why do some carreras have a third (center) radiator; but others have a shield there to slow the car down?

 

I may be wrong but I think the cras with the third radiator are pdk.

 

makes sense, mine has the center radiator, and PDK. Anyone confirm? Why additional cooling for engine with PDK? Expect more thrashing?

 

auto trans = 3rd radiator. Manual = no middle radiator.


I don't know the science behind it.

 

The venerable GT3 design includes a center-mounted radiator that was sometimes installed on various Carrera models as well (mostly Tiptronic transmission equipped cars). A little info here.

 

I thought some of the C4S with MT have it too. Not positive though. Also it's a "standard" option for hot weather countries. And many of the track folks will add the third radiator to help keep oil temps down.

 

The center radiator is there if something on the car needs extra cooling - eg engine or tranny. The car comes with the cooling appropriate for the configuration of engine/transmission it was built with.

That radiator system is also aero balanced with the back end. So if you put a top of bumper cover vent in (vs venting center radiator to the sides) then ideally you want the full front end bumper cover or address it with an aero change on the back end as well, to maintain balance. (if you are tracking where such aero differences matter)

IF you are installing the center cover smile vent just or asthetics without an intake for it, you don't need to do any aero on the back so long as the center block is still in place where the radiator would be in theory.

 

If you see a MT with a center radiator then it either has the X51 option or the 3rd rad was simply added alone. This is what I did for extra cooling capacity on my 05 C2S. BTW, the Carrera center rad is designed to vent down, not up like the gt3 center rad. So cutting a hole in the bumper would only screw up the airflow. I had to cut a hole on the underside below the radiator.

 

sorry, I am trying to follow everyone, ... what does 'MT' mean ???

 

I have PDK and no center 3rd radiator.

 

Manual transmission

 

thanks

 

I don't know the science behind it.

 

Turbos have the third radiator too, even in cars with a manual transmission.

 

On Carrera models, the third radiator only came installed standard on 2011 and early 2012 PDK 997.2 models (not counting things like the Turbo as Dennis points out). It was an option otherwise.

I don't think the "shield" provides any appreciable drag over the radiator (the airflow would be cleaner). On the 997.2 models, it is not a simple "cup" but serves to divert air to the side radiators along the channels behind the front of the bumper.