[Mk2] [Turbo] Intake temps - any one with charge intake temp gauge

[Benmoore999]

Any one got a rough idea of their maximum intake temps and at what boost ??

intercooler type might be handy also.

[raptor95GTS]

rev3 std intercooler 16ish psi. Under a long pull from 3rd to 4th I've seen the intake temp rise from 25degC to 60+degC. It does cool down fairly quick too when off boost

[darryl_p]

running, the CC from the ST185CS with good airflow to radiator, and clean CC insides.

normally peaking at 1.3bar on a CT26 twin scroll i see 68degrees C in ambients of around 25.C (holding against a load, ie steep long hill)

high rpm's and thus less boost from my CT26, and its just under 55.C same ambient.

this morning however ambient of 7.C fraction over 1 bar. saw only a peak of 44.C

these temps are air temps, not affected by heat soak like many sensors mounted on the inlet plenum.

[darryl_p]

rev3 std intercooler 16ish psi. Under a long pull from 3rd to 4th I've seen the intake temp rise from 25degC to 60+degC. It does cool down fairly quick too when off boost

as you say, for any sensor, which doesnt start showing reduces temps, the moment you lift off, and boost goes down, then you are being affected by heat soak.

my temp sensor is a fast acting, and very low thermal storage, my display updates 3 times per second, and from lifting throttle on high boost, and thus high temps, the first update 1/3 second is already 15 degC cooler. by a second , and engine pulling very hard vacuum, its showing temps matching my coolant temp of the CC. keep on closed throttle, then both temps (air and water temp of CC ) continue to drop.

any guauge that doesnt work this fast is not measuring true air temp
(flaming can start ! hehe)

[fastgrant74]

Can I ask what you use to measure the intake temp? I have some of the LCD displays, but have removed the sensor as its a plastic coated bit of wire, and was worried it might fall off, and into the engine

[raptor95GTS]

rev3 std intercooler 16ish psi. Under a long pull from 3rd to 4th I've seen the intake temp rise from 25degC to 60+degC. It does cool down fairly quick too when off boost

as you say, for any sensor, which doesnt start showing reduces temps, the moment you lift off, and boost goes down, then you are being affected by heat soak.

my temp sensor is a fast acting, and very low thermal storage, my display updates 3 times per second, and from lifting throttle on high boost, and thus high temps, the first update 1/3 second is already 15 degC cooler. by a second , and engine pulling very hard vacuum, its showing temps matching my coolant temp of the CC. keep on closed throttle, then both temps (air and water temp of CC ) continue to drop.

any guauge that doesnt work this fast is not measuring true air temp
(flaming can start ! hehe)

what I remember from an Autospeed article on this very topic so forgive me if I'm slightly out
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not so. An intercooler acts as a heat sink - ie it removes the heat from the charge air into itself while you are on boost. After you come off boost is when it sheds the heat it has accumulated. Some of that heat is taken away by the air rushing through the charge pipes when you are off boost and some is removed by the airflow through the intercooler cooling fins. This means in effect the intercooler {heatsink} passes some of that thermal energy back into the now cooler (non turbo'd) off boost air thus resulting in the intake temp not dropping as fast as you'd imagine.

Hence under long and frequent boosting cycles the intercooler {heatsink} er heatsoaks and can't function efficiently

A chargecooler however works slightly differently as you're constantly replacing the heated water with cool fresh stuff so when you come off the loud pedal, the temps rapidly come back to 'normal'
-----------

i use a thermocouple that has sod all mass and a gauge, multimeter, that updates like instantly so aint no heatsoak in the system for measuring.

[Ayrton]

Radtec chargecooler
On a very hot trackday at spa the highest intake temp I saw was 50 deg
That's a rev 3 peaking at 1.2bar.

[Benmoore999]

Cool, interesting stuff. After a lap and a half of the ring I was seeing ~ 70 deg C. This was running 1.15 bar. The ambient it was in the 25-30 deg c range.

If you open the top of your chargecooler (st205) how fast does the coolant run through ? I tested the st205 cc pump it really did shift some water. I realise there will be some flow losses with the addition of cc core and rad etc. The flow through the chargecooler seems much much slower than i expected.