Improving BOTH Performance and Fuel Efficiency

Discussion in 'General' started by ealuema, Jun 17, 2013.

  1. ealuema

    ealuema New Member

    Hi, I'm a new member of this site and I think it is very informative in what I'm looking for.
    I just recieved a 1992 Toyota Camry 4 cylinder Manual car as a gift and I would like to further increase its fuel economy. It is certainly an upgrade in FE from my 8 cylinder 1994 Camaro Z28.

    My goal is to increase both the mileage and performance of the Camry.
    I have seen plenty of threads claiming you can't increase both but I don't believe that to be true.
    A few mods I am planning on doing is adding :
    undertray to decrease the air resistance from under the car.
    wheel skirts to decrease air resistance from the wheel wells and sides of the car
    Interior side view mirrors to reduce air resistance
    Partial Grille Block reduce air resistance
    cold air intake to let in more dense air by collecting air from a cooler region. Older cars usually have intakes that are not as strategically placed as newer cars.
    Anti-roll bar/strut bar to increase handling
    Remove excess weight such as spare tire/jack
    Magnaflow performance muffler to slightly decrease backpressure. Improves both performance and FE
    Aftermarket less restrictive catalytic converter Slightly relieve back pressure to increase FE and performance.
    Turbocharger Debating whether to add one. Mixed debate on whether it increases or decreases fuel economy.

    Let me know if there is anything I missed! Or if you guys have any other suggestions.
    What do you think about my steps for increaseing performance and FE?
  2. Welcome.

    Play with the top 4 items. The rest you will probably spend more money than you'll make up for in mpgs.
  3. ALS

    ALS Super Moderator Staff Member

    ealuema Welcome to the board.

    Looking at your list most will cost far more than the amount of gas you will save other than removing all the junk stored in the trunk.

    undertray to decrease the air resistance from under the car.
    How much highway driving are you expecting on doing?
    A lot maybe in two to four years depending on the cost of materials and labor.
    minimal? You'll never make back the cost in gas savings.

    wheel skirts to decrease air resistance from the wheel wells and sides of the car.
    Depending on material cost may pay for themselves over one or two years.

    Interior side view mirrors to reduce air resistance
    Not worth the safety issues for that amount of savings.

    Partial Grille Block reduce air resistance.
    Cheap but make sure you can closely monitor the coolant temperatures and not with the cheap factory idiot light or gauge.

    cold air intake to let in more dense air by collecting air from a cooler region. Older cars usually have intakes that are not as strategically placed as newer cars.
    Not needed for fuel economy only making power.

    Anti-roll bar/strut bar to increase handling,
    Helps the fun factor.

    Remove excess weight such as spare tire/jack
    I don't believe in it because you just know you're going to get a flat at the wrong time and have to wait two hours for a tow truck. Not that much savings considering the importance of the item if you ever get a flat that a can of fix a flat will not repair.

    Magnaflow performance muffler to slightly decrease backpressure. Improves both performance and FE. Again I wouldn't replace the factory unit unless it needs replaced due to wear and age. The cost of fixing something that ain't broke will never be made up in fuel savings.

    Aftermarket less restrictive catalytic converter Slightly relieve back pressure to increase FE and performance. The same response of the Magnaflow muffler.

    Turbocharger Debating whether to add one. Mixed debate on whether it increases or decreases fuel economy.
    Not an option on the Camry.

    Here is good starting point for you to start your journey into fuel savings.

    CleanMPG Primer

    The fastest way to save a large amount of fuel is slow down.
    Last edited: Jun 17, 2013
  4. ksstathead

    ksstathead Moderator

    Your aero mods could benefit from a visit to ecomodder site. Search for aerocivic for example.

    For highway driving, aero does improve performance and fuel economy.

  5. tribosessive

    tribosessive Well-Known Member

    Using one of the new ultra light synthetic motor oils can give you a 3% improvement in fuel economy and improved performance. Low rolling resistance tires can make a difference. Of course driving style has the most profound effect on mpgs and performance in a diametrically opposed way.
  6. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    In my Odyssey, I've measured a 4% difference in highway mileage between two supposedly LRR tires. Imagine what a non-LRR would do! (Goodyear Fuelmax > Yokohama YK580)
  7. WriConsult

    WriConsult Super Moderator

    Most of the stuff you're talking about will provide small incremental improvements at best. Might be worth it if you do a LOT of highway driving, but otherwise not likely worth it

    And adding a blower will create parasitic drag, reducing fuel economy while only providing an efficiency benefit at high levels of output that efficient drivers avoid most of the time.

    Overwhelmingly the best mod to improve fuel economy is to adjust the nut behind the wheel. Some people fetishize physical mods to the cars, which do feel satisfying by keeping your hands and wallet busy, but for most people there really isn't that much benefit. If you're not careful you can end up a poorer, still-inefficient driver in a very slightly more efficient car. Learning to drive efficiently can be a much bigger adjustment mentally for most people, but will provide bigger payoffs.

    On the highway the the biggest deal is to keep your speed down, because aero drag goes up with the cube of speed. Most of us limit ourselves to somewhere between 55 and 65 on the highway. Also make sure to air your tires up to the psi listed on the sidewall. This is a higher number than on your car's door placard, which was chosen by the automaker based on comfort and avoiding dangerously low pressure. Airing up to sidewall psi will also improve your car's handling a bit, definitely a helpful thing on a Camry and you should do it before bothering with bolting on an anti-roll bar.

    Around town, the biggest deal is to minimize the amount of energy lost to braking. Most people seem to think that going lighter on the gas is how you best save fuel, but that is far from the truth. All your gas pedal does is convert chemical energy into momentum: that energy isn't wasted until you press the brake pedal. This means:
    1. Keeping the speed down around town, where higher speeds from stop to stop means more energy thrown away in braking.
    2. Anticipate, anticipate, anticipate, anticipate. Try to predict bottlenecks, slowdowns, curves, corners, stop signs, red and green lights, and ANY other situations where you're going to need to slow down, so that you minimize the waste involved in braking. Most people move their foot directly from the gas to the brake as they approach a stop. This is WRONG! Basically you should accelerate up to your desired speed and then coast as far as possible. Your car can coast further than you think! Get off the gas earlier and SAVE!
    3. Leave a minimum of 2-4 sec following distance at ALL times so you don't have to abruptly lose speed (yes, sometimes people will cut in front of you -- just remember its their gas being wasted, not yours).
    4. In most non-hybrids it is better to accelerate moderately briskly through the first couple of gears (I often only spend a couple of seconds in each of the first two gears), keeping the engine RPMs limited to no more than 2000-2200. Don't creep up to speed like a grandma. First, because those low gears are extremely inefficient. Second, because your engine itself is probably most efficient at 70-80% load (as a fraction of power available at the current rpm). A ScanGuage is the best way to know this, and the FIRST thing you should spend money on, because it gives you immediate feedback on how efficiently you are driving. In fact, around town I spend 80-90% of the time I'm moving in neutral. No kidding! My car is only in gear when I'm accelerating, which I do fairly briskly then coast as much as I can, just "pulsing" to bring my speed back up as needed.
    5. Also avoid unnecessary idling, and make sure to kill your engine at long red lights. This is another area where a ScanGauge is helpful, because you can monitor your battery voltage and make sure you don't drain the battery too low to restart if you've killed the engine with the lights on or the fan on high.

    Things you should NOT be worried about yet (or ever):
    - High speed Pulsing and gliding. This is an intermediate technique that can provide huge benefits on the highway (in my car, 38-42mpg instead of 30-34mpg) BUT takes a lot of practice to get right, and passengers may not tolerate it. The basics I've listed are more important and will make a bigger difference. More importantly, P&Ging the wrong way (too hard, too light, too frequently, or in the wrong conditions) can actually reduce your mpg. You'll need a ScanGauge to do this properly. Once you've learned the basics you SHOULD do this, but I'd focus on the other things first.
    - Driving with the engine off. This is an advanced technique that can provide a benefit in local driving, but the benefit is pretty small in most situations, with significant dangers if you don't do it right. Don't even think about bothering with ICE-off gliding until you've mastered the basics. Until you're a fairly advanced hypermiler, just focus on avoiding idling while you're stopped.
    - Back-in parking and trying to park in the highest point in a parking lot can help, but are of very incremental help. Again, don't bother unless you've mastered the basics above. If you do want to make one change to your parking habits, try to park near the entrance of your lot and minimize inefficient trolling around the lot.
    - Drafting. FORGET IT! The media have sensationalized this one as if it's our main "trick", which is out-and-out bull. Hardly any of us do it. Driving closer than 2-3 sec behind a truck is extremely dangerous, and not worth any aerodynamic gain! Not only that, but the speed profile of a truck over rolling terrain is different than what is optimal for a car, so you might get an aero benefit but it's going to hurt you otherwise. And once you're 2-3 seconds back and into the safe zone, the aero benefit drops off and turbulence can sometimes make things worse. Best advice is don't even think about it, and just stay the hell away from trucks.
    Last edited: Jun 17, 2013
  8. tribosessive

    tribosessive Well-Known Member

    PaleMelanesian, I have used the relatively old design Goodyears and definitely had better mpgs. Are you saying that the Yokohamas are even better?
  9. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    Other way around. The FuelMax's were better. My new Yoko's are not as good. Now I'm stuck with them for a few years. :(
  10. tribosessive

    tribosessive Well-Known Member

    Yes. I was very happy with the fuelmax tires. I've got some el cheapo Kumho LRRS and some plain jane black wheels coming in tomorrow on special order. I like the look too. It looks like NASCAR. My driving style is mild hypermiling. I am going to study up on pulse and glide, etc soon. That Fit is a nice sled.
  11. worthywads

    worthywads Don't Feel Like Satan, I am to AAA

    The logic that increasing performance/efficiency but then not using the power will result in increased mpg is flat wrong. You say you don't believe this so you clearly don't want to hear/understand this.

    Cold air intake doesn't work, here people get success with warm air intakes during winter, and see no benefit from cold air intake. Cold air is meant to "allow" more gas.

    Exhaust, same thing, freer flowing usually reduces torque where you want it the most...wrong direction.

    Turbo, you won't increase mpg by adding a turbo. You benefit with a turbo by starting with a small engine that can use the turbo as needed. Adding to a properly sized motor doesn't increase mpg. You need to swap in a smaller engine with a turbo.
    Last edited: Jun 18, 2013
  12. ealuema

    ealuema New Member

    Thanks for the advice guys. Perhaps I should have mentioned that my primary goal is to increase the performance with modifications that will benefit my fuel economy, or at worst, not affect it negatively. I am not concerned with my gas savings paying back the investments I made on the car, as it is for performance as well. Thanks
  13. ealuema

    ealuema New Member

    You may claim that cold air intakes don't work, but others claim they do. As for the explanation behind it, I think it helps, even if a negligible amount.
    As for the exhaust, there are many who have increased Fuel Economy by just replacing their old restricting catalytic converter, or using a less restrictive performance muffler. Reducing backpressure TOO much would result in a decrease of fuel economy. But for older cars with a more restrictive exhaust system, a decrease in backpressure would benefit their fuel economy.
    Perhaps it is you who refuses to hear/understand that it is possible for a modification to improve both efficiency or performance.
  14. RedylC94

    RedylC94 Well-Known Member

    The scientific reasons why cold air intakes can help torque, but not normally fuel consumption, have been well known for a very long time.

    Generally, the only modifications that improve both acceleration and fuel consumption of a vehicle are those that involve reducing mass, friction, or drag.
  15. worthywads

    worthywads Don't Feel Like Satan, I am to AAA

    Good luck. You realize a negligible amount means zero (imperceptible) results, which I agree is the results you will see. You won't find people here with CAI, headers, exhaust, etc. They don't work to improve mpg.

    Check out They have a list of 65+ efficiency mods. None of the engine modes you think will increase efficiency are on that list.

    Your first 4 ideas have merit as already stated.
  16. MaxxMPG

    MaxxMPG Hasta Lavista AAA-Vee Von't Be Bach

    You seem to be searching for increases in volumetric efficiency with less restriction in the intake and exhaust and denser intake air. The lower restriction can theoretically increase torque at higher rpm, but results can be mixed unless you know how well the Toyota head flows (shape and size of the ports, valve area, etc) and specific cam grind.

    To remove all restriction won't help much if the engine isn't otherwise designed to produce much power higher in the rpm band. Think of it as two people at rest, breathing through their noses. Air supply is ample when there isn't much work to be done. Get up and start running, and you breathe through your mouth to allow more air. But opening your mouth wider won't help much when the restriction is then in the trachea and so the whole "system" is designed to allow only so much air flow. And if one of the two people is out of shape, adding more air isn't going to lead to better performance.

    We at CleanMPG seek to improve efficiency in order to reduce fuel consumption. Perhaps you're not getting the performance answers you were anticipating because you are chatting with people who measure performance in gph rather than hp.

    The basic theory of the gasoline engine is that that power comes from gasoline. More power comes from more gasoline. To get more power from each drop of gas means more efficiency, but that means specific changes to the basic engine design - higher compression, very high combustion temperatures and ceramic engine parts, and likely multiple spark plugs and direct injection. Trying to apply any of the above to an older engine is going to not only run into large sums of money, it will dramatically increase NOx emissions.

    Power, fuel economy, emissions, reliability - increase any one with aftermarket modification and the other three will usually suffer. You are still free to update your car as you see fit, and at any stage of the game, we can still provide the link to the "Beathing the EPA" article if you wish to learn how to dramatically improve fuel economy without spending a dime.

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