Guest *Jedimaster* Posted October 4, 2005 Share Posted October 4, 2005 Why would an engineer design a modern vehicle to use gas in this situation? What would be the purpose of that? If you're coasting down hill at 2500 rpm and the engine is using gas, it would also be producing power. You wouldn't get much engine breaking that way. I'm asking because I don't know. I'm more used to carbeureted engines which do feed gas in. Link to comment Share on other sites More sharing options...
mwiener2 Posted October 4, 2005 Share Posted October 4, 2005 No Gas!!! My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
Langosta39 Posted October 4, 2005 Share Posted October 4, 2005 If this is true then coast down a hill in 1st gear and look at your instant mileage, it should be 99.9, but its not. You are using gas and not going fast enough for the mileage to be over 100. Link to comment Share on other sites More sharing options...
mwiener2 Posted October 4, 2005 Share Posted October 4, 2005 that's becasue first gear has enough engine braking to slow the car to the point where the engine would drop below it's idle speed. At which point, the computer adds fuel to keep the engine running. If you were on a steep enough hill that would overcome the braking ability of first gear, it would read 99.9 My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
Langosta39 Posted October 4, 2005 Share Posted October 4, 2005 wrong, get in your car and try it Link to comment Share on other sites More sharing options...
rallispec Posted October 4, 2005 Share Posted October 4, 2005 wrong, get in your car and try it dude.. listen to what wiener is telling you -- run some data logs if you have time --- the injectors SHUT OFF if your coasting above something like 1200 rpms ( i forget the actual cutoff RPM off the top of my head) YOU USE NO GAS when coasting in gear. Link to comment Share on other sites More sharing options...
Langosta39 Posted October 4, 2005 Share Posted October 4, 2005 I have no idea how to get data logs from my car so why dont you show me some. Link to comment Share on other sites More sharing options...
Drakuun Posted October 4, 2005 Share Posted October 4, 2005 Maybe it's time to learn how so you can back up your own arguments instead of using it as scapegoat "oh they can't prove me wrong, nor can I prove myself right, therefor, I = right. Sorry had to.. This little pissing contest has been entertaining.. nothing like people who have no clue how to debate. Link to comment Share on other sites More sharing options...
Langosta39 Posted October 4, 2005 Share Posted October 4, 2005 Weiner is the one that started this by telling me to "suck it up" but offered no proof. I'm willing to learn if someone shows me the facts. I'm going off of my own experiences with my trip computer. I don't have the hardware to read my car's ECU, so somebody show me the data and I'll shut up. Ralispec, on page two you said you had no idea how the fuel injected stuff works, and now all the sudden you are telling me to listen to weiner. Why do you now think he is right? Blindly following? Or did you do some fact finding? I'll concede the point if you show me I'm wrong, and this doesn't have to be an arguement, just show me the data. Link to comment Share on other sites More sharing options...
ChrisK Posted October 4, 2005 Share Posted October 4, 2005 To bring it back on topic, yeah, I coast in my 5MT sometimes. Pretty much the only time I'll do it is when I'm going down a long deserted downhill road (lots of those in hilly Wisconsin). Freewheeling from 55mph up to 80mph+ is a strange, cool feeling. The reason I do it is to AVOID the engine braking I would have gotten otherwise. While it's debateable if engine braking to maintain your speed downhill gets you different fuel usage than braking dowhill, the "free" speed you get from coasting downhill is certainly real. You're trading height for speed, quite simply. Using the brakes (engine or wheel) you're burning off energy. I don't hold any illusions that I'm going to save more than a dollar over the life of the car doing this, of course. But it's fun. Link to comment Share on other sites More sharing options...
mwiener2 Posted October 4, 2005 Share Posted October 4, 2005 There is no reason to datalog. It's fairly simple. What does gas do in our engines? It is ignited to make power so the engine spins. At idle, fuel is added to keep it spinning. Under acceleration, more fuel is added to increase the spinning. When you are coasting in gear, under engine compression, which is used to for deceleration, the engine wants to slow down. If fuel were added, there would be no engine braking, the car would coast forever because the added fuel would overcome the friction of everything. But we all know this isn't the case. When you take your foot off the gas, the car slows down. If you are driving down a hill, and you take it out of gear, you may speed up. This is because you've disconected the engine from the drivetrain. The engine is now using fuel to stay spining at it's idle speed, say 800rpm. Put the car back in gear, the engine revs up and the car begins to slow, stay the same speed, or gain speed at a much slower rate. This is becasue the engine is under compression braking. If it was using any fuel at all, you would have the same effect as not being in gear. This is all assuming you are staying above the idle speed of the engine. When you get near the idle speed, fuel will be added to prevent the car from stalling. This really isn't an argument. NO GAS IS USED UNDER COMPRESSION BRAKING My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
Langosta39 Posted October 4, 2005 Share Posted October 4, 2005 If you change from 50% throttle to 25% throttle you will slow down becasue there isn't enough gas being injected for the engine to make the necessary torque to move the car at the original speed. So you're more recent statement is horriblly generalized and false. In old carb'ed engines there is always fuel being squirted in to the engine during coasting and you still slow down don't you? Having done my own research I've found that EFI engines do cut the fuel above a certian RPM threshold when the throttle is closed, so you are right, but you should be a bit more careful about your comments. Link to comment Share on other sites More sharing options...
mwiener2 Posted October 4, 2005 Share Posted October 4, 2005 :lol: My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
richip Posted October 4, 2005 Share Posted October 4, 2005 If this is true then coast down a hill in 1st gear and look at your instant mileage, it should be 99.9, but its not. You are using gas and not going fast enough for the mileage to be over 100. Well, I just verified coasting and the instantaneous meter displayed 0.2 L/100km (which is probably the equivalent of 99.9 mpg in meaning). Link to comment Share on other sites More sharing options...
Langosta39 Posted October 4, 2005 Share Posted October 4, 2005 At what RPM does the computer change from 99.9 indicating fuel flow has restarted? Link to comment Share on other sites More sharing options...
mwiener2 Posted October 4, 2005 Share Posted October 4, 2005 not rpm based. speed vs throttle angle My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
panos Posted October 5, 2005 Share Posted October 5, 2005 Just hit the freakin "Eco" button. That's what it's there for Economy. Link to comment Share on other sites More sharing options...
richip Posted October 5, 2005 Share Posted October 5, 2005 Whoa! What "Eco" button? Link to comment Share on other sites More sharing options...
melayout Posted October 5, 2005 Share Posted October 5, 2005 Yeah, just hit the "Eco" button and if you don't have it ask the dealer to install. I keed I keeed Link to comment Share on other sites More sharing options...
Slickvic Posted October 5, 2005 Share Posted October 5, 2005 Whoa! What "Eco" button? Sorry, "Not available on U.S. domestic vehicles" Link to comment Share on other sites More sharing options...
rallispec Posted October 5, 2005 Share Posted October 5, 2005 Sorry, "Not available on U.S. domestic vehicles" You dont have an "ECO" button?! maybe its only available on the 5MT. kidding Link to comment Share on other sites More sharing options...
Guest *Jedimaster* Posted October 5, 2005 Share Posted October 5, 2005 I <3 my ECO button. Link to comment Share on other sites More sharing options...
rallispec Posted October 5, 2005 Share Posted October 5, 2005 I <3 my ECO button. seriously, I think it's great the Subaru included that in the car. are you sure that you 5EAT guys don't have the 'eco' button? Link to comment Share on other sites More sharing options...
Slickvic Posted October 5, 2005 Share Posted October 5, 2005 You dont have an "ECO" button?! Nope. I have seen an ECO button on non-USA brochures that show the the 5EAT. It's kind of like having an appendix. You dont really need it, do you? Just keep it in "Drive", use the throttle sparingly and let the lockup torque converter do it's job. But fun would that be? That's what a Prius is for. Link to comment Share on other sites More sharing options...
PhilT Posted October 5, 2005 Share Posted October 5, 2005 OK, out of interest I did a quick log on the way home from work, full throttle up to 90 in 3rd, then coasted with my foot off the throttle. Results showed that the fuel injectors are still operating, all beit a minute amount of fuel being injected. Log is attached.TARI DL1 2005-10-5 17h10m44s.pdfTARI DL1 2005-10-5 17h10m44s.pdf Double Award Winning Legacy GT Wagon Link to comment Share on other sites More sharing options...
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