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Plenum finish


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On 5/4/2020 at 9:20 PM, zedhead said:

So, wide awake at 2am and I get to thinking...

We know that forced induction increases the temperature of the inlet charge, which is why people fit intercoolers, charge coolers and water injection. So, with that in mind, what is the best finish for the plenum chamber?

A polished plenum will reflect heat from the engine, but will also retain any heat built up in the plenum material.

A satin finish will soak up radiated heat but will also radiate eat from itself better than the polished one.

Powdercoating the plenum will be like covering it in a blanket and keep it hot.

I've yet to see a forced induction bike fitted with the 'carb shields' that keep heat away from the carbs, would they be of equal or better efficiency that with a normally aspirated bike?

Given that most of our bikes are cooled by air (yes, even oi boilers) why don't any plenums have finning?

And the final question should i be taking sleeping tablets instead?...

 

My up pipe is made of stainless steel, yesterday after a 50km trip I took my temp gun, my up pipe was just 22 degrees, the up pipe nearest to the exhaust headers the pipe was just over 30 degrees.

It was a lot cooler as what I expected..

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6 hours ago, Reinhoud said:

 

My up pipe is made of stainless steel, yesterday after a 50km trip I took my temp gun, my up pipe was just 22 degrees, the up pipe nearest to the exhaust headers the pipe was just over 30 degrees.

It was a lot cooler as what I expected..

I hope you did not use a infra red thermometer on a very shiny stainless steel pipe because of this:

"EMISSIVITY AFFECTS INFRARED READINGS
Think of a mirror, it reflects nearly all of the energy directed toward it. It will emit the infrared energy from the thermometer as well as its own radiated energy. Because of this, infrared temperature readings from low emissivity materials such as aluminum and stainless steel are not accurate. However, if an aluminum or stainless steel pan is coated in oil (organic material), the pan’s emissivity increases because of the thin film of oil on its surface"

I have the burn marks to prove it ;)

Lessons learned.

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On 5/7/2020 at 3:24 PM, Gixer1460 said:

Interesting! SS is a poor transmitter of heat but would have also expected higher than that . . . . . . . obs. not making enough boost! 

I know.. Hehe, you're right, only 7 psi, but it goes better as with 17psi in the past, what a different adjustment of ignition and carburetors can do..

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22 hours ago, Blubber said:

I hope you did not use a infra red thermometer on a very shiny stainless steel pipe because of this:

"EMISSIVITY AFFECTS INFRARED READINGS
Think of a mirror, it reflects nearly all of the energy directed toward it. It will emit the infrared energy from the thermometer as well as its own radiated energy. Because of this, infrared temperature readings from low emissivity materials such as aluminum and stainless steel are not accurate. However, if an aluminum or stainless steel pan is coated in oil (organic material), the pan’s emissivity increases because of the thin film of oil on its surface"

I have the burn marks to prove it ;)

Lessons learned.

I know, temp guns don't work very well on shiny materials... We use it at work quite a bit.

It was ss, but brushed, not shiny. It's not exact science, but it gives a bit of an indication..

 

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