Originally Posted by Maniacmechanic1
I Like that BBC Bright Red C3 Too Wiz.
So one of the things we struggle with on this car is the temps. They very slowly creep up the longer you drive the car. It is not just any BB, but a 502. And the exhaust manifolds hug the block which only further adds to an engine that just wants to be hot. I have been down this road before not just with BB C3's but with others we have had to chase temp issues on. So it's time to share some cooling knowledge with the group.
When the car is moving down the road. Any car. It should be plowing the radiator through air, right? And as such by the time a car hits just 30mph, again ANY car, there should be so much more air moving across the radiator than what the fans are capable of doing that they become useless by this vehicle speed. In all truth, if you need to turn your fans on to cool your car while it is moving you most likely have a poor setup that is in some way impeding airflow across the radiator. So true is what I am saying that most engine controllers today and for some years now have tables and settings to disable the fans at a certain vehicle speed just for this. Sadly as our C3 racecar goes down the road it really does not dispel heat but just holds its temp.
The radiator being swept back makes it difficult for airflow to find its way across the radiator. It just wants to go up and over the core support. But we are not without a real answer to this dilemma from the manufacturer of these great cars. For GM didn't get wise to sweeping the radiator forward until the c7. If we look at both C5 and C6 we see the radiator and condenser are still swrept back but these cars achieve incredible cooling efficiency because of the plastic ductwork that forces air to take a specific path. Unfortunately I can not build a complete enclosure to force all air that enters the nose of the car to go through the radiator because on the C3 the nose of the hood goes down almost to the condenser. But I certainly can create a lip around the radiator in the front to scoop some of the air that just wants to go up and over the core support. Let me show you guys how I achieve such an end.
Here is our first problem with airflow. There is a gap between the front lower air dam and the bottom of the core support. This alone lets so much of the incoming air just go under the car and not even try to go up to the radiator..
And from the back..
We obviously need to close this so all air picked up by the scoop goes up in front of the radiator and condenser. This car also has an electric headlight conversion. So I made these extremely specific plates to close out both sides..
Installed there is a small gap intentionally left in the center..
Then I made this small air deflector to go in the center..
While there have been no issues whatsoever out of the trans, I wanted to leave a path open for air to be forced across the trans cooler while at speed. If the trans starts getting hot, I will open this hole sideways a bit but if all stays well then it will stay just like this..