Everyone is always out to squeeze out more power out of their cars. Well I'm on a mission to save some gas. I believe last time i calculated my gas consumption i was getting about 17 to 20 MPG. Regular stop and go Driving and some highway millage. Thats not good for me since i sometimes drive up to 500 miles a week for work! I know some engine breathing mods help save gas millage but has anyone actually compared? Any comments would be greatly appreciated. Also a little side question. Has anyone ever adapted a MPG meter to our cars? Like some of the new cars coming out and most of the BMW's.

 

i was working on the one that came standard in 300zx's but soon after getting it to work it failed. Couldnt find another.

 

Best way to get top gas mileage is maintenance. Clean air filter / fuel filter. Also a tune up (new plugs, and maybe new KS/O2 Senors). as for mods, if you are a cali-spec max a good exhaust system from header to muffler tip might help in that department.

-edit: i have a ScanGaugeII from www.thinkgeek.com and it monitors MPG along with a bevy of other cool features.

 

Hows the MPG on boost ? is your car a DD ? Turbo does save gas when you take it easy... although who tha hell ever does ! lol

 

I dont know how to tell if its Cali-Spec. Im a 99 SE-L 5spd. Fully loaded so it has a little extra weight here and there.

 

whats a dd? my car gets about 28 when i take it easy 18 when im on it.

 

DD = daily driver.

My 03 has an MPG meter, but mine isn't very accurate.

Get some lightweight wheels. Helped improve my highway mileage 12-15%.

 

easiest way to find out is pop your hood and look directly in front of your front bank (valve cover with the "Nissan 3000 24 valve" cover on it). look for the sensors, if there are four that means you have 4 02 sensors and are cali spec and have a dreaded precat in the header along with the y-pipe. If you have only two, then you only have 2 02 sensors and both precats are in the y-pipe and much easier/cheaper to get rid of.

 

those are some good comments and thoughts I wouldn't have thought about that

 

^

oh and how does replacing the fuel filter save gas ?

 

a clogged fuel filter will deliver less fuel than a clean one. Thus ECU has to make adjustments to fuel delivery. Working more than it should.... Just my opinion.


and yes mine is Cali-Spec than. Original Dealer was in New Jersey, why would it be c-s? Oh well but yes the pre-cats are REALLY annoying i hollowed out one of them when i had the exhaust off for the clutch install. I dont really want to get headers though cause every car that i know of with headers sounds really obnoxious although my exhaust is ALL ****ed up, I really should replace it.

I'm going to try to change the Fuel filter, plugs and air filter with the next oil change. See if that helps a little.

 

well lets just leave it to sky jumper (a very thoughtful member of this site if u never heard of him) to argue what exactly the fuel filter affects, but as far as mileage, unless ur vehicle is in dire need of maintenance, the biggest factor in determining how much gas it burns is the weight of your foot.

remember, the throttle is a variable input device, easy, smooth acceleration off the line helps, easy passing at moderate speeds help, stomping on the gas when you see a civic that sounds louder then a jet engine does not help.

you get the point...a leaky exhaust btw will throw off ur a/f mixture and the car will eat more gas. do u have any codes ? hows the idle ? clean the TB lately ? whats the tire PSI ? r u on heavy rims ? got junk in ur trunk ? (yeah i consider sub-wooofers junk too), check for the ghost KS code, what gas r u using ?

PS: i love threads like this, finally not someone complaining about squeaks, suspension questions, brake pads, and other common and repetitive stuff. i too btw always search for ways of improving MPG

 

hahaha You caught me!

Anyways I have really given up on MPG with the Max.. New plugs, filters didn't do a thing to my MPG when I did it at 90k..

 

I got a light foot. Most of the time I'm never over 3k. I like to cruise at 2500.

No Codes.

700-800 i believe on warm No A/C and about 900-(more so)1100

Nope i have not touched the engine ever since i bought it at 73k its at 96k now.

Tire PSI... i believe im set at 44 on all 4 tires. Stock rims.

Trunk is free.

KS dunno, don't have a check engine light, and don't know how to check for the codes.

89 the car saw 87 only ONCE and only about 2 Gallons of it because the gas station didn't have anything else, and i was on E. She sometimes sees the Shell V-power when i run out of gas around a Shell gas station cause they never have anything BUT their damn V-P gas which costs like an ARM and a LEG, and maybe a left nut too!

 

www.gassavers.org

If you're serious about getting good MPG you'll check out that site. I see this thread is about squeezing out better MPG but I doubt anybody in the Maxima community is 'serious' enough about it to do what some of those guys do. I mean, underbody paneling, grill delete kits, closing in wheel wells, etc.

It seems a few big things to do are ignition-off coasting, limiting idling, and being cautiously steady/easy on the gas. I'm not sure how feasible the coasting is on Maxima's with power steering and whatnot, but the limiting idling will certainly help as well as driving a bit slower.

I actually picked up an '89 Civic DX hatchback a few months ago to serve as my daily driver for work. The thing has 240k miles, is pretty rough, and by practicing some 'techniques' I learned on gassavers.org I've consistently gotten just under 50 MPG over the past two months of commuting to work. And I kid you not, this isnt even highway driving. I cant imagine the mileage I'd be getting if the car was in good shape. Before I started doing all that stuff, I was getting about 32-34 MPG in it.

I haven't tried any ignition-off coasting in the Maxima and I'm not sure I care enough to try, but I have tried to limit my idling and driving a bit slower and have seen a 2-3 MPG increase by just doing that.

 

yeah there are just too manu variables, hey did u check for a frozen rear caliper ?

just checking...

yeah i replaced my plugs, pcv valve, put on a 300z Fuel filter, replaced air filter, and did every fluid except the brake fluid and AC refrigirant, cleaned the TB and IACV by taking them both off, tried various bottled injector cleaners which never work.

basically instead of doing all this, i could have saved my money and got an extra tank of gas (or two) hows that for helping your MPG ? save your money and spend it on gas...i guess people will say in the long run this that and this...oh well, i tried.

 

i rarely stop on the gas harder then 3000 RPM, the VQ is just so damn strong down low there is rarely the need to do this. up hill or off the line there really is a lot of power in that engine. i only kick it hard when my GF pisses me off or i am mad for other reasons but this has not been since i left the mental hospital and the alcoholics anonymous as well as anger management helps too (just kdding really i am kidding)

this would be a good time to check out the stickies, there is a page called fault code diagnostics, there is a way there to check for codes manually by turning the screw on the ECU, but i dont feel like spoon feeding at this moment

the KS code is a ghost code, meaning it does not set off the CEL, because its not part of the emission system, thus it is very possible that when u bought the car, it passed emissions even while having the KS code and you never knew about it. the code is 0304 but u will have to search the stickies to find out how to retrieve it !

normal idle is 700 or so, some people like to set it higher some like it lower, but one thing is for sure, it should not ever be higher then 1000, even with the AC on, and whatever other electronics u can think of. so this may be a place to start.

cleaning the TB is good to do if u never knew the history of the car, it may be very gunky n there and restricting the air flow. people do claim MPG improvements after cleaning the TB

44 PSI ? are you sure ? my tires say 35 PSI MAX on the sidewall but as long as the tire is not lower than 30 you are fine

now here is the cherry on top of ur cake: 89 gas, hmm this is a touchy subject, most people you ask here will say u MUST run 91 (this is actually recommended by nissan) but nissan is a tricky animal, is suggests that 87 can actually be used if 91 is not available, so try it for yourself. but do it for like 3 tanks in a row to let the ECU adjust its readings

Seeing how u have a calispec, the KS is gona be a major biatch to replace, but it can be done, get some alcohol and lots of band aids, ure gona need em...!

 

... Not on my max... the only power i see before 3500 RPM is in 1st gear!

yes 44 PSI, I'm also running 205s Free tires cant complain. Potenza forget the exact model.

My A/C is also ****ed up, ever heard of the whining noise from the A/C the A/C clutch is messed up some how so i dunno. I want to reinforce the ground wires on the car sometime within the next two weeks. Also i found this little video


http://www.metacafe.com/watch/524517...as_mileage_2x/

you think it actually works ? What would be the consequences if that stuff was used on the VQ? Ive heard horror stories that our motor's don't take kindly to 110 octane neither.

 

sorry i meant STOMP the gas, not stop, basically i dont go past 3k much at all

acetone ? no i dont think so, there was a thread here on this a while ago, try searching for it.

i think its just the nature of the beast, its a 3.0 V6 how much mileage do you expect ?

here is my mpg record so far
341.754/15.155 = 22.551mpg apr.11.07 (petro-canada)
316.899/15.208 = 20.838mpg apr.22.07 (petro-canada)
313.792/15.691 = 19.998mpg may.03.07 (petro-canada)
(229.907/7.925 = 29.010mpg may.04-05.07 Niagara falls trip 120-140kph) (petro-canada)
347.968/14.259 = 24.403mpg may.11 (niagara trip + city hard driving avg) (petro-canada)
363.502/16.516 = 22.009mpg may.29.07 (petro-canada)
332.433/14.538 = 22.866mpg jun.09.07 (petro-canada) jun.9 cleaned TB, IACV, replaced KS filled 91oct
319.385/14.935 = 21.385mpg jun.20.07 (petro-canada) 91

this tank thats almost done now will show a big improvement as i am at 520KM already and i still have a quarter tank left, i plan on pushing it past 600 for the first time. i think the 91 gas (and my new KS) is the main difference, but i am planning to switch to 89 and then to 87 to see any significant difference

its basically a money to mpg ratio, with 91 u get higher MPG but pay more for gas, with 87 u get less MPG but pay less for gas, the trick is ti accurately calculate whats worth it for u in ur circumstances. even tho we both have a 4th gen, our cars are different because they have been treated differently and live in different climates.

 

i think some tips for getting better gas mileage goes as follows

-lose 100 lbs
-replace air filters, spark plugs,
-change oil when you should
-check tires, fill up tired when needed
-don't drive fast


my friend was telling me about some new spark plugs that should help save you gas but i haven't gotten around to actually looking it up yet. i think he called them pulse plugs or something.

and to the poster above me using 91, i'm pretty certain you don't get better gas mileage your engine just runs alot cleaner. less problems like your o2 sensors failing and what not (from what i've read, i think mine are bad, CEL is on )

 

Since you haven't touched the engine for about 20k miles, do the tune up. I see you say you cruise around 2500rpms, isn't it supposed to be under 2krpms?

 

Bro...I'm in the same boat as you. Trying to improve my mileage any way I can. New Air/Fuel Filter, new spark plugs, and I just changed my entire exhaust with the following: SS AutoChrome headers and Y-Pipe, Warpspeed High-Flow cat, Budget B-Pipe, and new OEM 4th gen muffler. It was a little loud at first but I got used to it and the sound is growing on me. It's not loud like a riced out civic...sounds more like a Camaro/Corvette to me. Throaty...very throaty...but not loud.

 

The most productive ways to save gas; keep up the regular maintenance schedule, reduce unsprung mass (i.e. lighter wheels, lighter suspension/ brake components), remove unneeded weight, and of course as your car gets older replacing various sensors , cracked vac lines etc.

As far as driving methods, I read a Road & Track article a couple years ago where they actually tested various methods of accelerating for the best mileage. The best mileage they got was by doing the following: Progressively (smooth steady gas pedal engagement) accelerating as quickly as possible to roughly 40% (2600-3000 RPM in the maxima) of the RPM range through each gear (again smooth steady pedal engagement is key, don't mash the throttle). If you are on flat ground on the freeway/ highway, cruise control will net the best mileage. On hills, cruise control wastes more gas because going uphill it will accelerate and downhill deaccelerate.

I drive this way most of the time and get 3-4 mpg better in my truck since doing it consistently (with automatics, you may have to let off the gas a little to coax an upshift when you want). The Maxima however is a different story, I floor it every day in every gear .... and love it.

 

yes actually trough the city its actually 2k because 5th gear and 2k is 50mph. I try to be in 5th for the better duration of time. If not possible, 3rd 2k and 4th 2k are the best alternatives. Because they do have the same thing as the 5th. 3rd 2k = 30 mph and 4th 2k = 40mph.



So far we have. What I'm not sure about I've put a "?" in the end.


Don't Abuse the gas pedal.
Slow and steady is key

Maintenance
Seems to be a MAJOR factor in determining on how much gas your VQ eats up.
- Change spark plugs, oil and fuel filters, replace clogged up hoses, clean out clogged pipes, change oil regularly.
- Also KS sensor, o2 Sensors, our cars have AFM they aren't immune to damage either, and WILL affect the MPG greatly!

Weight
Rid of unnecessary weight. If your real serious replace body panels with lighter ones. Light weight rims. Big sub's are heavy and make the car work just a little more than it should sometimes thats enough to steal a $ or two off ya. Seems like not much but that adds up!

Higher Octane fuel
Mixed feelings on this some say the higher the lower the fuel consumption some say it does not matter!


MEVI mod?
Being that it produces more air flow? ... is it Gas conservative ?


SAFC(fuel delivery tuning device *piggy back system*)?
Anyone who has ever taught of boosting should know what this is! But question is would it SAVE gas ?

Would a light weight flywheel help ?
I don't think this was addressed yet.

Dare i say, Turbo ?
Gas saver ? or too much temptation to save gas ?

and last but not least
Built motors?
Lighter pistons, lighter internals that make for an easier cycle. Saves gas ?

 

i think def the cheapest and easiest things to start with are cleaning IACV and def the TB. Also, there is some MAF cleaner u can buy and i'd give ur MAF a spray with that (carefully) to get all the dirt and crap off. These def inc power while also inc gas mileage. Win win situation.

 

MEVI is not worth it, even if it does save gas, you would have to drive so much to save money off its cost.

 

Flow mods don't really help you save gas, since your tuning has not changed. Adding an SAFC and tuning extra close may help save some gas, although the 4th gen is tuned reasonably well from the factory.

Mod your right foot. Cruise on the highway at 70 instead of 80. Take off slower, and avoid maneuvers that require using a lot of throttle.

Keep tire pressure at 32psi all around. 35psi if you're convinced more pressure saves gas. (It doesn't).

Keep the A/C to a minimum. Avoid the 'auto' setting on your climate control if it's the fancy kind, and when you do need A/C set the temp as high as you can tolerate it. In winter be sure to turn off the defrost mode as soon as your windows clear.

Definitely check for ecu codes. O2 sensors and knock sensor codes may point you toward fuel-saving fixes. Test your engine coolant temp sensor if you're feeling saucy. Replace the fuel filter.

Replacing parts that aren't indicated to be bad is a loss. It will take forever to reclaim your investment unless it results in 5mpg difference.

For many people 20mpg is about all they'll get out of their car. Mine gets 25mpg (been tracking mileage for 2 years, so this isn't made up). I got 20-23mpg doing 50/50 highway and traffic light driving, then it went up to 25mpg now that my daily drive involves less traffic lights and slower highways. I think that's a reasonable maximum for most 4th gens.

Higher octane does not save gas unless you've been running too low of octane (87 for example) and your knock sensor has tripped the ECU to advance timing. I run 89 octane for a year and it has not changed mileage one bit.

Lightweight flywheels will save a little bit of gas but not enough to pay for itself. Ditto with lighter body panels.

Built motors in theory can save gas but in 99% of instances they are designed to burn more. They certainly cost more than the potential savings even if you optimize for fuel economy. Turbos definitely waste gas; they are only put in to boost torque, which if you're driving for fuel economy is something you won't use a lot of.

The bottom line is that most of the parts in your car are already built for fuel economy. There are a lot of aftermarket parts out there that claim to save gas, but it's a case where they are telling you what you want to hear, with little risk of being

Dave

 

COAST try it. Conservation of momentum

If you could drive and never use the brake (which is impossible but the brakes can be used less) your car would have very similar mileage to a hybrid maybe 30-35 mpg in the city for the Maxima. If you accelerate then immediately brake HARD all the gas you use to build up the cars momentum is wasted through the brakes in the form of heat. Using the brakes less in the city gives you mileage around 24 or 25 in the city instead of 19 or 20.

Less say you drive on a road with 10 stop lights spaced 1 mile apart and you had to stop at everyone. If you weren't trying to coast you might accelerate to a speed for 25% of the mile (12 mpg) Maintain speed for 50%(31 MPG) then brake the last 25% ( 0 gas used until idle) Roughly you would use .36 gallons over the 10 mile trip and get 27.7 mpg

If you were coasting more you would accelerate for 25% (12mpg) then maintain speed for 25% (31 mpg) then coast 25% (0 gas used) then brake the last 25% (0 gas used). It may take longer but with 25% mileage you could accelerate to a higher speed. Over the 10 mile trip you would use .28 gallons of gas and get 34.6 mpg

These numbers are a little high because it's hard to coast a half mile but it goes to show that increasing braking distance by half increases gas mileage by 21%.

I achieve about 25 mpg in with 80/20 city highway and about 29 MPG 10/90 city highway. I coast more then usual but I still use the brakes but less.

 

5-speed conversion will net you anywhere from 4-10mpg, even driving it fairly aggressive, allthough you'd have to put ALOT of miles on it for the $$ to equal out......

 

?? Really?

 

Hey no need to be a jerk, especially considering I just finished trying to put food on your plate in a different thread if your assistance is needed, I also mainly mentioned that since you weren't the only person in this thread mentioning there 5-speed mpg and not making note of it.......

 

kool it boys, the play ground is that way if u wanna throw sand at each other --->

anyways, i think its not worth the money swapping in a 5spd and then enjoying it.

basically the whole point is to spend LESS money on gas and everything else, so buying countless fuel injector cleaners for example is a bad idea. i just say keep up the maintenance, lower the weight u carry in the vehicle, close the windows at highway speeds and use AC, open the windows in the city at low speeds. thats it (well besides what else was mentioned all the way from the beginning)...

 

Im already 5spd but thnx for the advice.


As far as A/C goes. Thats one thing i am NOT willing to sacrifice to save money. I tried that today, jesus i almost passed out !

 

Not trying to be a jerk at all.

Everywhere I've ever seen mpg rating the autos have been maybe 1-2mpg behind the manual trannys. 5mpg is whole lot.

Dave

 

EPA rated the A32 4AT better than its 5MT counterpart re: highway MPG.

 

I averaged out about 80miles/quarter and I was shifting at 2k and kept my speed at/below 65 on freeway. I went to Autozone and got myself a bottle of Valvoline Injector Cleaner for like $5.50. My first tank with the valvoline inside, I was pushing a little bit above 100miles/quarter. I squeezed well around 380miles before I filled up (saw cheap gas) and it was nowhere from giving me empty light. I'm now on my second tank and driving 70+ on freeway and flooring it occasionally for no reason and I'm still pushing give or take 100mile/quarter. True story.

 

um ok lets settle this once and for all

from the consumer guide site or the nissan site
http://www.nissannews.com/site_libra...ma/index.shtml
http://consumerguideauto.howstuffwor...n-maxima-6.htm

EPA Estimated:
22/27 mpg City/Highway for 5SPD
21/28 mpg City/Highway for Auto

the auto Torque converter drops the RPM by about 500 to about 2300 or 2400 in my car when i reach 100 to 110 Km\h, thats already in 4th gear (auto), but as i heard many people here say that the 5th gear in a manual is too short or something and thats why the RPM is like almost 3000 going the same speed.

so pick ur poison, do u drive on hwy more or city? then thats what kinda tranny u should have if u wanna think of gas savings

DONE!!!

 

assuming that your car got nice tuneup & a good clean air filter .
1) be realistic about mpg expectations.
2) check for bad knoc sensor & dying o2 sensors, they will not throw code. If you have access to autotap try to take a trace of tps & o2 output & see how they are doing.

 

This thread seems to be becoming somewhat repetitive.

 

just like every other gas mileage thread....

for the windows being down mention before. Putting your windows up with A/C on the highway is not better. And having the windows down is not that hot. I have blck leather and I still don't use the A/C too often in the summer.