BOOT wrote: ↑Sat Oct 16, 2021 8:54 pm
So if the air or fuel is hotter than the carb, alum will absorb heat faster than zinc
Agree. Faster than zinc.
BOOT wrote: ↑Sat Oct 16, 2021 10:00 pm
I think it's been covered earlier that alum dissipates heat better already
But if it's hotter around the carb, then it absorbs heat soooo that means it's not dissipating!
Because I have given you such a poor example of why I think the aluminum carb is dissipating heat as well as absorbing it your going to have to explain the last sentence above in more detail. I read it that an aluminum carb will readily absorb ambient heat around it and because it does so will not lose that heat?
Do you think in the same ambient temperature an aluminum carb will run hotter than a zinc carb?
I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
Black is the best at absorbing heat. Black is also the best at radiating it. (Look up blackbody radiator)
That being said, it's not that simple. Will a layer of black paint insulate the object better than the black color radiates? lol
Plus, there are a LOT of heat sources under the hood of a car. Heat travels from the object with the higher temp to the object of lower temp. If the carb is the coolest object in the engine bay, it is going to be gaining heat. Therefore, black may not be the best color. This is likely the case, as it will have a constant flow of relatively cool fuel through it.
This being said, just how big of a difference will the color make? Will it be significant? In 99.9% of the cases... NO. It won't make one bit of difference. If you think it looks good and is worth the price difference... go for it. In the real world, you won't be losing anything.
HQM383 wrote: ↑Mon Oct 18, 2021 2:04 am
Because I have given you such a poor example of why I think the aluminum carb is dissipating heat as well as absorbing it your going to have to explain the last sentence above in more detail. I read it that an aluminum carb will readily absorb ambient heat around it and because it does so will not lose that heat?
Do you think in the same ambient temperature an aluminum carb will run hotter than a zinc carb?
Poor Comparison is what I said.
Where can the carb disperse the heat to, if the air around it is hotter?
BOOT wrote: ↑Sat Oct 16, 2021 12:22 pm
That depends on how hot the air around it is or the fuel running thru it.
HQM383 wrote: ↑Mon Oct 18, 2021 2:04 am
Because I have given you such a poor example of why I think the aluminum carb is dissipating heat as well as absorbing it your going to have to explain the last sentence above in more detail. I read it that an aluminum carb will readily absorb ambient heat around it and because it does so will not lose that heat?
Do you think in the same ambient temperature an aluminum carb will run hotter than a zinc carb?
Poor Comparison is what I said.
Where can the carb disperse the heat to, if the air around it is hotter?
BOOT wrote: ↑Sat Oct 16, 2021 12:22 pm
That depends on how hot the air around it is or the fuel running thru it.
I’m not saying the aluminum carb will be cooler than the air around it. My apologies if I gave that impression.
Everything that gains heat will also dissipate some of that heat unless in a controlled environment like an oven. Under the hood isn’t thermostatically controlled like an oven and temps will fluctuate with airflow through the engine bay. An aluminum carb will respond to these fluctuations better than the zinc carb that cannot lose its acquired heat so efficiently. Overall average temps of an aluminum carb will be lower than zinc. Fuel flowing through will have less an effect on regulating the temp of zinc too.
I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
HQM383 wrote: ↑Mon Oct 18, 2021 6:09 pm
I’m not saying the aluminum carb will be cooler than the air around it. My apologies if I gave that impression.
Everything that gains heat will also dissipate some of that heat unless in a controlled environment like an oven. Under the hood isn’t thermostatically controlled like an oven and temps will fluctuate with airflow through the engine bay. An aluminum carb will respond to these fluctuations better than the zinc carb that cannot lose its acquired heat so efficiently. Overall average temps of an aluminum carb will be lower than zinc. Fuel flowing through will have less an effect on regulating the temp of zinc too.
Again it Depends, some vehicles are hotter than others underhood. Some tuners also say having a hood is a more controlled(less fluctuation) environment than no hood.
You can debate that the alum carb temp will fluctuate more than zinc, depending on airflow. Or if the air is ducted(cooler) that an alum carb will transfer more heat into the air/fuel than zinc But in the end there are other ways to manage underhood heat that I myself don't worry about the carb metal type.
A wood carb spacer will make much more real difference on controlling carb body temps under hood, than any colour difference. Aluminum BOTH absorbs surrounding heat AND gives up heat (cools off) faster than most other metals.
It is subject to "hotsoak" + temp spikes but also cools off quicker -temp once the heat source is relieved.
On holley carbs that under carb heat shield that shields the fuel bowls from radiated intake manifold runner heat really works.. White is best on these.
Even better when combined with a (wood) carb spacer.
F-BIRD'88 wrote: ↑Thu Oct 21, 2021 2:31 am
A wood carb spacer will make much more real difference on controlling carb body temps under hood, than any colour difference. Aluminum BOTH absorbs surrounding heat AND gives up heat (cools off) faster than most other metals.
It is subject to "hotsoak" + temp spikes but also cools off quicker -temp once the heat source is relieved.
On holley carbs that under carb heat shield that shields the fuel bowls from radiated intake manifold runner heat really works.. White is best on these.
Even better when combined with a (wood) carb spacer.
Going to try the wood spacer but I'll wait until after the dyno session when I know which style the engine wants , if any. Meaning I'm no carpenter. The way I handle heat soak is I run the secondary float a little lower and when I'm around 1/8 mile from my house I shut the electric fuel pump off, this way there isn't much fuel to percolate when its shut down. I do this in the hot months and put the secondary back to its normal setting during the cooler season.
