Quote:
Originally Posted by Cloud9blue
1. You wanna point out the specifics of what makes N55 cooling system so different from N54/52, which is what you and feuer are arguing about the whole time? oh, nvm, I know the answer to that already: NOTHING. That's why you cite the whole article instead, no? There is nothing in any of the N5x series engine that defies the simply laws of heat transfer.
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OK, don't read and interpret things for yourself. Believe that engine design hasn't changed in decades and you're still driving grandmas cast iron Cadillac that required several gallons of water to be pored into the cooling system to make it to the grocery store and back.
Overview (page6):
Cylinderhead: •Speciallydesignedwaterpassagesintergradedintothec ylinderheadenhance injectorcooling.
VANOS: •TheN55VANOSoilpassagesaresimplifiedcomparedtotheN 54engine. (read further to see how the oil flowing to lubricate VANOS does not transfer as much heat to coolant in its new path. This is the only oil really flowing through the head.)
Oilsupply: •Anenhancedandsimplifiedoilcircuitdesignisused.
Page 27:OilSupply Thefollowinggraphicsshowanoverviewoftheoilcircuito ftheN55.Comparedtothe N54engine,thereareconsiderablyfeweroilductsinthecy linderhead.Thisismainlydue totheuseofthenewVANOSsolenoidvalves.
Page 31: TheN55engineisequippedwithoilspraynozzlesforthepur poseofcoolingthepiston crown.Aspecialtoolisrequiredforpositioningtheoilsp raynozzles. (I quote this one because AUDI and VW tuning almost always increases the flow of these oil sprayers as they also increase power levels. I've never heard a BMW tuner ever mention increasing the pressure of these sprayers on an N55 when tuning...)
Page 32:CylinderHead: TherearenownoconnectionsfortheVANOSnon-returnvalvesastheyhavebeen integratedinthesolenoidvalves.Thecylinderheadalsof eaturescoolingpassages nearthefuelinjectors;providingindirectcooling.
Page 44: oilpassagesarerequiredandthatthenon-returnvalvesarenolongeronthe cylinderheadbutratherincorporatedintothesolenoidva lvesonN55.
Page 75: CoolingSystem ThecoolingsystemoftheN55isenhancedwithadditionaloi lcooling. Twodifferenttypesofoilcoolingsystemsareuseddependi ngonthemodelandapplication.Inthe“hotclimate”versio n,heattransferfromtheengineoiltotheenginecoolantis avoidedbyseparatingtheoilcoolerfromtheenginecoolan tcircuit.Theotherversion usesanauxiliaryradiatorincombinationwithanoiltocoo lantheatexchangerboltedto theoilfilterhousing.Theauxiliaryradiatorenhancesco olingefficiencybyaddingsurface areatothecoolingsystem. (review the picture carefully and realize how taking the "oil to coolant" heat exchanger out of the equation, coupled with the aforementioned changes to oil flow, places more burden on the oil cooler to cool oil rather than shed heat via the cooling system.)
Page 78: Note: Ifaseparateoiltoaircoolerisnotinstalled,anauxiliar yradiatorin conjuctionwithanoiltocoolantheatexchangerisusedtoc oolthe engineoil.
Page 79: Note: MostcurrentUSvehiclesuseaseparateengineoiltoairhea texchanger tocooltheengineoil(hotclimateversion).
Page 80: CoolantPassages Thecoolantpassagesinthecylinderheadarealsousedfori ndirectcoolingofthefuel injectors.Thefollowinggraphicclearlyshowsthattheco olantflowsoverthevalvesand thefuelinjectors,thusreducingtheheattransfertothec omponentstoaminimum. (This infers the coolant passages are being more used as a buffer to protect vital components like injectors from rising heat due to increased engine oil temperatures. The hot climate system is depending on the external oil to air cooler to reduce that heat.)
Quote:
Originally Posted by Cloud9blue
2. Define what you mean by "hard driving" and please also the power output of your N55. A stockish N55/54 just fooling around on winding back roads with traffic lights and stop signs are
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By hard driving I mean I was driving 60-90 MPH (3.5-6k rpms in 3rd to 4th). I was driving as if I was on track. I had the roads to myself. Over 4 hours I did every variation of driving I could to come to my conclusions. 10 minutes straight of driving at 4-6k rpms up a hill and engine oil increased rapidly while engine coolant temps stayed steady...
Quote:
Originally Posted by Cloud9blue
a lot different from a FBO car hauling ass at triple digit speed on a road course for 20-30 mins straight. Think heat soak, air flow, etc.
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Funny you say that too because I found that at WOT at 90+ mph coolant temps actually dropped/stayed the same throughout a straight away while oil temps rose rapidly as rpms climbed. This demonstrates that on the N55 thermal transfer within the block, or "heatsoak," doesn't happen fast enough for the cooling system to remove excess heat. Heat continues to build in the bottom end relying on the oil cooler to shed it.
I am FBO pushing 22psi peak with a custom tune from COBB. No oil cooler on this car yet.
Quote:
Originally Posted by Cloud9blue
In any case, I don't think you are interested in an intelligent discussion and I don't really have any interests in getting into a piss match with someone like you. So feel free to believe in whatever you want to believe in and answer the above questions with whatever BS you can think of.
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Feel free to continue to makes claims without any basis when I am doing my best to present FACTS that say otherwise. Keep citing nonexistent threads of people coolant overheating.