Mejia

Well with gas prices not getting any lower..... and money not coming in any faster....
I dont want to sell the car... dont want to regret it later.... I'm thinking of picking up another mazda...or honda...but in the mean time... i just wanna gets some upgrades that'll improve some type of gas mileage... aything ill help ... thanx...

farberio

iTrader: (7)

Full tuneup, proper air in the tires, not putting the gas pedal down all the way.

CarzArKoo1

don't fill gas all the way up, fill the amount you need, why carry the full tank of gas with all that weight on the car, lighten out your car. hope this give you some help

daviddeep

iTrader: (4)

You have the obvious:

1. Do a complete tune up (including spark plugs and wires, check timing, replace O2 sensor if you need to, etc.);

2. Replace air filter;

3. Make sure tires are properly inflated.

4. Remove any unnecessary weight. Get rid of subwoofer boxes, don't carry around your entire tool collection, etc.

5. Upshift when prompted by the shift light, i.e., around 3000 RPM to avoid using your secondary injectors whenever possible.


Then the slightly painful. This kind of stuff will help your fuel economy but could make the car less fun to drive:

1. Remove power steering, A/C and all related components to reduce overall weight.

2. Gut interior to reduce overall weight. If you want to get the best possible mileage, spare nothing. Out goes the sound system and all speakers and wiring. Remove passenger seat (it's pretty heavy). Remove spare tire and join AAA instead.

3. Get rid of wide, heavy, aftermarket wheels and tires. Replace with something skinny and light: If you have a 4-lug car, 14" Phone Dials with 185/70-14 all-season tires will be extremely light plus the harder compound will have less rolling resistance and the narrower width will reduce drag - all helping with fuel economy. If you have a 5-lug car, go with some 15" 'Vert wheels for extreme light weight.

4. Replace steel hood with aluminum if you don't already have one. (Grab the hinges and latch from the aluminum hood donor car if you want to do the swap the "right" way.) Remove sunroof tracks and mechanism and weld the opening closed with sheet metal.

5. If you have any aftermarket ground effects, wings, or body kits, remove them to save weight. If you mainly drive in the city, you can also remove your factory rear spoiler because at low speeds the loss of drag and/or downforce benefits are easily outweighed by the weight reduction benefit.

AreExSevenProject

iTrader: (1)

big one is the tire pressure...
also dont accelerate rapidly
(except for redlining it every now and then to clean carbon buildup off apex seals)

InsomniacFC

iTrader: (4)

A big one that was already mentioned is keeping it under 3,800 rpm's. My car had issues before i swapped the motor and i could not shift over 4k or it would smoke bad (blown oil control seal). The good thing is I did not drive it hard and would get great gas mileage. Now that I have a new motor I dog it all the time and get about 200 miles out of a full tank.

Another thing, drive on the freeway as much as possible. Around town mileage is not as good as highway. I was a commuter and that's how I got my 370+ miles out a tank.

Aaron Cake

iTrader: (1)

See the mileage section in the FAQ.

Aside from a good tuneup and making sure the car works properly, the best upgrade is the one between the seat and steering wheel. The way you drive is the most important factor. This is covered in the FAQ.

cloudx189

iTrader: (3)

CDI box also helps...

AreExSevenProject

iTrader: (1)

SAFC
tune down the gas in cruising... (highway driving)

Roen

iTrader: (2)

A lot of tuners actually don't like the CDI box, if your stock coils and wiring are in good shape. FC coils are one of the strongest things on our cars.

Besides that, if you need aftermarket products to increase your fuel mileage, and are able to give up emissions, you can buy a fuel computer (AFC Neo) and a pre-silencer. Remove the O2 Sensor to get rid of closed loop fuel correction and lean out your fuel mixtures with the AFC Neo. The pre-silencer for cat replacement prevents any damaging of the cat due to increased NOx emissions.

ericgrau

iTrader: (1)

Ya, there's not much you can upgrade. Tire pressure and the weight of gas does hardly anything. Just keep everything well maintained. Look up ALL the maintenance not just the few things you hear about. Keep your speed down (speed matters, not acceleration), and leave plenty of room between you and the guy in front of you to limit unnecessary braking. When cruising try to keep the throttle fairly constant to put the ECU in closed loop mode. The SAFC helps but reduces the safety margin on popping your engine (wide as that may be).

The following things may add a teeny tiny bit of mpg: A few extra psi of tire pressure, 10w30 (vs. 20w50), premixing 1/2 oz. 2 stroke per gallon of gas (for sealing & compression) maybe, the aero body kit, quality gas & oil & ocassional redlining (all to keep the engine clean in the long run), keeping windows rolled up. Umm can't think of much else, and I'll bet those add up to 1-2 mpg. 150lbs. of weight reduction should give add up to 1 mpg in the city, though removing 150lbs. may take some effort. Just see first paragraph.

Roen

iTrader: (2)

with the O2 sensor on, even if you lean out the fuel in cruise, the O2 sensor will correct it back to 14.7:1 AFR.

Forcing it to open loop by unplugging the O2 sensor and leaning out the fuel mix to leaner than 14.7:1 AFR will save more fuel in cruise, at the expense of higher risk of detonation. Use at your own risk. Additionally, you will burn cats out this way, so make sure you either have a pre-silencer or test pipe.

It's a crude method, the better method is to buy an expensive standalone capable of setting closed loop to whatever AFR you want. Those are a couple grand, at least.

This is my method to save the most gas......some of it is illegal, some of it is extreme and reduces car control, which can lead to serious injury or death, so do this at your own risk. This is only information, I do not take responsibility for your actions.

A 4-lug base model works the best.

Make sure your car is in excellent operating condition. Make sure tune-ups are done regularly, coolant system flushed, all oil/fluids changed.
Use less viscosity synthetic oil whenever possible. (i.e. Royal Purple, Mobil 1, Redline, Amsoil, Idemitsu) 10w30 instead of 20w50.
Keep weight in your car at a minimum.
Use lightened versions of parts if available (Steel hood to aluminum hood comes to mind)
Always keep your windows up
Shift before 3000 rpm
Remove power steering and a/c
If you have an S4, remove the airpump
If you have an S5, it's debatable whether removing the air pump and saving weight will give you any meaningful gas savings. Realize that it does save weight and reduce some parasitic drag, but is it worth it to lose your top end? Wired open 6 ports may work to save gas at the expense of low end power in this case. For the best compromise, look at an electrically activated RPM switch.
Install electric fan
Install lightest flywheel possible that you can handle
Verify that your clutch is in good shape. Slip the clutch as little as possible.
Install lightened driveshaft (CF is the best, but expensive at 1,000 a pop. Aluminum is a cheaper option)
If avaiable, use an electric water pump. (As of this post, I do not know of any available, but there has been discussions regarding finding a suitable product)
Fully open up the exhaust so the car breathes better
It's debatable whether installing the sport spoiler to reduce drag is worth the extra weight. Remove the spoiler regardless, but it's up to you to find and install a sport spoiler if you like.
Keep your speed down. Optimal is 55 mph on the highway.
This step may or may not work, it's based on the Honda Insight method of heating up the intake charge in the winter by blocking half of the radiator with cardboard to gain extra mpg: Use a cone filter unshielded in the engine bay. This is an inferior method of setting up your intake with respect to power. Also, you increase the risk of blowing your motor due to having hot air in the intake and leaned out fuel mix.
Buy a fuel computer and lean out fuel mix below 14.7 AFR as far as you can take it without the engine stumbling/misfiring
Inflate your tires to the maximum allowed tire pressure on the tire sidewall to decrease rolling resistance.
Use S4 aluminum phone dial 14 x 5.5" wheels
Use Bridgestone Potenza RE92 tires (lowest rolling resistance, stock Honda Insight tires)
When conditions allow (space around you is clear, no cars/trucks/vehicles near you), perform forced auto-stall on downhills that you do not need to turn in (i.e., shut off your car's engine, then turn it back on at the end of the hill) This practice is ILLEGAL in most states, only the most desparate gas savers do this. You will lose power brakes when the engine is turned off, so step extra hard, but make sure you do not lock the brakes.
Keep brake use to a minimum, coast from stoplight to stoplight, use enough gas that the car coasts to a stop right at the next stoplight. Coast onto an exit ramp where your car can slow down enough to take any turns without braking.

Basically, you want to make sure that all energy produced by the car goes to propelling the car, instead of given off as heat (i.e. braking). Additionally, you want to reduce parasitic loss whenever possible. If I think of more, I'll add it on.

Roen

iTrader: (2)

Also:

Install convertible 3.9 Ring & Pinion
Tire Size for RE92 tires: 185/65/14
If you have a 5-lug car, use the vert 15 x 6.5 wheels
Tire Size for RE92 tires: 205/65/15

Note that your speedo will be off using either of these options. Plus, your acceleration will suffer.

nvrdone

It might look stupid but a smaller side wall makes lighter wheels. And you're going slower then what your speedo says which helps in gas mileage too.

Roen

iTrader: (2)

That depends on the weight of the tire as well. You may have a smaller sidewall, but if your tire was heavy to begin with, it coudl still be heavier than another tire with a taller sidewall.

Taller sidewall tires act as final drive gears anyway. A taller tire will roll at a lower rpm at a given speed than a shorter tire.

scathcart

That is one of the dumbest recommendations I have ever read. Our cars are fuel injected! When the engine is decelerating, the ecu cuts fuel. Upon restarting the car, even by letting the clutch out, the ECU will set to afterstart enrichment, and inject more fuel than is necessary for a few cycles, effectively burning MORE fuel than you would be just leaving the car running.
Not only is it dangerous and burns more fuel than leaving the car on, it also makes you look like the cheapest and dumbest driver on the road... which you would be if you did this.

This would only ever effect a carburated car.

Yeah, good luck getting the car to detonate at cruise. Pretty hard to do without any load, and pretty much impossible with stock timing.

Roen

iTrader: (2)

Tell that to the Insight drivers who get over 100 mpg. Almost every single hypermilier challenging for most MPG will use this technique.

I wouldn't have posted up such a controversial recommendation if I hadn't done my research on it. The fact is, even if you fuel cut, engine compression is still slowing you down, which makes you use fuel to get back up to speed. Can't forget to account for that amount.

Now, the area that I may have erred in is start-up fuel, but that can be dialed out with an AFC as well, assuming you know which rpm ranges to adjust.

scathcart

Who cares what Insite's use? Our cars are not Insites. Our ECU, engine, and drivetrain do not even come anywhere close to functioning like that of an Insite. Next you'll be telling us how you use regenerative braking in your RX-7.

Engine compression slowing you down while going downhill while the throttle plates are closed and the engine is in nearly complete vacuum, and the engine at an extremely low rpm? How much air is actually getting compressed in this state?
Gravity not work where you're from? These aren't high-compression engines. When I go down hill with my foot off the gas, gravity tends to keep the car from decelerating... but maybe thats just a Canadian thing.
Next you'll be telling me you want to shut the car off, put the car in neutral, and let gravity ACCELERATE the car down the hill...
But then you still have to restart the car. So you either let the clutch out while moving, which brakes the car, or use the starter, both of which put the car back into accel-enrichment.

And good luck tuning the accel enrichment out of the car with an S-AFC. You can't use an S-AFC to turn off the enrichment, so all you could do would be to tune out the extra fuel injected during afterstart.... although the extra fuel is injected across the entire rpm range, so you'd have tp pull fuel out everywhere, and in order to pull out enough fuel to negate the enrichment at that rpm, and the car will run far too lean to fire... so the car either won't start, or stay once it has started.
But nice try.

fcforlife

iTrader: (9)

just watch how you drive i have made 24 mpg on a street ported engine. thats right cruise control works wonders i found 71 is about optimal for me on mileage. that whole 55 thing was from back when 5 speeds were just coming out. now that 5 speeds are as common as they are you can cruise at a higher speed for optimum fuel mileage. this mileage of course came from very long drive 200 miles plus but even just everyday commuting i could get 21-22 on the highway.

scathcart

Besides that a taller tire will weigh more of a shorter tire of equal width, A taller tire (larger diameter) will also increase the centerline of the vehicle axis, which raises the ride height of the car and thus decreases the aerodynamics of the car. Increased aerodynamic drag will reduce fuel economy under all operating conditions.

There is a reason why you adjust final drive via... the final drive gears.

Roen

iTrader: (2)

Everything's a compromise right? Gearing vs. drag

Do you select the shortest tire possible to decrease drag and pay for it in rpm? or do you select the tallest tire possible to decrease cruising rpm and pay for it in drag?

My hypothesis is that the drag penalty is a smaller hit than gearing penalty. For a half inch extra ride height, you gain about 4% reduction in RPM.

Obviously, I don't have the exact numbers to back up my guess, but if I did, we wouldn't exactly have questions anymore.

From my own personal experience, foot off gas on a downhill wastes more gas getting back up to speed on the next flat section vs. foot off gas + neutral on a downhill. Since accel enrichment takes place, instead of shutting the car off, clutch-in to neutral, coast the car down the hill, and rev match back up once you finish the downhill.

But, I'm sure in your experience, using gas to replace the speed lost due to engine compression works better than idling the car down the hill. To each his own, I'm just stating what worked better for me on two uncontrolled unscientific tests.

I've gotten 24 mpg cruising as high as 80 mph. Not the best, but not bad.

fcforlife

iTrader: (9)

24 imo is great for our cars 24 on a 90 accord however is like ehh it should do better haha

Roen

iTrader: (2)

I've heard 28 and claims as high as 33......wanting to know either what they did or what they were smoking.

scathcart

I've gotten 32-34 highway only with an aftermarket standalone. A search under my name will give more details.

ericgrau

iTrader: (1)

Add convertable ring & pinion and tire material to my list, I forgot those. The convertable's final drive ratio will make a big difference on the freeway, but it'll hurt acceleration. The tire should help somewhat. The rest of the stuff mentioned I think would hurt if anything.

I can get 27 just with good maintenance and slow driving. Beyond that the great numbers come from an SAFC and/or convertable final drive (everything else is minor).

Btw, wanna add one more reason why cutting your engine is dumb. Besides the others. If you accidentally turn the key too far you'll engage the anti-theft system: steering wheel lock.