cooling issues..., fine when driving, spikes when stopped. Options

[malaga_red75]

subaru JDM EJ25 DOHC

So, got my conversion finally road worthy and have noticed that while I am driving around, the car stays at around 200 F. when i stop, or let it idle in my garage... the temp slowly climbs and doesnt stop (i shut it off around 230 F). I am assuming this is an issue with my fans.

I am running a front mounted radiator, using 2 push-style fans. A few things that i think may be wrong...

-There is no shroud around the fans... just the shroud that seals the radiator to the front (since they are push fans, they are mounted on the front side of the radiator, in between the radiator and the nose of the car)

- there is about a 1 1/2" gap between the fans and the radiator (this was just the way that ended up working for mounting the fans)

anyways, i am pretty sure that the cooling system is working (no kinked lines, thermostat working, fans do turn on) as indicated by driving and the temp staying cool, there is just something not working when i stop moving. let me know what you guys think.

-Peter

[ArtechnikA]

published reference...

[DBCooper]

published reference...

That's hard to do because you can find published results supporting either or both, depending on how they're set up. There's an awful lot of research about fan cooling of electronics, for example, where there isn't any restriction on how things can be configured, push or pull. Those results are published and could be cited (let me know if you want a list) but they really aren't applicable for what we do.

For our cars the difference is often what's viable and what's not, and not what's theoretically better. In our cases, for example, we get forced air movement whenever the car is in motion and using a lot of energy, when the fan isn't needed at all. You COULD put the fan in front in push mode, but with the shroud that's required to make it cool efficiently at rest that would mean the shroud, along with the fan blades themselves, would be blocking some of the radiator's surface area and slowing down airflow. Or you could run without a shroud, like the Cobra replicas, but only at the risk of not having enough cooling capacity at rest or in stop-and-go traffic. So as a practical matter it makes more sense to pull the air from behind the main air flow, so air can pass through the full radiator surface unimpeded when in movement and only then be funneled through the fans. When the car's at rest you don't have all the cooling air originating from the round fan opening in the front of the shroud, in a pusher application, then being dispersed at much lower pressures through the larger radiator surface.

I don't want to argue anything, but whether pusher or puller is more efficient really depends on how the thing's configured.

For the original question I'd also guess there are air pockets that need to be exorcised. My car has a turbo motor with a very small opening in the front, and I've only heard the fans twice in use, both times in mid-summer after I'd come to a stop after thrashing it through the mountains. Renegade Chevy radiator, but it seems that all in all the Subaru motors are pretty efficient.