Performance gain without losing gas mileage?
#22
10-06-2006, 01:07 PM
Originally Posted by DRum
The biggest performance gain that also greatly helps gas mileage is to get the manual transmission. The best part about it is that it even saves you nearly a grand.
#23
10-06-2006, 01:12 PM
So the problem is you wish to have performance gain.
But at the same time you want to keep or improve mpg.
Here is an option. It's easy to improve performance but it isn't as easy to improve mpg. Both can be achieved but you have to be careful.
Increasing performance-
Upgrade the intake
Upgrade the cat back exhaust- maybe add a header
Upgrade the brake pads
Add a short shift kit
Add a lightweight pulley
Have a set of performance wheels and tires that are solely used for performance situations- larger wider rim and grippy rubber. Not for using daily on the streets.
Keeping or increasing mpg-
Keep your FIT as light as possible.- if you are the only person in the car then remove everything non essential. Can the rear seat be removed?
Can the spare tire be removed if you do only short trips driving?
Can you switch to any alloy lightweight rims from tirerack.com as close to the stock 14x5.5" et 45mm rims (they have 14x6 rims at less than 10 pounds). Choose 175/65-14 or 185/60-14 tires to give a measure of low rolling resistance but some grip (it's a compromise).
Keep tire pressure to the recommended amount at all times. Very important as low psi will hurt mpg.
Drive with the cruise control as much as possible. Always accelerate from a stop evenly and smoothly. Never over rev the engine and resist idling for long periods waiting for filling gas, or in congested traffic. Drive during the least busy periods when possible.
-----------
Ok so now you have done both things. You have the capacity to drive fast due to the performance upgrades. You can do it anytime you want. BUT you also have the capacity to drive smoothly and slowly if you want. It's up to you to turn on the performance or not.
The problem is after adding performance many owners forget to drive with economy in mind and they have just too much fun driving and carried away. They forget they have a highly efficient car and that it is possible after the upgrades to get good mpg. They have got sports car mentality.
Remember folks it's up to the driver to choose how to drive. There is nothing keeping you for driving with high mpg in mind. Don't be in a rush and choose carefully when and where you want to have performance.
------------
About transmissions.
Modern automatic transmissions tend to be very fuel efficient. They are designed with some performance and mostly good mpg in mind. If you drive smoothly and don't stomp on the accelerator you will get good mpg. Don't sit in heavy traffic.
Manual transmissions require the driver to not high rev the engine and do full throttle accelerations too often in order to do well with mpg. Since you get more performance you will be tempted to go faster but that just burns gas. Manuals driven easily and slowly with shift points at lower rpms will do very very well but if you shift late and rev high you will burn more gas and be worse than with auto transmission. It all boils down to how you drive and less about manual vs automatic. CVT is also very fuel efficient.
But at the same time you want to keep or improve mpg.
Here is an option. It's easy to improve performance but it isn't as easy to improve mpg. Both can be achieved but you have to be careful.
Increasing performance-
Upgrade the intake
Upgrade the cat back exhaust- maybe add a header
Upgrade the brake pads
Add a short shift kit
Add a lightweight pulley
Have a set of performance wheels and tires that are solely used for performance situations- larger wider rim and grippy rubber. Not for using daily on the streets.
Keeping or increasing mpg-
Keep your FIT as light as possible.- if you are the only person in the car then remove everything non essential. Can the rear seat be removed?
Can the spare tire be removed if you do only short trips driving?
Can you switch to any alloy lightweight rims from tirerack.com as close to the stock 14x5.5" et 45mm rims (they have 14x6 rims at less than 10 pounds). Choose 175/65-14 or 185/60-14 tires to give a measure of low rolling resistance but some grip (it's a compromise).
Keep tire pressure to the recommended amount at all times. Very important as low psi will hurt mpg.
Drive with the cruise control as much as possible. Always accelerate from a stop evenly and smoothly. Never over rev the engine and resist idling for long periods waiting for filling gas, or in congested traffic. Drive during the least busy periods when possible.
-----------
Ok so now you have done both things. You have the capacity to drive fast due to the performance upgrades. You can do it anytime you want. BUT you also have the capacity to drive smoothly and slowly if you want. It's up to you to turn on the performance or not.
The problem is after adding performance many owners forget to drive with economy in mind and they have just too much fun driving and carried away. They forget they have a highly efficient car and that it is possible after the upgrades to get good mpg. They have got sports car mentality.
Remember folks it's up to the driver to choose how to drive. There is nothing keeping you for driving with high mpg in mind. Don't be in a rush and choose carefully when and where you want to have performance.
------------
About transmissions.
Modern automatic transmissions tend to be very fuel efficient. They are designed with some performance and mostly good mpg in mind. If you drive smoothly and don't stomp on the accelerator you will get good mpg. Don't sit in heavy traffic.
Manual transmissions require the driver to not high rev the engine and do full throttle accelerations too often in order to do well with mpg. Since you get more performance you will be tempted to go faster but that just burns gas. Manuals driven easily and slowly with shift points at lower rpms will do very very well but if you shift late and rev high you will burn more gas and be worse than with auto transmission. It all boils down to how you drive and less about manual vs automatic. CVT is also very fuel efficient.
Last edited by MINI-Fit; 10-06-2006 at 01:16 PM.
#24
10-06-2006, 01:27 PM
I agree w/ the idea that modern autos are just as efficient (fuel), just not in power transfer. Has anyone noticed that our 5 spds autos actually seem to have a 'second' gear in between each gear? I think this is likely a combination of the lockup convertor going on/off, the intake manifold runner sizing, and VTEC, all working together. I can leave the car in 4th gear in manual mode, and w/ minimal throttle inputs, the car cruises great...step into the gas and the engine seems to step up about 600-800 rpm to accomodate acceleration.
#25
10-06-2006, 02:03 PM
Aerodynamic changes to reduce drag will help mileage at highway speeds and should likewise improve top speed (which is apparently drag-limited) and acceleration at high speeds. However most of the changes that would have the greatest effect are not appealing to the cosmetic-performance aftermarket (read: look dorky) so no one offers them commercially.
#26
10-16-2006, 09:54 AM
Thanks again for all the input. I finally received and installed the K&N filter about a week ago, and I don't really think I'm getting any better fuel economy, but the engine does seem to run a little smoother due to the increase in air flow. No regrets, but no mind-blowing change.
#27
10-16-2006, 01:27 PM
It seems like all the mods to increse performance don't show any real improvement unless the engine is reving above the 4,200 rpm level. Mpg increase as the rpm's drop below 3,000. Therefore, it appears that improved engine performance and high mpg are mutually exclusive goals.
Most engines produce maximum HP/ torque at higher rpms while fuel economy results from low rpms. If you don't rev the engine above 3,500 rpm it is doubtful that any of the engine performance modifications will make any perceptual difference, so why spend the $$ on engine performance in an economy car?
IMHO the only changes worth making to the Fit are to improving the suspension. These mods will result in more comfort and the ability to drive more aggresively on twisty roads while still obtaining good mpg. Seems to me to be the most bang for the buck. Strut bars, tires, springs/coilovers, brakes, etc. will improve performance on a twisty road without losing mpg.
Just my 2 cents, but I do think the engine mods are cool and I'm tempted,
Most engines produce maximum HP/ torque at higher rpms while fuel economy results from low rpms. If you don't rev the engine above 3,500 rpm it is doubtful that any of the engine performance modifications will make any perceptual difference, so why spend the $$ on engine performance in an economy car?
IMHO the only changes worth making to the Fit are to improving the suspension. These mods will result in more comfort and the ability to drive more aggresively on twisty roads while still obtaining good mpg. Seems to me to be the most bang for the buck. Strut bars, tires, springs/coilovers, brakes, etc. will improve performance on a twisty road without losing mpg.
Just my 2 cents, but I do think the engine mods are cool and I'm tempted,
#28
10-16-2006, 11:15 PM
In my experience, given the displacement of an engine held constant, modifying for increased power usually results in shifting the power band higher. Big V8s don't have as much of an issue here...who cares if you give up some low end torque, as if going from, say 350 ft-lbs to 300 ft-lbs is going to make a tremendous difference, especially if the car is geared correctly for the engine power band. Bigger displacement engines make torque naturally and easily, and usually have smaller power bands.
The smaller displacement engines usually require hi-rpm operation to make power, outside forced induction (some would still argue that they don't make low-end power!) I don't think these little engines can afford to loose any power down low.
The cam, intake, and transmission gearing for the Fit are all designed to compliment each other, which is why most people are suprised at how nimble it is. As soon as parts are interchanged, the combo can potentially be upset. From what I've seen, the Honda philosophy is to make only enough power at cruise to overcome drag & rolling resistance to maintain steady speed. So if any power is lost on the low end it may tend to be more noticeable on the Fit.
The smaller displacement engines usually require hi-rpm operation to make power, outside forced induction (some would still argue that they don't make low-end power!) I don't think these little engines can afford to loose any power down low.
The cam, intake, and transmission gearing for the Fit are all designed to compliment each other, which is why most people are suprised at how nimble it is. As soon as parts are interchanged, the combo can potentially be upset. From what I've seen, the Honda philosophy is to make only enough power at cruise to overcome drag & rolling resistance to maintain steady speed. So if any power is lost on the low end it may tend to be more noticeable on the Fit.
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