Dog Posted December 15, 2008 Share Posted December 15, 2008 Just thinking the other day of a money saving thread when this appeared.So beat the conspiracy to defraud us of all our money.When diesel went up I started to economise and start rolling, using less revs and slowing down in good time rather than braking. I now get 4.5 litres per 100k thats roughly 62mp gallon and in a 7 seater Turkish car.Rolling is no problem with modern brakes and I can only think that Rover that used to use freewheeling hubs must have the patent and want to charge other car makers to much for it.Any household tips? Link to comment Share on other sites More sharing options...
Chezstevens Posted December 15, 2008 Share Posted December 15, 2008 Actually rolling, with a modern engine, burns more fuel than decelerating with the engine in gear - do a web search to check the facts. Link to comment Share on other sites More sharing options...
Dog Posted December 15, 2008 Author Share Posted December 15, 2008 It may, but why decelarate on a hill? Link to comment Share on other sites More sharing options...
Chezstevens Posted December 15, 2008 Share Posted December 15, 2008 Foot off accelerator - high gear and ....?Certainly cheaper than new pads and discs. ''Your Honour, I was not in control of the vehicle cos I thought, wrongly, that out of gear was cheaper ......'' Link to comment Share on other sites More sharing options...
Bob T Posted December 15, 2008 Share Posted December 15, 2008 I prefer to leave it in top gear and let it go down hills on its own. That way the fuel system does not use any fuel rather than using some to keep the engine at tickover. Link to comment Share on other sites More sharing options...
Dog Posted December 16, 2008 Author Share Posted December 16, 2008 You shouldn't believe everything you read on the internet.When saving fuel you most look at the total solution. If the engine is in gear with no throttle it will produce approx 20% drag. Tickover uses very little fuel. Try it you will find you roll further, faster and use less fuel.If you think it is dangerous being in neutral - don't go out in slippery conditions, when you may need to use it.Yuletide greetings... Link to comment Share on other sites More sharing options...
Chezstevens Posted December 16, 2008 Share Posted December 16, 2008 Dog,There is no telling you is there? Well try this bone. Find a Renault Scenic II, such as our 2.0 Dci, that has a fuel flow indicator - try the 2 methods which I have - then report back. It is basic engineering and it is well documented on the internet.I am sure you will gnaw away - your original argument was decelerating. Link to comment Share on other sites More sharing options...
Dog Posted December 16, 2008 Author Share Posted December 16, 2008 Lol get real. I checked it out with a extremely well qualified engineer. You have been sold a pup.Just because no fuel is injected doesn't alter physics.Back down you are wrong. Link to comment Share on other sites More sharing options...
Chezstevens Posted December 16, 2008 Share Posted December 16, 2008 What a heating engineer? - no offense to heating engineers. My own engineering knowledge is limited to aero piston and jet - before I started flying so again I can only comment on my own observations with our Scenic and what is readily available on the internat. Nice bluff but you or your friend are talking out of the proverbial. Next you will explain that you are talking about carbs not injection! Never mind the legalities of prolonged coasting in neutral.From one of many forums:I have confirmed to my satisfaction that the answer to my originalquestion is, Yes, modern computer-controlled fuel injection will stopinjecting fuel while coasting in gear, as the wheels will turn theengine and all of the accessory belts. I am glad I asked, because thiswas news to me. I presented this same question over at a Consumer Reports forum, and their staff expert said: "We have fuel meters that are tapped into the lines to readactual fuel consumption. Coasting in gear uses no fuel to speak of.Coasting in neutral still requires fuel to keep the engine running. Themost efficient way is to come to a stop in gear for as long as possible and coast down hill in gear." [emphasis mine] Any time you are engine braking, you are using no fuel to speak of. If you have a Consumer Reports membership, you can view that thread here: http://dis...r-38aujohn Post numbers 2 and 8 were the most informative. By the way, no part of my consideration of this question involves turning off the engine at any time. Link to comment Share on other sites More sharing options...
Chancer Posted December 16, 2008 Share Posted December 16, 2008 I have minutieusemently (now theres a franglais melange) been saving every last drop of diesel over the last 3 years, with the same car (equipped with fuel computer) and also doing the same two 50 mile brico-runs several times a month plus the shorter but much hillier return trip to my girlfriends house several times a week and can confirm categorically that my overall diesel consumption is significantly lower when I coast down hills out of gear with the engine running.I agree totally that it uses fuel while the engine is ticking over and that remaining in gear on a closed throttle above a certain rev limit (about 1.5k) uses none but our wallets see overall fuel consumption not just the fuel used (or not) going downhill.A diesel engine has massive engine breaking on a closed throttle such that to maintain my cruising speed I have to get back on the gas much much earlier on the flat or going up the next hill than if I coasted, try it for yourself and you will see, it is a dramatic difference.FWIW on my brico runs I get 65mpg when coasting and 61 when not. On the shorter but hillier trip to my girlfriends house I get 56mpg on the way and 64mpg on the way back when coasting as opposed to 54mpg and 60mpg when not, the difference between the outward and return journeys are due to the fact that I live just along from the bottom of a long long hill.I can even see the differnce in consumption if I am baulked by another car on my freewheeling homeward descent causing me to brake and therefore drive in gear the last km or so.So all the world now knows what a tightfisted anorak I am [:D]Editted: I am glad to see this section though! Link to comment Share on other sites More sharing options...
Cacknanty Posted December 17, 2008 Share Posted December 17, 2008 I'm with JR & the Dog on this one.My problem is that I have gone to a VW with DSG auto box so can no longer coast. The 'box may overheat apparently. Previously had a Fiat JTD with trip computer and got better mpg figures using the coasting method. Link to comment Share on other sites More sharing options...
Dog Posted December 17, 2008 Author Share Posted December 17, 2008 Sorry to disappoint you. No heating Engineer involved although he did fit his own central heating.My source is marginally better qualified. With over 50 years as a designer of jet engines, gas turbines, nuclear power stations and has also designed car and motorcycle engines. He is also a certified aircraft crash investigator. He was praised by none other than Frank Whittle for his expertise and text books on the design of Jet Engines. He also has over 300 patents to his name.I won't bore you with how he went to University at age 15 and can do complex mathematics in his head.I do know him fairly well as he is my father.He thinks you are pandering to fallacy. Link to comment Share on other sites More sharing options...
BIG MAC Posted December 21, 2008 Share Posted December 21, 2008 Gee whizzz desgned a complete Nuclear Power Station...Wow!I would have thought that there would have been...Geotechnical Engineers, Physicists, Architects, Structural Engineers, Metallurgists, Electrical Engineers, Boilers and Pressure vessel Engineers, Pipeline Engineers, Surveyors, Cost modelling specialists, Town Planners..............Guess he must have saved a few quid not using them.....What Power Station was it? So I can book my Plane ticket to the Opposite side of the World!No it wasn't a serious response............ Link to comment Share on other sites More sharing options...
Théière Posted December 21, 2008 Share Posted December 21, 2008 J.R's gone native wrote I have minutieusemently (now theres a franglais melange) been saving every last drop of diesel over the last 3 years, with the same car (equipped with fuel computer) and also doing the same two 50 mile brico-runs several times a month plus the shorter but much hillier return trip to my girlfriends house several times a week Does your wife know [:-))][;-)][:D] Link to comment Share on other sites More sharing options...
Dog Posted December 22, 2008 Author Share Posted December 22, 2008 You'll be glad to know the company where he was Head of Advanced Research had the majority of those people onboard, probably not the town planner though. He is a Metallurgist too I forgot to mention that. Sadly the nuclear plant was not built and won't be because UK government has just sold/given away the technology. Link to comment Share on other sites More sharing options...
BIG MAC Posted December 22, 2008 Share Posted December 22, 2008 Hmmmmmm a guy in charge of a failed enterprise in America is an entrepaneur...A guy in charge of a failed enterprise in England is a failure...Getting a Jet engine guy to design a Nuclear Power Station when it clearly isn't rocket science!...My Dads bigger than your Dad.......Laughing here! Link to comment Share on other sites More sharing options...
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