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Gas is not cheap and I am not rich, so every extra MPG that I can squeeze out will make my day
I was wondering what can I do electronically (as in with electronic mods), to increase the good old gas mileage.
Will pointed me in the direction of using the Calum ECU and possibly a wideband. What else can I use? Can I just get a wideband and tune down the A/F ratio, or will the ECU will also be needed?
I wouldn't mind getting as much MPG on the higway as possible. So if I could make the 5th gear run really leany etc.
Goal is, 30 City, 40 Highway.
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A wideband O2 sensor by itself will not get you better gas mileage. It can only tell you what your air/fuel ratio is. This is good information to have, but won't change anything. While we're talking about O2 sensors, it would be good for you to know the difference between a wideband, and a narrowband O2 sensor. Narrowband sensors are accurate within a very small area of mixture. I don't know exactly, but it's good at 14.7:1 air/fuel ratio, and probably reads well up to 15.1:1 and down to 14.3:1. Widebands are typicall good from 9:1 up to 17:1 or thereabouts. You may not need a wideband if you're going to keep the ratio below 15.1:1, but that might be pushing it.
More importantly, you're going to need to control fuel delivery somehow. There are many ways to do this. You could try a fuel piggy-back, or a tunable ECU like Calum's or similar.
I dunno, if you're trying to save money you might even try an adjustable fuel pressure regulator, and turn the fuel pressure down from 3 bar to something like 2.9 or 2.8 bar. That might be a poor man's solution. But I have no idea how that would fair.
Basically, you want to control fuel delivery, and lean out the car. I would recommend something like Calum's ECU, where you'll have control over the fuel delivery map. I'd put a lean area in the map around where you cruise on the highway. This is very common practice.
Last edited by BenFenner : 11-26-2007 at 03:29 PM.
I know that the outlaw engineering intake plenum spacer for a 350Z nets 10+ HP at the wheels and 3+ MPG. That might not help you, but know that they make a spacer for the SR20 also. Food for thought.
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Quote:
Originally Posted by Serban
Making your car RHD would be the MOST pointless mod ever. Go get a job for the Post Office, you can be JDM 8 hrs a day.
1991 SE-R -- Hot Shot intake w/ Pop charger, Megan cat-back exhaust, SSAC headers, JWT S4 cams, 2000 SE disc, ACT HD pressure plate, B&M shifter, ADV22 brakes w/ SS lines, FSTB & RSTB, ES sway bar bushings F/R, & Prothanes. Boost soon to follow
A wideband O2 sensor by itself will not get you better gas mileage. It can only tell you what your air/fuel ratio is. This is good information to have, but won't change anything. While we're talking about O2 sensors, it would be good for you to know the difference between a wideband, and a narrowband O2 sensor. Narrowband sensors are accurate within a very small area of mixture. I don't know exactly, but it's good at 14.7:1 air/fuel ratio, and probably reads well up to 15.1:1 and down to 14.3:1. Widebands are typicall good from 9:1 up to 17:1 or thereabouts. You may not need a wideband if you're going to keep the ratio below 15.1:1, but that might be pushing it.
More importantly, you're going to need to control fuel delivery somehow. There are many ways to do this. You could try a fuel piggy-back, or a tunable ECU like Calum's or similar.
I dunno, if you're trying to save money you might even try an adjustable fuel pressure regulator, and turn the fuel pressure down from 3 bar to something like 2.9 or 2.8 bar. That might be a poor man's solution. But I have no idea how that would fair.
Basically, you want to control fuel delivery, and lean out the car. I would recommend something like Calum's ECU, where you'll have control over the fuel delivery map. I'd put a lean area in the map around where you cruise on the highway. This is very common practice.
Thanks for the help Ben!
About the Wideband, I thought about using it to get information, then adjusting that information. Does the Wideband not allow for adjustments?
Does the basic Calum ECU allow for A/F adjustments? I thought only the Real Time allowed for that.
I was also thinking about a SAFC II, because it allows you to have presets. This way I could almost instantly change from a gas hog to a gas saver, etc.
About the fuel pressure, will lowering the fuel pressure ruin the performance etc.?
I wouldn't mind having the car run really leany under 4k rpm, but above that having a beast
you can use the ecu to pull a little fuel and timing at cruising speeds to save some fuel. I tuned my last car like that. I had an LM-1 for reference though. I definitely would not recommend going leaner than low 15:1s and only that lean for part throttle and low load.
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About the Wideband, I thought about using it to get information, then adjusting that information. Does the Wideband not allow for adjustments?
Yah, see, this is a common mistake. A wideband O2 sensor and gauge (or what ever you use to view the info) is just a gauge. You can't use it to adjust anything. It's just a tool used to see your instantaneous air/fuel ratio. A very select few stand-alone ECUs can make use of the WB02 information, and adjust fuel delivery on the fly (my VEMS does this) but this is uncommon, and only used for minor and slow adjustments as the reaction time is a bit slow. Works great for cruising though.
Quote:
Originally Posted by CovertRussian
Does the basic Calum ECU allow for A/F adjustments? I thought only the Real Time allowed for that.
I believe the basic Calum ECU can do everything the Realtime ECU can do, except change configuration while the car is running ("on the fly" or in "realtime"). I could be completely wrong on this, as I'm not familiar enough with Calum's work. Their section of the forums will be a lot more informative.
Quote:
Originally Posted by CovertRussian
I was also thinking about a SAFC II, because it allows you to have presets. This way I could almost instantly change from a gas hog to a gas saver, etc.
If SAFC II has presets as you describe, that could be a great way to accomplish what you're going for.
Quote:
Originally Posted by CovertRussian
About the fuel pressure, will lowering the fuel pressure ruin the performance etc.?
Lowering the fuel pressure a little bit would (in theory) slightly lean out the entire fuel delivery, which (again in theory) would result in more power everywhere, a bit better throttle response, and better fuel mileage. The problem is, you may run into a fuel atomization problem, where the fuel and air don't mix very well due to the lower pressure, which could cause major problems.
Quote:
Originally Posted by CovertRussian
I wouldn't mind having the car run really leany under 4k rpm, but above that having a beast
This is done all the time with stand-alone management without the use of two different settings as you describe with the SAFC II. I can get into it more later, but I have to run.
I believe the basic Calum ECU can do everything the Realtime ECU can do, except change configuration while the car is running ("on the fly" or in "realtime"). I could be completely wrong on this, as I'm not familiar enough with Calum's work. Their section of the forums will be a lot more informative.
THE ABOVE IS A QUOTE..from above
The calum fixed ecu.. is just what it says, you can not change it unless you get new or burn new chips. If you want to change your a/f with the safcII, emanage, or what ever you want..they will.. also a afpr will do it in wider way.
Erick
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the only difference between realtime and basic....is you cant make on the fly changes on a basic. all the tweaking you are doing is to the tables....and its just on the realtime its stored in a flash instead of a burnable rom.
sure you could lean yourself out...or you could do both lean and pulling timing. but over all you still have x ammount of weight to pull though the air with a y ammount of drag, and a certain z gear ratio. you loose the fuel, you have to loose the spark, which means you loose the HP. so you have to give it more pedal to move the car.
you would have better luck improving your mileage by removing weight. sure you probably could eek out 1 or 2 mpg out of it...but you could do that by coming up off your right foot and going 55 instead of 60.
i just dont see you making any increase in mileage by a leaner tune, that you couldnt do by slowing down or loosing weight.
you loose the fuel, you have to loose the spark, which means you loose the HP.
All things being equal, if you lean out the car (removing the margin of safety Nissan put in to begin with) you will make more power, and get better gas mileage.
Don't pull the spark back. Thank would defeat the purpose. =D
Hell, I'd increase spark a tad too, if you had control over ignition. Up base timing to 19 degrees I guess would be the easiest.
Last edited by BenFenner : 11-27-2007 at 12:03 AM.
All things being equal, if you lean out the car (removing the margin of safety Nissan put in to begin with) you will make more power, and get better gas mileage.
Don't pull the spark back. Thank would defeat the purpose. =D
Hell, I'd increase spark a tad too, if you had control over ignition. Up base timing to 19 degrees I guess would be th easiest.
but...adding spark and removing fuel. Means you should in theory to be safe should be running higher octane of fuel. You know the rule of thumb, bump timing add 93 octane. So any fuel savings you get from more hp and less throttle needed...canceled out by more expensive fuel.
Im not saying you couldnt improve the fuel economy by leaning out the mix or adding more spark.... but your net at the end of it all...will not be all that great.
slowing down will get you more savings than you can get my messing with the maps. and do you know how hard it is to do part throttle low load tuning...not much fun. cant easily do it on a dyno. and driving around with a wide band....the tank of fuel you'd likely loose, and someone's help which you should factor into the cost...would buy you a tank or two of fuel.
I have seen a magazine where like an sti guy was trying to make better mileage and leaned his car way out with messing with just his aftermarket ecu. it worked he got a big increase in mpg
it could help if you run fuel pressure at 4bar, or also maybe mess around with retuning for ethonal like those flexfuel cars
"...to pull though the air with a y amount of drag..."
I think Bowlcut brought up a good point here^
streamline some of your car it will help that mileage according to the guy in the link below, maybe get a hood with a hole in it to vent the radiator above the car rather than below http://www.recumbents.com/car_aerodynamics/
4 BAR with tuned Calum ECU using a wideband O2 sensor sounds A+ to me. What's better than almost perfecting the maps with even better fuel atomization? I guess weight reduction.. heh.
I know Eric with his VE and his tune, which isnt very radical....can get like almost 36mpg out of that car when he went to the Convention. 200sx with a VE + sr16ve cams. When I last drove the NX long distances...intake is my only performance mod...other than the tuned ECU. I was getting like 30-32mpg out of it.
I dont see getting much better out of a sr20 in any of these cars. My classic would occasionly throw out like 35mpg if it was coming all down to nashville with the a/c off but windows up and vents open. then again i love my altima, 32mpg or so with the a/c....and its a huge car compared to the nx
