Shiny or black carb for heat
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Re: Shiny or black carb for heat
Did the guys that started FST come from Quickfuel?
Yes same people. They had plans for a 800vs which I was waiting on for my 400 street engine but Covid slowed everyone down and they are quoting me 2 1/2 weeks for the 750 carb which I'm thinking will be fine
Yes same people. They had plans for a 800vs which I was waiting on for my 400 street engine but Covid slowed everyone down and they are quoting me 2 1/2 weeks for the 750 carb which I'm thinking will be fine
Re: Shiny or black carb for heat
JMHO - Black and never look back! Easier to clean, always looks good. Heat does not seem to be an issue. We have two sets of QF black and two sets FST black.
For info... Phil @ FST is from QF, he does the design work for FST.
For info... Phil @ FST is from QF, he does the design work for FST.
Re: Shiny or black carb for heat
Good question that most people don't talk about. In my race applications, I use 1:1 linkage since I want the carb to work correctly and not have to switch calibrations between primary/secondary. I also don't think there is too much carb or TB except when dealing with electronic trans that use TPS for control. The engine takes what it wants, it's up to you to control the fuel curve, EFI or Carb.HQM383 wrote: ↑Fri Oct 15, 2021 10:25 pmApologies for jumping in on this question but what is the intended use of the 550hp 383?steve cowan wrote: ↑Fri Oct 15, 2021 1:58 amsince you have bought several this year i suspect you like them ,what do you recommend for a SBC 383 that makes 550 ish
I ask because I have tested on my 383 a 650, 750, 825, 850, 850AN, and 975 (that I would actually put inbetween 825 and 850 due to venturi/throttle sizes) cfm carbs. All mechanical secondaries. Every one of them worked great when tuned but the way they drove was different and it was in a way most people don’t contemplate when choosing cfm size. All would break traction @ 100kp/h when foot mashed to the floor, as one method of comparison but when driving was primaries only as 95% of cruising the streets would be that’s where the biggest difference was. And it’s backwards to widely accepted theory.
Heat is energy, energy is horsepower...but you gotta control the heat.
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Re: Shiny or black carb for heat
I think a small fuel return line can work wonders compared to a dead-headed system. It can keep the fuel going into the carb quite a bit cooler than letting things percolate under the hood. Maybe not so effective if the fuel tank is being heated up by the track surface radiation.
Another case where a few measurement experiments some times make my best theories go down in flames.
The thermal emissivity of paint etc of different colors does not always behave as expected.
https://www.thermoworks.com/emissivity-table
https://www.europhysicsnews.org/article ... n07102.pdf
https://www.transmetra.ch/component/jif ... -table-pdf\
Differences in emissivity is Something to consider when using an infrared thermometer to compare a painted engine block to an aluminum radiator or header tube or rusty iron manifold etc, and etc.
Another case where a few measurement experiments some times make my best theories go down in flames.
The thermal emissivity of paint etc of different colors does not always behave as expected.
https://www.thermoworks.com/emissivity-table
https://www.europhysicsnews.org/article ... n07102.pdf
https://www.transmetra.ch/component/jif ... -table-pdf\
Differences in emissivity is Something to consider when using an infrared thermometer to compare a painted engine block to an aluminum radiator or header tube or rusty iron manifold etc, and etc.
Re: Shiny or black carb for heat
That depends on how hot the air around it is or the fuel running thru it.
Channel About My diy Projects & Reviews https://www.youtube.com/c/BOOTdiy
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If I didn't overthink stuff I wouldn't be on speedtalk!
Re: Shiny or black carb for heat
Nothing to do with the air temp or fuel in the carb. The substance just sees it as a temperature difference, whether it be a liquid or a gas coming in contact with the substance. Every substance has a thermal conductivity quotient. Alum is about twice that of Zinc.
Re: Shiny or black carb for heat
So if the air or fuel is hotter than the carb, alum will absorb heat faster than zinc
Channel About My diy Projects & Reviews https://www.youtube.com/c/BOOTdiy
I know as much as I can learn and try to keep an open mind to anything!
If I didn't overthink stuff I wouldn't be on speedtalk!
I know as much as I can learn and try to keep an open mind to anything!
If I didn't overthink stuff I wouldn't be on speedtalk!
Re: Shiny or black carb for heat
Agree lefty o. Simply, it’s harder to get heat into aluminum because it loses it so easy. Very apparent when welding stainless and carbon steels v aluminum.
I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
Re: Shiny or black carb for heat
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!
But if it's hotter around the carb, then it absorbs heat soooo that means it's not dissipating!
Channel About My diy Projects & Reviews https://www.youtube.com/c/BOOTdiy
I know as much as I can learn and try to keep an open mind to anything!
If I didn't overthink stuff I wouldn't be on speedtalk!
I know as much as I can learn and try to keep an open mind to anything!
If I didn't overthink stuff I wouldn't be on speedtalk!
Re: Shiny or black carb for heat
Let’s look at another part of an engine with constant heat input.
Why does an aluminum cylinder head allow for higher compression ratios than iron?
The head is always being given heat by combustion but the aluminum takes on and loses that heat better than iron heads. Same with alum v zinc carb. Same reason heat sinks are made from aluminum. Heat passes through easier.
By your logic an aluminum head, and throw manifolds in too, should run hotter because it absorbs heat easier.
I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
Re: Shiny or black carb for heat
At first I was like Humm, can this be right but the more I looked at the carb the more I figured that their idea must have been to get a better booster signal from this animal. Must have worked, my little 358 ran pretty sweet with it out of the box , no changes other than tightening up the sec vacuum pod a bit.
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Re: Shiny or black carb for heat
PM sentHQM383 wrote: ↑Fri Oct 15, 2021 10:25 pmApologies for jumping in on this question but what is the intended use of the 550hp 383?steve cowan wrote: ↑Fri Oct 15, 2021 1:58 amsince you have bought several this year i suspect you like them ,what do you recommend for a SBC 383 that makes 550 ish
I ask because I have tested on my 383 a 650, 750, 825, 850, 850AN, and 975 (that I would actually put inbetween 825 and 850 due to venturi/throttle sizes) cfm carbs. All mechanical secondaries. Every one of them worked great when tuned but the way they drove was different and it was in a way most people don’t contemplate when choosing cfm size. All would break traction @ 100kp/h when foot mashed to the floor, as one method of comparison but when driving was primaries only as 95% of cruising the streets would be that’s where the biggest difference was. And it’s backwards to widely accepted theory.
steve c
"Pretty don't make power"
"Pretty don't make power"
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Re: Shiny or black carb for heat
the 950HP carb is the same -750 main 850 base1980RS wrote: ↑Sun Oct 17, 2021 12:14 amAt first I was like Humm, can this be right but the more I looked at the carb the more I figured that their idea must have been to get a better booster signal from this animal. Must have worked, my little 358 ran pretty sweet with it out of the box , no changes other than tightening up the sec vacuum pod a bit.
i just purchased a new 850hp main body i am going to swap out the 750 main body and test.
steve c
"Pretty don't make power"
"Pretty don't make power"
Re: Shiny or black carb for heat
This is a very poor comparison for several reasons, the Total Surface Area exposed to a much higher temp is very small, that's like if only the fuel bowl bolt heads were exposed to a higher temp of course the rest of the carb would disperse the heat. The pathway is small! Not to mention the engine coolant system dedicated to disperse the combustion heat!HQM383 wrote: ↑Sat Oct 16, 2021 11:56 pm Let’s look at another part of an engine with constant heat input.
Why does an aluminum cylinder head allow for higher compression ratios than iron?
The head is always being given heat by combustion but the aluminum takes on and loses that heat better than iron heads. Same with alum v zinc carb. Same reason heat sinks are made from aluminum. Heat passes through easier.
By your logic an aluminum head, and throw manifolds in too, should run hotter because it absorbs heat easier.
If you check the temp like I have(open hood venting HOT AIR) most likely your intake is cooler than the heads/block and the carb cooler yet, heck my front fuel bowl is hotter than the rear, wanna guess why? And I've taken several measures to reduce carb temp. Do a search people have recorded pretty HIGH underhood temps in some vehicles.
I'm gonna assume you mean hotter than iron because LOLBy your logic an aluminum head, and throw manifolds in too, should run hotter because it absorbs heat easier.
Have you ever considered header wrap or ceramic coating to reduce underhood temps? Turbo wraps/blankets? This has been discussed over n over in those type threads.
There are also discussions on why iron may be better than alum, heat = power. In control obviously.
I don't even want to get into a compression discussion because it would have noting to do with this thread.
Channel About My diy Projects & Reviews https://www.youtube.com/c/BOOTdiy
I know as much as I can learn and try to keep an open mind to anything!
If I didn't overthink stuff I wouldn't be on speedtalk!
I know as much as I can learn and try to keep an open mind to anything!
If I didn't overthink stuff I wouldn't be on speedtalk!