Intake Air Temp, Some Observation

I've been doing some observation on intake air temperature for quite a while now and this is my finding.

Stock Intake Box: +3 to +6 of ambient temperature day/night

Open Pod Intake: +3 to +6 during night, +6 to +12 in the day.


After I change my bonnet to the carbon one, I did realised the increase of intake temperature I believe the stock bonnet acts as a giant heat sink for dissipating heat, as well as the carbon bonnet being black absorbs heat from the engine bay and under strong sun.

In addition, if the car was driven from cold to a destination, the intake temperature always remain at around +5 above ambient. However, after stopping the car for a few minutes and driving again, this figures will climb to +10 or even +15 above ambient throughout even at higher speed.

I suspect that the intake itself and the parts around it absorbs heat while the car was stopped and upon starting again, constantly heated up the surrouinding air.

I will want to try sticking some reflective material around the intake area, as well as heat wrapping my intake to see if it helps the situation.

I don't want a closed up air box as I STRONGLY believe that a closed up air box will also absorb ambient heat from engine bay, and will be worst because the air within is dead and hardly flowing to dissipate the heat absorbed.

I can confirm this effect. I've done a few temperature trials, and it's clear that once you let heat soak get in it's very hard to get temperatures down again.

Obviously when moving through the air the car is just managing to keep the engine bay temperature constant, as soon as you stop and let the heat soak though to the intake side there's very little you can do.

Lesson: Don't stop driving!

How are you measuring ambient and intake temperatures, this could have a lot to do with the variation in temperature??

Typically you will always see higher intake port temperatures than ambient ( I would expect +3 to 6+ to be acceptable), as for heat soak this is a big problem for all engines that have been running hard then stopped, sat for a period and restarted. With the introduction of EFI these issues have been alleviated/reduced by compensating for the higher temperatures at restart. In N/A vehicles the thermocoupler (temp probe) is placed close to the intake ports (not so in a Turbo Install) this allows for the most accurate measurement of air temperature entering the cylinders (allows for correct fuel /air mix). Heat soke is typically less noticable in crossflow engines (less exhaust heat to heat intake manifold etc) in older non efi vehicles it is common after running hard, stopping for 10 to 15 then restarting to not be able to restart the engine with ease and at times engines will flood. Hope these ramblings provide some info.......

Three thermocouples (ambient, inside engine bay (intake side) and inside intake) hooked to a datalogger sampling every minute. All three were put in iced water and boiling water before starting to calibrate.

Did you also see the large variation between day and night temps ??? and after what sort of stand times??? This is an interesting subject and I suspect any effects are negligiable once the vehicle is moving again.....

please refer to thunderbird2's post about 2/3 down the page in this thread
http://forum.altezzaclub.org.au/index.php?...topic=2020&st=3

theres some interesting facts about intake temp

Thanks Brian will read on

Ambient temperature from temperature reading on center console disply

Intake temp from R-Vit, and now from FC Commander.

Variation between day and night is colosus!

Intake temp during a hot singaporean day is about 46~50 (80 kph) deg celcius with ambient temp of about 33 deg celcius. Difference of 13~17

During the night, intake temp can go as low as 32~36 (80 kph) deg celcius with ambient temp of 28 deg celcius. Difference of 4~8

Water temp and oil temp at a stable 75 C and 95 C respectively.

By using a laser temp gun, my carbon bonnet register an alarming 74 deg celcius on a typical sunny day!!

Chi,

i have a Apexi Cold air box. I am using a IS300 air scoop, then funneling a silcone hose into the box. The box will be layered with Carbon fibre and i will also use a layer of bitumen inside. Hopefully no warm air gets in, but i will be monitoring this when its finished!

Sirnixalot found a good gain when he used his Apexi induction kit with and without the cold air box. He said it was imperitive that you use one.

BTW, how does the FC commander pick up the temp? or is that an add on piece?

The Power FC is still using MAF for A/F. MAF all comes with a built in temp sensor. Some sort of heated wires and when air passes it, the drop in temp is the intake temp.

The power FC can display that. In addition, injector duty, knock level, and about 10~12 readings in all.

Thats good to know