On my base vehicle I noticed that half of the front inlets for the radiators are covered by a plastic piece



but on S models the inlet is completely open:



i would assume this is like the previous model where the larger engine needed more cooling? but I honestly have never heard of "too much cooling" to merit covering the holes to prevent air crossing thru the radiator.


is there any other reason for this? (lack of PDCC or something that needs more cooling on "S" models?

 

Riley,

As soon as you change your amber side markers to clear markers, the inside cover on the inlets will magically disappear!

OK, seriously, I do not know why the inlets on the base Carrera are only partially covered.

 

You can see what looks like a perforated panel or mesh next to the radiator. There must be some thing behind it that requires additional cooling on the S; but we'd only be speculating. Need an S owner to get down there with a flashlight.... (Or maybe Tim is on to something.... )

 

You want to play you have to pay.....

 

 

I don't know the answer to the partial covering question. But this statement made me think of something that I always wonder about in design makeovers. Typically there will be some marketing line about how the air inlets have been enlarged and/or redesigned for better cooling.

This always begs the question in my mind -- was there a problem with overheating on the outgoing model? And if the knowledge that more cooling is better is so universally accepted, then why were the original air inlets not designed to sufficient capacity?

I did always look at my 997.1 T4 center "air inlet" blank with some bewilderment, knowing that some models higher up the food chain had functional inlets there. Yet the drag coefficient wasn't higher on those that had functional center inlets funneled to the radiators, or was it?

Of course the center thing is a blank again on the two current 991 models. Will there be a GTS that has it functional -- and if so, will that be because of need, or for the marketing language to be able to say how the air intakes have been modified for improved cooling?

 

perforated parts are on both vehicles.. the only difference is the half blocked inlets on base vehicle..

 

Maybe the difference instead has something to do with the one car being equipped with ParkAssist sensors and the other not?

 

You must have forgotten to check off the "Enhanced Cooling Package" on the Porsche License to Print Money, I mean Option List.

 

I think you will find all the manuals have the centre vent blanked whereas the PDK cars have the transmission oil cooler... hence the open vent. It was the same with 997.

 

Not true for all 997. My non-S 997.2 has just a snow plow-shaped plastic "air splitter" in the center.
But I don't think the center intake was the issue here. The initial post was referring to the left and right side openings (very observant Rijowysock). Maybe it's indeed an "S" vs. "non S" issue?

 

Sorry, my bad. I thought the issue was the question of the blanked centre piece. My take on the partially covered radiator vents would be to do with the radiator sizing. If the radiator cores were smaller then it stands to reason the air needs to be redirected into the cores rather than escape through an unused gap on the side of the core. The 3.8 would logiclally use larger radiators i would imagine. The cooling system on an engine is normally matched to the engines capacity.

 

And here we go, un-blanked center air intake on the Club Coupe, with a center radiator (credit to Sapster for link):

"Porsche engineers have increased the power rating of the 3.8 liter engine to 430hp, a gain of 30hp over the standard 991 Carrera S. Modifications include a new set of cylinder heads and camshafts, a newly developed variable resonance-type intake system with switchable flaps, a center radiator, a sports exhaust system with two dual tailpipes, the Sport Chrono Package with dynamic engine mounts and an optimized engine management system. The engine bay styling has also received enhancements with a titanium-colored cover and inserts in carbon fiber."

http://www.gtspirit.com/2012/05/27/o...11-club-coupe/

 

Piece of plastic reduces drag. I would assume that Porsche engineers decided that inlet you have is sufficient for cooling so there is no reason to make it as big as on C2S. It reduces drag and therefore improves fuel economy marginally. It is somehow becomes increasingly important nowadays.

BTW, there are several cars that have inlets with blinds which open when for example brakes actually need cooling and are shut when they not for the sake of fuel economy.

 

Re the open center vent: Is your non -S 997.2 manual or PDK though. Never seen a manual 996 or 997 base or S with an open centre vent.