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-   -   Use your A/C to cool your engine! (http://forums.pelicanparts.com/porsche-911-technical-forum/273344-use-your-c-cool-your-engine.html)

porschenut 03-24-2006 08:05 PM

Quote:

Originally posted by RoninLB
what about my question.. huh?
Oh...I never have any cooling problems in the mountains. The only time cooling becomes an issue is when I'm burnin' up the track on a hot day. That's the scenario I had in mind when I was trying to think of a way to cool the thing down some more. I want to keep the stock front valance so a front-mounted oil cooler is off the table.

I'm probably going to try the Rubbermaid Solution this summer just for giggles. If it works, maybe Grady and I can put it on a dyno and document the advantages of it on a 3.2 Carrera.

And Ryan....unemployed? Never! I'm just, um...resting between jobs.:p

porschenut 03-24-2006 08:27 PM

Einstein, Da Vinci and the Wright brothers were in the first group.

DARISC 03-24-2006 08:31 PM

My Dad always drove Detroit V-8's. One thing he told me, when teaching me how to drive, was to turn on the heater full blast if I'm in a situation where the engine is heating up, that this might slow the temp.rise untill I could stop safely and see what the problem was.

I know it worked in his 51 Olds 88, because it happened to me and it got me to a country gas station 10 miles or so down the road w/o burning up the engine. Seems to me that might work even more effectively on an air/oil cooled engine.

island911 03-24-2006 09:51 PM

Boxes
 
"Genius is one percent inspiration and ninety-nine percent perspiration." Thomas A. Edison.

Edison tried all kinds of stuff "outside the box" . .. and threw it in the bin.

There is a difference between discovery and engineering, BTW. Both methods may lead to a solution, but, the engineer is well versed in previous discoveries . .. AND how to optimize their effect(s). --That's a pretty big box!

ianc 03-24-2006 09:57 PM

island, that's the first post from you I recollect seeing in a helluva long time! Have you been hibernating?

Good to see it,

ianc

RoninLB 03-24-2006 10:31 PM

Quote:

Originally posted by porschenut

Oh...I never have any cooling problems in the mountains.

issue is when I'm burnin' up the track on a hot day.


I'm probably going to try the Rubbermaid


thx for reply.

Have you ever checked your spark plugs after these hottie runs ?
If not it may be advantageous to monitor them ?

Personally I'm combustion neurotic in a learning sort of way.

also another oil cooler can go under left fender.

island911 03-24-2006 10:44 PM

Quote:

Originally posted by ianc
island, that's the first post from you I recollect seeing in a helluva long time! Have you been hibernating?

Good to see it,

ianc

:)thanks.
Just waaayyyyy too absorbed in too many projects. Busier than I want to be.

. .and I'm really kicking myself for not having time to see all those cool engines at Waynes open house. You Californians have got it good!

klaucke 03-24-2006 10:53 PM

Quote:

Originally posted by DARISC
My Dad always drove Detroit V-8's. One thing he told me, when teaching me how to drive, was to turn on the heater full blast if I'm in a situation where the engine is heating up, that this might slow the temp.rise ...
... Seems to me that might work even more effectively on an air/oil cooled engine.

On our air/oil cooled motors, this could actually hurt. The air for the heat comes off of the front of the fan shroud, so turning on the heat will reduce the amount of air going over the heads and cylinders, although I suppose it may cool the exhaust (moot point). On earlier cars w/o an auxiliary fan, this effect may be more pronounced, because air is being drawn from both sides of the motor.

To keep the motor cool when temps are rising, Grady Clay has suggested keeping the rev's up to keep a large amount of air flowing over the cylinders and heads. A front mount cooler is really key in this situation so that you can use speed (and reduced engine load) to reduce temps, on cars w/o front mount coolers it is hard to reduce oil temps once they have risen, because the engine mounted cooler is all there is.

bigchillcar 03-24-2006 11:19 PM

Quote:

And Ryan....unemployed? Never! I'm just, um...resting between jobs.
you and me both, buddy..SmileWavy
ryan

ianc 03-24-2006 11:46 PM

Quote:

The air for the heat comes off of the front of the fan shroud, so turning on the heat will reduce the amount of air going over the heads and cylinders
Air is always being blown through the heat exchangers; its path is determined at the heat flapper valve. If you have the heat on, the air is blown into the cabin, assisted by various blower fans. If it's off, the hot air is exhausted out the bottom of the car at the valve. There is no throttling mechanism at the fan shroud. Granted that if the blower fans are on, more air will be drawn through this route, but cooling the heat exchangers has a beneficial effect on engine cooling as well.

Quote:

To keep the motor cool when temps are rising, Grady Clay has suggested keeping the rev's up to keep a large amount of air flowing over the cylinders and heads.
I read this too, but God help me, it may be the one time that I dare disagree with Grady. My experience shows that with increased RPM's, so come increased engine temps, so you don't really gain much. I believe Ryan tried this at Grady's suggestion before he fitted a front cooler (you did do that, didn't you Ryan?), but didn't find any benefit from it in the hot Arkansas summer. Am open to more discussion, and of course, YMMV,

ianc

kach22i 03-25-2006 05:27 AM

Banks tech talk
Cool Air Equals Power

Cool air is good for making power, but could hot air be even better?

http://www.bankspower.com/tech_coolair.cfm
Quote:

Most people know that engines make more power when the inlet air is cooler. Let’s take a look at why this is true — at least in most applications. We’ll also tell you right up front that this article might leave you with more questions than answers. Then again, you might be the one that provides the additional answers and takes the world to the next generation of internal combustion engines.
http://www.bankspower.com/tech/cool-...v10-engine.jpg
The Banks Super Scoop, as shown on this Ford V-10 gasoline engine, provides both cool air and a mild ram-air affect. The Super Scoop also incorporates a water drain to separate any rainwater from the airflow entering the scoop.

RoninLB 03-25-2006 05:48 AM

Greater fuel than should be necessary for power will cool the heads. It's not so much that the fuel absorbs heat as we would simply think. It's that the greater fuel slows the speed of the flame combustion event producing power at the piston. This could also be created by retarding the ignition timing instead of dumping fuel. So instead of cooling the heads from greater oil cooling a wrench could install maybe $8k of EFI.

Meanwhile hot heads at high hp output makes denotation a possibility. Burned exhaust valves is bonus coupons.

Grady's thoughts relate to cooling the heads. If it can't be done simply by greater air flow then it has to be done another way.

planeguy67 03-25-2006 07:15 AM

Quote:

Originally posted by BrokeMyCar
(added thought - we keep calling our cars air-cooled, but are they not oil-cooled?)
I think, technically, it's both. After all, the car isn't going to last long without either an oil cooler or an engine fan, right???

And what about cars that have a radiator and an oil cooler??? Are they both water cooled and oil cooled as well???

Ok, this thread is getting too philisophical for me. ;)

RoninLB 03-25-2006 08:08 AM

It's simple. You need combustion for power. Combustion needs an environment. You engineer the environment.

BrokeMyCar 03-25-2006 08:20 AM

>"The world is divided into two groups: those that believe in the impossible >and those working on the improbable. Pay attention, so you end up in the >second group."

Now's a fun time to point out that thermodynamics only applies to systems in equilibrium... and thus definitely not to our cars. In a non-equilibrium state there are plenty of examples of the "laws" being broken. Keep the ideas coming Dave!

Babak

bigchillcar 03-25-2006 08:43 AM

Quote:

My experience shows that with increased RPM's, so come increased engine temps, so you don't really gain much. I believe Ryan tried this at Grady's suggestion before he fitted a front cooler (you did do that, didn't you Ryan?), but didn't find any benefit from it in the hot Arkansas summer.
hi ian...yes, i tried this last summer and you're correct..it didn't work. driving the car in 4th gear instead of 5th saw my temps creep up..how much so, i can't recall off the top of my head.
ryan

Grady Clay 03-25-2006 08:52 AM

ianc,

Pelican kobaltblau and I are going to repeat ryan’s experiment this summer. I’m going to measure the head temperatures and the temperature of the oil as it is first pumped out of the engine. We are going to try this with fairly controlled road conditions and on track.

Aside from the speed issue I want to have some quantitative data using the Rubbermaid Solution.

Once we have that repeatable, Andy wants to change the crank pulley to turn the fan 1.82:1. We will then repeat the measurements.

Best,
Grady

klatinn 03-25-2006 08:54 AM

Hi,

Just to add to the quote contest:

One should always keep an open mind, but not so open that the brain falls out.

BrokeMyCar 03-25-2006 09:08 AM

>Only if you fail to define a control volume.

Jim, did you know Jarzinsky when he was at Los Alamos?

bigchillcar 03-25-2006 09:21 AM

grady,
looking forward to the results of your more controlled study. btw, i never did change my fan ratio..of course it being winter, i'm happier with my 'slower fan' for the time being. :) but just wait until july..then august..:(
ryan


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