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-   -   Thermostat question (http://986forum.com/forums/showthread.php?t=54070)

j.fro 09-15-2014 02:11 AM

Thermostat question
 
Ok, so we know that excessive heat/ poor cooling can be an issue with the m96 engine. There also seems to be consensus for the 160 t-stat over the factory 180. A trick we used to use with Chevy drag car engines was to remove the spring and plug from a t-stat, creating a restrictor plate. Running without a t-stat wasn't so effective because the coolant moved too quickly through the engine to accumulate heat, but with the plate, it did the job and the engine stayed cool. How about this for the M96? I know the heater won't be very warm afterwards, but for a racer, I don't really care about that. Thoughts??

BoxsterSteve 09-15-2014 03:49 AM

One issue that you may see would be oil change interval. If the coolant and consequently the oil never warm up enough, how often do you change oil because you're not burning off moisture and fuel that accumulate in the oil?

jb92563 09-15-2014 05:49 AM

Why use a restrictor when you can simply install a "variable restrictor" ie 160F T-Stat that will try to match the temp to optimum all the time.

Not sure I see any benefit to a restrictor as it only allows one fixed flow rate regardless of coolant temp.

Really whats needed is an electronic ECU controlled T-Stat.

thstone 09-15-2014 07:18 AM

Engines have a preferred operating temperature and the goal is to keep the engine at that temp at all times, under all conditions. Running the engine hotter or cooler than the preferred temp hould be minimized and/or avoided if possible.

In a perfect world, what we'd really like is an engine heater to warm the engine and oil to operating temp prior to even starting the car! Then we'd like a thermostat to maintain that optimal operating temp throughout all ranges of use and external temperature extremes. This could be accomplished by having infinite cooling capacity at all external temp extremes.

Problem solved! :)

Running the car without a t-stat will delay getting the engine up to operating temp. On cool days, the engine might not ever get to operating temp because the cooling system (radiators) are always in the loop.

Thus, the low temp t-stat is an easy and cheap way to get the engine up to the preferred operating temp and keeping it there without modifying the cooling system and spending $$$ to do so.

To carry this discussion on to the next logical step; the next move towards that perfect system would be to increase cooling capacity by installing the Boxster S model center radiator into the base cars or install more efficient raditors.

Our Forum owner has provided a convenient DIY that shows how to install the Boxster S center radiator. The parts kit new is $1,100 but you can often find a used S radiator and piece together the hoses and other parts for much less: Boxster Center Radiator Installation.

More efficient radiators for the Boxster base cars can be found here (among other places): Porsche Aluminum Radiators

jb92563 09-16-2014 08:13 PM

With all the electronics these days I cant imagine why the coolant system is not ECU controlled to maintain the perfect operating temperature.

Perhaps the benefit does warrant the extra effort to add the necessary components?

opus69 09-17-2014 03:27 AM

Once the thermostat is open operating temperature is ECU controlled by the fans. With thermostat open it is the air across the radiators that help to regulate operating temperature.

JFP in PA 09-17-2014 12:41 PM

Quote:

Originally Posted by jb92563 (Post 418481)
With all the electronics these days I cant imagine why the coolant system is not ECU controlled to maintain the perfect operating temperature.

Perhaps the benefit does warrant the extra effort to add the necessary components?

Buy a new Boxster and you will get your wish; they call it a "thermal management system".

epapp 09-17-2014 02:34 PM

Any idea how the 'cooling policy' works in this system? They don't talk much about it on the website. Do they have an adjustable thermostat or is it something simple like a more aggressive fan control?

JFP in PA 09-18-2014 01:07 PM

Quote:

Originally Posted by epapp (Post 418584)
Any idea how the 'cooling policy' works in this system? They don't talk much about it on the website. Do they have an adjustable thermostat or is it something simple like a more aggressive fan control?

I have not seen one apart yet, but it has to be more complicated as it runs the car super hot (225F+) until you open the throttle wide, when it quickly drops the coolant to around 180F for the duration of the WOT power, then jumps back up over 225F when the thottle closes.

Got to be bypass valves and such involved to pull that kind of temp drop that quickly.

epapp 09-18-2014 01:33 PM

I guess it isnt SO bad that our high speed fans come on at 217 then??

..here I am designing my own fan controller based on driving conditions..

gurkanbo 09-18-2014 01:51 PM

I have 996 3.4 carrera m96 engine has warm problem but problem solve is basic. I live in istanbul and istanbul warm city it has traffic jam also water temperature up to 100c sometimes 105c. Radiator fans have a 3 Level first Level on 96c second Leve on 103c its late for engine but you try open ac radiator fan open level 3 so water temperature must under the 96c. I perefer you buy 73c termostat Arabic countries or warm countries use it. And in the traffic you must open ac.


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