Let's talk about IC heat soak?

[WydRyd]

OK, we all know heat soak in the intercooler after the car sits for a while robs your engine of precious HP until it cools down again. So what are some of the solutions people have been using to minimise heat soak in these top-mount IC's? The only thing I can think of is a water spray kit, or perhaps even two large fans beneath the intercooler which periodically turns on to provide constant airflow through the core? I find it a bit of a pain having to wait ~10min for the inlet air temps to drop before I can start applying some serious throttle I've read that the WRX guys tilt their IC's to improve heat dissipation. This typically results in the lower intake air temps and the time taken for the IC to recover from heat soak is halved! Hmmm, maybe that's why the C2T units are tilted?!?

[hobieboy]

My 2 cents...

If you are on track, after the warm up lap, with all the fresh air blowing thru it, it should be normalized.

If you are on the street, for the amount of time that you can be on boost (<5 sec; or maybe its just where I'm ) I don't think another 10-20deg will be that important?

I have just installed a new HUGE Bell full bay. Temp had been low ever since (max of 60degF/15degC), but my inlet air temp had never been a few deg higher than ambiance other than the 1st 2 min (after heat soak) before the car pick up any speed.

BTW - I think this will be my 911 posts

[Emission]

I don't think a water spray kit will help unless you have air flowing through the intercooler.

[930turbo]

Porsche intercoolers have an advantage over the WRX or any other top-mounted I/C whereas it is forced-air cooled. The fan is capable of moving somewhere in the neighborhood of 2800 cfm of air with a rev of the engine - sitting still. A couple of late shifts under light acceleration and the heat soak will be long gone, way before the WRX has a chance to move enough air to make a difference.

[Craig 930 RS]

Fan under the IC!

[WydRyd]

Originally posted by 930turbo
Porsche intercoolers have an advantage over the WRX or any other top-mounted I/C whereas it is forced-air cooled. The fan is capable of moving somewhere in the neighborhood of 2800 cfm of air with a rev of the engine - sitting still. A couple of late shifts under light acceleration and the heat soak will be long gone, way before the WRX has a chance to move enough air to make a difference.

I have one of those Davtron Intercooler digital guages. If the car sits for a while after a run, I am seeing post IC temps of between 40-50DegC When I drive again, the guage shows the temp drop to a more "normal" reading after about 10-15 minutes. When I say normal, I mean a few degrees above ambient. During this cool-down period, the car is noticably more sluggish, but once the inlet temps have dropped and stabilized, power is restored.

Personally, 10-15min to cool down is a bit too long

The fan under the IC sounds like a good solution. Anyone got pics? How well does this work?

[Craig 930 RS]

40 to 50C = 104 to 122 degrees farenheit -- for us good ol' USA guys.

I also have the Davtron/Andial gauge - mine is hooked up for inlet temp and post IC temp.

Cool down lap on the track takes only about 2 minutes to go from maximum (at times about 140+) to virtually ambient -


After sitting, it takes about the same amount of time when back on track - on the street probably double at about 4 minutes.

The faster the ground speed and higher the engine speed the better for my setup - it is a shrouded IC that does well with the fan pulling a majority of it's air through the IC. An under IC SPAL fan would really help with your concerns - IMO. Superb quality, huge selection - available on EBay and through Iowa Impot/Export here in the States.

[WydRyd]

Originally posted by Craig911
Cool down lap on the track takes only about 2 minutes to go from maximum (at times about 140+) to virtually ambient -

Ah OK... I'm talking street driving here in moderate traffic. On a track, for sure the heat soak would dissipate fairly quickly, because of the greater airflow

In traffic, it's a real b!tch to get the heat-soak out fast enough

[Craig 930 RS]

See my addendum above ;-)

[WydRyd]

Thanks for that

I'll check out the SPAL fans.

[WydRyd]

BTW, @ idle, would the SPAL fans really make much difference to the airflow into the engine bay?

Anyone know how approx many CFM's the engine fan is drawing into the engine bay @ idle?

[Craig 930 RS]

Aren't you trying to cool the intercooler from at rest heat soak..........?

[WydRyd]

Yup, at idle, immediately after a period of rest.

[Craig 930 RS]

IC fan. Bottom mount, pull type.

[WydRyd]

On a full-bay IC, where's the best spot to position, say a 12" fan? Closer to the inlet, or closer to the outlet (or in the centre)?

I guess it doesn't really matter as long as air is drawn through the core.

[RarlyL8]

Merv,
Is your intercooler properly shrouded? If all of the air that feeds the fan has to first go through the intercooler you should not be having a heat soak issue.

I have a question to add to this discussion.
What do you do to shroud an intercooler that is NOT the full bay type?
I fear that a stock sized intercooler would not allow enough air flow for the fan and it would try to pull hot air from the cracks in the engine tin.

[WydRyd]

RarlyL8, I have no shroud surrounding my full-bay IC, so yes, there's a high possibility air is taking the path of least restriction

I think I'll look into that first, before adding a fan below the IC. Certainly be less added weight too

What are people using to shroud their IC's? Welding an aluminium shroud around the perimeter or something?

Would greatly appreciate any pics!

[911rudy]

I used the dark gray one inch pipe polyfoam insulation, (The foam is about 2 1/2 inches in diameter) to surround the IC where the engine bay lid makes contact with the IC and it forms a real nice seal. It comes with a slit the full length of the insulation and is pre-glued with a sticky but not messy glue. If you just pry the piece apart and place it along the edge of the IC and miter the corners, it makes a safe non-marring seal. It also allows a little more tolerance because it crushes when pressed so it dosen't have to be an exact fit. I would try something like this for about $10 before I would spend a lot of money on fans and shrouds that are made of exotic materials.

[WydRyd]

Thanks 911Rudy - sounds like a cheap viable solution

Care to share some pics?

[Craig 930 RS]

I'm not Rudy, but here is mine: