Has anyone mod'd their intake at all so it pulls in more warm air?

(warm air = less dense = requires less fuel for given A/F ratio)


Simplest thing I can think to do is just block the feeder that runs along the hood, though I'm not sure that'll help much.

Thoughts on easy mods to draw more air from within the engine-bay?

 

I'm going to try this next winter for sure but its seems there's still going to be air getting in thru the grill but yeah, blocking off the scoop should stop a good amount of cold air getting in there. I have a K&N typhoon, so it could really help me out

 

That sounds plausible but raising it up to much would cause problems because of less fuel being injected compared to what is needed. The ecu would be confused and unless running higher octane for sure knock would happen. Winter gas has alot of butanes which is a gas and dont need lots of heat to vaporize. Toluene needs heat to vaporize and definitely give better mpg heated.

 

I can't imagine the air getting any hotter than it would be stop/go bumper-to-bumper traffic a hot summer day? I'm just thinking instead of like a 30F intake temp, it might be, if I'm extremely lucky 60-70F... maybe?

 

I've been watching intake temps on the UltraGauge and see that they typically run around 10F above outside air temp in the winter time on my stock 2010. Not sure what the mod is, but capturing a bit more engine heat might get 20F more, eh??

 

Yes, but heated air and butanes will cause it to vapor lock. keeping intake around 40 in the extreme cold will help mpg but the Cat and o2s would not read correctly. Heat the fuel in the summer especially toluene would work better. The F1 racing heats the fuel before it goes into the motor because the fuel is dense. Even though your only heating the air the butanes will vaporize before the burn and more fuel might be burned. Lots of heat is lost due to the cold and the Cat heats up to 800 degrees in 2 minutes after start up. It all goes to fuel density and butanes are a gas at 40 degress and others parts of gasoline need to heat up before vaporizing. In stop and go traffic the Cat temps cool off to 900 degrees compared to 1200 or higher at 45mph. At 65 my Cat temps are in the 1350 range.

All in all its a good idea to heat up the intake but not too much and I could see it working in theory but not with all what the ecu does and needs to do for good driveability. In the older cars they had a hose run off the exhaust to open a valve to let in cold air but that was for carburetors that need heated air to help vaporize the fuel.

 

Not sure I understand your concern. The MAF measures the volume of air going in (using temperature) and adjusts the fuel appropriately to maintain the proper ratio. When slightly less [slightly warmer] air goes in, are you saying it won't slightly reduce the fuel as needed?

The ECU just cares about intake air temp right? not ambient?

If the intake air is 50F, it'll squirt in some volume of fuel, regardless of whether it's 20F, 30F or 40F ambient?

 

There is a correction for cold temps and if the MAF sees less air then less fuel is added and a poor running motor and possible engine damage. Heating the fuel to a point would be better. Also adding more fuel pressure would add more fuel and the ecu would take fuel out and better vaporizing of the fuel and thats good to a point too. I believe there is a 2 step fuel pump and when the vtec kicks in the fuel pressure raises so if the fuel pressure was higher at lower vtec then less fuel is injected but a bigger correction. Thats why premium is pulling fuel because its denser so less fuel and a more efficient use of the gas.


Here is the correction Fuel parameters It give the correction the intake see and how much fuel is added.

 

Looking at the charts there would be little if any mpg gain by heating up the air. It would probable go in to open loop and throw a code if to much heat is added and then worse mpg.

 

There is a sweet spot for pre-heating the fuel but this is more of a concern on ethanol engines in cold weather.

That spot or range of ideal temperatures changes car to car and configuration to configuration.

So what the target would be for my Fit is going to be different than that for your Fit. Still something worth playing with if you have exhausted all other means of decreasing fuel consumption.

The best thing you could do would be to install a restrictor plate in the intake, or an electronic throttle controller.

Modding your intake to make the air warmer is not necessarily a good idea on a pump gas car. But as long as your IAT's arent heading north of 120F couldn't hurt.

But again, this would be where I would recommend a restrictor or ETC first.

Let us know which route you go.

 

I just talked to my mechanic brother in law, He just said bad, not needed because of fuel trims.

 

Um. <squint>

I'm suggesting running the engine with intake temps in the 50-60 degree range at MOST... which would be 20-30 above ambient.

To use that I guess I need to know how temperature affects to kPa? I don't



regardless... I want my summer fuel economy in the winter. How do I do that?

 

That goes to gasoline composition. Butanes are less dense and more needed. The temperatures being cold and the engine only using 32 percent of the fuel and the rest going to cooling and other loses more fuel is needed. Toluene is dense but is not good winter fuel. If there was a way to get summer mpg in winter it would be done, some one would have figured it out. Gas price are usually lower in the winter by half of summer gas. So dont be surprised by 6 dollar gas prices this summer.

 

 

On MAF systems they usually use 10F = 1Psi lost past 90F IATs when they do not already have a barometer in the system.

Altitude density will affect this too.

An open cone filter, like a short ram that takes air from right next to the radiator, or mounted toward the firewall to be warmed by the exhaust would certainly help raise IATs

 

Place cardboard over the radiator
One guy I read about does this and says that a cold engine reduces fuel-efficiency. He uses Office Depot’s silver-colored cardboard to warm up the engine faster. He covers his radiator with cardboard to block the wind, thus retaining heat and keeping the engine running at a warmer temperature. Knowing that this could cause his engine to overheat, he says, “I’ll take off the piece of cardboard if I know that I’ll be driving a long distance, say 100 miles, but it’s fine for my daily commute.”

 

It goes to not needed, what happens when the IAT sensor stops working it runs rich. Colder air is denser and is what makes horsepower. Heating it to summer temps would cause the ecu to lean out the car but there would not be enough fuel because more is needed to keep engine running right.


I agree warming it to 40 when its 0 out would possibly work but using premium does the same thing. `You have the MAF saying this much fuel and The IAT saying take out fuel and not enough to keep the motor running. I sometimes have a problem running premium at idle in a fully warmed up vehicle. It wants to stall thats because more fuel is needed and the car is running lean.

 

This is true as well.

Mostly diesel guys do this in cold climates.

You can even leave a mostly covered rad on the freeway, because there will be air flowing over it. A mostly covered rad in traffic might not be such a good idea because this is what can lead to overheating. Less cold airflow over the core.

 

Covering 3/4 of the radiator is a good idea but thats in extreme cold. We sometimes cover the front intake on our trucks but thats only when the thermostat doesn't work before the mechanic fixes it.

 

Enjoying this discussion/lesson, thanks guys


hmmm... sorry i'm being a bit dense... I'm still not understanding this. Everyone seems to be saying that the engine won't work right with IAT of, say, 60F? IAT of 60F has the same effect, regardless of if it's 60F outside or 20F outside right? i.e. the ECU doesn't care at ALL about the outside, ambient air temp... just the IAT, no?

I dont' understand this either The volume of air being ingested is more when IAT=0F than when IAT=40F, right? So an appropriately increased fuel rate is also required - regardless of the fuel's ability to avoid pre-det?