# Fuel Economy hints



## SentGXE99 (May 8, 2004)

I have a 99 Sentra GXE, 1.6 with automatic. I have been driving very conservatively considering fuel but still only getting 25 mpg. I only weigh 185 so I'm not weighing it down to much. I have the 1.6l engine with auto, keeping overdrive on, with K&N panel filter, NGK V-Power plugs, Taylor plug wires,synthetic oil (Mobil1), 15" SE-R rims with Firestone Firehawk 500 tires. Any have any ideas to increase efficiency? Can any gear ratios be changed, gears swapped like in Hondas? Underdrive pulleys any help? Any tweaks to MAF meter or TB to help? I will eventually get a better exaust but that won't help fuel consumption. Thanks, I do a lot of driving everyday.


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## dmroberson (Jun 24, 2004)

SentGXE99 said:


> I have a 99 Sentra GXE, 1.6 with automatic. I have been driving very conservatively considering fuel but still only getting 25 mpg. I only weigh 185 so I'm not weighing it down to much. I have the 1.6l engine with auto, keeping overdrive on, with K&N panel filter, NGK V-Power plugs, Taylor plug wires,synthetic oil (Mobil1), 15" SE-R rims with Firestone Firehawk 500 tires. Any have any ideas to increase efficiency? Can any gear ratios be changed, gears swapped like in Hondas? Underdrive pulleys any help? Any tweaks to MAF meter or TB to help? I will eventually get a better exaust but that won't help fuel consumption. Thanks, I do a lot of driving everyday.


I have an 04 1.8s sentra, automatic, and I'm getting 35/50 mpg, city/hwy now. I've only put in a Weapon-R intake in the car. I'd suggest putting in an intake, this would help the car "breathe" easier, which will help with mileage. Also, an exhaust system WILL help too. Stock systems, both intake and exhaust, are not really designed for performance, but are designed more to keep the noise down, that the engine would otherwise generate under heavy load. Aftermarket systems would increase the noise, yes, but these systems are designed with performance in mind, mileage would increase if these are upgraded.

Rest of my car is stock, aside from the Yokohama Avid T4's that I have on. I also run 3qts standard Penzoil mineral oil and 1qt Lucas Synthetic Stabilizer, but that's cause I put 200 miles on my car every day.

Like I said, I only did the intake so far, and I've gained about 10 mpg in city, and highway, give or take. don't tweak the MAF, these you dont' wanna mess with. They'll adjust with the new intake if you decide to put one in. same with the TB. Gears, I'd say leave'em be.


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## ASxa86 (Feb 23, 2006)

I drive a 98 GLE auto and have been getting 28-29 mpg with mostly city driving. Only thing I have had done to my car is CAI and new exhaust. 

Btw this is up from originally 27mpg.


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## IanH (Feb 11, 2003)

SentGXE99 said:


> I have a 99 Sentra GXE, 1.6 with automatic. I have been driving very conservatively considering fuel but still only getting 25 mpg. I only weigh 185 so I'm not weighing it down to much. I have the 1.6l engine with auto, keeping overdrive on, with K&N panel filter, NGK V-Power plugs, Taylor plug wires,synthetic oil (Mobil1), 15" SE-R rims with Firestone Firehawk 500 tires. Any have any ideas to increase efficiency? Can any gear ratios be changed, gears swapped like in Hondas? Underdrive pulleys any help? Any tweaks to MAF meter or TB to help? I will eventually get a better exaust but that won't help fuel consumption. Thanks, I do a lot of driving everyday.


How many miles ?
Consider changing the front O2 sensor if you have 100K or more.


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## SentGXE99 (May 8, 2004)

The car has 140k on it. Change the o2 sensor huh? yeah, may try that.


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## Mattster2k5 (Jan 22, 2006)

Man im getting 33mpg average all stock with a crappy filter that is like an inch thick. K&N Filter soon I hope.


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## azkicker0027 (May 31, 2002)

if i shift at 2k and keep the revs down, i get good fuel economy. other than that, i'm breaking the law and pushing the car.


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## nova73guy (Mar 30, 2004)

Do all the stuff the so-called "experts" say to do and you'll be fine (proper regular maintenance, slower speeds, etc.) With a 1.6 you should be getting better mileage. Hope you get it figured out. Oh, and Mobil1 in a 1.6=HUGE waste of money.


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## DrumBum05 (Jan 18, 2006)

I'm pulling anywhere between 33 to 40mpg (I drive hwy 90% of the time, although I AM cruising at like 70-75). Nonetheless, the only mods I've done are both O2 sensors, crank postion sensor, and a bottle of STP fuel injecter cleaner every 3rd or 4th tank. (oh btw, it's a '95 200SX, 5-speed)


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## SentGXE99 (May 8, 2004)

I use Mobil 1 because I have always had good luck with it. Whenever an engine has been looked at, it's very clean. No gunk, wear, buildup, etc... Mines an auto, but I drive easily on it and do about 120+ miles daily. Tires are inflated to 32psi, on 195-15-15s, Firestone Firehawk500s, not racetires. I plan on replacing the O2 sensor, plugs new, plug wires new. I just figured at 55-65 mph I should be getting better than 25mpg.


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## Mattster2k5 (Jan 22, 2006)

To get the best fuel economy you want to keep everything lubed well. Change your fluids with synthetics in the engine. Royal Purple makes the best synthetics for trannys, engines, and gears. It may run a little higher but its good stuff. I saw a Dodge 4x4 have all fluids changed to it and got 9 more horsepower and 3mpg more all dyno proven there was a dyno run before the fluid change and after.


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## SentGXE99 (May 8, 2004)

I run Mobil 1 5/30W synthetic in the motor and Amsoil synthetic Auto trans fluid in the tranny.


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## Oyveychris (Jul 2, 2007)

What about using some fuel injector cleaner (like Lucas), or running some Seafome through one of the vacuum lines to get rid of deposits in the engine? At that many miles, the intake is likely gummed up. 

You should also adjust your Flux Capacitor... Just kidding! 

I'm currently averaging 30 city/ 35+ highway...


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## Tavel (Aug 21, 2004)

SentGXE99 said:


> I have a 99 Sentra GXE, 1.6 with automatic. I have been driving very conservatively considering fuel but still only getting 25 mpg. I only weigh 185 so I'm not weighing it down to much. I have the 1.6l engine with auto, keeping overdrive on, with K&N panel filter, NGK V-Power plugs, Taylor plug wires,synthetic oil (Mobil1), 15" SE-R rims with Firestone Firehawk 500 tires. Any have any ideas to increase efficiency? Can any gear ratios be changed, gears swapped like in Hondas? Underdrive pulleys any help? Any tweaks to MAF meter or TB to help? I will eventually get a better exaust but that won't help fuel consumption. Thanks, I do a lot of driving everyday.


that's consistent with my 98 GXE. There's the "city" driving that is in the EPA estimate, and then there's real city driving with stop lights every 200ft and 45mph max speed. Real city driving will get you 25mpg...you could do a little better with a manual. But beyond that, there really isn't' anything wrong with your car.

You could run a tank of Chevron Techron, that's the only injector cleaner I would ever recommend. (anything but lucas!!!). you might also want to clean the throttle body and plate. careful though, the engine floods really easily! clean it in small steps, not all at once. I just used STP throttle body cleaner. 

...but i never really saw any gains from these products. cleaning the TB made it run somewhat smoother....but taking it on the highway for a few hours did a much better job of smoothing everything out and boosting the power. I didn't even do that on purpose, my GF took the car for a trip and didn't tell me. I drove it and was like "woah, wtf did you do to the car? it runs great!"

BTW: I do mean CITY driving when i say city driving, my cars touch a highway maybe once a month...and even then it's only a few miles at a time.


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## SentGXE99 (May 8, 2004)

Yeah, I have run Seafoam thru the crank before changing oil, and thru the fuel system. I run a K&N filter, make sure my tires are pumped up, and cleaned my intake with some intake spray from AutoZone. I also got some special stuff to clean the MAF sensor. The tranny has Lucas in it because it started slipping in June, but runs fine now. I am considering Carbon/ Fiber glass body parts to reduce weight. I also contacted JWT to see if they could retune the ECU, and I am awaiting response. A Subaru STi, making about 400hp in Sport Compact Cars Ultimate Street Car Challenge, got 42mpg on the test loop. I have 1/4 that power, I want more mpgs from my mule. I also have had all 4 wheel bearings replaced. Not really for mpg reasons, but they failed and I hoped it would help it cruise smoother and easier, but no.


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## IanH (Feb 11, 2003)

SentGXE99 said:


> Yeah, I have run Seafoam thru the crank before changing oil, and thru the fuel system. I run a K&N filter, make sure my tires are pumped up, and cleaned my intake with some intake spray from AutoZone. I also got some special stuff to clean the MAF sensor. The tranny has Lucas in it because it started slipping in June, but runs fine now. I am considering Carbon/ Fiber glass body parts to reduce weight. I also contacted JWT to see if they could retune the ECU, and I am awaiting response. A Subaru STi, making about 400hp in Sport Compact Cars Ultimate Street Car Challenge, got 42mpg on the test loop. I have 1/4 that power, I want more mpgs from my mule. I also have had all 4 wheel bearings replaced. Not really for mpg reasons, but they failed and I hoped it would help it cruise smoother and easier, but no.


I get 24 - 26 in town here in north Dallas.
Stop and go, with the go being up to 65 or so, particularly at lunch time.
Very hard on gas mileage.
Car will do 32 mpg at 80 or so on round trips to Austin.
I am going to try changing the front O2 myself. but would be nice if someone who has done this would say if it improved gas mileage.


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## ilikespeeding (Dec 9, 2006)

Im going to bypass my coolant line into my intake manifold soon. That should help. I get about 27 mpg. Fuel injector cleaner is all bullshit. The only way to really clean them is to remove them and have them cleaned on a bench cleaner. Remove the A/C relay for better gas mileage. Check to see if your plugs are blown out. NGKs are bad about blowing out. Remove each one and look for a brown ring where the white meets the metal near the bottom. If no brown ring, dont replace. 


I'd go with lightened pullies before I'd go with underdrive. Underdrive hurts low rpm p/s and a/c.


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## GA16DE (Jun 23, 2005)

Unless it is Unorthodox Racing. They state that their underdrive pulley makes about 85% of its gains from lightening (about 1 pound to the stock 4) and 15% from underdriving. They also say that it keeps things charged enough to use like usual. There used to be an article on Nissan Performance Mag's site, but it is nothing but code now: Project 200SX - Unorthodox Racing Pulley.


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## SentGXE99 (May 8, 2004)

I may try an underdrive pulley. Along with an O2 sensor. I may even tape some botle rockets to the car for more thrust.


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## Tavel (Aug 21, 2004)

SentGXE99 said:


> I may try an underdrive pulley. Along with an O2 sensor. I may even tape some botle rockets to the car for more thrust.


 supplement the drive train with bicycle pedals :idhitit:


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## Recian (Sep 30, 2008)

my B14 has been getting about 25-27mpg and that was 202k miles with the timing 2 teeth off. it was at 23 when i bought the car. i poured Lucas fuel injector cleaner in the fuel tank that upped me to 25 consistantly. i put a SAI on it which bumped me to 26-27 and new platinum plugs and irridium wires made it a consistant 27. i also noticed it got better mileage when i drove it medium/hard not conservative. i rebuilt the engine a few days ago, cleaned the valves, cleaned the pistons removed so much carbon so im interested to see what mpg i get now with combustion chamber cleaned and timing chain replaced


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