wwest

Race cars are expected to be operated at or near WOT a LOT more of the time, HIGH engine loading, vs our street cars.

wwest

But it is "worthless" for a specific individual's car provided the factory cooling system provides adequate engine cooling.

In answer to OP's actual question, the dealer was answering honestly and correctly!

Macster

What coolant and if possible what oil temps is your car producing under tracking conditions? If they are at the high side then a 3rd radiator provided you can also allow for the air flow/ducting this requires should help.

For high side I"ve seen under spirited driving in high ambient temps (>90F) and with the A/C off I've seen 226F. The coolant has never gone higher in spite of the fact I parked the car one day on the side of a mountrain and raised the rpms to nearly 2K and watched the coolant temp with an OBD2 code reader.

I note that when Porsche wants to deal with a higher heat load like that produced by a Tip/Pdk car or a Turbo it adds a 3rd radiator, and I suspect a more aggressive cooling fan map. That is the fans come on at a lower temp though they may run at a slower speed, or run longer or have 3 speeds instead of 2, etc. I've never had the chance to really delve into this. (My 06 GTO had around 6 different cooling fan/speed ranges which I mildly tweaked with a Predator tool to increase the cooling since I live and drive in very high ambient temp areas quite a few months of the year.)

white out

I was told that the 3rd radiator was made for tiptronic cars. True?

I might add one, just to look like a baller.

BruceP

Just to add to my previous answer, here's why I say that additional surface area is of minimal value on the street, whereas airflow is what really matters:

A few years ago, I was having some concerns about cooling (end result was new radiators). I got in the habit of watching the coolant temp on the dash, courtesy of the OBD hack available on early cars. There was an absolutely certain pattern whereby the temp would climb while sitting in traffic, and then fall with surprising speed with even a little car movement (until it got up over 100C or so, after which it wouldn't budge until I was able to move without interruption for a few km).

I always wondered why nobody offered aftermarket fan blades for this car.

jrgordonsenior

Random thoughts and keeping 996's cool is always on my mind....

White out: yes it's a tiptronic option. It does lower temps, I have the data to prove it. I have one on my race car though I'm going to change to the larger cup center radiator next summer.

Ducting of the center radiator is important too. Tips and TT's direct the airflow downward under the car while GT3's and cups direct it upward and out thru the vents in the top of the front bumper. That system is more effective and provides some downforce though quite a bit more expensive and probably unncessary for a street car.

I would think intalling a switch for the side radiator fans would also be effective for street usage. In race cars we remove them altogether along with the shrouding for better air flow.

And finally for the OP, I think it would be more cost effective to just replace your side radiators or at least have them pressure tested and hydrostatically cleaned. If they're old and original I'd replace them first and install some mesh to protect them...

white out

Obviously it would help with cooling as there is more surface area to cool the fluid (and more fluid to keep temps low).

Since you're running a race car, do you have the vent through the top or bottom? If you go through the top, do you have any pics of your set up?

philooo

So it seems the final word is that the 3rd radiator is not of much use for track weekends, unless I can see temps going up.

I have done a couple of track days, coolant temperature stay on dead center, so I think I'll skip it until I can get faster

ivangene

agreed agreed agreed but the OP said My dealer tells me they are useless even for the track -

YES there are many ways to improve cooling and the OP never said he had cooling issues - he is getting an Aero kit and thinking about this - wondering if it is "useless - even for a track car"

the simple answer is that is B.S.

I know - lots of ways to solve this but I am not debating the value, the need, the reason for wanting needing or whatever - I am saying it is NOT useless

I also said to the OP that he most likely doesnt need it and many cars are just fine - including DE driven and street cars without ANY mods

and I am notupset, just blabbing so dont take this as a rant....I am just being very pointed in my reply back to the OP question and NOT getting off track - which I am sure is making people think I am on drugs since I never stay on topic

- no drugs....some beer (s)

ivangene

BINGO!

jrgordonsenior

Through the top but no pics of the ductwork. I can tell you that we took the OEM TT ducting and just reversed it along with the brackets holding the radiator. Requires a little bit of finesse but it works just fine and much cheaper than the cup hardware.....

philooo

the reverse turbo duct work must be something, is there a gallery of picture of your car somewhere ? It must be quite something for us 'stock 996'

white out

That sounds great. Definitely post up some pictures if you don't mind.

TomF

I have the factory option third radiator in my C4 Tip Cab. I can tell you that as an added benefit, it gives me an additional 40 hp! or was it 30? "These are not the droids you are looking for..."

ivangene

LOL @ Tom -

my son has braces and its messing with his speach right now - when he asked siri that he got some "odd" replies

"I found four stores that sell drawers in your area"
"did you want me to search the web for doors"