Can oil make that big a differance!

Jerry Madderra · 06-03-2001, 05:33 PM

Spent most of the day saturday in the garage checking this and adjusting that , then decided to change my oil.Had Mobile 1 from a sale at wal-mart, so out came the drain pan and rubber gloves and i go at it. changed oil ,filter and installed cool collar with heat sink grease i got at an eletronic store. Sun was the first chance i had to drive test, although a cool day in sunny So Cal i noticed a marked decrease in eng. temp . could the change to Mobile 1 have had that much impact on the temp and performance of my SC . needless to say i am surprized, i kind of thought the syn oil myth was just that a myth. we will see when the weather heats up . iI tried telling this story to my wife , she just nodded and said yes dear so i thought i would tell someone who cares
Jerry 911sc

Thomas Crown · 06-03-2001, 05:49 PM

Hi Jerry, I am a true believer regarding Mobile 1. I have a freind who drag races. His ET and MPH are always constant. He switched to Mobile 1 and not only did his engine temperature drop, his had lower ET's and more MPH. Not much, but enough to see the improvement of using Mobile 1.

Jack Olsen · 06-03-2001, 08:51 PM

On a tangent, I have a car that gets too close to 250 and a laptop that does the same thing (its processor is at 224 degrees as I write this). I use ducting and oil cooling for the car, and recently came across the heat sink grease in making a change to the laptop.

What does that stuff do? Where do you put it in relation to your oil filter and that collar? Also, does that collar make a noticeable difference? It looked (to me) a lot like the K&N filter until I saw it in this engine bay (click for a larger image):

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Jack Olsen
1973 911 T (3.6) sunroof coupe
jackolsen@mediaone.net

[This message has been edited by JackOlsen (edited 06-03-2001).]

Zendalar · 06-03-2001, 11:04 PM

The stuff, it is meant to be used between the heatsink and the thing to what needs the cooling.

The stuff is silicone grease, and the purpose for it is to fill the "air" gaps between the heatsink and the object that needs the cooling. Using the grease the heat spreads better to the heatsink (collar)

The cooling collar, needs to be BIG in order to do anything for the oil temperature. If you check out the specifications for ex. a computer heatsink (BIG ONE) you can see that they are able to remove some 70 watts of heat.

If you think that the collar can remove much more than 70W of heat maybe it will make a difference, but I will not believe before somebody actually proves that its worth anything.

70W-100W is nearly nothing, when talking about the heat cars engine produces.

82SC · 06-04-2001, 01:39 AM

yeah the heat sink grease is used to eliminate all air bubbles since air is a really bad heat dissipator...

some of the quality ones come in silver (dielectic spelling??) compunds with real silver in it...but it is expensive...and to do it for each new oil filter...look at overclocking sites because that is were it is used when chips are overclocked and produce copious amounts of heat....

they do have a double sided thermal tape that is supposed to be good too...eliminating air pockets...

can't imagine the cool collar does that much...you would need a fan to cool the fins...and even then...my cpu runs at 38C or 98F with the heat sink and a fan...but the oil is 160F or so...I would say my heat sink is 1/8 of the cool collar with 2 fans spinning at 5K RPM about 20 cfms and the cpu contact patch is about the size of a quarter...

but without the heat sink and fans the cpu can exceed 180F before they blow out....these chips run at an excess of 180F or 90C...and the heatsink fan combo brings it down to 98F...so it is effective...but the ratio of contact patch and heatsink area must be much greater....

I wonder what the vent on the side of the RUF yellow bird is for...it is right next to the oil filter area....was it for brake cooling, although I doubt rear brakes need excessive cooling....

but with a cool collar and a steady air stream the oil tmeperature could be brought down...I wonder is there is a way to do some ducting to get airflow to this area...and then right back out of the engine bay....hmmmm...

but by itself and in an enclosed engine compartment with no FRESH air supply I doubt the benfits are more then 2-5 degrees.

Jerry Madderra · 06-04-2001, 08:11 PM

The cool collar has been bench tested and shows a 12% reduction in oil temps. road tests on a 911 porsche show about the same . A computer heat sink has to do all the work of cooling , the cool collar is only a secondary cooling element for that extra margine of safety. I have looked onto the possibilty of ducting air to the collar from one of two points , either put a t fitting on the smog air pump and running that to the cool collar or drill a hole in the shrowd and bleed off some air flow to the collar. In any case i don't think it would necessary to vent the air from the eng. bay . Not that much heat added to the vast quanity of air moving through the bay . Jerry 911SC

wckrause · wckrause's Garage

Jerry, do you know about the cool colar testing? Who did it? Is there data published somewhere that describes the test?

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Bill Krause
'79 911SC Euro

island911 · 06-04-2001, 09:34 PM

Hey Jack,
On the CPU cooling; thermal grease to a copper spreader/heatsink is the way to go.
The Sony with the Magnesium case is a great idea for moving heat . . .the Titanium ones are just a little better than plastic for moving heat. (which isn't so good)
The low voltage chips have much lower dissipated heat, but those always lag in available processor speeds.

On the filter collar; K&N did you say?

Consider where the heat, taken off the filter, is going . . .right back past the (or into) the engine.
For reasonable people, any additional cooling is going to come from moving more air past the engine, or additional cooling on the oil circuit; outside the engine compartment.
Putting in a larger oil cooler. . . up front RS style? Okay, so we know you don’t want to do “that big box” on those sweet lines. Your oil tank, is it the copper clad aluminum? If not, that switch would help.
Well I’m sure you can come up with a creative sol’n. Just keep in mind what moves heat:
1) temperature difference; the bigger, the faster it moves. (2nd law stuff) . . .Hot air doesn’t do a whole lot of cooling.
2) the larger hot surface area, the better the air can take the heat away. (cooling fins)

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'81 Platinum Metalic SC Coupe

[This message has been edited by island911 (edited 06-04-2001).]