Four years ago I installed a center radiator on my 2014CS and used the CSF aluminum radiator in place of the OEM Porsche radiator. All the hoses, brackets, ducts and other parts were OEM Porsche parts. I decided to use the CSF aluminum radiator in place of the stock Porsche radiator because of the quality and claimed to be 20% more efficient plus it was on sale for $250 which was about the same price as the stock radiator. The stock Cayman CSF-7060 radiator core size is 15-3/8” wide x 7” high and the GT2/3/4 CSF-7068 radiator is 6” wider and the same 7” height. The standard width radiator bracket tips the radiator in a position for downward venting and the wider GT4 radiator bracket tilts the radiator for upward venting through the GT vent in front of the frunk lid that would also include a GT4 front bumper to allow room for the ducts and upward venting. I came to the conclusion that the more efficient stock size CSF radiator was a lot easier and drastically cheaper than installing a complete GT4 front bumper conversion. If you really feel you need to maximize the cooling capacity you could also replace the two side radiators with CSF aluminum radiators another $500 each but IMHO that would probably be overkill.🤔
Jim

7060 stock size, 7068 GT2/3/4 size, 7066+7067 right/left side radiators

 

Sorry, I was entering my above post and didn’t see this. I was not aware of the turbo being vented downward but I think you would still have an issue with finding or modifying the duct that connects the bumper to the radiator as it snaps into the stock width radiator. I stand by my suggestion to use the more efficient CSF aluminum radiator.
Jim

 

Thanks for the input! I would most likely go for the gt3-sized CSF radiator if I went that route vs paying more for oem.

I wonder how much the center air duct actually impacts cooling. I read previously on forums that some part vendors/shops didn't include the center air duct in early iterations of 3rd radiator kits because they felt it wasn't needed.

 

After installing the the “system” I consider the connector important in guiding and forcing air through the radiator. It snaps into the bumper and into a frame on the radiator making a seal. IMO the weak point is the four relatively small vent holes (3-1/4"x2-1/4" equals 29 sq in.)that need the forced / pressurized air provided by the duct. The connector duct was the hardest part number for me to find and verify as it can vary depending on the model and options and it is an expensive $300 part. I wondered if it was a matter of price and convenience putting a package together by omitting the connector duct.
Jim

The four downward vent holes are 29 square inches and the radiator core is 15"x7" equals 105 sq inches for the standard radiator and 21"x7"equals 147 sq inches for the GT4 with the same 29 sq inches of downward vent. So I am not convinced that the larger GT4 radiator would be of much benefit unless you could increase the venting. IMO I still feel that the standard size increased efficiency CSF aluminum radiator with the connecting duct is the best solution unless you want to go with a complete GT4 front end upgrade which is very expensive.
Jim

 

I think you're going to have fitment issues with getting shrouds to properly direct airflow through the GT4 radiator without the GT4 bumper.

https://www.porsche.com/all/media/pd...W_GB_981-1.pdf See Page 88, 262
https://www.porsche.com/all/media/pd...981C%20GT4.pdf See Page 75, 204.

When I installed the 3rd radiator kit on the Boxster, it came with all the shrouds and everything snapped together perfectly from the radiator through to the bumper.

 

Agreed, coolant temps with the OEM third radiator are a non-issue. Oil temps still creep up so the next step would be a larger water-oil heat exchanger to better cool the oil. That would of course put more thermal load on the coolant, but I haven't heard reports of issues. Ultimately, I don't think many people are having actual oil temp issues, they just get worried temps are higher than they'd like. I hit 265F+ regularly and my oil analyses come back great with no signs of thermal breakdown, etc. I forgot who, but some race shop reported they run endurance races at 275+ and its fine.

 

There was an article in Panorama a couple years back about the Club Sport racing series regularly seeing 290F oil temps in the GT4 ClubSport in 73F ambient temps.

 

I did my first track with my Cayman S at Chuckwalla this Saturday, it was in the 60-70 F with lots of 30-40mph winds. It is a dessert track so lots of sand to go with the wind, there were a few times I could not see apexes ugh! Since its my first time I did not push it too hard but I did put the throttle to the floor every chance I got, the oil temp never went above 245 degrees. My oil level shows 3 or 4 bars when I checked. So I am going to run a few more tracks and see if I really need an additional radiator. I am running 18" wheels with Goodyear F1 S3 (220TW version), I am on stock suspension (no x74 or PASM or PTV) with a GT3 control arms. Also running Sports+ the entire time without my intervention. BTW I love having TPMS on my track tires, all showing around 35-36 on the track and I manually checked pressure for accuracy. I am really pleased how well this car handles on the track!

 

I would also like to mention that my CS has the center ducting that feeds air into the two side radiators. I have seen a few Caymans where the center intake is just capped. Also, my CS is not tuned for more power and I am guessing people who track might be applying tunes that could result with higher temps at the track. This is just my guess as I am fairly new Porsche mechanics.

 

As far as I know all 981's with PDK come with the center opening/panel that guides air to the side radiators to provide additional cooling. The manual transmission cars have the "capped off" center panel. Suncoast sells a kit for manual transmission cars to add the PDK ribbed vented panels for additional cooling and a better look. My Cayman S with PDK had the same vented panel as yours that I changed out for the connector duct when I installed my CSF aluminum center radiator and I also switched the two radiator side panels to the manual transmission panels to make three separated radiator openings.
Jim

 

981 Boxster S with PDK does not.

 

Correct. Maybe it's a Cayman-only thing.

 

It's always made me wonder why Porsche would put a big drag and turbulence-inducing air scoop on the front bumper of the Boxster. It would seem to really mess up the aerodynamics.

 

Maybe it’s to provide the extra cooing that the Cayman S needs because of the extra 10hp the Cayman has over the Boxster? lol 😆 Don’t ever try to second guess a German engineer.
Jim

 

Since only female hairdressers driver Boxsters, the extra 10 hp isn't needed. All that matters is looking good.