heat shielding the intake system

[Calum]

Originally Posted by notout86

Sorry. I still do not understand and neither does my wife. Please spell it out as if to a 7-year-old.

Some people will put "/s" at the end of a statement to indicate they are turning off their sarcasm. It comes from HTML tags, where you write [B]blah blah blah[/ B] (without the space) and you get blah blah blah.

Basically I'm saying he was being sarcastic but forgot to indicate it.

[steve99]

You probably better ceramic coating header
as @Kodename47 said little to be gained except in traffic.

its probably easier to adjust the fan temps so fans run when your in traffic see @Wayno s tune thread.

[sw20kosh]

No

[Ultramaroon]

Originally Posted by notout86

Sorry. I still do not understand and neither does my wife. Please spell it out as if to a 7-year-old.

Ok, now I'm officially backing down. I appreciate a good joke but not if it goes too far.
@Captain Snooze said it in his reply to you. To add to his argument, the plastic intake components are already pretty good thermal insulators so, especially above idle, the IAT reduces to ambient pretty quickly.

BTW, your observation regarding the aluminum foil on your wood stove has merit. Aluminum is highly reflective and therefore makes for a pretty good shield for radiant energy, which is partly what makes it so difficult to weld. It is, however, highly thermally conductive, which is what makes is such a good material for convective heat transfer ...and is also what makes it difficult to weld.

[notout86]

OK. Thanks for the input and oxen sling everyone. I think we can summarise now.
BTW = by the way, IAT = intake air temperature. WOT = wide open throttle

Since an example of actual measurement shows IAT exceeds ambient for 10 minutes following idle/standstill until normal road speed has resumed, any measure to reduce IAT WILL help. Depending on driving following that heat soak period, a power increase will be useless while idling but have benefit as you drive off (but could help you hit the front at the start of a race).
In our example, fuel usage at idle and for 10 minutes will be reduced as the ecu adjusts the air:fuel ratio for cooler/denser air. If you spend time in bumper to bumper traffic this could be quite significant.

These benefits will be low but cumulative and become significant over time.

Two measures have been suggested i.e. adjust fan speed and/or intake heat shielding. The latter has no downside other than a slight weight penalty and rise of the COG = centre of gravity.

[Wayno]

Originally Posted by steve99

You probably better ceramic coating header
as @Kodename47 said little to be gained except in traffic.

its probably easier to adjust the fan temps so fans run when your in traffic see @Wayno s tune thread.

THIS. The many benefits of lowering the temp of the entire engine bay and keeping it vented far outweigh the ridiculously poor value of trying to change materials or insulate the intake.

[Ultramaroon]

Originally Posted by notout86

Since an example of actual measurement shows IAT exceeds ambient for 10 minutes following idle/standstill until normal road speed has resumed, any measure to reduce IAT WILL help. Depending on driving following that heat soak period, a power increase will be useless while idling but have benefit as you drive off (but could help you hit the front at the start of a race).
In our example, fuel usage at idle and for 10 minutes will be reduced as the ecu adjusts the air:fuel ratio for cooler/denser air. If you spend time in bumper to bumper traffic this could be quite significant.

These benefits will be low but cumulative and become significant over time.

Two measures have been suggested i.e. adjust fan speed and/or intake heat shielding. The latter has no downside other than a slight weight penalty and rise of the COG = centre of gravity.

If you're going to go for it, I suggest cutting up a mylar survival blanket. Don't forget the intake manifold and plenum.

[Captain Snooze]

Originally Posted by notout86

any measure to reduce IAT WILL help.

How would you prove that? Say you reduce the intake temperature by 3 degrees Celsius. Any variation on a dyno would fall within experimental error.

Originally Posted by notout86

(but could help you hit the front at the start of a race).

If you are racing then you should consider doing more significant things.

Originally Posted by notout86

These benefits will be low but cumulative and become significant over time.

I look forward to seeing the documented results.

Originally Posted by notout86

The latter has no downside other than a slight weight penalty and rise of the COG = centre of gravity.

This is like my sig.
A BRZ with a LSx swap is completely stock except for the engine, gearbox, electricals.....
Whilst grammatically correct I can't but help think there is a logic failure somewhere in there.

[notout86]

I have no way to measure the effectiveness of the fan speed method versus the shielding so I don't know how ridiculous my thinking is. I would like to see readings. Meanwhile, surely, every little bit helps.

[Sleepless]

Originally Posted by notout86

The air filter box and the air tube from it are black and I think they must absorb radiant heat from the engine, thus raising the temp of the air within and reducing its density.

Is it worth shielding with thick shiny Al foil on the engine side?

Has anyone a way to check the temp. before and after shielding, or better still has anyone with a dyno to test the theory / measure the power increase?

Engine bay radiant heat transfer is a function of the material's composition, not its color. So any color plastic is perfectly fine for the intake.

radiation from the sun on the other hand is indeed absorbed by darker colors and converted to heat.

[Ultramaroon]

[notout86]

Originally Posted by Sleepless

Engine bay radiant heat transfer is a function of the material's composition, not its color. So any color plastic is perfectly fine for the intake.

radiation from the sun on the other hand is indeed absorbed by darker colors and converted to heat.

Thanks Sleepless. So engine radiant heat is IR = infra red and absorption by the intake tube and filter box depends on their nature other than color.
You have taught me something. Others have alluded to it too but did not explain.

Hopefully then the makers have chosen materials that absorb low amounts.

I read that shiny Al is a great reflector of IR, so its addition will help regardless.

p.s.Probably kidding myself ... I was surprised that I thought I could FEEL a bit of pep after shielding just the tube, but I am far from sure as I had filled an empty tank 100Km prior with a different fuel said to clean the system and maybe it had taken effect. Too many variables to know.

[avishenoy1]

There's really no need to heat shield the stock intake system or any other silicone inlet tube. Silicone has a very low thermal conductivity coefficient, meaning, even if the outside of the tube gets hot, there will be very little heat transferred to the intake air on the inside. Therefore, wrapping a silicone tube will make a marginal difference on intake temps, if any at all.

However, If you have an aftermarket intake with an aluminum pipe, that thing will get hot quickly. Since aluminum has a thermal conductivity coefficient 3 orders of magnitude greater than silicone, once that pipe gets hot, it is transferring that heat to your intake air VERY well. In this case, wrapping the pipe with exhaust/heat wrap will make a BIG difference on intake air temps.

Anyone who has an Injen intake (or any other intake with a metal pipe) should see my post on heat wrapping and sealing around the snorkel.

Also, here's a reference on thermal conductivity of common materials: http://www.engineeringtoolbox.com/th...ity-d_429.html

[stevesnj]

Originally Posted by avishenoy1

There's really no need to heat shield the stock intake system or any other silicone inlet tube. Silicone has a very low thermal conductivity coefficient, meaning, even if the outside of the tube gets hot, there will be very little heat transferred to the intake air on the inside. Therefore, wrapping a silicone tube will make a marginal difference on intake temps, if any at all.

However, If you have an aftermarket intake with an aluminum pipe, that thing will get hot quickly. Since aluminum has a thermal conductivity coefficient 3 orders of magnitude greater than silicone, once that pipe gets hot, it is transferring that heat to your intake air VERY well. In this case, wrapping the pipe with exhaust/heat wrap will make a BIG difference on intake air temps.

Anyone who has an Injen intake (or any other intake with a metal pipe) should see my post on heat wrapping and sealing around the snorkel.

Also, here's a reference on thermal conductivity of common materials: http://www.engineeringtoolbox.com/th...ity-d_429.html

Yeh to me a "cold air" intake is misleading in my opinion. If the outside air is more directly focused in a straight line somehow that would be more effective. Corvettes have their air direct from the front in a straight line to the intake. Very effective.