1987RX7guy

iTrader: (3)

Well I know some of you all are going to come out and say "Oh look another dumb idea" but I want to know and not assume.


Ok here is what I was thinking: why not use an eleectric fan controlled by a thermostat to keep the intercooler from heatsoaking at low speeds. I was thinking about this because I remmember riding along in Jame's car and we were seeing some kind of a detonation or miss when taking off from low speeds but after driving for a while at mid-high speeds it wouldn't detonate/miss anymore. So what I was theorizing was that his IC was heatsoaking at low speed from not enough air comming in. Perhaps this is just a draw back from having his stock IC but I am thinking about a fan for an FMIC not a TMIC as I don't really know where you could fit such a think on the stock TMIC setup the way it is. This would probably have to be a 4 or 5 bladed design fan so when in the off position it doesn't restrict the air flow of the IC at high speeds. Perhaps an air temp sensor could be setup with a guage so that you could actively tune the fan to turn on and off at a desired intake temp? Perhaps using this kind of a setup on a stock TMIC as an FMIC would help its efficiency a bit? Maybe coupled with water injection this fan idea would elminate the need for larger IC cores for relatively low to mid power FC's. A popular FMIC kit is around 900-1200 dollars and this could probably be done for under 300 dollars not including the water injection system. Has anyone thought of trying it on an FC? And before anyone starts with "if it was usefull all the top racers would use them" thats not what this is intended for a street driven car that sees anything from bumper to bumper traffic to 75mph on the highway. If it was for a racecar it would be useless because at the speeds they are at normally the fan would be off all the time. So if your going to start that debate just close the window or something. Another reason for me starting this thread is that I live in a desert area which sees 100 degree temps in the summer so it would probably help to keep air moving through the IC at all times.


Santiago

SpeedFreak03

Sounds like a pretty good idea! I really don't see why that wouldn't work!

Bambam7

Of course is would work....
You obvisoulsy can't do it on a top mount though.
I have my IC right in front of the radiator..
I already have an electric fan on the radiator (hence, also drawing air through the IC) that I can override the thermo-control and turn on from in the cabin.
My next step is to add an external water mister to the IC.. can be done REALLLLLY cheap with a washer motor, resevoir and any kind of nozzle.
Together, those are a great advantage to have while staging!

NZConvertible

There's not a lot of point doing this with a front-mount, because it shouldn't be getting heat-soaked at all. It is a good idea for a top-mount though, and I've put quite a bit of thought into it myself. You have to be aware that it's only purpose is to minimise low-speed heat-soak; it will have no effect at all on peak performance. But lowering the temp of the core should make the engine feel punchier at low speeds and when leaving intersections for example. It'd be good for drag racing too, because heat-soak while lining up to race is a performance killer.

The problem with the FC's TMIC is that it's too close to the manifold/TB to use a puller fan (prefered), and it's difficult to fit a decent-sized fan on top. The trim on top of the IC only allows a fan ~6" in diamter. It could be trimmed a little, but should not be removed because it would compromise the IC's high-speed performance. It also has to fit inside the hood scoop. So you're looking for a low-profile 6-7" 12V pusher fan. A fan that small doesn't cover much of the core, so it may not be all that effective. It might be possible to fit two fans, but you'd have to check that airflow through the core isn't blocked too much. They sell IC fan kits for WRX's which use three small fans, and apparently they work OK.

About the only application I could think of for 12V fans that size is motorcycles, but they're all puller fans. You'd need to find one that is able to have it's impeller removed and reversed so it flows in the opposite direction (need to reverse the wires too). So far I haven't located a suitable fan.

The best way to switch it is by sensing core temp, not intake air temp. You only need to run the fan when the core gets hot. If you trigger the fan from intake temp it won't be turning on when it's really needed. So far I haven't found a temp switch that turns on and off exactly when I want. The closest I found (from an industrial electronics supplier) switches on at 40degC (104degF) and switched back off at 25degC (77degF). I was hoping for something with a smaller hysterisis (difference between on and off), but I might just try it and see.

Note that this is not a replacement for a bigger, better FMIC. It's just an option for those who can't afford to fit a FMIC and like tinkering with stuff.

Tofuball

Some peple have theirs rigged up to spray isopropyl onto the intercooler to cool it down pretty fast if you're racing

bbmac

mount the puller fans upside down. just flip the whole unit same idea as flipping prop.

NZConvertible

Most fans are designed to be mounted one way only, and won't sit flat if flipped.

YearsOfDecay

Why wouldn't it work on a top mount????

I bet that would be a GREAT way to pull some air in the scoop when you are standing still.... you would have to use a very thin fan.... but they make some electronics fans that push some BIG air..

Hmmmmm I might have to try this on the beater TII...

honegod

since the stock tmic has to have a way for the cooling air to leave after it does its work, would it be feasable to make a duct to enclose the stock air exit path until it gets to a place where you CAN mount a decent puller fan ?

Bambam7

I stated that it wouldn't work... well, simply because of clearance issues. If you can get a fan to fit, then you have a fan that would work.

NZConvertible

None of which are durable enough to use in an engine bay. It must be weather and heat resistant, and run off 12V. This limits you to automotive fans.

Have a look back there. Anything that fits would be more of a restriction than anything else.

Scott 89t2

the other problem is nobody has proved which way the air flows through the IC... some say air goes in and down the IC and some say it goes up and out the scoop.... you'd have to figure that out before you put a fan on. unless it's on a speed sensor that only turns on when stoped then it woudln't matter.

Cory Simpson

OK, I haven't read this entire thread.... BUT, I did find the perfect size fan for your idea, I sold my last stock TII TMIC a while ago so I don't have anyway to fit it. But the fan is one of the side vent fans off of an MR2. The thing is tiny (probably about 5-6" across), And it would probably fit in the scoop nicely, although it pulls air so it would be going out the scoop.


Anyways, thought I would tell you that one.


And if anyone wants to buy the fan, we tested it, and it works

NZConvertible

I think those people need to lay off whatever they're smoking...

dubrc

yes isopropyl has a much better heat transfer than water, but with so much heat near by (turbo, exhaust manifold, etc) wouldn't that go boom?

j9fd3s

iTrader: (3)

a friend of mine used computer fans on his oil cooler, fmic + oil temp guage = panic, and it works really well

mike

Elysian

from what i understand of water cooling on pc's etc, isopropyl is not as efficient at transferring heat... i think it is probly used on intercoolers because it dissolves quickly

Bambam7

Not quitecorrect there....
It draws out MUCH more heat than water due to the fact that it evaporates so much quicker- it reduces dramatically in density, which takes energy to do, it draw it in the form of heat from it's surroudnings.
The same thing happens when any gas is decompessed- it's cold! It's reducing in denstity.
You could actually get the IC below ambient temps by evaporating alcohol on it.
Put some nail polish on the back of your hand, and it will feel cold after about a second as it evaporates. Try that with water- almost no cooling.

Transferring heat (Ie radiator/heat exhanger) is completely different than evaporation, since there is no density change- the system is closed. It's all based on the liquid's ability to absorb heat, usually the higher its density the better... isopropyl alcohol is less dense than water.

Digi7ech

iTrader: (1)

I say just use your windshield nozzles with water/alcohol in the resevoir.

Just reroute the hoses to a nozzle in front of/in the scoop.

It will spray onto the IC when ever you hit the button.

I'm going to do something like this since I never use the sprayer.(Just use a misting head instead of jet)


The fan on the IC would be good IF we had room.

There isn't enough room to get one under there and to get it functioning while on and not restricting when off.

NZConvertible

As you mention, you would have to replace the nozzles with proper misting ones. Since it's a lot harder to push air through these nozzles the stock pump may not be adequate.
That'd be very impractical, since most people would be spraying it at the wrong time and not for long enough. An automatic method is required.

Click here for a brilliant series of articles on building and controlling IC sprayers.