I've got an idea but I'm not sure how to execute it. Help me?
 

Alright so here is the preliminary info.

I'm building a track oriented car that will still be street legal.
4 port turbo block with hybrid turbo
I'm buiding a vmount and having difficult finding a nice spot for the oil cooler.


Here is my idea. I'd like to put the oil cooler behind the radiator down near the sway bar with fans on it. NOW the question is, how could I activate the fans? A simple relay system that turns the fans on at a certain temp? Is there a way to utilize the Megasquirt? I figure I could tap the same line powering the coolant fan but then they run at the same time even though it may not need to be running.


The only other place I could think of putting the oil cooler was where the bumper meets the round support bar with the oil cooler laying horizontally.
halp!

Before you relocate the cooler and depend on fans to make it work, seems like sourcing the fans would be the first step.

I've found the oil temp and coolant temp to mirror each other closely, so having the rad fan and cooler fans activate together would make sense to me.

Fans shouldnt be an issue. I know of fans that pull 250 CFM.

Tell me they're not PC fans.

That's incredibly low.

Technically they are server fans clokker....

250 may sound low but it puts out a lot of air for its size. Plus, I could fit a total of four of them on top of the oil cooler for a total of ~1000 CFM moving across the oil cooler...

https://img.photobucket.com/albums/v...ps1aa40bd8.jpg

OK, two things....

PC fans (even "server" fans) are not made to withstand the environment you want to put them in, and...

In order to even approach the CFM flow you hope for, those fans would need to be spaced a few inches off the cooling matrix with a shroud. Otherwise the hub and frame will be blocking most of the airflow through the cooler.
Does your plan account for this added width?

The fan you showed doesn't strike me as anything special, certainly not "server grade".
If you must persist in this folly (and I just don't see it ending well), look into Comair Rotron "Muffin" fans. They feature sealed motors, metal frames and three blade rotors and might give you a chance at what you hope for.
Attachment 680550

Attachment 680551

Yes I figured I need to find a way to seal the edges to make sure that air is being pulled through the radiator and not just moving air. To go with that I didnt want the fan sitting right on top since usually the blade shaft has a bit of in and out play.

The fan pictured was just a dead 120mm fan, I wanted to see if the size was about right. I figured this would be an easy shot since the fans are small, DC, easily attainable and easy to wire up with the e-fan. Those Comair fans do look hefty. I have a set of metal fans from an old rack mount system that used the fans to vent air out of the top of the unit. I will see if they are any good...

Here is a link to one of the fans I had messed with. Delta TFB1212GHE 120x38mm Extreme High Speed Damn thing was as loud as a vacuum.

Here is how it's mounted on the new rotary extreme v-mount kit, it uses a scoop to get air into it:

https://lh4.googleusercontent.com/-Z...0/P5170050.jpg

https://lh6.googleusercontent.com/-X.../oilscoop1.JPG

Ok then, here's what I would do...

(I assume you have an oil temp gauge already installed)

Leave the cooler in the stock location and mount the fans as best as you can (when I was using the Muffins on my watercooled rig the optimal distance of fan to cooling matrix was @4").
See if they actually are capable of dropping the oil temp when activated.

Essentially, the cooler is already positioned to take advantage of the incoming airflow.
As you move the cooler to a less optimal position, you'll be relying on the fans to make up the difference in airflow and you should determine how capable they are before you move the cooler.

Use dual oil coolers in brake ducts.

here is a video of a very similar output fan. The Comair rotron 3 blades put out roughly what the other large fan did (110CFM). I think 240 will be enough if I combine 2-3 fans. I'll definitely keep this updated.

its not so much an issue of how much air they can move, so much as they will last you a week in the elements

Well, it kind of is, isn't it?

More to the point (all fluttering sheets of notepaper aside), how much air can it suck through the rather thick, densely finned oil cooler?

You would be surprised what a PC fan can stand up to. I recently was working on an Okuma lathe, and had to remove about a pound of grease from one, and it was still spinning just fine.

Probably not, actually.

I am interested in the outcome of this experiment although I think it will end up badly.
Besides the fact that PC fans are not designed/built to withstand the rigors of this proposed environment, there is a second consideration not yet mentioned.

Computer fans are designed for a static environment, the only airflow present is what they generate themselves. There is no scenario where air is actively pushed at them.
This narrow design focus means that they can be total obstructions to airflow because it's not an issue in a PC...but it sure will be in this application.

It's all in the ratio of hub size to fan blade length and designed fan speed.
To mitigate the effects of the large motor hub, the fan will need to be spaced off the cooling core with a shroud (figure a minimum of 1 1/2", so you add @3" to the depth of the cooler, which needs to be accounted for as well).

Unlike the PC though, your fans will not be running all the time and during those off periods your setup will become an effective restriction of the airflow generated by the car's movement.

I'd guess that this setup could possibly improve idle/static oil temps but get much worse as speed and load increase.

But, it's worth a try and I'm curious about the outcome.

well, yes lol

The point I was trying to make there was that if the setup actually works, some people might be willing to swap the fans out regularly...they're relatively cheap, after all.
Race vehicles regularly sacrifice longevity for performance.

Money is best spent once. Using PC fans in an engine bay is about the stupidest thing I have ever heard.

It's pretty much up there with Direct Exhaust Injection.

SPAL USA

See? If you know where to look there is ALWAYS a properly-engineered solution.

You're still better off using two big fat cores in the brake ducts though...

The CFM rating of fans is based on a given pressure. Those PC fans were not intended to pull air through a thick automotive heat exchanger.

As for controlling fans, keep in mind that a moving fan becomes a restriction once there is a significant amount of ram air flowing through the heat exchanger. Therefore, if you mount the heat exchanger in an area where it will receive ram air when the vehicle is in motion, the fans should be shut off around 30-35mph vehicle speed.

You may want to consider putting a flow divider between the intercooler and the radiator. I am concerned that air will stagnate at the intercooler with your current setup because the intercooler will receive ram air from both the top and bottom at high vehicle speed, and at low vehicle speed the air will stagnate because the radiator fan will pull the air down while convection tries to pull it up.

I'm not sure if you will have room for proper ducting, but here is a link that will tell you how it will work best:
Cooling Systems

I see. You guys do make good points. I figured it would work, and it just seemed "right" since the PC fans would fit easily as well.

Valkyrie - I wish I could afford it but for now considering many say the factory oil cooler is more than adequate I can justify spending more (especially since I should be saving for a home.)

Evil - I do plan on making a divider to force air up to the intercooler since it's angle would seem to force most air through the radiator.

Clokker - I appreciate the criticism and saving me from blowing my shit up. If that happens its bye bye rx7 :(

Why wouldn't you put the cooler somewhere in cold air?

If you can't at afford to build a car right the first time, or at least use the right kind of fans, you have zero fucking business modifying cars.

Just a thought since it hasn't been mentioned, if your on a tight budget, why a vmount as opposed to a less costly and easier fmic setup?