Heat Exchanger Fan or Duct

Gtstorey

Member
Is there any consensus on which will provide lower iat2 temps for general usage (mix of tight backroads and in town driving but track driving not likely) for turbo? I'm working on finalizing my order prior to shipment. If the ducts can provide even slightly lower temps under "normal" usage, $225 is likely money well spent.

I also have the stock heat exchanger from my Camaro that I can add if it looks like iat2 is a real problem.

Thanks.
 

JBINTX

Goblin Guru
I am one of the few who have the fan as well as the ducts so far.
I ran 12 laps at the autoX last weekend with minimial rest time (about 2-3 minutes) in between runs. The ambient temp was around 80. My thermostat opens at 192. The coolant temp never got over 198 sitting.

I did not track the IAT or the HE coolant temps, but can tell you they were not an issue. I also have the intake filter mounted outside the engine bay which made a big positive difference.


Not an exact answer, but maybe help you a little. :)
 

JBINTX

Goblin Guru
Are you still running both the heat exchanger fan and the ducts at the same time?
yes, sir. My thoughts were that there would be no air flow when not moving. Not ideal. I am sure the NACA ducts work very well while moving. And the plenum keeps the hotter radiator air off of the heat exchanger.
Adding the fan was very easy and it just checks off one of those little unknowns.
 

George

Goblin Guru
For racing they make some for brakes and in car ventilation. That is the idea you showed.

brad
 

Indy Lonnie

Well-Known Member
I have the NACA ducts without the fan installed. My IAT1 (before turbo) and IAT2 (after intercooler) are always within 12-15 degrees of each other while moving/part throttle. After a hard run the IAT2 will climb but return to normal after a minute or two. The IAT2 temp will climb while sitting in traffic, maybe 20-25 degrees difference. I have never seen it above 135... I have the fan, but never installed it after Lonny advised against it. I have thought about it, but apparently if you place the fan in front of the radiator, you can inhibit the air flow (30% if I remember correctly). There is no room to mount it underneath, and very little wiggle room if mounted in the NACA ductwork.
I have recently added side scoops on both sides on the engine compartment. It would be very easy to mount another radiator near the gas filler area behind the scoop and possibly mount the fan on it behind the radiator. It would take minimal routing of the hoses to do so and it would double the cooling capacity. That coolent could be routed so that the front radiator feeds the back and cools on the second pass. I have the optional button panel around the instrument panel. The fan could be switched there on the "unused" switch like Lonny has his fan wired. The fan for the intercooler is loud, so I would switch it so I wouldn't hear it unless needed.

Food for thought...
 

Indy Lonnie

Well-Known Member
Brad reminded me. I had looked into a ducted fan at one point.
Here is an example:
There is not enough room to mount that fan between the NACA duct and the intercooler ductwork. There may be 2" between them... If you did squeeze it in there, getting the hood on and off would be a nightmare.
I think the supplied intercooler fan is rated at 1250 cfm, almost 10x the rating of that fan...
 
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