2004 to 2020 Mazda 3 Forum and Mazdaspeed 3 Forums banner

1 - 20 of 36 Posts

·
Registered
Joined
·
381 Posts
Discussion Starter #1
I'm currently planning on making A Warm Air Intake for my 3SGT.

The difference temperature plays on fuel economy in my 3 is extreme.
I was able to find A 10 MPG difference between 50 F and 75 F.

I will probably use high temp drier duct hose and tap it in below the factory air filter. Not wanting to add the noise of A CAI.

Any suggestions or ideals welcome as long as your not an ECO hating machine.

Thanks for any help.
 

·
Registered
Joined
·
1,791 Posts
Before you do that, you should study the physics behind it. First of all, by any reasonable calculation, there cannot be a 10 mpg difference because of the physics of combustion. Furthermore, as temps get really high, performance decreases. Secondly, airflow is more important than temperature and you will get less airflow with a warm air intake. Thirdly, cold air is denser than warm air and that is why combustion decreases with temperature. These types of solutions don't work even with internet claims to the contrary. Don't you think that some manufacturer's would make a warm air intake standard if you could get 10 mpg more? Besides, if you're an ECO guy, a little extra noise shouldn't bother you????

You might want to test your assumption with an SRI. I don't think you'll see 10 mpg increases. SRI manufacturers don't even claim that.
 

·
Registered
Joined
·
103 Posts
I'm currently planning on making A Warm Air Intake for my 3SGT.

The difference temperature plays on fuel economy in my 3 is extreme.
I was able to find A 10 MPG difference between 50 F and 75 F.

I will probably use high temp drier duct hose and tap it in below the factory air filter. Not wanting to add the noise of A CAI.

Any suggestions or ideals welcome as long as your not an ECO hating machine.

Thanks for any help.
Ya I see this working out especially on cold days however if you drive on a hot day you would really notice your engine lacking in performance after stopping at a light.

Did you consider a Short Ram intake or are you considering actually warming the air consistently like drawing from the exhaust manifold?
CorkSport 2014 + Mazda 3 Short Ram Intake
 

·
Registered
Joined
·
381 Posts
Discussion Starter #4
In the winter I don't A short Ram intake would work as well. I'm thinking of pulling air from above the exhaust manifold.
 

·
Aspiring Mad Scientist
Joined
·
1,716 Posts
Uh... your engine's 13:1 will do a fine job of heating up the air already. If your warm air intake causes knock retard you will lose performance and efficiency all in one go.

As far as I have been taught, warm temperatures aid fuel economy not from improving engine performance but by reducing some of the resistances (air drag, tire drag, etc.) that fight it. From 50 to 75F you should be seeing a significant change in tire pressure, around 3psi. If that gets you from 36psi to 39psi in your stock tires, you're likely to see an mpg change from that alone -- that is what the hypermilers do over on Ecomodder.com.

Aside from our opinion that a consistent and verifiable 10mpg improvement is extremely unlikely, you can shut us up by grabbing data from your car to back up your claims, and we can probably pick through that to figure out what factors are actually pointing you to your conclusion thus far. Hint, it's probably not the intake temperatures.
 

·
Registered
Joined
·
381 Posts
Discussion Starter #6
Before you do that, you should study the physics behind it. First of all, by any reasonable calculation, there cannot be a 10 mpg difference because of the physics of combustion. Furthermore, as temps get really high, performance decreases. Secondly, airflow is more important than temperature and you will get less airflow with a warm air intake. Thirdly, cold air is denser than warm air and that is why combustion decreases with temperature. These types of solutions don't work even with internet claims to the contrary. Don't you think that some manufacturer's would make a warm air intake standard if you could get 10 mpg more? Besides, if you're an ECO guy, a little extra noise shouldn't bother you????

You might want to test your assumption with an SRI. I don't think you'll see 10 mpg increases. SRI manufacturers don't even claim that.
A few of us on this forum Have noticed a significant difference in MPG with air temp much more than normal. I would not believe how much difference until my recent trip from Florida. Now bare with me I'm using the cars computer for data. It was a long trip and I believe the driving conditions were pretty similar, both test have been timed for an hour of driving on the same day and the same tank of gas.

Flat land going north entering Georgia from Florida the outside temp showed 50 F so I pull over shut the car off and reset the computer and drove for 1 hour, outside temp got a little better and I was able to get 37.8 MPG at 65 MPH.

I later noticed the outside temp reached 75 F and I pulled over reset current AVG mpg and drove for an hour. Avg MPG 48.34 at 65 MPH. On my second test I know the road was A little bit hilly.
Both condition were close except for temp.

As for warm air intakes there is such thing as overdoing it with pulling the air directly off the exhaust. People in Eco moders forum have had mixed result with Warm air intakes. It all depends on the car. But the Mazda 3 s might be one to try this on.
 

·
Registered
Joined
·
381 Posts
Discussion Starter #7
Uh... your engine's 13:1 will do a fine job of heating up the air already. If your warm air intake causes knock retard you will lose performance and efficiency all in one go.

As far as I have been taught, warm temperatures aid fuel economy not from improving engine performance but by reducing some of the resistances (air drag, tire drag, etc.) that fight it. From 50 to 75F you should be seeing a significant change in tire pressure, around 3psi. If that gets you from 36psi to 39psi in your stock tires, you're likely to see an mpg change from that alone -- that is what the hypermilers do over on Ecomodder.com.

Aside from our opinion that a consistent and verifiable 10mpg improvement is extremely unlikely, you can shut us up by grabbing data from your car to back up your claims, and we can probably pick through that to figure out what factors are actually pointing you to your conclusion thus far. Hint, it's probably not the intake temperatures.
Before my trip I raised my tire pressure to 42 PSI. For those who want to see it my results from the computer I posted it recently under the post "your fuel economy high scores".
 

·
Registered
Joined
·
1,791 Posts
A few of us on this forum Have noticed a significant difference in MPG with air temp much more than normal. I would not believe how much difference until my recent trip from Florida. Now bare with me I'm using the cars computer for data. It was a long trip and I believe the driving conditions were pretty similar, both test have been timed for an hour of driving on the same day and the same tank of gas.

Flat land going north entering Georgia from Florida the outside temp showed 50 F so I pull over shut the car off and reset the computer and drove for 1 hour, outside temp got a little better and I was able to get 37.8 MPG at 65 MPH.

I later noticed the outside temp reached 75 F and I pulled over reset current AVG mpg and drove for an hour. Avg MPG 48.34 at 65 MPH. On my second test I know the road was A little bit hilly.
Both condition were close except for temp.

As for warm air intakes there is such thing as overdoing it with pulling the air directly off the exhaust. People in Eco moders forum have had mixed result with Warm air intakes. It all depends on the car. But the Mazda 3 s might be one to try this on.
First of all, you are talking about outside air temp, not engine air temp. By the time the air gets to your engine, it is already heated significantly. Secondly, using the car's average mileage is the wrong way to test. Do you know how that is calculated? Do you know that if you stop at exactly the wrong point it changes the numbers significantly? You do realize when you "reset" the computer the average mpg is not really reset as it is not calculated from a zero base.

You need to do a designed test in order to get good data. You need to cover the same route from point A to point B just after a fill-up at two different outside temps and you need to repeat the test at least three times. You need to make sure the tire pressure at the beginning of each run is the same. You can do this by taking two to three runs during a warm day and two to three runs at night. You have to make sure the car is at operating temperature before you start each run. I think you'll see virtually no difference if you do a controlled test. This will take between 4 and 6 hours out of your time, but the good news is that you won't spend any money, other than gas, to do it. Otherwise, you are just operating on anecdotal evidence which is not worth much. Again, you have to make sure the tire pressure is the same for each run. There is also a human factor which you have to fight. Since you want there to be a difference, you will unconsciously favor the run with warmer temperatures. You have to fight this urge.

Again, I doubt that you will see hardly any difference in the end. The reason you have to do it multiple times is that the average mpg by the computer is not calculated from a zero based calculation. You need the multiple runs to average out computing differences.
 

·
Aspiring Mad Scientist
Joined
·
1,716 Posts
@rvoll covered the main points, so I just wanted to add one more; the human eye and inner ear are kinda bad at distinguishing what is flat road and what is just slightly uphill/downhill. A bubble level obviously won't help here so one way to help control the test is to travel in both directions and pray that you don't have significant head/tailwind. That unfortunately complicates the test quite a bit as you'll have to get the conditions just right.

As far as intake temperatures go, I'm not disbelieving that there's an optimal IAT to shoot for. But before you spend your time doing this you should log IATs and make sure there is a significant difference at the intake runners between 50 and 75F ambient.
 

·
Registered
Joined
·
381 Posts
Discussion Starter #10
I'm not going to waist a lot of gas and do a very thorough test. But from my total tank MPG and the previous test. The numbers are fairly close. Be a hater or disbeliever I'm not here to change minds it's all free will. That particular tank of gas MPG was 42.5 MPG. Not a milestone to post about but a good ECO driver MPG to post about. If the temp was the same the whole trip I would expect a more constant MPG.

A few of us here are finding some significant differences believe it or not.
 

·
Registered
Joined
·
1,791 Posts
@color0

The test is only as good as the measurement tool. I believe the car's computer calculates average mpg on the basis of 5 minute intervals and is not zero based. I have not confirmed this, but given how it is reported, it looks like the programmers made a calculation shortcut and thought that people educated in the sciences, engineering, and math wouldn't notice. If you take a very long trip, it shouldn't make that much of a difference, however. As I understand it, gas usage is calculated number based upon injection pulses and duration and there is NOT a meter in the system. So the gas part of the mpg calculation is quite suspect. The only real way to measure is to travel the same route from gas station to gas station and fill up to the top -- not to the bubble.

I'm not going to do a test like this because I bought this car for the fun it gives me. But it is an interesting problem, nonetheless.
 

·
Registered
Joined
·
1,791 Posts
I'm not going to waist a lot of gas and do a very thorough test. But from my total tank MPG and the previous test. The numbers are fairly close. Be a hater or disbeliever I'm not here to change minds it's all free will. That particular tank of gas MPG was 42.5 MPG. Not a milestone to post about but a good ECO driver MPG to post about. If the temp was the same the whole trip I would expect a more constant MPG.

A few of us here are finding some significant differences believe it or not.
You really need to inform the Mazda engineers of your findings. They probably don't know a lot about achieving good mpg.
 

·
Aspiring Mad Scientist
Joined
·
1,716 Posts
Nobody's disbelieving you -- yet. I'm only warning that if you're pulling in actual warm air, you should be mindful of your engine. You're playing with unknowns here.
 

·
Registered
Joined
·
381 Posts
Discussion Starter #14
You really need to inform the Mazda engineers of your findings. They probably don't know a lot about achieving good mpg.
Again Rvoll

I'm not alone here ECO drivers are finding some great MPG numbers. I don't even think I'm up near the best yet. Read more in the Best MPG area and find more that claim the same. But I understand your belief I see 90% of other cars pass me everyday. I'm one of few that cares about MPG. It does not bother me that you don't care about MPG. But is quirks my boat when You deny A different kind of drivers claims.

Sometime people just don't want to hear the truth.
 

·
Registered
Joined
·
381 Posts
Discussion Starter #15
Nobody's disbelieving you -- yet. I'm only warning that if you're pulling in actual warm air, you should be mindful of your engine. You're playing with unknowns here.
I'm hopping to find the happy medium here.
Thanks for your warning.
 

·
Registered
Joined
·
27 Posts
A few of us on this forum Have noticed a significant difference in MPG with air temp much more than normal. I would not believe how much difference until my recent trip from Florida. Now bare with me I'm using the cars computer for data. It was a long trip and I believe the driving conditions were pretty similar, both test have been timed for an hour of driving on the same day and the same tank of gas.

Flat land going north entering Georgia from Florida the outside temp showed 50 F so I pull over shut the car off and reset the computer and drove for 1 hour, outside temp got a little better and I was able to get 37.8 MPG at 65 MPH.

I later noticed the outside temp reached 75 F and I pulled over reset current AVG mpg and drove for an hour. Avg MPG 48.34 at 65 MPH. On my second test I know the road was A little bit hilly.
Both condition were close except for temp.

As for warm air intakes there is such thing as overdoing it with pulling the air directly off the exhaust. People in Eco moders forum have had mixed result with Warm air intakes. It all depends on the car. But the Mazda 3 s might be one to try this on.
Uh, you really think you were getting 48.34 MPG?? Come on, think about it if that were actually possible EPA HWY MPG would have been more like 48MPG instead of 39! It ain't going to happen. The avg MPG indicator in the car is not, and is not meant to be exact. It is for reference only. the car has no way of measuring the exact amount of gas it's using as you drive down the road - it does not have an on-board gas measuring meter. Only way to really see what MPG you're getting is to fill the tank full, drive XX miles, then fill up again and see how much gas it took and calculate you MPG by dividing gas used into # of miles driven.
Oh, and also the "outside temp" given on the dash is not that accurate either! Mine said 84F the other day when I know for a fact it was no more than 75F outside!

And warm air is NOT going to make a car run more efficiently. Maybe warm air would help if it were extremely cold and your engine and trans were not warmed up yet, but that's about it.

Every car has a IAT - Intake Air Temp sensor, usually integrated into the MAF sensor. It measures the intake air temp, and that data is sent to the ECU. As IAT rises, the ECU subtracts ignition timing advance. This is done to help prevent the engine from pinging as intake temps get hotter as in hot weather. When ign. timing is less advanced, the engine makes LESS power, and therefore is less efficient!
There are many more arguments I could give here as to why warmer air to the engine would not produce better MPG, but since the difference you gave here is only from 50 to 75 deg. the difference in mPG is not going to be that much.
Actual MPG, not what the cars calculated Avg MPG says on your dash.
 

·
Registered
Joined
·
381 Posts
Discussion Starter #17
Uh, you really think you were getting 48.34 MPG?? Come on, think about it if that were actually possible EPA HWY MPG would have been more like 48MPG instead of 39! It ain't going to happen. The avg MPG indicator in the car is not, and is not meant to be exact. It is for reference only. the car has no way of measuring the exact amount of gas it's using as you drive down the road - it does not have an on-board gas measuring meter. Only way to really see what MPG you're getting is to fill the tank full, drive XX miles, then fill up again and see how much gas it took and calculate you MPG by dividing gas used into # of miles driven.
Oh, and also the "outside temp" given on the dash is not that accurate either! Mine said 84F the other day when I know for a fact it was no more than 75F outside!

And warm air is NOT going to make a car run more efficiently. Maybe warm air would help if it were extremely cold and your engine and trans were not warmed up yet, but that's about it.

Every car has a IAT - Intake Air Temp sensor, usually integrated into the MAF sensor. It measures the intake air temp, and that data is sent to the ECU. As IAT rises, the ECU subtracts ignition timing advance. This is done to help prevent the engine from pinging as intake temps get hotter as in hot weather. When ign. timing is less advanced, the engine makes LESS power, and therefore is less efficient!
There are many more arguments I could give here as to why warmer air to the engine would not produce better MPG, but since the difference you gave here is only from 50 to 75 deg. the difference in mPG is not going to be that much.
Actual MPG, not what the cars calculated Avg MPG says on your dash.
I believe I did post my findings with the car computers AVG MPG was not true an accurate. For the full tank of gas I hand calculated 42.5 MPG. In real life I think the car's MPG is always A little optimistic by 1 or 2 MPG.

There are mixed results with warm air intakes. Go to ecomodder.com for more results. This is not a debate it's real data and I'm not the only one here.
 

·
Registered
Joined
·
278 Posts
you got nowhere near what you thought you did. resetting everything/ doing only once, will no equate to your final conclusion on +10 mpg. im all for more mpg, but anything less than 3 times of doing the exact same route with all the same variables, does nothing for us. it means nothing.
keep doing what you do, im all for it. but right now, it means nothing, unless you show us data from 3 to 4 plus drives with the same variables. i would hope to see those results
 

·
Registered
Joined
·
1,791 Posts
Again Rvoll

I'm not alone here ECO drivers are finding some great MPG numbers. I don't even think I'm up near the best yet. Read more in the Best MPG area and find more that claim the same. But I understand your belief I see 90% of other cars pass me everyday. I'm one of few that cares about MPG. It does not bother me that you don't care about MPG. But is quirks my boat when You deny A different kind of drivers claims.

Sometime people just don't want to hear the truth.
I'm all for the truth, which is why I tried to explain why your numbers were meaningless. And you are right, some people just don't want to hear the truth. It seems like you are one of them. If you are really after the truth, you would do some objective testing using the methods outlined. I'm all for ECO drivers getting the most out of their cars. But if you were a serious ECO adherent, you would want to prove your case correctly. Color0 and I have outlined the parameters if you want to prove us wrong and help other ECO drivers.
 

·
Registered
Joined
·
752 Posts
I manually check my MPG every time I fill up and my dash readout has never been off by more than .3mpg .. Its pretty darn accurate..
 
1 - 20 of 36 Posts
Top