I have a 06 C2S and have been thinking about installing a third radiator. I've been getting into DE weekends and want to do whatever I can to prolong the life of my car.

At what point does it become necessary?

I haven't noticed my temps being to out of control but keeping the engine cool is always a good thing right?

 

I was looking into this option earlier this summer (Hot Sacramento Summers!) But from talking with my tech at Niello the water cooling is regulated by a thermostat to keep the temperature at that 175ish mark. So supposedly it doesn't do much, however, it does look cool and not that expensive of an add and if it gives you peace of mind then go for it!

 

The third radiator is useful for .2's with PDK due to the additional heat that must be removed. For your 6 sp, it's not necessary and will only add weight and cost. I wouldn't do it.

 

I noticed that you are in the SF area. I was sort of expecting Oklahoma or Texas.

Your car is really well set up from Zuffenhausen as it is with the two radiators. A third adds weight and complexity to a car--which is negative for racing.

Talk to your mechanic about the pros and cons. I think he would agree that you really don't need that third radiator--if he is truly honest, and not just looking for additional work.

What sort of oil temperatures have you seen--worst case--when tracking?

 

That's what I was hoping to hear. My oil temps have only gotten up to about 250 in 98 degree ambient temps on the track. I'll talk to my tech and see what they have to say but I'm glad to hear that it's probably unnecessary.

 

Porsche is usually pretty good at their thermal engineering, setting up the cars right from the start. They do extensive testing in all environments, from Finland in the winter, to the Sahara in the summer. If they decided that 2 radiators was proper for your Carrera, then it should be fine--unless you're doing something really none-standard.

 

Only?
Assuming you are using M1 0W-40, at 250*F your oil is in XW-20 range, at 9 cSt or very close to that mark.
The 3-rd rad + LT T-stat combined are what? $350 or so + labour?
And that does not take into account any debris in your well engineered radiators, deterioration of your coolant (fill for life), possible leaks (coolant reservoir) that lower your boiling point, etc., etc.
Cheap insurance to me.
However YMMV.
Cheers,
=L=

Edit:
I forgot to mention how ugly that concave piece of plastic looks like (and how anti - aerodynamic it looks like w/o 3-rd rad.
Extra weight? In front of the car? Really?

 

I think the third radiator is excessive unless you track your car often. A third radiator equals more parts that could fail and or leak, i.e. more moving parts!

 

if it were really unneccesary why was it standard on 2011 cars? i dont think there were really any major difference with the 2010 cas except that the thirs rad became standard...did porsche just run out of was to differentiate the new model?

 

I'm using motul x-cess 5w-40. When the oil reached that temp I backed off and it cooled back down to 225 very quickly. I'm not worried about the weight but more parts are more worries. I also clean out my radiator debris with every car wash.

 

Edgy: I agree with what you say, and I did the third radiator install as I have PDK and live in Texas. As for the weight increase while very minimal it is actually a good thing as it is weight low and far forward which helps to balance the car as so much weight is far aft in the 911.

 

I tracked my 4S before I got the GT3, and I saw 250-260 oil temp as well. Here in Houston I will see 235F on a hot summer day, ie 95-105F. From others that track their Carrera, the third radiator will do nothing for water temp as stated above but will lower oil temp to more normal of 210-225F.
To balance weight, just remove the mufflers.

 

This is exactly why I've been considering this for my Targa. I live in Chicago and occasionally have to drive in rush hour traffic. If the temp is north of 85 degrees, my oil temp will routinely get north of 225, at which point I typically turn off A/C and roll down windows (often sooner if I know it's going to be long traffic jam). I will easily hit 250 if I don't, and I start getting worried around 250. If a third radiator will help, I can keep the A/C on longer, keeping ME and the car cooler. Being October, it can wait until next spring though.

I know Porsche's are not designed for start and stop rush hour traffic in warm temps since the radiator fan is an afterthought at best, but it is largely my daily driver and I do live in Chicago with some horrific traffic.

I may need the radiators cleaned out, but I do not want to do that myself. I've seen the DIY, and it seems like a fairly sizable project, thought I guess I need to figure out how to do it sooner or later...

 

Standard on PDK only? Or was it standard on the 6 sp as well? I suspect the former but would appreciate confirmation.

 

Standard on 2011 pdk models