More power when dipstick on MIN ?

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djones
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Joined: 17 Mar 2005, 15:01

More power when dipstick on MIN ?

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I was wondering...

If your engine oil is at the minumum mark rather than maximum will your engine produce more power?

This might sound daft but with less oil for the crank to churn its almost like having a semi dry sump setup.

donskar
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Joined: 03 Feb 2007, 16:41
Location: Cardboard box, end of Boulevard of Broken Dreams
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Re: More power when dipstick on MIN ?

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Theoreticaly, you will gain a bit of power because you are reducing the drag caused by the crank counterweights and other components whipping through the oil.

However, running less oil means the oil you do use will run hotter, becoming less efficient, and the entire engine will run hotter, reducing power and eventually going BOOM.

That's a thumbnail of what some of our more technical members can elucidate in more detail.
Enzo Ferrari was a great man. But he was not a good man. -- Phil Hill

donskar
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Joined: 03 Feb 2007, 16:41
Location: Cardboard box, end of Boulevard of Broken Dreams
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Re: More power when dipstick on MIN ?

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Sorry, I forgot to add just four little words: DO NOT DO IT!
Enzo Ferrari was a great man. But he was not a good man. -- Phil Hill

Belatti
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Joined: 10 Jul 2007, 21:48
Location: Argentina

Re: More power when dipstick on MIN ?

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Generally in my VW Gol I change oil every 8.000km upto 10.000km when I do a couple of 1.600km road -thus constant speed- trips.

The manual says oil cap is 4 litres. With those 4 litres the dipstick mark is at maximum. I usually fill the engine with 3.5 litres (mark still a bit above the middle) and left the can in the car in case I´m in the middle of nowhere and have a leak -something hardly occurs BTW-.

In my old "carburated" Fiat I used to fill that 0.5L arround 4.000km but with this one its not neccesary, oil consumption = 0

djones, a personal quiz, why do you want more HP? Racing car or just feeling to own a DTM? For the first install a drysump system, for the second, grow up!
(also mind that any seal failure and your engine is lost)
"You need great passion, because everything you do with great pleasure, you do well." -Juan Manuel Fangio

"I have no idols. I admire work, dedication and competence." -Ayrton Senna

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Ciro Pabón
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Joined: 11 May 2005, 00:31

Re: More power when dipstick on MIN ?

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Well, some of us will never grow up (that much!). There is a "ricer" inside me... or at least I once had one. :oops:

I think djones asks more out of curiosity than out of "ricerism" (well, maybe a little, Belatti has a point). Anyway, I rephrase the question:

How much "margin of safety" the level of oil has? And how much power it robs your car of?

I think those are legitimate questions. After all, the dipstick has full and minimum marks. Why? And how much do those marks influence efficiency? Good question in a world of 100-dollars-the-barrel oil. Or, to put it in another way: does it pay to use a dry sump?
Ciro

DaveKillens
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Joined: 20 Jan 2005, 04:02

Re: More power when dipstick on MIN ?

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Oil is the very lifeblood of an engine. If you run the bare minimum, and somehow the oil pickup sucks air for just a second (hmm, that nice looping ramp onto the freeway), damage will happen. It may just be scuffed bearings, or a total, catastrophic failure.
There's really no difference in crankase windage anyways. If the crankase sump was full, or minimum, it takes about the same time to allow the crankase oil to drain down into the sump.
Racing should be decided on the track, not the court room.

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Ciro Pabón
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Joined: 11 May 2005, 00:31

Re: More power when dipstick on MIN ?

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I normally don't answer directly, waiting until some other comments arrive, but I'll make an exception to that "rule".

Dave is right, of course (Dave is always right... :)), but I can serve as witness: an XK, that holds 12 quarts (!) can pump oil when there is only 4 quarts in it. I used to drive one, and like Belatti's car it used to leak or burn oil. The fact is that I once ran it as low as 4 quarters, confident on coming back home to fill it with the oil I had in my garage. The problem: the last kilometer was a steep one: the gauge for oil pressure failed a couple of times. As I said, Dave is always right...

On the other hand, I imagine djones is talking about racing. You have to finish, but preferably first. The logic of a dry sump is not only the fact that it has a double stage pump, that it is easier to put an oil cooler and that (perhaps more important than anything) that you can install the engine closer to the ground and get a lower center of gravity: the fact is that the windage losses will be smaller. Normally you will find a "low half cylinder", close to the pump, that has a channel on it that collects the oil and distribute it to the length of the engine. This causes some losses. How much? I don't know, but that's what is needed to answer the question properly. If you take the risk to burn the engine, well, it's racing, not inheriting to your son the Volvo of your dad: in the second case, the answer is self evident. What a racer needs to know is how large is the gain and how large is the risk. Different models of cars (it comes to my mind the Porsche 911, with another 12 quarts!) will have different margins of safety.

Finally, on most pumps, at least in all the dry sump type I've seen, the oil is degassed, precisely to avoid the "bump-effect" Dave mentions.
Ciro

Carlos
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Joined: 02 Sep 2006, 19:43
Location: Canada

Re: More power when dipstick on MIN ?

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I meant to post but got caught up in the Ferrari nose thread :wink:

Other advantages of a dry sump - when cornering centrifugal force can't slosh the oil to one side and starve the oil pump, you can design the oil tank with as many anti-surge baffles as you like and help balance the car by putting the tank anywhere you like.

djones
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Joined: 17 Mar 2005, 15:01

Re: More power when dipstick on MIN ?

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My question was purely out of interest. I have strange thoughts every now and again. :D

Belatti
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Joined: 10 Jul 2007, 21:48
Location: Argentina

Re: More power when dipstick on MIN ?

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djones wrote:My question was purely out of interest. I have strange thoughts every now and again. :D
I usually happens to me, too! :D
"You need great passion, because everything you do with great pleasure, you do well." -Juan Manuel Fangio

"I have no idols. I admire work, dedication and competence." -Ayrton Senna

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