bubblegoose Posted January 3, 2011 Share Posted January 3, 2011 this is my new hobby, saving gas thought id start a fred to discuss ways of improving overall economy my first questions, ive been given conflicting views on compression ratios vs. required fuel and hot air intake vs, cold air intake i can see where both sides of the arguments get there ideas but still put me no closer to reality (i only know what makes more power ) next mod is to seal off engine bay better and add some body under trays Quote Link to comment Share on other sites More sharing options...
Simon Posted January 3, 2011 Share Posted January 3, 2011 If you're serious about it go to an agent for http://zeroe.co.nz/ and get an aids test which will be a starting point and will tell if your car is running ultra crap spec. Theres a top 10 "tips" to saving fuel here My faves are pump tyres up hard. My Alto tyres are so skinny that over inflating them does no damage. So I run about 43-45psi. They wear normal. Take the back seats out. They might be foam but there is still some weight to loose. Put a block or notch or extra spring in the throttle that is in the perfect position to "rest" on at 100kmh and to go any faster than 100k you have to actually think about pushing the pedal further. Never go past said point. It will take you like a k or more to get to 100kmh but meh. My next thing is build a nicer exhaust system for the poor little motor so it can breathe properly which would mean I could pull the "block" back to an even lesser throttle position. May get another carb and semi block the jets to run it a little lean. Will be slower but use less fuel. Funny that I still havent put any fuel in is since signing up to that fuelly thing. heh. More tips: Don't pass people. Hang behind them. Especially trucks. I can draft a truck at 90kmh on the choke. If you're not in a hurry and have a good song on, cruise along at 80kays/wagon speed. Because the air resistance vs velocity is an exponential you save a lot of fuel going 20kays slower. Kind of like the Richter scale for earth quakes. Use the right gears. Don't drive an auto. Quote Link to comment Share on other sites More sharing options...
bubblegoose Posted January 3, 2011 Author Share Posted January 3, 2011 also, riding herrafrush with moon hub caps is good for the trees Quote Link to comment Share on other sites More sharing options...
cubastreet Posted January 3, 2011 Share Posted January 3, 2011 I think compression ratio depends on the engine design. If you can raise CR and not have problems with pinking, you should get better power and economy. If you have to retard the timing heaps, I think the benefits can be cancelled or reversed. Quote Link to comment Share on other sites More sharing options...
yoeddynz Posted January 3, 2011 Share Posted January 3, 2011 I'm interested in fuel economy. Must be from my dad who used to run his morris minor about Surrey till it ran out and had little fuel economy notes. He missed my sisters christening- he was taking her to the church (we ain't godly btw!!!- its just what they did back then eh) and the minor ran out of fuel- he actually left her in the back seat while he walked to the nearest farmer for more petrol. good ol' days.... I used to keep all fuel receipts for my Rx3 - on long runs it would get 30mpg which is great. Did a big trip about Belgium and Luxembourg with some very fast driving thrown in and it still did 30mpg. But many people especially rotary owners scoff at my interest in in economy saying things like if you own rotaries that's the last thing you worry about. Fuck them. I like the idea that I can drive a car somewhere on a long trip not break the piggy bank open and then when I want to go fast I can give it a good thrashing on the twisty bits. So I'm interested in economy- especially as fuel has gone up again. On my Viva- it will have the turbo running low boost on a high comp 12A. does that mean that if I just cruise along with out giving it much stick it should be as economical as a normal 12A? I know that old school 70's turbos with really low CR were thirsty. I understand that my rotaries will never be proper economical due to inherent bad combustion from the large surface areas involved cooling the burn. But there is the challenge.. Quote Link to comment Share on other sites More sharing options...
Thousand Dollar Supercar Posted January 3, 2011 Share Posted January 3, 2011 I'm also guilty of an interest in fuel economy. This is despite my Rover getting about 21mpg / 13.4l/100km from the last tank on reasonably gentle driving. I suspect it's running very rich and I'll get it tuned as soon as garages knowledgeable about twin SUs reopen after the holidays. I also regularly shut off the engines in my cars when stationary e.g. if I know the traffic light phasing or I'm far enough back in the queue that there's time to restart. I've been doing this for years in the Alfa and haven't worn out the starter motor yet. I will never fail to be at motorway speed by the end of a merging lane, as I hate people who do that. Onramps are for hooning, and being cheap with the throttle doesn't save the planet because of the traffic ripples you'll create. Considering economy is sometimes the only way to amuse myself when driving my yucky Colorado work ute. I always have the instantaneous fuel consumption displaying on the dash. It gets lousy figures for a modern turbodiesel but not for an outdated 1.9-tonne 4WD POS 4-speed automatic brick I suppose.. Re your question on whether cold or warm air's best for economy, it surely has to be cold air? But if I were to bypass my Rover's intake manifold heater in pursuit of that, I might make things worse because that system might be important for fuel atomisation and hence good combustion. Quote Link to comment Share on other sites More sharing options...
bubblegoose Posted January 3, 2011 Author Share Posted January 3, 2011 should really get a vac guage put in, shame i just send 4 to carboon RE:hot/cold air cold air, more power/use lower throttle position hot air, hotter faster burn....? as for CR's i think its safe to say many econoboxes have quite low compression to suit 87RON fuel and would benefit being brought up a little to meet the 91 that's available here? not talking silly high Quote Link to comment Share on other sites More sharing options...
R100 Posted January 3, 2011 Share Posted January 3, 2011 Buy a Diahatsu mira. Thats what i did. Saved myself heaps of fuel Quote Link to comment Share on other sites More sharing options...
jakesae101 Posted January 3, 2011 Share Posted January 3, 2011 buy a motorbike save even more but you get reamed by rego so it probably works out the same Quote Link to comment Share on other sites More sharing options...
bubblegoose Posted January 3, 2011 Author Share Posted January 3, 2011 i have a charade 1L 3cyl Quote Link to comment Share on other sites More sharing options...
R100 Posted January 3, 2011 Share Posted January 3, 2011 Im selling one of my wagon Rs its a 650cc manual. Around $43 to fill the tank. Lasts for friggin ages. I find if your seriuos about saving fuel your better off to buy a cheap run around, or scooter and use your other car for the weekends etc. Quote Link to comment Share on other sites More sharing options...
Simon Posted January 3, 2011 Share Posted January 3, 2011 Im selling one of my wagon Rs its a 650cc manual. Around $43 to fill the tank. Lasts for friggin ages. I find if your seriuos about saving fuel your better off to buy a cheap run around, or scooter and use your other car for the weekends etc. This ^ It's cheaper for me to register two cars for a year than drive my MR2 35 kays per day. ( Haven't worked it out ) But I can blow a tank of fuel in the MR2 in 250 kays. It's very difficult to actually use petrol in my daily. Quote Link to comment Share on other sites More sharing options...
bubblegoose Posted January 3, 2011 Author Share Posted January 3, 2011 going to get a moped when i have some spare coin/job but for now ill stick with the charade and some aero dynamic ductape Quote Link to comment Share on other sites More sharing options...
Testament Posted January 4, 2011 Share Posted January 4, 2011 my first questions, ive been given conflicting views on compression ratios vs. required fuel and hot air intake vs, cold air intake higher compression is more effcient providing the engine and fuel octane can handle it. e.g. my mums punto sporting (which has quite high compression for a silly 86hp 1.2L) not only runs noticeably better on 98, it gets nearly 20% better fuel economy than on 95. a hotter combustion is more efficient as long as detonation doesn't occur - but is the engine carby or fuel injected? a carb will run slightly richer with warmer air as it doesn't meter the density difference. only a pretty small difference though. I would probably just keep the standard air intake system. Another thing that is often overlooked is that having more power doesn't mean you use more fuel neccesarily. It's heresay, but in the real world I've generally found when you have a bit more poke and can choose judiciously when to use it/can keep an even throttle while maintaining the desired speed nets better economy than an underpowered vehicle where you are foot the the floor a whole bunch and on and off the gas more often rather than keeping a steady state. The on and off the gas thing is quite significant as you activate acceleration enrichment (or the accelerator pump on a carb) when you move the throttle. Quote Link to comment Share on other sites More sharing options...
fuel Posted January 4, 2011 Share Posted January 4, 2011 oh lols, added the VR-4 to fuelly to keep track of how thirsty it is. oohhh yeah Quote Link to comment Share on other sites More sharing options...
Roman Posted January 4, 2011 Share Posted January 4, 2011 Get an understanding of what a BSFC map is: http://en.wikipedia.org/wiki/Brake_spec ... onsumption It's unlikely you'll find one for your engine, but it's good to know what it means, and how this applies to saving gas. If your car is fuel injected, then rig up a gauge (multimeter?!) which shows you injector pulse width. There's nothing else which will show you more specifically how much fuel you are using than that. If you wanted to get fancy you could divide it by your speed, but meh. People often say "Turbo charged engines are more efficient than NA ones" Which is true in terms of having a better PEAK BSFC, but when off boost / low load they dont compare. Having a smaller engine under more load generally brings the motor closer to its optimal BSFC point when putting around town and cruising at low throttle/rpms. Spending money to save money on gas is a bit of a pointless exercise though, if your mods are going to take 800 years to pay themselves off. Start out with an aerodynamic car, strip the hell out of it, and run skinny tires. Much more than that, and the cost/benefit factor starts to get a bit gay. VVTI (and similar) engines which can adjust the dynamic compression ratio of the engine based on load, boosts the efficiency of the engine across the board. Quote Link to comment Share on other sites More sharing options...
bubblegoose Posted January 4, 2011 Author Share Posted January 4, 2011 its more af a giggle for me than serious coin saving skimming the head will only cost me a HG under body panels are free vac guages are cheap sealing off gaps isnt hard etc etc then when its done ill sit and wait for a fuel crissis and sell it for 4 bazzilion dollars Quote Link to comment Share on other sites More sharing options...
fuel Posted January 4, 2011 Share Posted January 4, 2011 instead of skimming the head and potentially running into other issues - have you thought about running water/meth injection? It's pretty easy to set up on a carb vehicle and the water/meth charge effectively increases the compression ratio (and its rate would be variable) and cools down the combustion temp and fuel charge therefore getting away with more advanced timing etc. Quote Link to comment Share on other sites More sharing options...
Simon Posted January 4, 2011 Share Posted January 4, 2011 Yeah I want a vac gauge back (took it out cos I thought i was going to sell it). And triple keen to play with water injection. Quote Link to comment Share on other sites More sharing options...
bubblegoose Posted January 4, 2011 Author Share Posted January 4, 2011 sounds expensive Quote Link to comment Share on other sites More sharing options...
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