Mods that increase fuel efficiency
#82
05-25-2008, 11:37 AM
Yep. I'm gonna say this one again:
If you can't measure it, you can't manage it!
If you can't measure it, you can't manage it!
#83
06-03-2008, 04:54 PM
I know that when I put large heavy tires on my jeep, it became harder to stop and hard to accellerate. My fuel consumption droped quite a bit as well. I read on another thread that the stock fit sport rim weighs 16lbs. I saw they have rims as light as 9lbs. i would bet that would make a HUGE difference. I know it did in my jeep. Also, has anyone looked into changing their gear ratio? Make it taller for freeway MPG?
#84
06-05-2008, 01:40 AM
A taller 5th gear, or better yet a 6th gear, would do wonders for the highway mileage on this car. I found that anything above 65mph or roughly 3,000 rpm and the mpg start dropping off, unless there is some kind of aero help in front of me.
#86
06-05-2008, 08:14 AM
CP
#87
06-05-2008, 08:39 AM
The fact that you mention unless there is some aero help in front of me, seems to me that it is the aero dynamics of the car itself that keeps the Fit from getting great mileage above 65mph (and all cars for that mater). The auto doesn't rev as high as the manual, and it doesn't get any better mileage.
CP
CP
As far as a taller gear, I didnt mean replacing one of the 5 drive gears, I meant the single gear that drives the wheels. this one effects ALL the gears. I saw they have LOWER gears for racing. But If you can find a TALLER gear, it would help MPG (at the cost of acceleration). There is obviously a point of diminishing returns in respect to resistence.
#88
06-05-2008, 07:40 PM
I'm not convinced of that. The front of this car presents a pretty big surface area to the wind, dare I say "barn door"? I'd like a taller final drive too, but I'm not sure it would improve fuel economy. I'm looking into improving aerodynamic efficiency at this point in time; if I see an improvement, then I'll start wanting a taller final drive.
#89
06-22-2008, 05:48 PM
It does on the highway, at least according to the EPA and its Canadian equivalent. Must be due to the taller gearing and the locked torque converter (no loss vs. manual).
#91
06-22-2008, 06:40 PM
The fact that you mention unless there is some aero help in front of me, seems to me that it is the aero dynamics of the car itself that keeps the Fit from getting great mileage above 65mph (and all cars for that mater). The auto doesn't rev as high as the manual, and it doesn't get any better mileage.
CP
CP
#92
06-23-2008, 05:23 PM
That only matters at low speeds, at highway speeds every modern automatic locks its torque converter so that there is no slushing in the slushbox.
#93
12-18-2008, 08:30 PM
Ok, i may be wrong about this but here we go:
***The intake portion of this assumes the intake air temperature is the same as stock (so CAI's may actually draw denser air, thus more air, yadda, yadda, yadda*****
adding an intake, exhaust or header does not necessarily mean more air is going into the engine. Think about it, the engine is a 1.5 liter (USDM Fit) correct? That means that inside the cylinder there are 1.5 Liters of volume that will be filled with air after the engine completes the intake stroke. You can not put more than 1.5 Liters of air into a 1.5L engine without forcing the air in (ie turbo or super charger).
--- Thats Volumetric Efficiency buddy!! Modern Otto cycle engines are not 100% efficient (does not take 1.5l of air at each revolution!) ... but they should be at least 80% efficient... (VE) varies with RPM also (Cam timing!)... Peak efficiency is acheived at peak torque!!
So keeping this in mind the conclusion you will come to is that adding I/H/E will not actually flow more air. Then the question must be raised: well then how is performanced gained by doing these mods? Well, the engine isn't bringing in more air, it is just pumping in and out the air that is inside it. If the engine is pumping air, that means there is a power loss associated with moving the air. Basically what ever cylinder is on the powerstroke is not only using the power it generates to turn the wheels, some of this power goes to forcing air into and out of the engine.
---At higher RPM there's power to be gained with at least an intake... the stock intake box inlet is a 44mm one where the throttle is a 50mm one... what you gain at higher revs you may lose at the low end though... (Velocity Vs Quantity on air...)
Now if you take a look at how fluid flow works, flow is inhibited by tight turns (like 90 deg bends), ledges (ie exhaust port is larger than header primary), and things like generally unsmooth materials (ie ribs in the intake pipe).
--- Each 90 degrees bends will reduce airflow by 8 or 9 percent...
Knowing this, you can say that these things cause resistance in the flow path (much like when trying to move electricity, resistance = bad) Knowing that the more resistance there is in the flow path the more power the engine must use to bring the air in or push it out, leads to the conclusion that by decreasing this resistance more power will be transported to the wheels.
---Absolutely correct!!
Keep in mind that at now point did the engine actually take in more air...
***********Disclaimer************
I am an mechanical engineer, but not some engine genius, this is just a thought process that I went through when trying to decide whether or not to mod my Fit. All of this could be wrong and I am open to hearing other peoples opinions, I would love to discuss this theory.
***The intake portion of this assumes the intake air temperature is the same as stock (so CAI's may actually draw denser air, thus more air, yadda, yadda, yadda*****
adding an intake, exhaust or header does not necessarily mean more air is going into the engine. Think about it, the engine is a 1.5 liter (USDM Fit) correct? That means that inside the cylinder there are 1.5 Liters of volume that will be filled with air after the engine completes the intake stroke. You can not put more than 1.5 Liters of air into a 1.5L engine without forcing the air in (ie turbo or super charger).
--- Thats Volumetric Efficiency buddy!! Modern Otto cycle engines are not 100% efficient (does not take 1.5l of air at each revolution!) ... but they should be at least 80% efficient... (VE) varies with RPM also (Cam timing!)... Peak efficiency is acheived at peak torque!!
So keeping this in mind the conclusion you will come to is that adding I/H/E will not actually flow more air. Then the question must be raised: well then how is performanced gained by doing these mods? Well, the engine isn't bringing in more air, it is just pumping in and out the air that is inside it. If the engine is pumping air, that means there is a power loss associated with moving the air. Basically what ever cylinder is on the powerstroke is not only using the power it generates to turn the wheels, some of this power goes to forcing air into and out of the engine.
---At higher RPM there's power to be gained with at least an intake... the stock intake box inlet is a 44mm one where the throttle is a 50mm one... what you gain at higher revs you may lose at the low end though... (Velocity Vs Quantity on air...)
Now if you take a look at how fluid flow works, flow is inhibited by tight turns (like 90 deg bends), ledges (ie exhaust port is larger than header primary), and things like generally unsmooth materials (ie ribs in the intake pipe).
--- Each 90 degrees bends will reduce airflow by 8 or 9 percent...
Knowing this, you can say that these things cause resistance in the flow path (much like when trying to move electricity, resistance = bad) Knowing that the more resistance there is in the flow path the more power the engine must use to bring the air in or push it out, leads to the conclusion that by decreasing this resistance more power will be transported to the wheels.
---Absolutely correct!!
Keep in mind that at now point did the engine actually take in more air...
***********Disclaimer************
I am an mechanical engineer, but not some engine genius, this is just a thought process that I went through when trying to decide whether or not to mod my Fit. All of this could be wrong and I am open to hearing other peoples opinions, I would love to discuss this theory.
check my points... it's the --- :P
Another thing that should help to save fuel is an lightweight underdrive pulley!!
Weight should matter the most in low speed city driving and aerodynamics should matter the most at higher speeds!!
Marko!!
#94
12-18-2008, 10:14 PM
My mods for MPG will be
*lighter forged wheels.
*lightweight crank pulley
*lighter Odyssey battery.
*keeping it waxed and Rain-X on the glass to make that surface slippery as well
*lighter forged wheels.
*lightweight crank pulley
*lighter Odyssey battery.
*keeping it waxed and Rain-X on the glass to make that surface slippery as well
#96
12-30-2008, 03:10 AM
Join Date: Jul 2008
Location: SoCal rockin' it. 909/323/818/714/626
Posts: 689
Don't add a roof rack. It'll kill your MPG.
But with my current setup, I'm getting about 31-33 MPG WITH the roof rack on 24/7. Then again, I'm dumped to the floor.
I just added my own intake system and it feels as if I'm getting better mileage, but only time will tell!
But with my current setup, I'm getting about 31-33 MPG WITH the roof rack on 24/7. Then again, I'm dumped to the floor.
I just added my own intake system and it feels as if I'm getting better mileage, but only time will tell!
#97
12-30-2008, 10:41 AM
Interesting all the helpful notes on what to do with many lacking any data to make it factual or proven with DATA. Wonder how many will take the bait and make changes that have never been proven at all.
Besides changing your driving style, the only change that has shown real results is increased tire pressure, under car air control plate, a grill block in cold weather and the Scan gauge to help you learn how to improve your driving style.
What has not worked:
Air filter and air inlet pipe
Exhaust system
Tire size
lowering the car
Fuel Octane
and all the BS advertised that says it does like the Vortex deal or Hydrogen deal
Besides changing your driving style, the only change that has shown real results is increased tire pressure, under car air control plate, a grill block in cold weather and the Scan gauge to help you learn how to improve your driving style.
What has not worked:
Air filter and air inlet pipe
Exhaust system
Tire size
lowering the car
Fuel Octane
and all the BS advertised that says it does like the Vortex deal or Hydrogen deal
#98
12-30-2008, 11:02 AM
Join Date: Jul 2008
Location: SoCal rockin' it. 909/323/818/714/626
Posts: 689
Interesting all the helpful notes on what to do with many lacking any data to make it factual or proven with DATA. Wonder how many will take the bait and make changes that have never been proven at all.
Besides changing your driving style, the only change that has shown real results is increased tire pressure, under car air control plate, a grill block in cold weather and the Scan gauge to help you learn how to improve your driving style.
What has not worked:
Air filter and air inlet pipe
Exhaust system
Tire size
lowering the car
Fuel Octane
and all the BS advertised that says it does like the Vortex deal or Hydrogen deal
Besides changing your driving style, the only change that has shown real results is increased tire pressure, under car air control plate, a grill block in cold weather and the Scan gauge to help you learn how to improve your driving style.
What has not worked:
Air filter and air inlet pipe
Exhaust system
Tire size
lowering the car
Fuel Octane
and all the BS advertised that says it does like the Vortex deal or Hydrogen deal
If we're gonna get nitpicky, all the factors that you named that "won't work" CAN work in comparison with something that may hinder MPG. How? Take tire size for one-- I believe there's a big difference in rotational weight/drag between a tire that's 255/45 16 and one that is 185/40 16. Sure, they're totally different tire sizes, but one definitely will yield better gas mileage than the other, even if the difference is only by a fraction.
Just my .02
#99
12-30-2008, 12:32 PM
Have you tried any of the modifications under your "what has not worked" section? Just like there isn't any data proving that they may NOT help MPG, there isn't any data that proves they don't work either. Unless of course you've tried them all..
If we're gonna get nitpicky, all the factors that you named that "won't work" CAN work in comparison with something that may hinder MPG. How? Take tire size for one-- I believe there's a big difference in rotational weight/drag between a tire that's 255/45 16 and one that is 185/40 16. Sure, they're totally different tire sizes, but one definitely will yield better gas mileage than the other, even if the difference is only by a fraction.
Just my .02
If we're gonna get nitpicky, all the factors that you named that "won't work" CAN work in comparison with something that may hinder MPG. How? Take tire size for one-- I believe there's a big difference in rotational weight/drag between a tire that's 255/45 16 and one that is 185/40 16. Sure, they're totally different tire sizes, but one definitely will yield better gas mileage than the other, even if the difference is only by a fraction.
Just my .02
I have not tested the items on my list, but have read every note on this Eco area, helped a few with testing methods here, around my shop and on the Cleanmpg form.
Tire size was just proven by mayout to NOT work read this
https://www.fitfreak.net/forums/eco-...ring-mods.html
Shawn and others tested a K&N and inlet pipe.
Fuel type is been debunked many times and proven more costly