hellraZor

Ok a buddy of mine has a Subaru WRX and thinks the the cold we get here in Minnesota could possibly be bad on his car with the intercooler being where it is. I told him colder is better but he thinks that he should cover it or something. The intercooler sits atop the engine and is fed air via a forward facing hood scoop. Can there actually be weather too cold for this????

emo236

some people actually spray nitrous right onto the intercoolers to give them a cool charge. The cold air will be denser and will help his car make more power. you're right, he'd be dumb to cover it.

jfairladyz

Its not the cold air persay, its the fact that the intercooler can get blocked up with ice and not allow any air to pass through. In which case the charge air wouldn't be able to dissipate it's heat. Emo's right in that the cold air itself isnt a problem. But your friend is also right in a way. This is why you see freighters and vehicles with HUGE grill openings covering them in the winter months in cold areas. Snow can build on the intercooler and as it warms from the car being run it starts to melt. Well as the car moves through the cold air it can then freeze again turning it into a solid chunk of ice. The incoming air can't pass through a chunk of ice. A frozen intercooler doesn't sound like a problem but it is. Remember though, we're talking some serious buildup to completely hinder air flow here, but hey, MN is one of the coldest winters in the country right

Now all that being said: The Sube's intercooler is in the engine compartment so I don't think that would be a problem for that particular vehicle. I've only ever heard of this being a problem with front mount intercoolers and we're talking a lot of driving in some really nasty weather (like what a trucker would see) to get to the point of a solid intercooler. So tell your friend he'll be alright.

91zxtt

I don't think that makes sense. An intercooler's job is to reduce the temperature of the charged air down to as close as possible to the ambient air temperature outside. If the IC is frozen, then wouldn't that drop the temperature of the charged air even more; hence more power. If the air can't flow through the IC because the IC is frozen, how is that bad? The air can't get any colder than running through the frozen IC.

emo236

I agree, the intercooler cools the air going into the motor so that it A.) is safer and B.) creates more power due to denser air. a frozen intercooler would be a ultimate cool I would think...then again, I'm in Cali and don't have to worry about that.

Heat Rave R

Here's another agreement. The only point of air passing through the cooling fins is to try and lower the intake charge temps. If the intercooler is frozen solid, it no longer needs flowing air to cool it because now the ice is doing the cooling. If anything, that means you'd get greater cooling efficiency even at low speeds because now the cooling is no longer dependent on moving air.

hellraZor

thanks for the help everyone!!!

veyenyl

If it's frozen it should cool by conduction rather than convection.

jfairladyz

All's the ice is doing is cooling the very outside layer of the intercooler. The inner most layer of ice that WOULD be touching the intercooler is melted by the heat of the charge air. But if it's cold enough out, it wont melt all the ice off, only the thin layer touching the IC. So the whole ice cooling theory there is moot after a certain amount time. Which is however long it takes the IC to melt that inner layer of ice. Well the majority of the charge air is flowing through the inner part of the intercooler. So the only air the ice is coolling is the very outer most layer of air thats skimming by the front side of the intercooler. And if you're thinking hte ice is going to penetrate the entire IC to cool all the air then you're wrong. See the outer layer of ice is also acting as an insulator and the warm charge air melts the ice that forms on the inner fins of the IC so guess what, no cooling going on there. And of course the backside of the intercooler isn't going to have ice OR air flow either, so no cooling going on there either. It sounds like a couple of you are also under the misconception that the air itself is whats cooling the charge air. WRONG. Alls the air does is remove the heat from the intercooler fins. The metal is what cools the charge air. The airs repsonsibility is just to disipate that heat from the fins. So the heat dissipating through the fins is whats melting all the ice off of the IC. So the ice isnt going to cool anything, cause chances are its not even touching the IC.
Comparing all of this with an intercooler sprayer is unjustifiable. Two completely different situations, and an assumption that they are one and the same is just foolish. I'm not just pulling this crap out of my ***. I'm telling you, that a frozen intercooler, and I mean frozen solid, as in no air can get to it cause it's completely blocked up by ice, will not be able to do its job. Again, this is the reason you see freighter's and large turbo trucks with their grills covered during the winter months on long hauls. This can even render a radiator useless if you're driving for long enough in cold enough weather. You should also know that on low boost you're probably not going to generate enough intake heat to have to worry about something like this. The chances of this happening are not likely. But it can and it does.
Your theories are not bad, and I understand where your thoughts on the subject come from. But you cant rely on common sense here cause it just doesn't apply here. And like I also said, the guy who originally mentioned it, his friend probably wont have a problem with this, especially with a top mount IC.

Oh and one more thing, before you go and assume a frozen intercooler is a good thing and that you dont need airflow: Think about the poor suffocating radiator behind the intercooler. That radiator is getting pretty hot without that USELESS airflow. Not only does this cause the vehicle to overheat, but that excessive heat in the intercooler is now forcing it's way to the IC and warming that up. So if the first part of this doesn't touch your fancy then that should
Sorry if I sound like an ***. Im just trying to get my point across.

emo236

so if they cover up their intercoolers, how does that help air flow? seems like it would block it just as much as the ice would.

Heat Rave R

That doesn't apply to the case of a WRX with its top-mount intercooler, which I thought this thread was about. I agree, the ice in contact would melt. However, in the aforementioned top-mount scenario, that melting water would have to drain through the fins of the intercooler and out the bottom. And since that water will be flowing over the fins, conceivably, that could act like a ghetto water/air intercooler(using water to transport the heat away). Of course, this is assuming the snow is continuously getting packed in to replace the snow that's melted away and no longer in contact with the intercooler. Not saying it's a good idea, just that it shouldn't hurt performance either.

Also, I agree, the top/forward part of the intercooler that is in contact with the snow would be colder than the back side of it. However, you have to remember conduction. That snow/ice will still lower the temp of the back of the intercooler, though I agree it wouldn't be as much as the front. Though you could also the same would apply to air flow over it too. After all, by the time flowing air reaches the rear-most fins, the air has already absorbed some heat from the more forward fins. and wouldn't be able to remove as much heat from the back as a result.


Emo236. I think he was saying those people cover up their intercoolers with a mesh screen, so that it lets air flow through but prevents larger particles (snow) from getting in. Though snow would be gathering on the mesh screen, it doesn't "pack in" like it would in the forward engine bay.

jfairladyz

But see the problem is that NO air or snow would be on the back side of the intercooler, so neither conduction nor convection would be happening in this case. The intercooler is solid now remember. You gotta remember that conduction is always present in the intercooler. The metal of the intercooler is always conducting heat away from the charge air. The intercooler then relies on convection to move that air off of the fins of the intercooler so that the fins can then conduct more heat out of the charge air.

I think this is all getting taking a little out of context. We are talking about a sever situation here and I've already stated that it is very unlikely and would take one hell of a cold and snowy situation to happen. On something like a small car making it's morning trek across town to work this is NEVER going to be a problem. But some dude in a big rig who has to drive from Nebraska to Canada in the dead of a bad winter in a blizzard, well that guy is probably going to have some serious issues if he doesn't take precautions for the situation above. And of course, I've already pointed out that none of this is really going to affect the sube because its a top mount. The chill factor of driving with a wet intercooler directly into freezing air is part of what freezed the intercooler. We're not talking just snow buildup here. And you gotta stop looking at it as a cold substance on the IC. It might as well be cement on there cause the layer of ice directly in contact with the IC is not going to be ice after a little while and will no longer be cold.

Emo, by blocking the direct path for airflow to the intercooler you do restrict it's effiency. It will still get airflow, though not so directly and not as much of it but better than nothing. But having to run lower boost temps due to restricting airflow over the IC is still better than your big rig overheating cause everything up front got blocked up.

And I want to take this time to say Merry Christmas to those who celebrate it. If you don't then happy holidays

jfairladyz

Yeah this is double posting, so sue me but: I should also point out that this whole frozen intercooler thing is something that large truck operators would have to worry about. Not small car drivers. I hinted at this but never specified that. And it takes one hell of a long drive in some very bad weather even then to make something like this happen. If you live in a region with pretty bad winters, just take a look at the front end of some semi's or snowplows during some bad winter weather and you'll see what I'm talking about. If you live in AZ, well you're just going to have to take my word for it