Water Pump

[jmatta]

pk2, if you are curious, do a search on the topic. The merits of the t-stat have been debated time and again. The temp reading on your gauge is a joke.

Porsche is more concerned with burning off oil containiments (for those extremely long oil change recommendations) than engine longevity, hence their choice in operating temperature.

[Blue-S]

Some people seem to think that the Boxster cruises at 180 degrees because the temp gauge needle typically sits between the "8" and "0" of the "180" label when at cruise. I don't think that Porsche labeled the gauge so that 180 degrees is indicated when the needle is in that positiion...even if they might have made it deliberately misleading. The temp gauge has a blue-tinged tic in the vicinity of the "100" label, then an unlabeled tic, then a tic above the left side of the "8" in the "180", then another unlabeled tic, and finally a red tic in the vicinity of the "250" label. That being the case, the common temp gauge needle position at cruise (between the 8 and the 0) might be inferred as 200 or maybe more. I suppose that the unlabeled tic to the right of 180 could be inferred as 225...

The Boxster engine actually runs above 200 degrees at cruise, but (in stock form) has a 180 degree thermostat. This is possible because the Boxster's thermostat is on the INLET side of the cooling system. This is made clear by the cooling system diagram on page 19-2 of the Bentley service manual. So if the coolant returning from the radiators has to exceed 180 degrees to begin opening the thermostat, then the coolant leaving the engine (headed for the inlets of the radiators) must be significantly hotter than 180 degrees...and that's why an engine with a 180 degree thermostat actually runs in excess of 200 degrees at the temperature sensor location. This also explains why the 160 degree thermostat can result in cruise temps in the 170s - 180s.

[pk2]

Jimatta, Lil_bastard, blue-Thanks for your interest.

Jimmata, As far as an “ongoing debate” about water temp, I’ll check it out. If there’s anything definitive (Blu_s seem plausible), I’m in. If it’s another XYZ headers vs. stock, K&N vs. stock filter vs. cold induction …bla bla bla…and they all the add hp… I’ll figure it out, not that hard to take an accurate coolant temps.

(Blue_s) Interesting facts. With temps all over the place from heads to block to radiators, could the 180 on the dash just be a calculated average of pertinent areas?

But (lil_bastard), I just cut to the chase and got a read on the oil temp in my car (seems to be the real issue). Unless someone finds fault with my methodology, mine is 188f… under pretty harsh conditions. Don’t know if 188f is good or bad or how closely it’s linked to coolant temp. I’m confident it’s pretty accurate, and from what you’all say, it is the real bottom line.

Anyway, below are picks of my little measurements..
Details of methodology are below pics.


By Kroak

I drove moderately hard about 4 miles with a few final full boost red lines, gauge read 180, ambient temp 97f (if not on fire) and dry, 22% humid, asphalt 157f (proximity to oil sump, might matter). Intake temp 175f (forced induction, Eaton M63)*, internally stock original 2,.5L, 32k, an extra 50-80 hp (depending who you talk to (like these threads)) but, a significant extra load worth mentioning.

To measure the temp I used a laboratory digital laser pyrometer and pointed it at 1“ from around the middle of the bottom of the crankcase. Most all the oil, cooled, or back from circulation should be there after a short rest (3mins.). Plus aluminum is a very good conductor of heat; After 3 mins. Oil inside should be about the same temp as the bottom of the case I figure.

So I don’t know, if my methodology is right, is 188f to hot for the oil under somewhat extreme circumstances, what should it be?

Regards, PK

* I only took 1 reading on the blowers exhaust to intake pipe@175f . Like to take 5 or 6 to verify accuracy & repeatability but, trust me, it’s frigging hot..

[JFP in PA]

Sorry, but while your "experiment" was at a minimum "entertaining", it did not give you a single accurate reading of the circulating coolant temps, which are much higher. From the factory, the M96 coolant typically runs between 210-215F when the dash gauge indicates 180 (the dash gauge is both inaccurate and non linear in its function), measured by the actual sensor in the coolant, which is pretty accurate when temperature tested out of the car. Changing the OEM thermostat to the LN 160 degree unit lowers the engine coolant and oil temps significantly; the coolant to 175-80, the oil by as much as 20-25 degrees. Oh, and rather than use a non contact infrared pyrometer to "attempt" to determine coolant temps, we also actually added aftermarket instrumentation (calibrated gauge units) to confirm the numbers, which they did. Getting the oil temps is a bit more complicated, requiring adding a remove oil filter mount to accommodate the test instrumentation.

If you really want to know the temperature of your coolant, connect a OBD II scanner with PID capability to your OBD II port and set the unit to coolant temperatures; then take your car for a ride. Under cruise conditions with a ambient temperature in the 70-73F range, let us know what you find…………………
…you just might be surprised as well................

[pk2]

JFP_PA,

Glad to entertain. I'm all for running cooler.Indeed, I'm on the verge of h20 injection/intercooling. But as blue_s stated, the reason for allegedly running it hot was to burn off oil (theory?). We have the most stringent emissions standards in the land...might not fly.

But, the point made here several times is you want your coolant cooler so the oil is cooler. Well, they don't seem so directly related. Obviously my oil temps of 188f (assuming good methodology) are lower then the 210 every body is talking about & the oil has it's own cooler (no?). So again, begs the question,Forget the water, How hot should your oil be?

The Digital laser pyrometer can indeed be "entertaining" at frat parties especially, drawing a laser bead on your friends crotches and zapping temp readings...laugh riot. But actually, it's a very accurate scientific instrument. I snagged it straight from the family biz/laboratory's where it's used daily while they accelerate, smash and other wise mess with atoms and ions at thousands of degrees and at the speed of light(not exactly frat. stuff). Also, can't think of a better place to take a read, can you?. (if ya do I'll do it).

Anyway you make some good points. OBCII reading sounds interesting, I'll try it. but you realize your taping into a pretty primitive sort of sensor, electro mechanical, through Porsche's apparently less than honest electrical system.

You'all are probably right, you've made some compelling arguments.... And god knows I can use all the cooling I can get. A blower generates lots of top end heat (I know, have 2 EGT sensors). But, so many people swearing they feel the unsubstantiated but advertised 5-10-15 hp with their new ebay headers, greasy air filters, what ever. Ya gotta be more skeptical the more logic is defied. So when someone here said the thermostat is good for another 5 hp...Ya gotta think "oh god, here we go". But as the science trickles in it seems compelling.

Thanks again, PK

BTW; In my BMW3.0 coup days, we used to just drill holes around the perimeter of the thermostat. They were really accessible so trial an error was easy.

[JFP in PA]

Originally Posted by pk2

We have the most stringent emissions standards in the land...might not fly.

A lot of states have stringent emissions standards, mine included; and as we have about a dozen or so clients running around with the 160 stats, and passing state emissions testing, I don’t see an issue.

But, the point made here several times is you want your coolant cooler so the oil is cooler. Well, they don't seem so directly related. Obviously my oil temps of 188f (assuming good methodology) are lower then the 210 every body is talking about & the oil has it's own cooler (no?). So again, begs the question,Forget the water, How hot should your oil be?

Actually, they are directly related due the oil/water oil cooler used on the M96 design. In fact, one of the best “bang for the buck” upgrades on a 2.5/2.7 base car is to install the “S” cooler because it is more than twice the size of the base unit. With the coolant running 210-215 normally, the oil is going to be 25-35 degrees warmer under cruise usage (not to mention how hot it gets under load or in high ambient temps); drop the coolant temp 20-25 degrees, and the oil comes down with it…………..a major gain for the oil and life of the M96.


BTW; In my BMW3.0 coup days, we used to just drill holes around the perimeter of the thermostat. They were really accessible so trial an error was easy.

The M96 stat already has a hole in it………..

[Blue-S]

Originally Posted by JFP in PA

From the factory, the M96 coolant typically runs between 210-215F when the dash gauge indicates 180 (the dash gauge is both inaccurate and non linear in its function), measured by the actual sensor in the coolant, which is pretty accurate when temperature tested out of the car.

When you say the dash gauge indicates 180, where is the needle pointing? Is it straight up, between the "8" and the "0"? I contend that the tic mark above the "8" is the 180 degree position, and the common cruise position (straight up, between the 8 and the 0) is intended to indicate HOTTER than 180 degrees. The gauge is certainly non-linear, and was apparently not designed to provide a precise temperature indication. If they had used a more serious-looking font, maybe they could have placed the number markings in a centered position below each respective tic mark. Maybe they should have just left the numbers off of the gauge altogether...

[JFP in PA]

Originally Posted by Blue-S

When you say the dash gauge indicates 180, where is the needle pointing? Is it straight up, between the "8" and the "0"? I contend that the tic mark above the "8" is the 180 degree position, and the common cruise position (straight up, between the 8 and the 0) is intended to indicate HOTTER than 180 degrees. The gauge is certainly non-linear, and was apparently not designed to provide a precise temperature indication. If they had used a more serious-looking font, maybe they could have placed the number markings in a centered position below each respective tic mark. Maybe they should have just left the numbers off of the gauge altogether...

Typically, we use the middle of the “8” as our reference point, and when the needle is there, the coolant is 210-215F; go past that and it gets even hotter, often reaching 225F by the time it is over the “0”. Because of the non linearity of the gauge, the relationship of position to actual temp is very misleading……

[pk2]

JPA_PA

Yup you do, Your a "CARB state", California has special status, its sets it's own standards, other states can choose between weak Fed standards and tough CA standards. PA and others follow CA. Lucky us lucky you. Unfortunately with the motor totally re-tuned for the blower, I barrrrrely squeaked by ...at idle no less!?!

A water to oil cooler makes them (the fluids) the same temp and that is 220-210, O.K. Why does my oil appear to be 188f. If you read my methodology & you get the logic, I think it's pretty sound. If you got a better method, let me know. Punch holes in mine. I don't care as long as the the numbers add up.

Funny thing though, I suppose if I already had a 160 thermostat (or 140 (?)), oil at 188f might be just about right and we could all go home. (Gotta get a good read on the coolant temp I guess.)


Regards, PK

BTWx2. Porsche has "a' hole in the thermostat, quaint. We just kept drilling till it worked right. 3 or 4 holes I think was the magic number. Did take longer to warm up though.