GsrSol

The only fan I could find to fit in that tight spot only flows 112cfm but works great...when stopped It's about 6" x 1.5".

I did it as a "pusher" type on the back of the oil cooler, inbetween cooler and bracket and it doesn't block any normal airflow. When stopped, you can FEEL it blowing alot of hot air out the front dam Since it doesn't flow that good it would be pointless to use on the highway anyways, probably just spin backwards.

I mainly did it for when turbo timing down, help cool that oil more and when in traffic.

I don't have an oil temp gauge yet but I will measure the differences once I do get one.

spooledUP7

Sounds good, but I would think that you would want it to pull rather than push.

94touring

Thats a pretty good idea. I hope you get some gauges to post results soon. Seems like you would want to reverse the fans so that they pull rather than push, but if it is used mainly for turbo timing after your stopped, than I can see where pushing would be better. Where did you find the fan?

GsrSol

I debated the push/pull decision for a long time and since the fan didn't flow much, I came up with this:

push: will blow the hot air out the front duct but can only work at low speeds.

pull: will blow the hot air into the winshield washer bottle and doesn't have much room for the hot air to exit. If the fan flowed more, it could exit better. Would only help at low speeds also.

I did want a bigger fan but couldn't find one. Based on the cfm rating, I think this was the best decision. Got it at Frys Electronics for $13.

Toadman

Sounds like a winner mod for cool-down. Got any pics, guy?

Red Rotary Rocket

You know, there is a duct that runs on top of the wheel well and back to the side vent. Unless you have done something to defeat that vent, there shouldn't be any restriction to having the fan pull rather than push.

I have heard people argue that running the fans won't make a difference at speed...I tend to disagree. Imagine your oil cooler with a fan behind it, and you don't have any power to the fans so they just sit there and spin as the air moves through them. That air is doing work to make the fan spin, and so that slows down the air moving through the oil cooler.

Now if you put power to the fans, the incoming air would not have to work as much to make the fan spin, so overall airflow through the cooler would be greater, even if the car is going 120 MPH. The same arguement can be made against those who say that pulling the AC fuse and running the radiator fans on high at the track doesn't make a difference because at 100 MPH the fans don't do anything....I completely disagree.

I don't know that it would make a huge difference, but if it were MY oil cooler fan, I would set it up to pull the air in and I would run it all the time...but that's just me.

user 84205

GSRsol,
Did you see that in Option? It was in there about 3 or 4 months back.. BEE racing did it on a FD. If I can find the article I will post it. Well after I change it into English I will post it hehe.. I remember they said it worked good, but I cant remembet where they got the fans. I know it was a junkyard, actually I think they were from a motorcycle...

Does it cut any power? How is it? Good luck dawg

Jason
www.jt-imports.com

GsrSol

Jason, I didn't see that in Option however it would have helped. I never even thought of motorcycle fans!

No power issues what so ever.

jspecracer7

I have a friend who has a fan on the back of his oil cooler. He accidentally wired the fan in wrong so that it pushed(he wanted pull). He also has an oil temp gauge. I talked to him today about it and he said that while cruising, the oil temps go UP, but when stopped the oil temps go down. With it as a pull type, the oil temps would not rise at stand still(or go down slightly), but would go definitely go down when moving. I would suggest turning the fan as a pull vs. push type fan.

RonKMiller

Hmmm... I don't see your logic since there is a thing called cavitation.........which will essentially block airflow
(no matter if it's push or pull) once the maximum designed flow for the fan (which is dependent on rpm and the number of blades as well as pitch) is surpassed. Airflow would be MUCH much less once this starts happening since you would essentially have a disk the same diameter as the fan blades blocking flow. Now, if you could design a variable pitch fan blade which could freewheel at higher speed you would have something that MIGHT work.

I think it's fun to play around with this stuff, and if you sat idling all day in your car it would probably lower your oil temp by a few degrees. But at speed all you are doing is blocking the airflow - the naca duct at the rear of the wheel well actually creates a low pressure area once you are moving. It literally "sucks" air through the cooler, and the faster you go the more it "sucks", until it too starts to cavitate! (Presumably at a very high rate of speed)

Like I said, this is great fun to think that an auxiliary fan like this would actually work, but, sorry it doesn't do anything significant. Time would be better spent straightening out bent fins on the radiator and oil cooler(s) with a screwdriver.

No flame intended here guys, 'cause it's always great to see new ideas or approaches. I've thought up some pretty wacky stuff in the past myself which of course did not work worth a damn, but it was ***** and grins trying. Good to see creative minds.

Dimcorner

Well, you also have to remember that once the 120mph wind hits a oil cooler the air will probably slow down a GREAT DEAL. I mean have you seen the oil cooler? it looks pretty damn packed with stuff. Maybe someone should stick a wind velocity measuring thinggy behind the oil cooler to see how fast teh wind is actually going.

Red Rotary Rocket

Hey Ron,

No flame taken. It sounds like you are interpreting my post as "At speed, an oil cooler with a fan will get more air flow than an oil cooler without a fan." This WAS NOT what I was trying to say.

What I WAS trying to say was "If you must use a fan, I think the oil cooler will get more air flow if you run the fan at all times."

Here's my simple logic, shout out if you don't agree with something:

The air flow through the oil cooler at speed is dependent on the pressure difference between the front of the car and the rear of the vent. At a constant vehicle velocity, the pressure at the front of the car (Pi) and the pressure at the rear of the vent (Po) are also constant. So the pressure drop across the oil cooler (Pd) = (Pi) - (Po).

Now if we add a fan to the back of the oil cooler, (Pi) and (Po) don't change, because they are dependent on vehicle speed. So the pressure drop across the oil cooler becomes expressed as (Pd) = (Pi) - (Po) - (Pf) where (Pf) is the pressure drop across the fan. Since (Pi) and (Po) are constants (because we are keeping vehicle speed constant) we can see that the pressure drop across the fan (Pf) has a direct effect on airflow through the oil cooler.

Now in real life, at real vehicle speeds with real fans, I expect the value of (Pf) to be positive...that is to say that (Pf) will never be a value that increases (Pd) and the air flow through the oil cooler.

The point of my previous post is that I think (Pf) is variable and depends on whether or not you are putting electricity to the fans. In the scenario that you don't put electricity to the fans, the fans will still spin as air flows through the oil cooler. The fact that the blades are spinning tells you that there is a pressure drop across the fans. Now, if you turn on the fan, I believe that the pressure drop decreases, because the air flow doesn't have to do as much work to spin the fan blades. There is still a pressure drop, but I think it is going to be less. If the pressure drop across the fan (Pf) decreases, then the drop across the cooler (Pd) increases and you get better flow.

So in conclusion:

1. If the vehicle is moving, the best air flow comes from no fan at all.

If you decide to add a fan to aid cooling when the car is stopped, then:

2. Position the fan such that it flows with the natural air flow, and keep the fan running at all times.

Item 2 was my original point. Does that make sense?

RonKMiller

Yup! Can't argue with physics, except that if the car is stopped there is no "natural" air flow. (j/k)

And, in my gut instinct I don't think there is a chance in heck that any measurable difference in oil temps can be detected with this mod.........it might make one feel better, and it might have a certain "gee whiz ain't this cool" cache to it, but it just is not going to work with a $15 computer fan..........Later.