Warm air intake on a Focus....
 

Am seeing what I think are some definite mpg gains from using a warm air intake with a Focus....after seeing a low 40s mpg trip on a 15 mile run under the conditions mentioned below....and this run involved a few stops and slowdowns for curves, etc.

This is after the car is warmed up and when ambient temps are above 80F.

My simple warm air intake results in IAT temps ~ 30F above ambient in these conditions (car warmed up/ambient above 80F) ...meaning IAT of around 110F to 120F.

So I'm thinking that if there was a way to maintain the 110F-120F intake temps or above under a wider range of conditions...mpg could be increased meaningfully.

Thinking of removing the heat shield from the exhaust manifold....and fabricating an outlet from sheet metal to allow attaching the intake tube for increased heat intake.

Not sure of the effect of removing too much heat from the exhaust tubes as far as efficiency is concerned though. Also might be an issue of too much heat for the plastic air box?

Interested in results or comments from anyone else using heated air on a Focus or other car. The Focus uses a MAF...not the MAP...which is supposed to be more effective with warm air.

Sounds odd to me, because cold dense air is favored for intake. Ford even developed a cold intake system using the A/C a few years ago.

Maybe the air the body of the car is passing through is thinner?

Could this be yet another reason why the wide open spaces of the Bonneville salt flats hold all the world land speed records?

EDIT: I found an old post of mine from 2005:
SEE THE FIRST LINK - AUTOSPEED.

http://forums.pelicanparts.com/porsc...ir-intake.html

If your Focus really is using a MAF and not the MAP then you have the effectiveness probability backwards. Apparently, nobody here has shown that a WAI works with a MAF (Sentra_SE-R ran the best test I have seen on that). I tested a WAI with my Honda's MAP sensor and found a modest gain in an ABAB test (see my signature file for the link).

In general, these benefits are close to the margin of error produced by driver variability and conditions, so a rigorous ABA test is the best way to try and see if something like this is working. When I bought my Ultra Gauge a few months ago I was amazed at the variability of my driving, even though I had been essentially hypermiling for years with the same car.

james

I driving a 2007 Focus ZX3 - 5 sp - and tried using metal and rubber tubing to get warm air to the K&N filter that I'm running - with little success - so I'm heading down the road of adding a second heater core - tapping into the lines that connect to the heater core in the firewall - and basically setting it in front of the intake - and then the air filter on the other side of that - so in the end I will get a constant warm air intake temp year around - since living here in Indiana - can range from -10 to +100 - - CRAZY - I'll post the results later this month hopefully.

ok, let me see if I understand your set up.
You took something like a heater core (looks like a small trany cooler?) and mounted it inside of the air box (infront of the air filter)
And fed hot water from the engine?

That is friggin brilliant!!!!!!!

Weather it works or not.......CONGRADULATIONS!!!!!
That is thinkin outside the box!!!

PICTURES!!!!!!?????

Yes - that is the idea - stopping tonight to get the heater core - $20 at Advanced Auto - and hope to get going on it this weekend - I'll post results and pictures - I have a netbook pc installed in the car with the ECM connected and running ODBWiz software - so I can monitor everything and log it - it's a sweet setup!

HURRY!!!!! lol

You know you would be better off warming the fuel and keeping the intake air cool. Its the fuel you want to vaporize better, not the air. A cooler intake charge also reduces combustion heat lost to the cooling system. Also a cooler intake charge results in lower NOx production.

Warmer air is less dense, which means you open the throttle wider for the same power. That means less pumping loss to pulling the air past the partly-closed throttle valve.

I think using a heater core would be counter-productive, as that will add a restriction to flow up in the air box. It's possible that it won't be enough to matter, but my first guess is that it would be. Testing would tell, and that's why it will be great to see the results from this!

-soD

Increase air temps have been known to increase flame speed which increases efficiency. Also, hot air is less dense requiring a larger throttle opening to maintain the same power. So there are benefits to be had from warming the intake air.

Even if the core is a restriction, you're simply moving the restriction from the throttle to the core. If that is the case he'll notice a drastic drop in power, so it should be pretty apparent.

Pretty sure the Focus is not a return loop fuel system, only one line from the pump to the injectors. The pressure regulator sends a signal to the ECU which sends another signal to the fuel pump module, which varies the voltage to the pump and the resulting fuel pressure variation.

Whew! complicated system, but bottom line is the fuel gets heated by the engine itself, potentially providing better vaporization.

Sentra's test while very thorough was in ambient temps no where near as dramatic as some members here experience, so the WAI may help your mileage to a significant degree if your ambient temps are below freezing, more so if they are significantly below freezing. Some here are dealing with cold so severe that they could probably cool their engine with just the heater core!

I love the idea of a heater core in the air filter intake housing. The only downside of that would be it might make the coolant coming out of the radiator even more cold which could reduce mileage a little but probably not much.

One of the things I think would make a heck of a lot of difference would be to have adjustable venetian blind like louvers in front of the radiator that were thermostatically controlled by the radiator return hose to the engine. This would be an automatic radiator block that maintained a constant return coolant temperature (radiator to engine) at temps similar to summertime.

If you feel the top hose (engine to radiator) then the bottom hose (radiator to engine) you will feel the difference in coolant temperature. With a new radiator and very cold temps the return hose will be pretty cool, sometimes even lower than your body temp.
The hotter temp you feel in summer means the coolant removes less heat from the engine so it should mean more heat dedicated to combustion.

Watch those FINGERS!

regards
Mech

Anytime you think of incoming air temperature, just take it to the extremes. Say 50 below 0 and 180 above. I think either one would give you problems, but I am sure the 50 below will not help your efficiency. When fuel is injected the huge increase in surface area absorbs heat. The is one of the reasons why direct injection allows an engines compression to be increased significantly and still run on regular fuel, but DI with sequential squirts cam also be done while combustion is actually occurring, which in the case of the Mazda SKYACTIV engines just coming out, allows compression ratios as high as 14 to 1 running on gasoline with no possibility of pre ignition, since there is almost no fuel in the combustion chamber before TDC.

Transonic is working on fuel heated to several hundred degrees under pressures approaching 200 atmospheres (almost 3000 PSI). The idea is to have the fuel self ignite when injected with no spark necessary like a diesel (but gasoline).

Semi hijack, my apologies.

regards
Mech

Run the heater supply hose (hot) to your additional heater core, then to the regular heater core. If the additional cooling reduces the need for the regular radiator to provide cooling then the thermostat will just close up some. Heaters are generally bypassing the thermostat anyway, which is why you normally should not turn the heater on until you get decent movement of the temp gauge.

Garages help when you leave the heater off and drive away immediately after starting the engine.

regards
Mech

To all the folks who think a warm air intake improves a car's fuel economy, a warm air intake is NOT good for fuel economy, I don't give a damn what anyone says the real reason it improves anything at all is because it governs (throttles down) the car's power hence allowing it to consume less fuel but if this is the case it is high time some drivers review their driving style because it also makes it LESS efficient, meaning if you're seeing gains in fuel economy then you are driving very inefficiently, you'd be better off keeping your foot off the floor or put a brick underneath your gas pedal, that will make your car's fuel mileage increase too.

And we should "give a damn" about what you say ;).

regards
Mech

My understanding is that the benefits, which only seem to accrue to MAP equipped cars and not MAF equipped cars, come from reduced pumping losses. Here are the results of my test on my MAP equipped car: http://ecomodder.com/forum/showthrea...tml#post233571 ...but you don't have to "give a damn" ... it won't worry me or reduce my fuel economy.

You can always spot an ecomodder noob when the topic of warm air intakes is brought up.

It comes from the fact that the rest of the world is trying to squeeze more power out of their engines rather than just better mpg.

To the noobs, of which I sort of am, but, been here long enough to 'get' WAI.....

CAI allows you to stuff more O2 into a cylinder for a given throttle opening. More O2 means more fuel and more power.

You might consider this more "efficient" in that you are making more power. But remember, the name of the game here is to make just enough power to push your car at a desired speed.

So, since power as a function of throttle opening, is higher with CAI, a WAI throttle must be opened further than a CAI throttle to get to the desired power output.

And since pumping losses decrease with throttle opening, the WAI will have lower pumping losses which means higher efficiency.

It requires a different way of looking at things and remembering that it all revolves around pumping losses and possibly better fuel atomization.

I am sure there is a better worded explanation somewhere around here. Perhaps someone could post a link to it.

Except for the fact that EGR and PCV offset pumping losses to a large degree. A colder air intake with a more closed throttle plate will increase EGR flow thus leading to more trapped mass in the cylinder which in turn reduces heat lost to the cooling system and allows more energy to be extracted from the power stroke. Also as mentioned before a cooler intake charge also reduces energy lost to the cooling system.

If you want more proof, cooled EGR bumps mileage compared to non cooled EGR.

Was that last line supposed to have a link? I'd like to see it, if so. And just as an FYI for readers who might not know, not all cars have EGR. Mine does not. What this all demonstrates is the need to know your car and test for results whenever there is substantial reason for doubt about a mod.

In November 1969 Nissan built the first 240 Z a car heralded by the automotive media as a revelation of economy reliability and performance. On the air filter of the early Z cars you will see a lever on the side of the intake snorkel. It was marked winter and summer.
A metallic hose ran from the air cleaner down to the exhaust manifold and the flap actuated by the lever closed off the intake snorkel in the front of the air cleaner and forced the air to be drawn from the exhaust manifold.

At the time emissions controls consisted of a PCV, EGR, and air injection.

Anyone here who has been around and driven cars of that era and actually worked on them and understood the operational principles, knows that almost all cars of the era had WAI to mitigate the effects of colder air, in particular air at just above and below freezing temperatures. The variable venturi carburetors of the era were particularly susceptible to "icing", a condition where the higher velocity of the air passing through a variable venturi carburetor would simply not atomize properly, the early Z car was undriveable unless you moved the flap to the winter position.

The same basic design carburetor is used on motorcycles to this day.

While fuel injection vastly improved atomization, it did not change the laws of physics. There is a freezing point of gasoline, and although it is very low temperature wise, you still have the "chill factor" of air at higher velocities making the actual temperature much lower than ambient.

Sentra spent a lot of time and found no benefit with his testing. This is more of a testament to modern fuel injection, than an attempt to defy the laws of physics. Every liquid has properties that change as temperature drop. His testing did not include temperatures that were low enough to freeze salt water, to the extent where you could drive a car across a 4 mile wide river.

I gets much more cold in places more north of here. I've seen 38 below F, some here see that every winter.

I have found that warmer intake air and warmer wintertime coolant exiting the radiator made a difference of about 10 MPG on my Insight and on my VX. I could feel the difference in power, power I didn't need was reduced while efficiency was increased.

regards
Mech

This has been an interesting read for me. Even though I don't understand the specifics (pumping losses:throttle opening etc.) I get the main understanding. Warm air is less dense and means less fuel.

I am not a mechanic by any stretch of the imagination. Just a guy who likes to tinker with his truck and squeeze as much as I can get out of it. I do have two questions that I hope someone can explain for me without going into too much techspeak. (I ain't got much fer smarts)

1) Why does this not seem to work with a MAF but does with a MAP? And what is the difference in these two doo-hickeys anyhow?

2) I have heard of the ZX2's using a resistor to "trick" the computer into thinking the intake air is colder than it really is. I realize it is to help advance the timing (I know what that physically means but don't know why it works), but doesn't it use more fuel to compensate for what it thinks is colder/higher density air?

I'm sure these questions seem trivial for the most of you, but I'm always trying to learn something new.

p.s. I made a what I think is a "poor man's WAI" but I don't know how to re-size my pictures to get them posted here. They are about twice as big as the site allows. Any help there would be appreciated also.

Thanks.

HOWTO - Images in Ecomodder
 

This may be of some help.. Post #10 deals with resizing images.

http://ecomodder.com/forum/showthrea...der-18279.html

Thanks Nemo. I think I did it right. Going to try and start a new post on my idea. If you don't see it soon then I didn't re-size properly.

WAI/CAI switch
 

That's a thought I had, because I don't like how hot the IAT is in the summer (140+). Thanks for this posting, one of the most welcomed I have seen in a while. Question: I looked for pics of the intake snorkel you mentioned and did not find one... do you know of any?

http://i263.photobucket.com/albums/i...4_145140-1.jpg

Here you go. You can see the lever that shuts off the air flow through the snorkel in front of the housing, also the opening at the bottom that went to the tube to the exhaust manifold.

Incidentally, the same model Z car also had cooling lines running to the intake manifold itself to use engine coolant to warm up the manifold.

Heck even my 1937 Ford had a passageway through the intake manifold that used exhaust gas to heat the manifold right under the carburetor.

The latest developments in fuel injection combine superheated fuel with 200 bar pressure injectors to achieve truly homogeneous mixture of the fuel and air in the cylinders. The result is emissions clean enough to eliminate the catalytic converter altogether. In the end you will see fuel injection evolve into a system that ensures the air and fuel molecules are perfectly distributed in the combustion chamber just prior to ignition, without any necessity for a spark to ignite the mixture. Even diesels would benefit from the same technology, and Argonne labs is actually working right now on an engine that uses a combination of gas and diesel fuel.

We will see 60% thermal efficiency in IC engines. The problem is the great variations in load encountered in normal operational scenarios makes such an accomplishment extraordinarily difficult.

It's one of the most basic premises of my in wheel hydraulic design, which eliminates all but the most ideal engine operational parameters which makes true homogeneous combustion much easier to accomplish. They are already there today as I write this post.

regards
Mech

MAF (MASS AIR FLOW) sensors are mostly fine wire that is heated by an electrical current. As the air flows past the wire the voltage differential, across that wire, is measured by the computer and this voltage signal is used to control injector cycling duration.

MAP (MANIFOLD ABSOLUTE PRESSURE) sensors read the amount of atmospheric pressure that is actually available to the cylinders. This pressure is equal to the atmospheric pressure minus the negative pressure created by flow restrictions. Otherwise know as manifold vacuum. MAP is the opposite of manifold vacuum. Take atmospheric pressure subtract MAP and you have manifold vacuum, the reverse is true.

Both MAP and MAF give the ECU a load signal and the ECU can calculate the amount of fuel to deliver to the cylinders knowing either MAP or MAF. This, combined with RPM, provides a amount of fuel which is then adjusted further by the feedback from the oxygen sensor which measures the content of the oxygen in the exhaust after combustion is complete.

MAP and MAF tell the ECU to deliver X amount of fuel. The oxygen sensor tells the ECU to trim the delivery of fuel slightly to achieve the ideal amount of residual oxygen in the exhaust when it leaves the combustion chamber.

Hope this helps and I hope the explanation is understandable. If not let me know what is still fuzzy and I will try to explain it further.

regards
Mech

So I guess it works with a MAP because with different air temps the same cubic volume of air can have more or less pressure because of it's density. The MAP would register this and the MAF wouldn't (based on design?). Am i in the ball park?

If this is the case would/could it be possible to physically heat the air "downstream" of the MAF (if it works with a MAP then why bother) and ahead of the combustion chambers and would it make any difference?

p.s. I posted pics of my "Poor man's WAI" but they don't look very good. Any comments would be appreciated from anyone. Even if they are just to laugh at me. I'm a big boy, I can take it.

I would say "probably" about one sensor working better than the other with a WAI. I would also say in my opinion WAI would make a difference with either as long as you are working with "severe cold temperature" as they are both using basically the same fuel.

Also consider the radiator block as a means of increasing the temperature of the coolant leaving the radiator and entering the engine. Since a cooling system is a "worst case scenario" design. it's capacity is far in excess of anything needed in very cold temperatures. In fact for some here, they could probably drive their car using hypermiling techniques with just the heater core for cooling, since their technique reduces waste heat significantly which exacerbates the excess cooling capacity of the stock radiator.

The colder coolant exiting the radiator and entering the engine will absorb more heat from the cylinder walls. Some manufacturers are using this knowledge to restrict air flow over the radiator in cold conditions to increase the temperature of the coolant entering the engine. That temperature can vary by as much as 100 degrees in the extremes of winter and summer conditions. Hotter coolant entering the engine means less heat loss through the cylinder head and walls, as long as it does not create an overheating condition in the engine.

regards
Mech

Many cars with carburetors or TBI injection had some form of hot-air intake to help with driveability while the engine was cold. They would typically have some form of temperature-based control which would shut off the hot air intake when the engine warms up.

If you try a Google search for "Thermac" or "thermostatic air cleaner", you should get plenty of results.

Found this from a 1990s Toyota 4runner parts supplier: AIR CLEANER. Fits: TOYOTA | Village Toyota Parts Seems the thermostatic air cleaner systems were around until quite recently. Know any on even more recent, perhaps OBD2, vehicles?

Proper engine bay insulation can increase the intake air temperature. That is what I am trying to achieve; some easily removable insulation blocks capable of retaining heat. I have noted a gain in terms of IAT; going from -2F to 16F when the engine is fully warmed.

With a properly working OBD1 or OBD2 system it shouldn't matter if you have a MAF, MAP, or both.
The MAF and MAP are key in the fueling equation that determines what part of the fueling map the ECM uses; however, the O2 sensor always has the final say in determining the injector pulse-width that is executed. The adaptive fueling routine is applied last and calculates any fuel trims necessary to the final pulse-width value in order to stay within proper AFR range as determined by O2 sensor feedback.

It is true that many systems out there are not functioning 100% correctly, and so you will get many variations on your results.

The WAI does work on our 03 Focus, and especially so in cold weather.
As mentioned in an earlier post here, the loss of power (throttle response) due to the warmer air will indeed increase throttle resolution, thus making it easier to drive the vehicle while using the least amount of power necessary.
More throttle resolution means more gas pedal movement for less opening of the throttle blade. That can be a big help on some vehicles depending on the mechanical leverage of the throttle cable connection, and the internal design of the throttle bore. Some throttle bodies are designed for very snappy reponse with little throttle movement, and others are designed to be much less sensitive at very low throttle openings (right off idle).

WAI systems that I have tested in the past have worked extremely well on carbureted and TBI systems where fuel vaporization and distribution are poor.

As for pumping losses, I'm sure they are a little less in some cases, but I don't feel that is the primary source of fuel economy gain by using the WAI.
It seems to me that the heat increases the quality of fuel vaporization, and speeds up the burn in the chamber.

I have seen an instance where a WAI caused a significant loss in FE. It was an underpowered engine that was needing to do a lot of work, - load carrying and hill climbing. The loss in power from the WAI created a need for so much throttle that PE - Power Enrichment mode was invoked by the ECM, which enriches the mixture to between 11.5:1 and 12.5:1 AFR depending on the model. In this case it would have been extremely helpful to have a driver controlled valve to switch between CAI and WAI.

I would like to see how you did yours.
I have had some ideas, but never did implement them.
There are a lot of factors to consider with something like that.

I found my problem with not getting warm air into the Intake - it was a closure of the hose that I was using - I had it too close to the heat source - and it stated to melt close - once I solved that problem - I get consistant 60 degree temp into the intatake - so now I can go back to collecting data to analyze - glad I checked the hose first - I could have taken the whole setup off - hose last - only to find the problem at the end - just lucky I guess -

OOPS! I forgot the link.

http://www.swri.org/3pubs/ttoday/Sum...n-and-Cool.pdf

It should be noted that they get vague as to if they are comparing cooled EGR to no EGR or ordinary EGR In this article.

I have seen others papers on cooled EGR improving economy over ordinary hot EGR as well but they cost money.

“Doing More with Less” - The Fuel Economy Benefits of Cooled EGR on a Direct Injected Spark Ignited Boosted Engine

That is a very good point. If you reduce engine output to the point where the PCM is in PE mode a lot, your fuel economy will be wrecked.

Also note that some ECMs / PCMs are programmed to richen up the fuel mixture, if the air and/or coolant temperature gets too hot (presumably to prevent pre-ignition).

So there is a break-even point which you can accidentally cross, if you're not careful. That point will depend on the vehicle, and the ECM / PCM programming.

I dunno about other engines, but on all the (mostly Toyota) vehicles I've driven you have to darn near floor it AND hit some fairly high 3000+ rpms to go into fuel enrichment. Otherwise the engine lives in closed loop very happily.

I have to watch my scangauge very closely in my B2300/Ranger truck to keep out of open loop. At low rpms like under about 1800 I can nearly floor it and stay in closed loop. LOD can be at like 98. But as rpms rise the open loop comes in at lower and lower LOD readings. At 2300rpm on the freeway open loop occurs at about 65 LOD. I usually run about 45-55 LOD on level ground so it doesn't take much to go to open loop full rich and kill mileage. No WAI on this engine.

Is that related to VVT ?