Ya ya I know search, I couldn't find anything

I have a 1990 crx si and get 29-31 mpg on a full gas tank, was wondering how I can get a better mpg. Nothing is really wrong with my vehicle, and don't really use a/c.

The only modification I have on my car is a aftermarket intake. Going stock intake will gain mpg? What else can I do to save a couple of bucks at the pump? New o2 sensor gain?

Thank u for your time

 

Seafoam

 

Theres really not much that you can do to get an si better fuel mileage. The problem with that is that the tranny revs so high so the motor uses more gas. You can swap out the tranny for a regular dx one and get what you want. Thats all I can think of at the moment.

 

I used to get 40 mpg in my CRX Si driving 80mph everywhere.

if you're not getting that then something is wrong

O2 sensor, "chipped" ecu (incorrectly chipped that is), engine out of sorts etc.

 

Mog,

What kind of driving do you normally do? Highway? Speedy pizza-delivery?

There are many mechanical and aero mods/improvements, but nothing is as effective as a conservative driving style.

 

Tire pressure.

 

Hmmm so, to both of u.

I drive 30% street and 70% highway

Havnt thought about tire pressure, ill need to check that. Thank you

 

tires make the biggest difference IMO. air 'em up to 40 psi and run the stock size tires and you'll get high 30's all day, maybe 40. thinner tires equal better mpg too. not sure if 13s will fit, but that would help

 

DO U SPEED A LOT CUZ WITH MY REX IF I PUNCH IT EVERY WERE I GO A TANK WILL ONLY LAST ME LIKE 3 OR 4 DAYS BUT IF I DRIVE NORMAL IT WILL LAST ME A WEEKAND I DRIVE A LOT CUZ MY GF LIVES LIKE 30MIN AWAY AND I GO SEE HER EVER DAY AND I GO TO THE RACES ON THU. AND SAT. SO U MIGHT WANT TO CONSIDER HOW UR DRIVING

 

pump those tires up to 40psi like said above, coast on hills in neutral , accelerate slowly out of a dig. do it for a tank and watch the diffrence log it and let us know.

 

Well lol tire test. The recommended psi is 44 on my tires. I had 30-35 rofl... We'll take a lot then after this next tank of gas. See ya guys in a week haha

 

and the recomended psi for the vehicle is in the 32-35 psi range.

Just know that increased tire pressure will increase braking distances and decrease traction especialy in the rain.

 

Hmmm very nice to know thank you. Didn't think about the braking and wet tracting but it makes perfect sense.

 

do the 4 wire o2 mod i did it helps a lot the car drinks gas on warm up so u use a heated o2 to fix the problem because the o2 works best at 200 or 300 degree C i think i got a right up here is the link http://www.geocities.com/speed...e.htm

thiss works a lot trust me iv dont it it helped in the winter it works even better
get a o2 off a 92 civic or a 97 civic not the cat one tho the one on the headers of the y8 only

 

Coasting in neutral has been helping me bigtime. Let the cars momentum carry you to a red light from way back. No sense in gassing it to a light and mashing the brakes. Red light means nobody is going anywhere. If the light changes while you are rolling in neutral, the better for you. Takes less gas for the car to get to speed when rolling than it does from a dead stop. Keep it at 60 MPH too. The faster you go, the more mother nature pushes against the car. I was getting 34 MPG but after doing this stuff I've raised that to 40 MPG... in an automatic!

 

Man you guys are lucky. I get about 20 mpg on regular n 23 if i drive it like a grandma. i think theres somethin wrong. n just to let you guys know i have a ZC with the stock dpfi n autobox so i think i just might have the worst combination posible in a civic LOL

 

i kno the d15z1 gets good gas mileage

 

Plan your trips. Keep lists of needs that will require a trip and try to accomplish multiple objectives with each. This will not increase your fuel mileage (the number of miles your car moves for each gallon of gas), but it will help you drive less (which, in turn, means you use less gas).

Lighten your load. Get the lightest car that will serve your needs. Weight is one of the biggest causes for loss of kinetic energy in non hybrid cars. If you're not shopping for cars, then take any extra weight off of the one you're already driving. If seats that you don't use can be removed, take them out. If you use your trunk as a storage space for heavy things, find another place for them. An extra 100 pounds increases fuel consumption by 1-2%.

When you fill up with gas, fill up completely and try and keep your tank above one third full. If your fuel runs low, the engine might not receive a steady supply of gas (since it will splash around while you're driving and it might momentarily splash away from the tube that leads gas out of the tank). Not having a steady supply of gas will make your engine less efficient. The benefits of having a full tank will outweigh the drawbacks of having the added weight.

Slow down. The faster you move, the harder your engine has to work to push through the wind. Speeding can reduce fuel efficiency by up to 33%.
Use cruise control. In most situations, using your cruise control reduces fuel consumption by maintaining a constant speed.

Accelerate smoothly. When the light turns green, resist the urge to bolt ahead of the car next to you. This keeps the engine at lower revolutions per minute (RPMs) thus using less fuel. Car engines usually are most efficient at low rpms.
Plan your route carefully. Take the route with the fewest stops and turns and least traffic. Take highways in preference to city streets when possible.

Avoid braking wherever possible. Braking wastes energy from fuel that you have already burned, and accelerating after braking consumes more fuel than driving at a constant speed. On city streets watch ahead and coast when you see a red light or traffic jam ahead.

Set your tires to the proper inflation. Properly inflated tires can reduce fuel consumption by up to 3%. Your tires also lose about 1 PSI per month, and when the tires are cold (e.g., in the winter), their pressure will decrease due to the thermal contraction of the air. It is recommended to check tires at least monthly, preferably weekly. Having properly inflated tires will also help you avoid uneven wear on the tread.

Tune up your engine. A properly tuned engine maximizes power and can greatly enhance fuel efficiency. Beware, though, that many tuners will disable efficiency measures when tuning for power.

Check the condition of your engine air filter. A dirty filter will reduce fuel economy, or make the engine stall when idling. Just like mowing dusty grass, driving dusty dirt roads will clog the air filter: avoid dust clouds.

Replace your fuel filter according to your manufacturer's recommended schedule. This will go a long way to enhancing fuel efficiency.

Avoid excessive idling. Idling a vehicle wastes a significant amount of fuel. The best way to warm up a vehicle is to drive it slowly until it reaches proper operating temperature.

Try to avoid using the air conditioner in stop and go city driving as it causes the engine to work hard and consume more fuel. However, studies show that at highway speeds cars get somewhat better mileage with the AC on and the windows rolled up. The drag caused by rolled down windows at high speed reduces fuel efficiency more than the AC.

Find your car's "sweet speed". Some cars get better mileage at specific speeds, usually 50 mph. Your car's "sweet speed" is the minimum speed at which the car is running in its highest gear (watch for rpm drops as you accelerate to determine when your transmission is shifting into higher gears). For example, most Jeep Cherokees are best at 55 mph, and Toyota 4Runners are best at about 50 mph. Find your vehicle's "sweet speed" and pick your roads accordingly.
Use synthetic oil in your car to save on average 5% gas. Plus, fewer oil changes are needed, saving trips to the oil change place as well as less used oil in the environment.

When getting your oil changed, use a synthetic oil additive to either natural or synthetic oil. This can increase your gas mileage by up to 15% if you follow the manufacturer's instructions and recommended usage.

If your car has an automatic transmission with overdrive, make sure you enable overdrive except when towing very heavy trailers. Overdrive is by default enabled on the "D" on most shifters. Several cars have buttons on the shifter which allow you to turn off the overdrive gear. Don't turn it off. Overdrive saves you gas mileage at higher speeds by using a lower ratio from engine speed to wheel speed - this places the engine at a more efficient operating point (by reducing throttling losses, etc).

Learn to watch and predict traffic signals. Stop-and-go driving is wasteful.
Don't circle in a parking lot, and keep well away from the store fronts. Look for a spot in the empty half of the parking lot. Many people spend significant time idling and creeping, waiting for a "close spot" to open up.

Maintain a log over time of how many miles you go (the main odometer) and how much gas you put in (from the gas pump, including fractions). Put it in a spreadsheet. It will keep you focused, and other methods are inaccurate; you will never know for sure if you're saving fuel, wasting fuel or just seeing errors from gas pumps that stop pumping at different points, or fractions of miles being dropped off your 'trip' odometer when you reset it.

Maintain a safe following distance! Don't stick to the bumper of the car directly in front of you. You will brake more and accelerate more to keep that unnecessary and dangerous narrow gap. Relax. Hang back a bit. You're still traveling at the same speed as the car ahead of you even if you're 100 yards behind. This also gives you a lot more room to play with when you are timing lights. When he slams on his brakes, you can coast down and see if the light quick-changes green again (some do). You might even coast by his car as the light turns green and he has to accelerate from a dead stop.

Avoid idling. For example, in cold weather warm the car engine no more than 30 seconds. This period of time is sufficient to ensure that the engine is properly lubricated for driving. Generally, if you can avoid 10 seconds of idling you will save gas by turning the engine off and restarting. However, starting an engine too often can lead to excessive wear and tear on the starter motor and wiring.
When traveling on a long road with the pace of traffic, draft the car in front of you.

This will improve the fuel economy of both cars. You will know it is working when the car or truck sucks you in and there is less wind noise. The less aerodynamic the car in front of you is, the better drafting you will achieve.

Select the narrowest possible tires for your vehicle that will satisfy your driving style and demands. Narrow tires have less frontal area, thus reducing aerodynamic drag. Remember, however, that narrow tires have less traction as well (which is why race cars have such wide tires).

Select a gear ratio that is appropriate to your engine, transmission, and driving conditions. If you travel on the highway often and do not carry heavy loads, try a numerically lower final drive ratio (known as a "higher" gear.) Careful not to go too "high" with the ratio, this can cause smaller engines to work too hard to keep up, damaging the engine. Some manufacturers offer optional gearing.

On fuel-injected cars, make sure the oxygen sensors, engine emissions system, and evaporative emissions control systems are in good shape. Often the "check engine light" coming on is an indication that there is a problem with one of these components. A damaged oxygen sensor may cause your car to have too rich of a fuel mixture, decreasing your fuel mileage by 20% or more.

 

wow where did you plagiarize that from?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by grog &raquo;</TD></TR><TR><TD CLASS="quote">wow where did you plagiarize that from?</TD></TR></TABLE>
Haha Seriously. i just kept scrolling and scrolling. i have like 300 posts and i dont think i have typed that much total.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Big red89 &raquo;</TD></TR><TR><TD CLASS="quote">Theres really not much that you can do to get an si better fuel mileage. The problem with that is that the tranny revs so high so the motor uses more gas. You can swap out the tranny for a regular dx one and get what you want. Thats all I can think of at the moment.</TD></TR></TABLE>


I can't find an LX transmission. Either they are really hard to find or I'm not looking in the right place. I want to get rid of my EX/SI transmission.

 

why dont you just put a crx HF 5th gear in your si transmission... i run a 4.9 final drive and a .702 5th gear, and i still get 34 mpg on my SI.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sanimalp &raquo;</TD></TR><TR><TD CLASS="quote">why dont you just put a crx HF 5th gear in your si transmission... i run a 4.9 final drive and a .702 5th gear, and i still get 34 mpg on my SI. </TD></TR></TABLE>

Thats not a bad idea. However I was hoping to do a complete swap rather than having my car down for more time. Is it safe to assume that the 4.9 final drive from the HF is a lot taller than 5th gear from the LX?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rexie &raquo;</TD></TR><TR><TD CLASS="quote">DO U SPEED A LOT CUZ WITH MY REX IF I PUNCH IT EVERY WERE I GO A TANK WILL ONLY LAST ME LIKE 3 OR 4 DAYS BUT IF I DRIVE NORMAL IT WILL LAST ME A WEEKAND I DRIVE A LOT CUZ MY GF LIVES LIKE 30MIN AWAY AND I GO SEE HER EVER DAY AND I GO TO THE RACES ON THU. AND SAT. SO U MIGHT WANT TO CONSIDER HOW UR DRIVING</TD></TR></TABLE>

So, when you "Punch it" everywhere it lasts 3-4 days, but when you drive normal it only lasts a weekend?

Riiiiight, goodluck with those races.

 

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

Thats not a bad idea. However I was hoping to do a complete swap rather than having my car down for more time. Is it safe to assume that the 4.9 final drive from the HF is a lot taller than 5th gear from the LX?</TD></TR></TABLE>

well, the 4.9 makes gas mileage worse, but the .702 fifth gear corrects the ratio a little so i am not at 5k at 80mph. The normal SI trans has a 4.25 Final drive, so with the hf 5th gear you will get even better gas mileage than i do. The next step would be picking up an hf trans, or putting the hf 5th in a dx trans which has a 3.88 final drive.

the real question is do you want any performance characteristic left in the trans, or do you want insane gas mileage? because if you want insane gas mileage, then you should go with the hf transmission. if you want 1st through 4th to still be fun, but fifth gear to be for cruising, then you should keep the SI trans and swap the 5th gear for an hf 5th.