jesseruns

I've got a 95 vx and was hoping to increase the gas mileage on it. I'm planning on trying to find some close-as-stock tires for it but thought if I could find out the difference between the CA models and mine then I might be able to boost the mpg. Best I can figure that is the difference between the two VXs described on fueleconomy.gov
Right now I'm getting 42.5mpg where the epa says I can get up to 51 (possibly 56)mpg. I was able to get better than recorded mpg out of my 96 accord so I don't think that it's the way I drive.
Any help would be great.

b18bturbo

first step is always do regular maintainance. Fuel filter, clean air filter, 02 sensor and oil

any used car such as this will need the basics done this will increase mpg

Low resistence tires help if you can add little pressure to your tires.32-35psi

Shift conservatily as well helps

datssoled

well i have a 98 civic lx but im getting about 260 miles on a full tank. I have a AEM intake , but does it take that much off mileage? tires are in 32-35 psi and i regularly change my oil filters.

Relic1

CA VX's got a standard 4-wire O2, no lean burn mode and no EGR. (ie less mpg)

http://www.gassavers.org is a great source.

in addition to b18bturbo's list... valve adjustment, synthetic engine oil, synthetic trans fluid, lighter right foot.


BTW, miles per tank is next to worthless, the VX has a smaller fuel tank than the other civics.

imzjustplayin

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Relic1 &raquo;</TD></TR><TR><TD CLASS="quote">CA VX's got a standard 4-wire O2, no lean burn mode and no EGR. (ie less mpg)

http://www.gassavers.org is a great source.

in addition to b18bturbo's list... valve adjustment, synthetic engine oil, synthetic trans fluid, lighter right foot.


BTW, miles per tank is next to worthless, the VX has a smaller fuel tank than the other civics.</TD></TR></TABLE>

So what? All he has to do is figure out how many gallons the tank supports which I believe is 11.9 though that could be for the over civics.. What ever your tank supports, just multiply that by the MPG you want and that's your limit to how many miles you can drive, theoretically.

Evs-One

35 psi? No....crank them suckers up to max allowable pressure in the rear!!

Run as narrow a tire as possible.

Keep ALL maintenance up to date- lots of guys are seeing good mileage using Amsoil.

Run a light into the ECU harness that illuminates when in "lean burn mode", so you can stay in that as long as possible- crazy fuel economy there!

Dark@Powers

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by imzjustplayin &raquo;</TD></TR><TR><TD CLASS="quote">

So what? All he has to do is figure out how many gallons the tank supports which I believe is 11.9 though that could be for the over civics.. What ever your tank supports, just multiply that by the MPG you want and that's your limit to how many miles you can drive, theoretically. </TD></TR></TABLE>

In order for that to work you would have to run your tank to empty to compare it to what you should be getting if you multiplied to EPA's MPG number x your tank capacity. It is much easier to just do it by MPG.

imzjustplayin

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Evs-One &raquo;</TD></TR><TR><TD CLASS="quote">35 psi? No....crank them suckers up to max allowable pressure in the rear!!

Run as narrow a tire as possible.</TD></TR></TABLE>

Uh I'd just crank them up to max sidewall pressure on both front and rear, you don't want to create an imbalance. Remember, it's COLD sidewall, COLD meaning in the early morning and before you have driven it. Also a narrower tire believe it or not does not necessarily mean less friction than a wide tire. Two tires with the same compound and max pressure and AT the same pressure, the wider tire will have less rolling resistance. However a wider tire will have poorer aerodynamics and wouldn't be compatible with the VX rims anyhow which are about as light as you can get so this point is moot. Stick with VX rims, get LRR tires, crank up the tirepressure to max Sidewall COLD and if you haven't adjusted your driving habits, do so.

Evs-One

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by imzjustplayin &raquo;</TD></TR><TR><TD CLASS="quote">

Uh I'd just crank them up to max sidewall pressure on both front and rear, you don't want to create an imbalance. Remember, it's COLD sidewall, COLD meaning in the early morning and before you have driven it. Also a narrower tire believe it or not does not necessarily mean less friction than a wide tire. Two tires with the same compound and max pressure and AT the same pressure, the wider tire will have less rolling resistance. However a wider tire will have poorer aerodynamics and wouldn't be compatible with the VX rims anyhow which are about as light as you can get so this point is moot. Stick with VX rims, get LRR tires, crank up the tirepressure to max Sidewall COLD and if you haven't adjusted your driving habits, do so.</TD></TR></TABLE>

max allowable, as in, pressure stated on sidewall NOT how much a compressor can fill it up to

wide tires have less rolling resistance?? Are you serious? There's no way!

The less material on the surface, the less friction = the better mileage. that PLUS areodynamics = better mileage!

And there's nothing wrong with running different tire pressures front and rear- as long as it's not extreme....run 36-40 fr and 40-44 rear and you'll be golden! As long as you're not trying to race on any streets, you'll be just fine

imzjustplayin

At first it may seem counter intuitive but when you read why it has less rolling resistance it does make sense.
http://www.schwalbetires.com/t...tance

Evs-One

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">Why do Pros ride narrow tires if wide tires roll better?

Wide tires only roll better at the same inflation pressure, but narrow tires can be inflated to higher pressures than wide tires. However, they then obviously give a less comfortable ride.

In addition to this, narrow tires have an advantage over wide ones at higher speeds, as they provide less air resistance.</TD></TR></TABLE>


Therefor, a skinny tire with higher pressure WILL roll better PLUS, it will be more aerodynamic.

Good link....that's why road bike tires run 120 psi

blinx9900

are you seriously complaining about 42.5mpg? you got some nerve tiger... i get 17mpg in my 01 cl type-s auto and that's if i drive like my grandma

richcon82

I wish I got 42 mpg

CTR Tranny on GSR FTL lol

imzjustplayin

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blinx9900 &raquo;</TD></TR><TR><TD CLASS="quote">are you seriously complaining about 42.5mpg? you got some nerve tiger... i get 17mpg in my 01 cl type-s auto and that's if i drive like my grandma </TD></TR></TABLE>You probably need a tune up if that MPG figure is a 50/50 combo of highway and City. That car is rated at 17/27 city/highway so the only reason you should be getting 17mpg is if you're doing 100% city or you really need a tuneup.

blinx9900

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by imzjustplayin &raquo;</TD></TR><TR><TD CLASS="quote">You probably need a tune up if that MPG figure is a 50/50 combo of highway and City. That car is rated at 17/27 city/highway so the only reason you should be getting 17mpg is if you're doing 100% city or you really need a tuneup.</TD></TR></TABLE>

yup, i drive ONLY on the street, the amazing thing is the few times i drive on the HWY i got 30mpg!! and thats driving at 80mph (please dont yell at me for speeding thats normal speed in California). This car would be great for someone who drove more on the HWY i just dont know what to do

also to the OP i would not try to hard to get the advertise MPG, remember that was a long time ago, the tests were dont differently...

per4mance

iTrader: (1)

Well one reason everyone is getting worse gas milage then stated on there car is because almost every gasstation is adding 10% ethenol and that right there can make you lose 50 miles or more a tank. We did a test on my accord here two monhs ago. I tested gas at the local shell station with 10% ethenol in it and got 350 miles to the tank. I then drained the gas remaining gas that was in the tank and went to the local chevron which dosent use the ehtenol yet and got 430 to the tank. So I gained 80 miles on my tank by not using the ethenol mixed gas. I have a 16 gallon tank and my car has 263000 miles on it. I changed nothing else.
So next time you got to the gas staion try and find one that dosent use ethenol.

blinx9900

holy crap! that sucks!! thank you per4mancer for sharing, how do we find out? like just ask the guy if they use ethanol in there fuel?

Evs-One

the 10% Ethanol results are completely true! Also, I've seen E10 fuel KILL fuel injectors as well- had a few cars towed in that had a bad batch of gas, and ended up cleaning the injectors and flushing out the tank.

I know in WA state, ALL gas stations are adding 10% Ethanol now...FTMFL!!

imzjustplayin

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Evs-One &raquo;</TD></TR><TR><TD CLASS="quote">the 10% Ethanol results are completely true! Also, I've seen E10 fuel KILL fuel injectors as well- had a few cars towed in that had a bad batch of gas, and ended up cleaning the injectors and flushing out the tank.

I know in WA state, ALL gas stations are adding 10% Ethanol now...FTMFL!!</TD></TR></TABLE>

Actually not quite. Ethanol will actually prolong your engine and is good for it. However the problem with ethanol on old engine is its cleansing properties. Running a 10% ethanol fuel mixture on that car to cause that problem clearly shows the car has a build up of carbon/old fuel which was dislodged by the ethanol and that clogged the injectors. Some people use E85 in their cars despite not being designed for it and have found it to really clean things up, unfortunately if you've got build up of LOTS of carbon and gunk, it's all goanna come out and will probably screw up your O2 sensors and a lot of other things too.

per4mance

iTrader: (1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by imzjustplayin &raquo;</TD></TR><TR><TD CLASS="quote">

Actually not quite. Ethanol will actually prolong your engine and is good for it. However the problem with ethanol on old engine is its cleansing properties. Running a 10% ethanol fuel mixture on that car to cause that problem clearly shows the car has a build up of carbon/old fuel which was dislodged by the ethanol and that clogged the injectors. Some people use E85 in their cars despite not being designed for it and have found it to really clean things up, unfortunately if you've got build up of LOTS of carbon and gunk, it's all goanna come out and will probably screw up your O2 sensors and a lot of other things too. </TD></TR></TABLE>

Well my boss has an 07 tc and he lost about 50 miles per tank when running the 10% ethenol. See they just started adding the ethenol at the first of the year to all most all the gas station here. And they have a decal that says 10% ethenol on the pump. I do agree that ehtenol burns better and can prolong the motor but i dosent help the gas milage.

suspendedHatch

You are right at what everyone else with a VX reports they get. Some EPA figures that you see are based on their old method of calculation. They have since changed to a more conservative method that more accurately predicts what people actually get.

There really is not much more you can do to a VX to improve FE. Honda did an excellent job. I mean come on, how many HYBRIDS today can match the VX? The stuff you CAN do to improve FE are not things that you will want to do. They involve some pretty embarrassing looking aerodynamic modifications. The driving techniques that people have used successfully on other vehicles apparently don't do much for the VX.

Running the tank empty to calculate mpg is neither accurate nor repeatable. You calculate mpg using the trip meter and using your next fill up to determine how much gas you used.

I have come across info that the 92 VX gas tank is smaller than the other model Civics but now that I have a 92 VX I know that to be false.

You can convert a CA VX to federal spec by swapping in the wideband O2 and federal P07 ECU. 92 VX's are pre-wired for the wideband O2.

Increasing tire pressure improves mpg to a point and beyond that is the realm of diminishing returns. When you get a flat at freeway speeds and the tire comes off the rim you will have second thoughts about inflating the tires over 35psi.

Ethanol is cheaper but does not give you as good of FE as gasoline. Ethanol is the better fuel however. But you can't run E85 w/out re-tuning your ECU and in some cases you have to beef up your fuel system.

imzjustplayin

That is true, it does hurt mileage but you can lessen the effects if you run a higher compresison ratio engine and or advance the spark timing further and whatnot.

greasemonkee

I have a non-CA d15z1 sitting here beside me. The previous owner claimed he was getting 50 on the hwy. Unfortunately the shell was totaled when I bought the car. I had a couple plans for the engine - would receive a full build:

Techline coatings - DFL-1 and WSX coatings will go a long way on moving engine parts

Intake ports and manifolds will be deburred and refinished. The intake ports will get "cats tongue" and modified golf ball texture to keep fuel in suspension and aid in fuel atomization.

Combustion chambers might receive some level of Polyquad technology if possible.

Would like to increase static compression for thermal efficiency, ect, but other than milling, doubt it's possible - will have to diagnose. The Z1 chambers are probably spherical shaped top and bottom (especially with dished pistons), but I'm not certain, if so, care must be taken to enhance swirl when chamber is at tdc, which may limit compression goals.

High flow/low restriction cat and exhaust may be beneficial.

Fuel heater to aid in atomization may help tremendously at the expense of power and detonation threshold, which neither should be of concern in this application. Possibly use engine coolant routed through an aluminum block along with the fuel - just an unbreakable heat exchanger of sorts.

Retune engine and experiment with later engaging of vtec, maybe engage at 90% tps. Might be able run leaner than stoichiometric afr's over greater portion of the map that would otherwise have not been done at the factory due to emissions - NOx emissions likely will go through the roof - many more variables/possibilities at work which must be accounted for...

That's all I can think of within my grasp for the engine. Someone proficient with electronics and ultrasound transducers may have the ultimate advantage.


I occasionally pass the guy with the aerodynamically modified EG, I think he posts on gas savers and had cleared 62 mpg with a stock cx engine at 70 mph? One can only dream of the possibilities if the whole system were reworked.


BTW, does anyone happen to know the correct stoichiometry value of gasoline and this 10% ethanol mixture? I guesstimate 14.2-14.5ish??

Relic1

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by suspendedHatch &raquo;</TD></TR><TR><TD CLASS="quote">I have come across info that the 92 VX gas tank is smaller than the other model Civics but now that I have a 92 VX I know that to be false</TD></TR></TABLE>
hmmm, I have a 92 VX. And I've drained it before. 10.4gal to fill it and the neck.
even the 92 civic sales brochure shows a smaller tank in the VX.
this may be one of those things that honda changed mid year for some reason. Maybe the smaller tanks were not produced as fast and the first part of the production didn't get them, or they didn't produce enough of them to finish out the 92 model year.
or different manufacturing plants...

there are a lot of things with the VX that are special.
like the Cali-spec VX in 92 has the 5-wire O2 all ready but the lean burn mode is disabled in the ECU, 93-95 cali-spec VX's have a standard 4-wire O2.