3rd Radiator kit - my dealer says it is useless - is it ?

I am changing my water pump, so while they are in there I was thinking may be to invest in a 3rd radiator kit https://www.suncoastparts.com/mm5/me...=996thirdradia My dealer tells me they are useless even for the track I have to say I tracked the car a couple times and in hot summer florida without any temperature problems. Any input on that ?

For hard track use in hot climates it is well worthwhile. Otherwise useless. I run one on my race car.

I think the third radiator is useless for the street, where the solution to high temps has more to do with airflow than radiator surface area. On the track, airflow isn't an issue. But if it were me, I'd do it anyway. Enough hot laps and I'm sure you'd heat soak the poor thing. If you're in there anyway, and plan to track the car, I'd do it just because a) it looks cool, and b) it seems like cheap insurance. My .02...

I'm in Miami as well NOT useless and i was looking into but unfortunately for me not so simple on my 2004 40th AE or I would have done already and my car never overheats. However, more surface area in cooling system is not a bad thing, plus it looks cool peeking out. too bad we cannot use this one: http://www.suncoastparts.com/product//SKU9971TRK.html P.S. I hope dealer you asked was not The Collection becasue talk about "useless"

Has no effect unless you remove the engine cooling regulator thermstat in order to "supercool" the engine. The engine control system will automatically disable the A/C if the engine coolant temperature level begins to exceed the nominal range. If that happens on a reguler basis then yes, add the third radiator.

OH LORD! removing the t-stat has nothing to do with coolant effectiveness more coolant - more surface area to cool more coolant = more cooling no t-stat with the same amount of coolant will saturate at exactly the same place as if it has a t-stat .... there is no where for the heat to go at some point I mean imagine having only 1 tea spoon ofwater in your car or having the pacific ocean - DUH!! adding more coolant capacity will 100% remove more thermal energy then keeping it exactly the same and removing a bottleneck

I personally think the extra Rad is worthwhile, ignore all the math and reasons that it doesn't make a difference, this is from my personal experience. I originally fitted the rad due to high the temps I was getting from tracking it and wanted to keep it cooler to let me stay on track longer. But I found out for normal road use when I fitted a low temp stat a few months before fitting a 3rd centre rad, (I can vouch for both mods) the Stat reduced running temps but a couple degrees C and when later fitting the 3rd rad it dropped the temp a couple more. This in turn takes longer for the engine to get really hot, like in heavy traffic, and it never gets as hot as it did, it also gives quicker cool down time when moving again which can only be good for our heat sensitive engines. Even at stand still heat is radiated off the radiators without the fans turning, all the extra square inches of surface helps.

+1 on the effect of the low temp T-stat. Provides more cooling sooner, rather than later, and with just that, I have lower cooling temps all around, maybe 10� F. I'm sure a massive thermal heat soak overload will be exactly the same final temp as wth the old T-stat, but haven't seen that yet in 4 years of owning it.

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how many track days are you putting in

BTW OP for a "few times" tracking I would not get too into modding the car - many people go years and years on ALL STOCK - save the money but the question came from someone saying it was useless even on track - and I hollar B.S. more coolant is more coolant - more area to cool coolant is more area to cool coolant stupid to say useless stupid maybe say, you dont need it, but not useless - else why wouldn't any race car in the world just skip the added weight and not use one

these guys could have just took out their t-sat and not put that big heavy thing up front we all know race guys like added weight with useless purposes

I assume the nuance stands between the word DE and Racing. DE are shorter period of time on track 15 to 25 minutes, while racing goes beyond that, sometimes for hours. I might hold off on that mod for now. Just that I am getting the full aerokit thing so I figured why no go all out while at it.

If cooling is a problem, it may be a worthwhile solution. If not, less plumbing, less weight, and less cost is better in my book.

like I said - for someone to say its worthless is stupid... it might not be (and most likely would not be) a benifit to you, I see amny many stock 886/boxster/caymans running around at a DE with no one screaming the sky is falling...worst case if you do get warm, you can always throttle back for a lap or two and cool her down

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The type of thermostat used for controlling engine via sensing the coolant temperature has something of a linear, incremental, flow control aspect. Even with the thermostat fully open there will still be a significant level of blocking of the coolant flow. If the thermostat never "saturates", goes fully open, then the cost of a third radiator will be wasted.

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

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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!

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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.)

I was told that the 3rd radiator was made for tiptronic cars. True? I might add one, just to look like a baller.

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.

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...

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?

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

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)

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BINGO!

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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.....

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'

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

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..."

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"

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As I said previously, I don't unfortunately have any photos of the center radiator and associated ductwork . Next time the front bumper's off I'll gladly resurrect this thread and post some pics.....

Did you cut a hole in the top of the bumper cover for the vent? If so, can you post a picture of it from outside the car?

3rd helps. Helped me on the street and track in the Texas heat. 40th have it standard. As do gt3. Saying it is useless is just bad info. If anything is useless, it's the sunroof. Wrt ducting, I vented my side rads to the rotors a la GT3 duct work. Great idea there to cool brakes. -td

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What does "helped me" mean? I know from simple physics that more radiator area makes little difference if there's no air moving through it, and I know from empirical experience that the standard radiators do a fine job once the car is moving. Common sense says that where an engine gets heat soaked from extended operation at high rpms (and thus speed, presuming lots of available airflow), more radiator is better. That explains the GT3, based on the intended use of that car. As for the 40th, well, that whole car was a marketing exercise, so let's set that aside. So, again, tell me what "helped me" means?

It takes more time to heat soak 3 radiators and extra plumbing than 2 plus there is more fluid, which takes more engergy to heat. So the 3rd radiator will help in any situation. However, the amount of help that it provides to a n/a car that not being pushed hard will be minimal.

Philooo: Your down in Miami which means (to me) hot and humid...so might make a lot of sense........ If you are still thinking about this upgrade, you might want to contact Chris at LC Motorsports, last I recall, he had a third rad kit (NIB?)and was looking to sell it....maybe for a price better than Suncoasts normally great pricing. GL.

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"helped me" = reduced operating temperature. Not rocket science or even complex physics. If you have more surface area to cool the fluid, it, well, cools the fluid. My car was a serious track rat. Temps decreased in use after the 3rd rad. I think I posted about this back in 2007 or 2008 or 2009. -td

40th AE DO NOT in fact have the 3rd radiator from factory lets stop spreading that myth If you look at a 40th AE and although it has x51 engine you will see it has turbo front end and yet no 3rd radiator. Why? Because Porsche decided the extra air flow through the larger openings and slightly different radiators were good enough and the 3rd radiator was not installed.

Thanks for stopping by td !!

Philoo, IMHO, its just not needed for what your doing. If you must spend $600, buy something your car really needs.

In Colorado at High Plains Raceway the 3rd Radiator was required to run my '99 C4 hard at over 85 degrees air temp. I was having trouble with heat and would have to back off a gear with the heater on FULL blast to keep temps under control with normalk DE sessions of about 25 minutes. I "lived" with it for 2 summers, then finally got tired of backing off during sessions or skipping hot-summer track days. I did an Aero Kit and decided to go for the 3r Rad at the same time that past summer. Previous to the 3rd Rad, I had cleaned the radiators and them flushed and inspected with no sludge, debris, etc. I took it to a couple shops and both recommended the 3rd Rad a few times as the best solution. I went after heat problem with full force and added the 3rd Rad, hi-fan speed mod and the lower temp T-stat. The heat problems are now GONE! One day this summer the temp was over 95 degrees and the car ran perfectly "cool" for 30 min sessions. It is very important to get all of the duct work in place to make sure the air flows as designed. I have seen this issue on other 996's and GT3's without proper ducting. lots of "unexplained" heating problems, until someone noticed the simple lack of proper ducts (to the center Rad).

Required for regular track use IMO. I don't think high temps caused my cracked head but it sure didn't help.

keep in mind people the OP is getting an Aero kit installed and NOT having cooling issues asked if these thing are useless - which we now can all agree they are not useless he should get more airflow out of an Aero front clip - so he's probably going to be better off than he was before. $600 = 2-3 track days

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Should we assume you knew to turn off, disable, the A/C compressor...?

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I don't doubt that one bit, because there's airflow. This is why people like Pelican and Carnewal are specific about advertising this as being for track use and hard driving. I'm just saying that doesn't translate into a meaningful difference for someone sitting in slow urban traffic. The third rad doesn't add much fluid capacity to the cooling system, and it's hampered by the same location issues as the other two are. Thus, a great track upgrade, but nearly "useless" for helping cool the engine in a typical street driven car. But it does look awesome. I've bought upgrades for less good reasons than that

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I make an appearance more than Tim these days. He used to come by before he got his 997 and now he's too good for us lowly 996 folks. -td