Stock intercooler blanking plate

[rampant]

Thing is that an air-to-air intercooler can’t cool the compressed (heated) air to a temperature below ambient. So the relative humidity of the charge air inside the intercooler cannot be greater than the ambient air at the intake.

Condensation can only occur if you cool air that contains vapour moisture content down to below its “Dew Point”, (when relative humidity is 100%).  The cooled saturated air cannot then carry the moisture in vapour form and the vapour is forced to condense into liquid.  The air is still at 100% relative humidity, but the moisture content is less, and the difference in moisture content is accounted for by the condensed water that the air has expelled.  Same process as clouds forming in rising air that cools as it ascends. Or fog forming as the air is cooled by the ground in the overnight cooling period when the ground radiates its heat back to space when the sky is clear.

But if the air going into the intake isn’t “saturated” (relative humidity of 100%), then it cannot saturate in the intake tract.  Clearly, if you drive through fog, then the intake air *is* saturated, and re-condensation *can* occur inside the intercooler tract, but no amount of blanking plate can prevent this, because you are taking saturated air mixed with water droplets into the intake itself anyway.

I propose that “condensation” is a non-issue.

 

Yours Aye

Mark H

---

// ’17 Nitrous Blue // Forged Alloys // Michelin Super Sports // Painted Calipers // Sync 3 // Lux Pack // Winter Pack // Black Gel Spoiler Badges // Blue Gel Wheel Inserts // GTechniq Liquid Crystal // GTechniq Alloy Armour // sold Jun ’18

[frenk]

Brilliant! Cheers Mark.

Any clue as to why Ford had that piece of PVC glued to the intercooler in the first place?

---

Revo Stage 1 – JCR super low seating frame – Mishimoto gas pedal spacer – DSC sport controller

[rampant]

Absolutely no idea. I’d be second-guessing, based on my conclusion that the designer didn’t really know what they were doing!

---

// ’17 Nitrous Blue // Forged Alloys // Michelin Super Sports // Painted Calipers // Sync 3 // Lux Pack // Winter Pack // Black Gel Spoiler Badges // Blue Gel Wheel Inserts // GTechniq Liquid Crystal // GTechniq Alloy Armour // sold Jun ’18

[71-bda]

@rampart, the stock intercooler certainly can reduce the inlet charge temperature below ambient ! The scenario Ford were fitting the blanking plate for was where a car was cruising on light throttle at highish speed at low temperature, there is no boost so no compressing the air, in fact the intercooler could be in slight depression ( vacuum) and the air flowing over the IC at speed with wind chill factor would be enough to freeze any slight moisture that has built up. I guess they were concerned that when you opened the throttle to accelerate after the prolonged cruise a sudden defrost could mean a big gulp of melted ice entering the combustion chambers and causing a momentary misfire. Its funny that a few folk have said that after a long cruise, when they go to give it some gas, it stutters/misfires for a second and then clears, classic icing situation I have had with a few cars in the past.

---

No nothing.

No Mods. No rockers. Just a chunky knob, thats now been replaced by an RS knob innit.

No tackiness.

Std as Ford intended, but with a space saver wheel and jack and nuts and wheel brace. oh.. and flaps, a man has got to have flaps.

Innit?

 

[frenk]

Oh, I see, they go testing where the Diesel thickens and you need an air box heater to start the engine:

http://www.autonews.com/article/20150601/OEM/306019952/swedens-hot-spot-for-winter-testing

Now I understand the launch of the Mk3 Focus RS in warm Valencia ?

---

Revo Stage 1 – JCR super low seating frame – Mishimoto gas pedal spacer – DSC sport controller

[rampant]

71-bda  –  “wind chill factor” is not a real thing for inanimate objects that aren’t being heated by some other internal means.

 

Question for you.

 

I have a bottle of warm water out of my hot tap.  I run water from the cold tap over the bottle to cool it down.  Can the water in the bottle get to a lower temperature than the temperature of the cooling water?

 

Think about that and get back to me when you have a better understanding of thermodynamics.

 

Yours Aye

Mark H

BSc (Eng) Aeronautical Engineering

---

// ’17 Nitrous Blue // Forged Alloys // Michelin Super Sports // Painted Calipers // Sync 3 // Lux Pack // Winter Pack // Black Gel Spoiler Badges // Blue Gel Wheel Inserts // GTechniq Liquid Crystal // GTechniq Alloy Armour // sold Jun ’18

[71-bda]

rampo, look, lets say ambient temp is 5c, and the important thing to include is high humidity, so there is water in the air blowing on to the intercooler AND entering the intercooler at around 5c  on light throttle while cruising at 70mph at zero boost, and as I said, possibly even below atmospheric pressure, the air going over the intercooler will cool the intercooler to below 5c thats what ‘wind chill’ does, well to be more accurate,

Windchill only describes what happens to warm dry objects like people. If something is cold and dry, then windchill has no effect. It doesn’t change the air temperature, but Ford are using the blanking plate for ‘certain atmospheric conditions’ ie humidity..wet probably cold air..

For wet objects, it is more complicated. Evaporation of the water requires energy, and this lowers the temperature. The lowest temperature a wet object can reach is called the “wet-bulb temperature”. This can be several degrees lower than the “dry-bulb temperature”, depending on humidity. If the wet-bulb is below 0°C, then freezing is possible.

Now in order for a wet object to get close to the wet-bulb temperature, there needs to be some convection to take the evaporated water away: There needs to be some wind.

So the wind can cause freezing under the right conditions

in the meantime I suggest you put your hot water bottle back in your bed and go and have a think !

---

No nothing.

No Mods. No rockers. Just a chunky knob, thats now been replaced by an RS knob innit.

No tackiness.

Std as Ford intended, but with a space saver wheel and jack and nuts and wheel brace. oh.. and flaps, a man has got to have flaps.

Innit?

 

[71-bda]

oh, and P.S, if you don’t think condensation can form, explain why the headlamps get condensation in when driving on a cold night ! Innit

---

No nothing.

No Mods. No rockers. Just a chunky knob, thats now been replaced by an RS knob innit.

No tackiness.

Std as Ford intended, but with a space saver wheel and jack and nuts and wheel brace. oh.. and flaps, a man has got to have flaps.

Innit?

 

[kr1s]

This is my favourite thread. By far.

I love the science and the examples you’re both giving.

Also it’s a proper debate not a childish row. Keep going please.

[9designs]

Is not also the case that these Ecoboost engines need to work over a very narrow and high temperature operating window, sucking cold air on a very cold damp day and little boost, then cooling it down through an inter cooler (or rather keeping it still very cool)  takes the intake charge out of the range they want to keep it at for efficient running and emissions.

Always makes me laugh when people suggest Ford don’t know what they are doing or didn’t test stuff.

Taking the plate off would only act as a placebo on a stock of mild tune.

---

Magnetic Grey with all the best bits

FPM375/COBB/MSD-  Quaife LSD,  DSC+Tractive  Suspension,  HJS200 cell sports cat and MT Cooler. Sync3 upgrade.

Was UK seller for DSC & Tractive  Active suspension !!!

    

[rampant]

Warning, long post…

 

bda – Your second post doesn’t really make me want to help you out in a polite way.

 

But I will. Because I am.

 

Since you didn’t answer my first question about the bottle of warm water, I’ll answer it for you: it is impossible for the warm water in the bottle to be cooled to a temperature less than the temperature of the cool water flowing over the bottle.

As I said before, wind chill is NOT a factor.  All that the *flowing* water over the bottle does is to keep a constant supply of constant temperature fluid coating the bottle and conducting the heat energy away, rather than sitting the bottle in a large bowl of cold water – heat transfer in the case of the bottle of warm water sitting in a bowl of cold water is that the bottled water cools and in doing so warms the bowl of water – which means the bottle of water stood in a static bowl will not be cooled down to the initial temperature of the bowl of cold water.  I isolation, both the bottled warm water and the bowl of surrounding water reach an equilibrium temperature somewhere between both original temperatures.  (If you include the surrounding air, the system becomes more complex.  Stood in your kitchen, the bowl of cold water from the tap will be warmed by the room temperature air.  All the water eventually settles at a temperature of room temperature. Stood outside in winter, the entire system of bowl and bottled water will cool to surrounding ambient temperature.)

 

Wind chill is a made up term to indicate only how *your body* reacts to the temperature and how it feels on the skin.  Consider a simple “baseline” that if the air outside is at 5°C and is still with no wind – you stand in it, your body will keep your core temperature at around 36°C, but your extremities will feel cold as the air conducts heat away from your skin in contact with the air. Your metabolism and circulation keep supplying heat energy to your extremities, though, and your fingers won’t cool down to ambient 5°C, well not in the short term, anyway.  Do nothing for long enough, however, and your body may die and *eventually*, after death your body will cool to 5°C.  Now consider a lower temperature of 1°C, but the air is still, with no wind.  Your body will extremities will cool down a little bit more quickly.  As before, do nothing and your body will die and eventually reach ambient 1°C

Going back to the air now being at 5°C, but adding a little air movement, it is a physical property that heat transfers away from you body a little bit more quickly.  There exists a wind speed that *feels like* being stood in ambient air of 1°C to your living tissues, and your body will cool and die in a similar time (not exactly the same time, but a similar time) as it took at 5°C with no wind.  However, your body will still cool to 5°C, NOT 1°C as you seem to be mistaken.

Change your body for a bucket of water at 36°C sitting outside in the same 3 conditions.  On the day there is 5°C ambient temperatures and no wind, the water will cool to 5°C .  On the day there is 1°C ambient temperatures and no wind the water will cool to 1°C.  On the day there is ambient temperatures of 5°C and a bit of wind, the bucket will cool more quickly, but will still cool to 5°C and no lower.  You could say here that wind chill assisted the speed of cooling, but you definitely cannot say that the water will cool to less than ambient just because the cooling air is moving.

 

They KEY and fundamental factor of thermodynamics (2nd law) is that you cannot cool the inside of an intercooler to a temperature lower than the surrounding air unless you do some “work” on it.  And we don’t.

It is a physical impossibility that the intercooler cools the charge air to a temperature lower than ambient.   (the second law of thermodynamics states that you can’t have a self acting fridge and this is what some people mistakenly think might occur.)

 

You touched on moisture on the exterior of the intercooler.  That is formally known as latent heat of evaporation.  For this to be a factor, actual evaporation needs to take place.

 

Let’s look at some real life conditions scenarios.

 

Scenario 1:  ambient air contains a “little” moisture content.  Let’s say 20% relative humidity, for argument’s sake. Car is on boost.

 

In this scenario, the air going into the intake tract goes through the turbocharger, gets compressed and therefore heated by the turbo and then travels to the intercooler warmer than ambient.  Although the relative humidity is reduced, importantly, the actual water vapour content is not changed.  The warmer air is able to carry more evaporated water, and this is the reason the *relative* humidity reduces, despite the water content being the same. No water vapour is added or removed.

Passing through the intercooler, the charge air can be cooled to a temperature not below ambient.  In actual fact, the charge air doesn’t get cooled to ambient, because of the second law of thermodynamics (entropy can only ever increase). The catch phrase is that “you can’t even break even”.

Just for argument’s sake, let’s consider a 100% efficient heat exchange, which is not a real consideration, but let’s argue this anyway and imagine that the charge air is cooled back to ambient temperature. Since no water content is added or taken away, the relative humidity returns to 20%.  No condensation occurs.  Fact.

 

Scenario 2: similar as above, but relative humidity of intake and ambient air is 90%.

In this case, exactly as above, the charge air inside the turbo is compressed, heated and relative humidity drops, but then inside the intercooler would be cooled (in a non-real 100% efficient theoretical sense) to be 90% relative humidity.  No more than that.  Condensation doesn’t occur. Fact.

 

Scenario 3:  ambient air at 90% relative humidity. no boost.

In the case of no turbocharger boost being present, the charge air in the intake will be at a pressure lower than ambient as the engine acts like a normally aspirated unit and sucks air in, creating a pressure drop and therefore a temperature drop.  The charge air is cooled due to expansion.  Quite conceivably, this may cause condensation to occur in the inlet tract.  Condensation occurs immediately at the point where pressure drops, so the air expels some moisture inside the air filter and this saturated air could travel down the inlet tract towards the intercooler.  At the point of condensation, however, the act of converting vapour into liquid produces a release of heat energy and the surrounding inlet tract needs to absorb this heat energy and keep carrying the released heat energy away.  If no heat energy is transported away, the condensation will not occur as readily as more intake air travels through the pipe.  In other words, the intake pipe-work gets heated by the condensation process.  And this can act to reduce the amount of condensation which occurs.

HOWEVER, because the air travelling internally through the intercooler is now cooler than ambient temperature, the intercooler (heat exchanger) will act in reverse and warm the charge air back towards ambient temperatures.  NOT cool it down further.  Condensation is therefore much less likely to occur in the intercooler and instead condensed water would be more likely to gather at the intercooler inlet side, not the intercooler charge air exhaust side.

 

***This is the really important part*** – it isn’t the intercooler that is performing the cooling process in this case.  The air is being cooled by expansion due to inlet pressure being below ambient (a bit like a venturi, if you understand about carburetor icing) and the cooling occurs immediately behind the air filter a long way upstream of the intercooler.

Given that the condensation which *may* occur has already condensed prior to entering the intercooler, any amount of blanking plate is *ineffective* at preventing any moisture gathering on the interior of the intercooler surfaces.  No amount of blanking would help with this proposed issue.

 

Scenario 4:  driving through wet saturated air above 0°C.  Fog.

In this case, the air entering the filter is already carrying 100% of what it is able to in water vapour content, plus a bit of condensed water travelling through the filter.  Condensation is already present in the inlet.  The filter can prevent a bit of liquid water entering the intake, so it is a little bit less wet in the inlet.

Case 4A – car is on boost.  Boost pressure temperature rise may cause the condensed water to re-evaporate.  However, cooling in the intercooler may cause this to re-condense and cloud inside the intercooler.  This is true.  But considering that the air was already saturated, this is no surprise.  Remember that the intercooler cannot cool to below ambient.  Any water droplets coating the interior surfaces of the intercooler cannot therefore freeze.

Case 4B – car is not on boost and pressure in the inlet is below ambient.  In this case, there is a small chance that any condensation occurring inside the inlet tract, due to expansion, may freeze on contact with the inlet tract surfaces.  However, because ambient air is above 0°C the intercooler is now acting to heat the charge air, there is much less chance of ice forming inside the intercooler.  Less intercooler blanking would actually help to minimise the chances of intercooler condensation and icing in these conditions.

 

Scenario 5:  Very, very specific conditions of freezing fog where the suspended water is “super-cooled” liquid water at less than it’s freezing point.

This is rare in motoring.  Very rare.  Not so rare in aviation where super-cooled water is a condition that occurs inside Cumulonimbus clouds.  Super-cooled water freezes on contact with solid surfaces that are close to freezing point.  The ice that forms is called clear ice and is transparent, adhesive and strong.  Some people may have encountered this in driving, when the ice forms on the frontal surfaces of their car.  Normally it is in the extremes of environment that this effect can occur on the ground.

Of course, in this case wet saturated air and condensation travels into the inlet tract.  Moisture may freeze on the interior surfaces of the intake piping.  Under-bonnet temps may prevent this from occurring on the majority of the pipework.  Except the intercooler interior.  Yes, in this case the ambient temps are below 0°C and it is entirely possible that condensed water or even clear ice may line the inside of the intercooler.  However, no amount of intercooler blanking can prevent this.  The size of the blanking plate has been calculated for a VERY SPECIFIC set of circumstances, and those circumstances are so very rare in temperate environments to be virtually non-existent.

 

Point 1:  A basic intercooler CANNOT cool the internal air to a temperature less than the air on the outside, regardless of whether the vehicle is in motion.  (to do so, this would violate the second law of thermodynamics,  and time would travel backwards as a consequence of the reduction in entropy.)

 

Point 2: In normal temperate environments, even if condensation occurs in the inlet tract, this would be due to expansion cooling, so no blanking plate can prevent it, because it is not the intercooler that is performing the cooling in these conditions.

 

Point 3:  We don’t need to be worried about this in the UK.

 

 

Finally, my headlamps don’t have condensation in them.

Two things:

1. Some headlamp designs are semi-sealed.  They are sealed in a dry manufacture process such that the gas inside the sealed chamber contains no water vapour that can condense.  Condensation only occurs to these units when the seal is broken and air that contains moisture ingresses and gets trapped.  Such as cracks that allow liquid water to ingress.  Or allowing water into the chamber during a bulb change…

2. Some headlamp designs are not sealed and have vents.  The vent is present and designed to minimise the chances of internal condensation forming by being positioned such that they are draining any liquid away.  If it is possible, the designer places the vent in an aerodynamic low pressure such that any liquid is actually sucked out while the vehicle is in motion.

 

Yours Aye

Mark H

 

---

// ’17 Nitrous Blue // Forged Alloys // Michelin Super Sports // Painted Calipers // Sync 3 // Lux Pack // Winter Pack // Black Gel Spoiler Badges // Blue Gel Wheel Inserts // GTechniq Liquid Crystal // GTechniq Alloy Armour // sold Jun ’18

[jasoni]

Erm..can i take the blanking plate off now?

[frenk]

Cool, mythbusters at work, without snake oil. I’ll get some popcorn and a beer ?

---

Revo Stage 1 – JCR super low seating frame – Mishimoto gas pedal spacer – DSC sport controller

[red-leader]

This is a great posting guys, the facts are clearly being documented and it makes a very interesting read. Thanks for not taking to throwing abuse at one another.  At last a real debate.

[rampant]

One more thing about bda’s notion of wet bulb and dry bulb temperatures.

The property he is scrabbling difficultly at and trying hard to refer to is “latent heat of evaporation”.

I mentioned previously that you cannot cool the interior of an intercooler – or any heat exchanger – to a temperature lower than the external temperature “unless you do work”.

There is the potential for latent heat of evaporation to be absorbed outside the intercooler and for the internal temperature to become cooler as a consequence. This, in a physics sense, is “doing work” on the system.

What I mean by this is that you may supply liquid water to the intercooler exterior. If that water evaporates, it absorbs heat energy in the process. The intercooler surface temperature drops as a consequence of it supplying the heat energy required to be absorbed by the liquid water in the process of changing state from liquid to vapour.

Importantly, this water needs to be supplied artificially.

Importantly, in the real world, if there is no fog in the ambient air, then there is no liquid water present to be evaporated.

Importantly, in the real world, if there *is* fog in the atmosphere, that is because the air is already saturated and cannot carry any more water vapour. Consequently, no evaporation can take place in this instance either.

My old Evo had an intercooler water spray. This is one method by which you can try to reduce charge temperatures to below ambient. Unfortunately, firstly, an intercooler is not 100% efficient in the first place and never cools the internal air to ambient. Particularly when it is needed = when the turbo is on boost accelerating at lower speeds. During cruise at high speed, the intercooler is not required, but is much more efficient. Cruel, isn’t it? Efficient when you don’t need it to be, but inefficient when you need it.

Unfortunately, secondly, a water spray is also a really inefficient method. It only really works on hot days when the air is also at a low relative humidity, which creates a beneficial gradient where enough of the water can be evaporated quickly to provide any useful cooling to the relatively much larger mass of charge air travelling internally through the intercooler.

 

So, in the real world, latent heat of evaporation is of very limited use. In practice, even a combination of intercooler and water spray still doesn’t cool the charge air back down to ambient temperature.

Yours Aye

Mark H

---

// ’17 Nitrous Blue // Forged Alloys // Michelin Super Sports // Painted Calipers // Sync 3 // Lux Pack // Winter Pack // Black Gel Spoiler Badges // Blue Gel Wheel Inserts // GTechniq Liquid Crystal // GTechniq Alloy Armour // sold Jun ’18

[Author]

Posts