Use of third / center radiator
 

As written in my project log I have picked up a chassis from a 03S yesterday. Amongst other things it has the center radiator on it as I thought it could come of good use once I put the bigger engine in.

However, looking at the radiator and especially where the air needs to escape I am doubting the efficiency of this third radiator. To me it seems like improving the air flow from the side radiators (these also don't really have a channel for the exit air) would be far more efficient.

Any input on this? Should I consider upgrading to three radiators or would just putting in the thicker pipes (also still on the car) be enough?

This past winter I added 3rd radiator to my 2001 2,7 Boxster. Before this addittion, I contemplated same kind of issues aboout efficiency and found out that 3rd radiator usually lowers the temperature approx 10 degrees C on heavy use (like track).
Last weekend was my first track day for 2025 and water temperatures stayed all day at 78-80 degrees C, but this is not yet really relative comparison due to still very cold weather... Upcoming summer will tell what is the actual benefit regarding lowering the temperature.

The center radiator directs the airflow into the front wheel area (brakes..) is not as ideal as the GT3 style which send the hot air to the top of the bumper

...hmmm.
In my car there is three roughly 10 x 15 cm openings under the center radiator directly at the airflow as the air has passed thru the radiator allowing the air to flow directly under the car. There the hot air goes after the center radiator as factory intended, at least in my car - not to the sides / brakes.
Bumber cover I purchased is from 2002 Boxster.

For downforce use (track only) I'd prefer the GT3 style hot air exit above the bonnet - that would also require the adjustment of how the radiator is placed inside the bumper cover - probably next winter projest...

Behind the center radiator is a plastic piece that moves the air down and into the sides, on the GT3, this plastic piece ruotes the air upwards trough the center vent between the top of the bumper and the front of the hood,

Not sure if this is the only difference, or the mounting bracket thet holds the center radiator to the car is also different..

Great, good to know about the plactic air flow parts. I'll check can I fot those in to my car.
Curretly after the center radiator is no airguides at all, just those openings under the car to allow the air to exit under the car. Radiator is also tilted from th factory so, that after the air passed thru the radiator it is already flowing downwards.

Pilot4fn, I just remember that in addition of the plastic air diverter that goes behind the center radiator, you are also required to 'cut off' the slots on the bottom of the bumper, these slots are pre-moulded on the bottom of the plastic bumper but not cut at the factory since not all the cars come from the factory come with the center radiator installed