heat soak so bad?

[1moreMPH]

you'll want aluminum for hardpipes. Stainless steel is much heavier and it doesn't flow heat away like aluminum -- aka, with aluminum hardpipes, even more heat is dissipated from the pipes themselves cooling the intake charge even more. SS traps the heat inside and doesn't transfer it.

 

[Cisco]

I am fairly new to the Mazdaspeed world and I keep seeing the term "heatsoak" come up. I wasnt sure what it meant but got the impression it had to do with the pipes from what everyone was saying. Then I googled it and go a definition from Garrets website that says its internal in the turbo and it was significantly reduced when they introduced water cooled turbos:

"Following a hot shutdown of a turbocharger, heat soak begins. This means that the heat in the head, exhaust manifold, and turbine housing finds it way to the turbos center housing, raising its temperature. These extreme temperatures in the center housing can result in oil coking.

To minimize the effects of heat soak-back, water-cooled center housings were introduced. These use coolant from the engine to act as a heat sink after engine shutdown, preventing the oil from coking. The water lines utilize a thermal siphon effect to reduce the peak heat soak-back temperature after key-off. The layout of the pipes should minimize peaks and troughs with the (cool) water inlet on the low side. To help this along, it is advantageous to tilt the turbocharger about 25 about the axis of shaft rotation."


Can anyone shed some light on what it actually means? How do you tell if you are getting heatsoak?

Thanks

 

[SeR_Cyclops]

well the just of it would be it uses water from the engine to cool the turbo instead of oil and this would prolly be better b/c the water is getting colder by running through the radiator, as we all know the oil does not have such a luxury. lol

 

[Knox Joe]

Can anyone shed some light on what it actually means? How do you tell if you are getting heatsoak?

Thanks

When we say heat soak around here we mean that the intercooler has gotten so warm that it is no longer really cooling the intake charge, because the metal that makes up the intercooler has become "soaked" with heat.

What Garret is talking about is all the metal components in the engine and turbo set-up getting hot, and also "soaked" with heat, so they want you to do a cool down before shutdown. I'm kinda anal about it so my turbo timer was set to 2 mins.

 

[TitaniumSpeed24]

Yeah, theyre saying heat-soak as far as their turbo maintanence goes. The heat-soak you hear about on this forum is dealing with the fact that after running the MSP for a while, the turbo is basically taking in hot air due to the innefficiency of the stock intercooler.

 

[Cisco]

That makes sense. How do eliminate or lower the amount of heat soak you are getting to a SMIC? would upgrading stock have any impact on this? Thanks for helping me understand....

 

[1moreMPH]

That makes sense. How do eliminate or lower the amount of heat soak you are getting to a SMIC? would upgrading stock have any impact on this? Thanks for helping me understand....

HUGE impact.

right now, your stock intercooler is smaller than the sheet of paper in your printer, AND it is tucked back behind the bumper so that no ambient (outside) air can reach it. Go read how intercoolers cool the charge air, and you'll see that if the only air around it is already hot from the engine bay, it cannot do a very good job heating it. Also the bigger it is, the better it cools, and our stock is TINY.

From those 2 things it would make perfect sense that a larger intercooler located at the front of the car in the lower grill will cool a hell of a lot more than the crappy smic. This is called a fmic -- a Front Mount InterCooler. Most fmic's that you see are at least 3x the size of the stock smic, and are again located in the front of the car so that air cool air passes through it as you drive along.

Upgraded the smic to a better will help a ton as well for 2 reasons. 1) better flow capacity -- the stocker is very restrictive in the amount of charge air it lets pass through with ease. 2) it is only so-so in the heat dissipation compartment. Upgrading to a customMSP or turbohoses smic will help muchos because they have better flow and cooling capabilities.

FMIC will cool more than SMIC hands down, it's a matter of flow, drivability, boost, and money. more boost = hotter temps = more cooling needed = bigger IC. the general rule around here seems to be if your 9psi or less, smic will work fine -- although fmic will always cool better and give you more power. hope that helps.