godlameroso wrote:Finally there's this:
5.16.3 The restrictions in Article 5.16.1(h) do not apply to the following applications :
a) Any component whose primary purpose is for electrical or thermal insulation.
It could be argued that a specific coating on the head is actually for the purpose of thermal insulation.
. . . and 5.16.2 seems to exempt thin coatings anyway.
5.16.2
The restrictions in Article 5.16.1 do not apply to coatings provided the total coating thickness does not exceed 25% of the section thickness of the underlying base material in all axes. In all cases, other than under Article 5.16.3(b), the relevant coating must not exceed 0.8mm.
Ultimately I think the cooler you can operate an engine the better
Hmmmmmmmmm I think that is wrong.
Certainly not regarding the exemplary posted tq/hp values of N/A 2T G.P. bikes, strad..
The ( ok, 'inefficient' fuel-wise) usage of fuel-based latent heat of evaporation for crankcase cooling..
..along with 'reverse' cooling loops - cool liquid from radiator exit - went to cooler components 1st, & then to hotter spots..
(conceptually a bit like the cool-cycle for sea-food, if you are familiar with that)..
The loss of this inherently advantageous characteristic was a factor that had to be addressed with ambient air temp DI 2T's..
.. which had to substitute that 'free' internal coolant system..
..with extra external liquid coolant - circulating in dedicated crankcase galleries..
.. & this is needful, to keep the fuel-air charge as cool as.. yeah.. for best/most - power output..
Engine cooling is only to stop things from getting destroyed and to reduce compression work but In theory if you can operate an engine hotter ie hotter combustion (they are heat engines after all) you get more power and more efficiency. Just real world deffiencies are the problem... materials expanding, melting, jamming, liquids getting thin, boiling, detonation, non-ideal compression..basically heat is the enemy of materials but not the enemy of power.
that's what I thought but wasn't going to argue about it.
It's why a drag racer waits to pull up to the line as long as he can.
I believe that sometimes when a guy "melts" an opponent down it's not really to melt him down so much as to cause him make enough power to throw off his tune up.
To achieve anything, you must be prepared to dabble on the boundary of disaster.”
Sir Stirling Moss
PlatinumZealot wrote:
Engine cooling is only to stop things from getting destroyed and to reduce compression work but In theory if you can operate an engine hotter ie hotter combustion (they are heat engines after all) you get more power and more efficiency. Just real world deffiencies are the problem... materials expanding, melting, jamming, liquids getting thin, boiling, detonation, non-ideal compression..basically heat is the enemy of materials but not the enemy of power.
Definitely unintuitive at first to distinguish between what's good for materials vs. good for power.
Here's another example of hotter engine parts making more power (and quicker response in this case). Turbo blankets on the exhaust turbine make the turbine run hotter-- seems crazy to do this intentionally, yes? But when the turbine is hotter it pulls less heat energy out of the exhaust thru heat transfer, and therefore more energy is left to power the turbine.
I used to drive a turbo race car with heavy-wall exhaust headers. You could see the manifold and turbine from the driver's seat. The improvement in performance and turbo response once those exhaust components are glowing is unbelievable.
When not glowing, the metal is drawing a lot of heat (energy) from the exhaust gas. Think about how much heat you need to add to a few kilograms of iron (eg using an oxy torch) to get it red hot.
Certainly not regarding the exemplary posted tq/hp values of N/A 2T G.P. bikes, strad..
The ( ok, 'inefficient' fuel-wise) usage of fuel-based latent heat of evaporation for crankcase cooling..
..along with 'reverse' cooling loops - cool liquid from radiator exit - went to cooler components 1st, & then to hotter spots..
(conceptually a bit like the cool-cycle for sea-food, if you are familiar with that)..
The loss of this inherently advantageous characteristic was a factor that had to be addressed with ambient air temp DI 2T's..
.. which had to substitute that 'free' internal coolant system..
..with extra external liquid coolant - circulating in dedicated crankcase galleries..
.. & this is needful, to keep the fuel-air charge as cool as.. yeah.. for best/most - power output..
Engine cooling is only to stop things from getting destroyed and to reduce compression work but In theory if you can operate an engine hotter ie hotter combustion (they are heat engines after all) you get more power and more efficiency. Just real world deffiencies are the problem... materials expanding, melting, jamming, liquids getting thin, boiling, detonation, non-ideal compression..basically heat is the enemy of materials but not the enemy of power.
There is at least one other benefit of cooling - charge cooling. A hot engine heats and expands the charge reducing VE. Not a problem for the current formula but very power-robbing for any airflow-limited engine.
& materials such as Fe with serious heat-soak characteristics - exemplify those conflicting issues..
Honda even experimented with water injection - straight into the exhaust pipe - of its 2T G.P. mills as a variable heat soak method..
..to provide a like-wise variable sonic response from the expansion chamber..
"Well, we knocked the bastard off!"
Ed Hilary on being 1st to top Mt Everest,
(& 1st to do a surface traverse across Antarctica,
in good Kiwi style - riding a Massey Ferguson farm
tractor - with a few extemporised mod's to hack the task).
"Heat soak" is a funny term. It is an American term. I think.
Americans like to use this word but a lot of the people who do, have difficulty describing what it is from a scientific or engineering stand point. When I just got into cars and reading car magazines in the 90's, for the life of me I could not tell what they were talking about with this "heat soak". Even up to this day it is word people are not sure about. Is it good? is it bad? Is it about a hot object taking a long time to cool down? Or a cool object quickly heating up? Is it having to do with a very conductive object? Or one of poor conductivity? The magazines never described what it was. But they sure used the term a lot.
Over the years, what I gather, is that heat soak describes when an object normally subjected to hot conditions is not cooled down in a desired time or manner? Am I close?
I've always taken it to be synonymous with heat transfer.
Especially the heat transfer that occurs when the heat source is switched off but through conduction parts continue to increase in temperature due to convection from adjacent parts.
In terms of intercoolers, as the compressed air is compressed, it gets warmer. As it passes through the intercooler, the air gives off heat to the intercooler. And the intercooler gives off that air to the outside air that passes over the intercooler. After a while, the intercooler "heat soaks" and can't absorb as much heat from the compressed air to cool it
Simply put, it's the build up of heat often in terms of exchangers or heat sinks..as the object becomes "heat soaked" it cannot absorb more, at least in terms of functionality.
I think the heat sink is a better example than the intercooler myself.
To achieve anything, you must be prepared to dabble on the boundary of disaster.”
Sir Stirling Moss
Heat soak is heat transfer that occurs when a machine is shut down. Machines like car engines have compression and combustion adding heat to some areas and cooling and exhaust systems removing heat from others. When all this gets switched off the hot regions get cooler and the cool regions get hotter.
...and to confuse the issue, when the U.S. EPA does an emissions test they "heat-soak" the vehicle in an environmental chamber for 24 hours at something like 70F. This is to ensure the entire car is at a fixed, known temp. So heat soak in that case means putting something in a larger environment to bring it to the environment's temperature.
I suppose the "soaker" and "soakee" depend on whether the car started out above or below 70F.
Another example of "heat soak" is when the engine power fades..
.. due to the inability of its cooling system to cope with the power levels, & waste-heat rejection..
This was a notable issue with air-cooled radial aero-engines - which when run hard - as fighter mills.. yeah, suffered "heat soak"..
The P&W R-2800 , as used in the P-47 Thunderbolt - underwent two major re-designs to increase cooling fin area..
..plus large oil-coolers, & additional internal liquid coolant with the fuel.. via water/alcohol metered - as ADI,..
The Germans like-wise found it needful to reserve their hi-test fuel for the BMW 801 radial used by their FW 190 fighter,
& even though they had a DFI system , found it necessary to pump extra C3 gasoline into the supercharger eye for cooling..
..when running hard out/WFO.
Later, in the `70s when G.P. bikes were exceeding 100hp, Kawasaki found their 750 2T triple would "heat soak" too,
& show power-fade, compared to the liquid -cooled Suzuki 750/3 & so had to introduce it on their own later KR 750 racer.
Oddly enough Suzuki later introduced their GSXR-750 4T Superbike, which featured a similar air/oil-cooled arrangement
to the WW2 radial aero-mills, but again - as power went up, were forced to accept direct liquid-cooling, due to "heat soak"..
"Well, we knocked the bastard off!"
Ed Hilary on being 1st to top Mt Everest,
(& 1st to do a surface traverse across Antarctica,
in good Kiwi style - riding a Massey Ferguson farm
tractor - with a few extemporised mod's to hack the task).
I understand heat soak (or cold soak) to be a condition where the system components have been heated/cooled to a particular uniform temperature. For example, if you were performing a cold start test procedure on a vehicle, you would cold soak the vehicle in an environmental test chamber for a period of time sufficient to ensure every component in the system being tested was stabilized at the test temperature. It can take a fair amount of cold soak time to bring an entire car or truck down to -20degF for testing.
"Q: How do you make a small fortune in racing?
A: Start with a large one!"
