The trip computer measures injector pulse width and when I fill the tank it's accurate within 1%. Have no doubts about its accuracy on fuel or speed. It measures that and a whole lot of other things like ignition timing, water temp, intake air temp, etc. Actually, by my reasoning you'd use about 1.3 gph spinning at 3K, more if actually in gear and moving, not a whole tank (unless you had less than 1.3 gallons in your tank). I'm confused as to why you're telling me where I use my fuel, like I don't know. I know where I'm using my fuel, I know EXACTLY how much I'm using at any given second. My other mods have gotten me up to 33mpg city 42mpg highway, well beyond EPA estimates. Lowering the idle will raise the city mileage. For me, increasing efficiency is like you guys increasing HP. Both is pushing the car beyond what it was designed/supposed to do. You guys telling me that a few mpg aren't worth it is like me telling you a CAI to lower your ET by 0.1 seconds isn't worth it. What's worth it for me and what's worth it for you are two different things, I didn't ask IF I should do this, I WANT to. For me, a P&P job is a ridiculous waste of time and money for 2hp, that's why I'm not doing it, or commenting in threads of people who want to do it.
2002 Cavalier 2200 5spd
a port and polish job may actually increase economy. so why not do that....
either way the guy has a point. lowering his idle WILL cause him to loose less fuel, even if it only amounts to 1 or 2 percent difference. as he said above, a CAI may only lower 1/4mile times 1/10th or so, but nobody rags on these people for doing this. He bought the car for economy not performance so why not just lower his idle for him.
i love how everyone on this site says somethign then it turns to a big argument.
How about this, lower the idle, see the improvement then start making other changes such as load based fueling leaning it out slightly and slightly. another area for improvement could be timing. more timing may make the engine more efficent and use less fuel... i dunno... maybe this is something to look into.
finally, isnt there an option in HPtuners to shut the fueling off almost completely when coasting? that would definately help out quite a bit.
farmerz24
use premo gas.... and do a n/a build... if you want fuel economy... also remove you air conditioner. i dont see how a cav doesnt get good mileage unless its turboed... i get 28-29 city with air...
***Need A Power Lock Switch?***
I DID lower the idle in a half assed way by screwing with the IAC valve, but it was prone to oscillating so it would not work in the long run. I did drive some city mileage this way and I could easily get 34 mpg. This didn't affect highway mileage much, so it stayed at about 43mpg highway. I wanted to program the ECU so that I wouldn't need to play any tricks on the car to get it to run the way I wanted. I don't think leaning out the fuel curve will help much because I'll just lose torque, which will make me rev the car harder only to spin the engine faster and probably lose efficiency. Accelerating is pretty efficient, pumping losses are lower, but I'm accelerating only for a small time on any given trip. The majority of the time, I'm either coasting, idling or maintaining speed which requires little fuel. When I need the engine, I want it to get enough fuel, it's when I don't need it that I could afford to slow things down or lean it out.
I'm not going to remove my A/C. It doesn't draw any power when it's off and when I run it, it's because I really need to.
2002 Cavalier 2200 5spd
Solid Snake wrote:You're telling me you spent $6500 on fuel to feed a four banger for a year? You spent more than your car is worth, just on fuel, just for ONE YEAR. That's enough fuel to move a Corvette (a real sports car) 40,000 miles. Despite how ridiculous that is, you have the balls to yell at me for not wanting to do the same. Someone WAS willing to program my car for $50 and if his program allowed him to tune an unlimited amount of J's for free, why wouldn't he spend a few minutes to do it. Sorry that not all of us work jobs where we regularly make $50 for a few minutes of work like you do. Even if I did make that kind of money, I still wouldn't piss away $6500 in gas on a $3000 car. If your job is so great, why are you dicking around with Cavaliers anyway? Maybe if you didn't blow $6500/yr on fuel, you could afford a real car.
Actually bringing the idle RPM from 900 to 600 saves 33% and bringing coasting RPMs from 1200 to 600 saves 50%. I spend the majority of my drive either idling or coasting. Changing the fuel map while accelerating won't help much because I actually need that fuel to make me go, and it already at a pretty good mixture for economy anyway. Idle and coast is where I spend most of my time, and during these periods, the car does absolutely nothing. I don't have a problem stalling out my car, that's what the gas pedal is for. I'll determine what is a WASTE of my time, and even if I want my J to get better economy for the hell of it, that's my business.
I love how everyone gets their panties in a bunch when someone breaks their illusion of the J being a dragster. Did you ever think to yourself that tinkering with fuel maps on a N/A four banger motor on a FWD car just to shave a few milliseconds off your 0-60 might be a waste of time? We drive ECONOMY CARS, that were designed to get us from point A to point B as cheaply as possible. This is a FACT. Sorry to crush your dream. I use this car to work and to drive to school. I don't give a crap about speed and I'm not going to dump thousands into a J just so I can piss off some assclown in a Civic.
Yeah i spent 6500 on fuel, got a problem with it? i didnt say what was/was not done to my car and what type of fuel i was using. And to be honest with you, the person that would tune a car for 50bux is either some jo-blo working a dead end job like you that doesnt know beans or is just desperate for cash. Whos talking about real cars? how do you know what i own and what i dont, just happens as a matter of fact that i got into my j because i think they are a sporty looking econobox (almost like a mini camaro/firebird if i may) not because i "HAVE" to have a jbody due to lack of cash.
ok so that saves you 33% and 50% of fuel, somewhat hypothetically speaking, i bet you'd save in the REAL WORLD around 10-15% at most if you idle all day long. and if you complain about idleing so much why the @!#$ ARE you idleing so much? just shut the bitch off unless your in bumper to bumper traffic all day long (pizza delivery in traffic jams however, i doubt it, atleast the way it works around here is you get yer pizza in 40min or less meaning your not sitting there at lights idling). I'm not bashing you about getting better economy in your jbody, i think thats a reasonable and very understandable thing, how your going about it (or trying to) is ASS BACKWARDS and STUPID. now your saying "i'm not worried about my car stalling thats what the gas pedal is for" hmm thought you were trying to GET economy not try to keep the @!#$ running waisting more fuel.
dump some acetone in the tank, that'll give you better economy (been there done that and it works). Anyways go about it how ever you feel, but your going to blow more money on all the small @!#$ to get small results
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** Flat Broke Racing Inc.**
