No room for a turbo??

[454Casull]

You might be right. I think most turbine housings are cast out of iron, and I don't know how well cast iron holds up to high thermal gradients.

[FYRHWK1]

I cant say either, but many brake discs are made out of cast iron, and we all know how hot brake discs can get. They do crack if abused, but thats a matter of them being heated & weakened and having massive amounts of stress put on them, they don't shatter or crack as soon as you hit a puddle.

You're right about the turbine housing, I was thinking of the compressor when I typed that.

[disco192]

It very well could crack. When you use water cooling there is already water inside it that warms up as the turbo does and is cooled by an outside source like a radiator. He is right, there is no sudden change in temperature with water cooling, but given the proper circumstances water could cause damage to the turbo.

If you dont believe me that it can break, get a cast iron pan if you have one and put it over your burner for about 10 mins until it gets REAL hot and then pour ice water over it and watch it crack.

My father broke his windshield because he washed his car on a really hot day in houston, now isnt that some crazy shit.

Whoever did that setup isnt exctly the brightest bulb in the box.

[FYRHWK1]

Originally Posted by disco192

It very well could crack. When you use water cooling there is already water inside it that warms up as the turbo does and is cooled by an outside source like a radiator. He is right, there is no sudden change in temperature with water cooling, but given the proper circumstances water could cause damage to the turbo.

If you dont believe me that it can break, get a cast iron pan if you have one and put it over your burner for about 10 mins until it gets REAL hot and then pour ice water over it and watch it crack.

My father broke his windshield because he washed his car on a really hot day in houston, now isnt that some crazy shit.

Whoever did that setup isnt exctly the brightest bulb in the box.

When I used to go camping as a kid we would use cast iron pots & pans to cook with. They would get red hot sitting over a campfire for hours at a time, when we were done we would take them over to the creek and dump them in to cool off so they could be repacked that night, they never cracked after years of that.

Like I said before, brake discs get very hot, not quite as hot as some turbos but those are on the extreme side as well, a typical EGT is in the 1000-1500* range, brake discs have been known to get into the 1000* range with hard tracking and you've never heard of sudden catastrophic failure due to hitting a puddle, nor have you heard of an exhaust manifold (almost ALWAYS made of iron) cracking due to getting wet, and those are glowing after an hour or so of driving.

It would take an extremely rapid cooling or heating to crack something like iron which has VERY little thermal expansion, the whole reason for a crack is that it cools too fast and shrinks in size (the molecules within it realign as they were before heating or cooling) exposing the weaker areas instead of having them shrink or expand with the rest of the material. When you have something like iron or steel with very little measureable expansion it's much harder to cause it to crack with rapid cooling or heating.

[Sluttypatton]

I am currently looking at a cast iron pot of mine with a crack in it. This crack developed when I poured cold water into it while it was still hot. I would love to show everyone pictures but attachments are not allowed here. Apparently some cast iron does have a problem with cracking when cooled rapidly.

Also, a quote from a website I found (although the site is unrelated to anything automotive); "During cast iron's heyday, many architects thought it to be structurally more sound than steel. It was also thought that cast iron would be fire resistant, and facades were constructed over many interiors built of wood and other inflammable materials. But, when exposed to heat, cast iron buckled and later cracked under the cold water used to extinguish fire. In 1899, a building code was passed mandating the backing of cast iron fronts with masonry. Most of the buildings which stand today are so constructed. It was the advent of steel as a major construction material that brought a rapid end to the cast iron era."

From the website for some sort of cookware (http://www.ridgewaybykelty.com/cookset.html):"2. Do not use cold water to cool cool your cast iron, this will cause the cast iron to warp or crack."

But I think that cracking (due the rapid cooling) generally only happens to low quality cast iron. Too much phosphorus makes cast iron brittle, as does chilling during the casting process.

Anyways, this is what I found.

[Neutrino]

and again for the third time....since i already posted this twice in this thread

what about the fact that the turbo is made out of several parts made out of different alloys with virtually 0 tolerances....what is it going to happen when those start contracting at different rates and push and pull against each other...can't that cause cracking even if the materials themselves can whistand therlmal shock

[SaabJohan]

If you have ever been taking a turbo apart you will find that are no zero tolerances, since there is a free floating turbine/shaft/compressor in it the tolerances are infact quite large. A turbocharger is also constructed with a turbine house and bearing house of a cast iron which can withstand high temperatures without cracking. The compressor is usually made of aluminum or in some cases of magnesium (housing) and titanium (impeller), but this side isn't that hot. The turbine is made of a superalloy, and then there are a few more steel parts and the bearings but there aren't much more than that.

I have also washed a hot turbocharger in cold water... nothing happend except that it caused a lot of steam.

Furthermore, there are cars that can run with their engines completely under water... I don't think the engines crack because of that.

[Sluttypatton]

As I said, none of my proof had to do with anything automotive. It's my opinion that only poor quality cast iron cracks due to thermal shock. But I know that it is possible for some cast iron, because I have seen it happen to pots and pans. I think that the cast iron they use in the automotive industry is probably fairly good quality.

[SaabJohan]

Some of the cast iron used in exhaust manifold can contain about 20% nickel... that's quite a lot.

[Meyaht]

alrighty
about the cracking in cold water, depends on the steel + brittleness. people think all steel is hard, dram on. its as different as ..... i dont know... 2 things that are different, im not an author...

by the way
oil fromt he turbo usually returns to the oil pan through GRAVITY!. thus making oil return in this case NEARLY IMPOSSIBLE. the only way i can see this working is with a ceramic bearing, which shoudl still get oil. not to mention that even if he had an oil pump on the oil return lineright near the turbo bearing, good luck getting back to the front of the car under any kind of acceleration.

by the way, tempering usually isint trying to use the shock to align the particles. its used to trap the alloyed composits and or carbon to change the molecular structure of the steel that would normally draw those composits out under lsow cooling.

[Sluttypatton]

Good point about the gravity drain. Usually in situations where gravity drain is impossible there is a secondary oil pan, and another oil pump. I don't see why acceleration would make it difficult for the oil to return to the oil pan. Also, remember that there are turbochargers with a self contained oil supply.