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Joined: Sun May 12, 2013 5:21 am
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Location: Michigan
cat herder wrote:
BOOT wrote:
Your opinion has been noted and unless you have any new info thx for your opinion.


I apologize for turning it into a personal attack on your worth as a human being, I forgot the discussion was supposed to be about the relative merits of some piece of metal. :\'(



:thumbr: Your argument has won me over and I have seen the light, thank you for your superior intellect! No need for any further discussion on the subject. :thumbl:

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Thu Jan 22, 2015 11:40 am
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Joined: Sun Jun 23, 2013 1:41 pm
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Location: Phila. Penn.
Although I threw that last bit in there in half jest, it was also half serious. I *think* that having the ambient air cooler is generally true, or more that we hope that is generally true. And yup, when its not, I agree it doesn't matter how good of an insulator is there. On a production based car with closed hood it can get pretty hot in there. I think inside the air tract is probably the coolest due to the vaporization of the fuel. Fuel bowl is possibly next coolest (hopefully). Intake manifold is hard to know. Some portion of the runners are subject to engine compartment air, the bottom may be getting with hot oil, and some have coolant, many use exhaust to warm the plenum, and all the other variables. If the air around the top of the intake is stagnant, it could be pretty darn hot. Anyway for all this I think the heat transfer of a carb is not straightforward.

As far as the new spacer you linked to, I seriously don't know if it is acting as a radiator or not. The fins are thick and the spacing is tight. Each of the spaces are tight enough for little convective currents to self actuate. That's not all bad. With a tight enough gap, air can be a good insulator. That's the theory behind double paned glass windows and works when done right.
Remember the scheme to use a stack of alternator metal and insulating material as a carb spacer? Some people said it worked good, and the principle behind it was sound.
BOOT wrote:
Mattax wrote:
I'm reminded of back in college heat trasfer class. It's not a given that fins will disapate heat. IIRC it depends on the spacing and the thickness of the fins and probably some other factors I don't remember off the top of my head. They can also conduct heat the wrong way. :O



Good point but I believe the ambient air should be below the metal temp and if not even a wood spacer won't help you.


Thu Jan 22, 2015 12:17 pm
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It will absorb heat as efficiently as radiate it. The rate of heat flow is the same in either direction.


Thu Jan 22, 2015 1:55 pm
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Location: Michigan
Yah some underhood temps can be pretty high, but lets say it's used on a well vented or even open air engine. I think the space between fins may be too small and maybe it would be more effective to have less fins and a wider gap, provided you had some air flow across. Even maybe a projected fin. Radiator as I stated in my 1st post isn't an ideal comparison because that has air drawn through, this is more of a heat sink.

edit: of course only the fin would be extended and still have the cut in for the reduced cross section of material for heat transfer.

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Thu Jan 22, 2015 3:28 pm
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Joined: Tue Jul 30, 2013 1:48 am
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You would have to ask yourself how many btus/kw of heat is being inputted to the material and where its coming from versus the ability of the pretty machined fins to dissipate it.

I think the removal of material makes the spacer quicker to heat but also quicker to cool and thats ok but why not machine the heck out of the sides and leave a bare minimum of wall thickness.

I would rather use a material of much lower thermal conductivity and avoid thinking too hard about the physics, me not so smart.


Fri Jan 23, 2015 6:07 am
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Location: Michigan
I think they may use a min wall thickness(or should) but if that thin wall has fins/heat sinks on it, then it should transfer even less than the thin wall alone. The path would be narrow either way just with fins the heat would have a fork(forks) in the road to the carb.

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Fri Jan 23, 2015 12:52 pm
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Joined: Sun Nov 02, 2014 2:32 pm
Posts: 24
tuner wrote:
It will absorb heat as efficiently as radiate it. The rate of heat flow is the same in either direction.

I agree, and "On a production based car with closed hood it can get pretty hot in there. I think inside the air tract is probably the coolest due to the vaporization of the fuel." But hey, it looks purdy. He needs to take an ad in Car Craft, then they will do a dyno "test" on it, and he will sell thousands... ;)


Sun Feb 08, 2015 1:30 am
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