12-21-2014, 07:12 AM
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#1
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Join Date: Feb 2005
Location: It's a kind of magic.....
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Quote:
Originally Posted by mikefocke
JFP.
Great response.
But the evidence based on immediate max power and racing revs is somewhat different than the 3500 RPM limit until 12 miles and warm I was describing in an every day car. Or is it? How much is enough? In racing every HP counts. But do I care if I lose 2 or 3. I'll still make it to the grocery store.
Is there any system in our cars that pumps/sprays the oil and delays the start for a few seconds to get the oil flowing? You would think there should be given what you describe.
The thermostat limits the water cooling until warm. The oil/water exchange helps warm the oil. The side air exchange fan doesn't come on till the engine compartment is hot. All show Porsche thinks quick orderly warmups are important. Is there any other system?
Sisu. Agreed. I'm just trying to establish the degree.
I used a rev limit until warm and even then I didn't hammer it. Is that enough or do we need heated garages and to what temp? Block heaters? Fluid heaters?
(Lets limit the discussion to moderate (28f to 100f) temperature climates with 0w-40 oils. Alaska is just different.)
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Mike, the entire point is about component wear due to dimensional shifts as the engine heats up. All alloy engines move around quite a bit as they warm up, enough that astute machine shops actually do their work on the major engine components only when they are at normal operating temperatures, which is where they spend most of their lives. And the dimensional differences between running temp and normal room temp are considerable, enough that engines prepped this way actually make more power because everything is where it is supposed to be at temp. Add in the high thrust angle inherent in the flat six design, plus the poor film strengths inherent in 0W oils, and you get excessive piston and cylinder wear (scuffing), which becomes even worse on DFI versions.
Coolant heaters, which are often used on race engines, greatly reduce the wear caused by dimensional stress induced wear that cold starts result in. Heated storage is always a plus for any vehicle, even for components outside the engines or drivelines, but normal storage temps (55-60F in our storage facility) is not warm enough to dramatically alter the engine warm up wear patterns. The coolant needs to be 150-170F to make a real difference.
Because of the differences in wear patterns we have seen, if a customer asks our recommendation, I would tell them to let the car sit and warm up at least until the heater starts to blow warm before moving the car, and then take it easy until the car is up to temp.
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Last edited by JFP in PA; 12-21-2014 at 07:55 AM.
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12-21-2014, 08:50 AM
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#2
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Registered User
Join Date: Sep 2013
Location: Montreal, QC. (currently expat to Shanghai)
Posts: 3,249
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Quote:
Originally Posted by JFP in PA
Mike, the entire point is about component wear due to dimensional shifts as the engine heats up. All alloy engines move around quite a bit as they warm up....
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As always, you are terrifying me, and my Boxster lol
I'd like think that the design team in that Stuttgart's studio have gauged the correct low & high expansion characteristics when it came to selecting the flat6's materials. Wear is beautiful, shinny and even, when engineered correctly.
As long as you don't quenched the hot engine in cold water, it should be designed to scuff to Porsche's tolerance/acceptance. Cold or hot - stop terrifying me, and others maybe lol
We get full AL/TI engines warmed up to 95degree (203F) before revving them (superbikes, manual thermostat!). What do you tell your customers is the acceptable go-temp range for the stock flat6, or your custom built?
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'97 Boxster base model 2.5L, Guards Red/Tan leather, with a new but old Alpine am/fm radio.
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12-21-2014, 09:01 AM
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#3
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Registered User
Join Date: Feb 2005
Location: It's a kind of magic.....
Posts: 6,614
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Quote:
Originally Posted by Nine8Six
As always, you are terrifying me, and my Boxster lol
I'd like think that the design team in that Stuttgart's studio have gauged the correct low & high expansion characteristics when it came to selecting the flat6's materials. Wear is beautiful, shinny and even, when engineered correctly.
As long as you don't quenched the hot engine in cold water, it should be designed to scuff to Porsche's tolerance/acceptance. Cold or hot - stop terrifying me, and others maybe lol
We get full AL/TI engines warmed up to 95degree (203F) before revving them (superbikes, manual thermostat!). What do you tell your customers is the acceptable go-temp range for the stock flat6, or your custom built?
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All predominantly alloy water cooled engines suffer from these dimensional shifting issues, so your Porsche is not alone in this area.
For a factory engine in a street car, minimum is to warm the engine until the heater starts throwing heat before driving. For a performance rebuilt engine, again on the street, warm it to at least 150F (assuming aftermarket gauges). Race engine should be 160-175F.
__________________
“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein
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12-21-2014, 09:24 AM
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#4
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Registered User
Join Date: Sep 2013
Location: Montreal, QC. (currently expat to Shanghai)
Posts: 3,249
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thanks
Dunno about you but seconds feels like minutes when warming up my little Porsche car here lol
Won't lie I've often turned the key, put on the seatbelt and GO. Just can't wait.....
kids huh
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'97 Boxster base model 2.5L, Guards Red/Tan leather, with a new but old Alpine am/fm radio.
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