need to stay very alert. I've had an average of 72mpg from a dirty, badly maintained Multipla with a boot full of junk (and that is an average, my car is too old to have an instantaneous read out.) I've got a friend who's got a dodgy theory about this. haha. It makes sense, but there's no way I'd condone it. Basically, his theory was that if you stayed 20 feet away from the back of a truck at 56, and they slam their brakes on, they'll slow down a fair bit, you wont react, and you'll slam into the back of it and nuns and kittens will cry. However if you stay 6 inches away from the back of the truck, and they slam their brakes on, then you'll hit it with virtually no speed difference, and you'll just be pushed to a halt with no real impact. It's also a lot more effective slipstreaming from stupidly close than from any distance. It does work for your mpg, and he managed over 1100 miles from a 62 litre tank in his 1.6 8v petrol A4 estate. That's at least 80mpg from a 1.6 petrol estate! As I said though, there's no way I could recommend it, even though it makes sense I'm pretty sure it'd take about 2 miles before you were pulled over!
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Raoul Duke
Part of things
Posts: 990
Club RR Member Number: 117
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Apr 23, 2012 20:38:28 GMT
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If you do this, you can get quite good economy - but you need to stay very alert. I've had an average of 72mpg from a dirty, badly maintained Multipla with a boot full of junk (and that is an average, my car is too old to have an instantaneous read out.) I've got a friend who's got a dodgy theory about this. haha. It makes sense, but there's no way I'd condone it. Basically, his theory was that if you stayed 20 feet away from the back of a truck at 56, and they slam their brakes on, they'll slow down a fair bit, you wont react, and you'll slam into the back of it and nuns and kittens will cry. However if you stay 6 inches away from the back of the truck, and they slam their brakes on, then you'll hit it with virtually no speed difference, and you'll just be pushed to a halt with no real impact. It's also a lot more effective slipstreaming from stupidly close than from any distance. It does work for your mpg, and he managed over 1100 miles from a 62 litre tank in his 1.6 8v petrol A4 estate. That's at least 80mpg from a 1.6 petrol estate! As I said though, there's no way I could recommend it, even though it makes sense I'm pretty sure it'd take about 2 miles before you were pulled over! How about if you actually drive with your bumper nudging the back of the truck? If it's big enough they won't even feel it, and there'll be no speed difference at all. You could even attach lumps of sponge/rubber to your front bumper before setting out, to further reduce the risk? ;D
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...a redder shade of neck on a whiter shade of trash...
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Apr 23, 2012 20:42:45 GMT
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basicly, higher revs and a 1/4 throttle was cheaper than lower revs and 1/2 throttle on my drive Depends entirely on the engine and the gearing. I suspect that the turbo was much less effective in 6th, so the engine's overall compression ratio - and thus efficiency - were much lower. I know that the engine in my car is more efficient at 5000 rpm (75mph) than 4000 (60) - but the increased aerodynamic drag more than compensates for that. With the same engine in a slippery shell, it might end up being more economical to travel at 75... A couple of hypermiling tricks are to over-inflate your tyres (not recommended as it will change the levels of grip - but it will reduce the rolling resistance) and to put tape over all the panel gaps on the car...
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Apr 23, 2012 20:43:49 GMT
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How about if you actually drive with your bumper nudging the back of the truck? If it's big enough they won't even feel it, and there'll be no speed difference at all. You could even attach lumps of sponge/rubber to your front bumper before setting out, to further reduce the risk? ;D Ah, but if you're touching it you're applying a force - which is being produced by the fuel in your tank.
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Apr 23, 2012 20:52:20 GMT
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Hit the nail on the head jrevillug!
In 5th I'm sat at where the boost is just about to come on most of the time, in 6th I'm below so have to push the engine!
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Too many projects, not enough time.
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OVY871
Part of things
Owner of Austin A35 Saloon
Posts: 321
Club RR Member Number: 66
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Apr 23, 2012 20:54:40 GMT
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How about if you actually drive with your bumper nudging the back of the truck? If it's big enough they won't even feel it, and there'll be no speed difference at all. You could even attach lumps of sponge/rubber to your front bumper before setting out, to further reduce the risk? ;D Ah, but if you're touching it you're applying a force - which is being produced by the fuel in your tank. Stick a remote operated hook that attatched your car to the rear bumper of the truck, turn the engine off and cruise for miles using none of your own fuel Real tips from me though are just to take everything smooth and then if you don't need stuff like air con on, don't have it on, same with heated seats, I'm guessing its also stupid having the two sides of a car at different temperatures with these dual zone climate control cars, really can't imagine that going well. I will add to this once I have my car on the road and see what I can get MPG wise.
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Dez
Club Retro Rides Member
And I won't sit down. And I won't shut up. And most of all I will not grow up.
Posts: 11,712
Club RR Member Number: 34
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Apr 23, 2012 21:02:06 GMT
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this is all very interesting reading, but I cant be the only one who goes out on a journey with the best intentions of driving frugally, and then ends up sat at 85mph in the outside lane as usual, cos I get bored of going to slowly or annoyed at getting cut up/boxed in/disregarded by other road users, especially lorries. and its not just in the dailies, even in cars I know I shouldnt be thrashing, I still end up creeping faster and faster! if i could find a way around this id be sorted tbh though, according to the mfa in my passat, and the amount of fuel it uses for set trips, theres pretty much no difference in economy between 70 and 85mph.
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Last Edit: Apr 23, 2012 21:03:53 GMT by Dez
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VIP
South East
Posts: 8,293
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Apr 23, 2012 21:08:06 GMT
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If you need to go faster, get behind a National Express coach as they don't seem to be limited to 56mph. Coaches aren't subject to a 56mph limit. Not legally anyway.
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Apr 23, 2012 21:08:52 GMT
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WHS^. I like the idea of saving fuel by accelerating smoothly and easing off and slowing down early, but then I get stuck behind a Hyundai Atoz doing 45mph and I have to overtake it, and then seeing as I'm going faster I might as well stick to that speed, and it is quite good fun, and it does make my car go "bbbbbbbwwwwaaaaAAAAARRRRP", especially that time when my back box had fallen off, and then...
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1989 Peugeot 205. You know, the one that was parked in a ditch on the campsite at RRG'17... the glass is always full. but the ratio of air to water may vary.
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Apr 23, 2012 21:12:28 GMT
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this is all very interesting reading, but I cant be the only one who goes out on a journey with the best intentions of driving frugally, and then ends up sat at 85mph in the outside lane as usual, cos I get bored of going to slowly or annoyed at getting cut up/boxed in/disregarded by other road users, especially lorries. and its not just in the dailies, even in cars I know I shouldnt be thrashing, I still end up creeping faster and faster! if I could find a way around this id be sorted You're not the only one here that does that. Ok, so I end up at 70-75 in the Imp (with very occasional 80-85 excursions to the outside lane) , as it's not too happy above 80, but yes I do the same.
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Dez
Club Retro Rides Member
And I won't sit down. And I won't shut up. And most of all I will not grow up.
Posts: 11,712
Club RR Member Number: 34
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Apr 23, 2012 21:13:46 GMT
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WHS^. I like the idea of saving fuel by accelerating smoothly and easing off and slowing down early, but then I get stuck behind a Hyundai Atoz doing 45mph and I have to overtake it, and then seeing as I'm going faster I might as well stick to that speed, and it is quite good fun, and it does make my car go "bbbbbbbwwwwaaaaAAAAARRRRP", especially that time when my back box had fallen off, and then... .....and then, cos its got coilovers, wide rims and low pro tyres, theres no body roll so no need to slow down much at all for corners, slip roads, or clear roundabouts. in fact, its becomes a challenge to see if itll do it at 70 this time rather than 60...... with more bwaaaarp(And maybe a touch of skreeeeeek too)......
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RobinJI
Posted a lot
"Driven by the irony that only being shackled to the road could ever I be free"
Posts: 2,995
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Apr 23, 2012 21:21:25 GMT
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Yep Dez, I do exactly the same. I've had every intention to see what mpg the Passat can give driven carefully since the day I bought it, but it's taken until a couple of weeks ago to actually manage to go a whole tank without getting bored, and that was mostly because of being stuck on congested dual carriageways where it's less stressful sitting in the left at 65/70 being overtaken than sitting in the right with a range-rovers HID's 3" from your bumper.
Stick me on the motorway though and I find it incredibly hard to do less than 80, just because like you say, you're constantly boxed in and treated like excrement by people, so you're always watching your back, if you speed up to a few mph faster than most other cars on the road then it's much easier to watch your back as people aren't always trying to push past you. I still get 47mpg even thrashing the arse backside off the Passat, so for the small amount it saves me I don't think I'll be bothered with eco driving again any time soon unless I'm very broke or running low and no where near a petrol station. I still find it interesting though, especially things that help without slowing you down, haha.
(Arrrggg. I'm all for amusing swear filters, but sticking a bloody great picture in the middle of posts for a really not at all offensive word just makes things hard to read.)
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Last Edit: Apr 23, 2012 21:24:33 GMT by RobinJI
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Seth
South East
MorrisOxford TriumphMirald HillmanMinx BorgwardIsabellaCombi
Posts: 15,513
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Apr 23, 2012 21:26:21 GMT
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Stick a remote operated hook that attatched your car to the rear bumper of the truck, turn the engine off and cruise for miles using none of your own fuel The safer alternative to this is to break down and get taken to you destination on the back of an AA/RAC wagon. Not so time efficient though.
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Follow your dreams or you might as well be a vegetable.
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Apr 23, 2012 21:28:13 GMT
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I had a different method of figuring out my fuel economy. As I earned so little and work so far away from where I live my "Pay-to-fuel ratio" was pretty slim. As in so slim I could only just afford to go to work! In my Audi I figured out that if I drove on the motorway UNDER 3k revs then I could afford it. If not I couldn't and the overdraft took the hit. Luckily I drive at very odd times, either very early in the morning or very late at night so I'm rarely in the mood to boot it.
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Well, that's won me over. * abandons logic*
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Apr 23, 2012 21:51:54 GMT
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Where is peak torque on your engine......... That's where you should be for maximum efficiency Oh and most modern stuff has far worse real world economy to meet the ludicrous European drive cycle for emissions...... I could list any number of fairly recent cars that run a regular 9.5:1 AFR under load to keep the cats from melting Need faster warmup from the cat for emissions ? Close couple it on the manifold Run it on the motorway at over 1/2 throttle, huge increase in exhaust gas temp Fuel keeps EGT down, so inject more fuel to keep the cats from melting...... Genius !! Company hits the targets - nice economical figures for the brochures Punter pays the price...... Fiesta st - 2L engine in a small light car Should be great on fuel...... Real world, you will struggle to get mid 30's mpg out of it........ Ludicrous Latest generation of stuff coming along now is better, as the penalties for not hitting the fleet wide average of 95g co2 are 95euros, per gram, per vehicle sold....... Hundreds of millions in fines potentially
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Apr 23, 2012 21:53:02 GMT
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golf balls and cars arn't the same thing so it doesn't naturally hold to be true that what applies to one does to another..... ....What matters is how fuel is metered and theres a whole pile of sciencey stuff I won't pretend to understand well enough to explain which says heat, barometric pressure and altitude are not going to affect the actual fuel dispensation or use.... I was always under the impression that the dimples in golf balls were to aid stability, not range. If it worked at reducing wind resistance then the aerospace and motorsport industries would have cottoned on a long time ago. As for the second part, there's theory behind it, but it's a little simplistic. In theory, the calorific value of fuel will never change, so the amount of it used to generate a set amount of energy/power will always be the same. However the engines ability to release that energy from the fuel, and then convert it into movement will definitely be changed by external factors as its efficiency's effected. the golf ball thing is all about how they spin when they go through the air. Something we generally try avoid with cars and aircraft, yeah? The thing with the fuel at temperature is that its less dense and when its cold its more dense and the petrol pump takes account of this when it dispenses it into your tank. You can get it as hot or as cold as you like but you only get a quids worth of petrol out either way. So I am fairly reliably informed anyway. You can get the fuel in your tank as hot as you like and you may be able to get the needle to rise, but you haven't magically made more petrol...
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1937 Austin Street Rod - 1941 Wolseley Not Rod - 1956 Humber Hawk - 1957 Daimler Conquest - 1966 Buick LeSabre - 1968 Plymouth Sport Fury - 1968 Ford Galaxie - 1969 Ford Country Squire - 1969 Mercury Marquis - 1970 Morris Minor - 1970 Buick Skylark - 1970 Ford Galaxie - 1971 Ford Galaxie - 1976 Continental Mark IV - 1976 Ford Capri - 1976 Rover V8 - 1994 Ford Fiesta
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djefk
Part of things
Posts: 844
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Apr 23, 2012 22:16:49 GMT
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basicly, higher revs and a 1/4 throttle was cheaper than lower revs and 1/2 throttle on my drive Hope that helps and makes sense! It most certainly does - Think of the loud pedal as a tap: If you're having to press it more in a high gear to get up a hill at a certain speed than you would at the same speed but in the gear down, then you're labouring the engine and you should change down. Another thing I realised I have worked into my driving style today is that when cruising on a fast road, I try to avoid increasing the throttle when going up hills if poss, just let the car slow down within reason, then use the downhill stretches to pick speed up again back up to cruising speed before backing off again to hold that speed.
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Last Edit: Apr 24, 2012 6:22:26 GMT by djefk
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