Ok, I'm a little currious. I thought that the increased air temperature was solely from the compression factor. But I've have some people telling me that Supercharger air temps are less than turbo air temps, implying the heat from the turbine housing is transfered over to the compressor houseing and then into the incomming air. How true is this?? This is intercooling asside theoretical question.

 

It all depends on how efficient the compressor is at the different boost levels, and airflows. This question is kinda broad, because every compressor has it's own characteristics. Efficiency's are seldom over the 75% range. Efficiency is defined as How much the compressor heats the air above what the ideal gas law says it should.

 

The heat in the intake charge is a result of the same principle for both Centrifugal Superchargers and Turbochargers. As you compress a gas, it gets hotter. That's part one. The next part is efficiency. As anything compresses any gas, some energy is used heating the charge. How much is merely a matter of the compressor's efficiency (usually a percentage) but dont think it's a simple thing! Look for "Compressor Maps" of the desired unit (whatever form it is) and that will tell you what flow it's pushing, what rpm it's at, to how efficient it will be.

If you pick the right headunit and supporting mods, heat will not be an issue. Choose poorly, and you'll be fighting tuning, detonation, and lower output then you expected.

Do a search and post questions. I've done some reading, but there are guys on here that could probably build a boosted lt1 while sleepwalking and have it start in the morning

 

What Geoff and SMOKNZ posted is absolutely correct.

But, I'm sure there is some compressor housing/wheel heating from the hot turbine side of the turbocharger. I'm not sure how much this is, but my gut feel is that it is small compared to adiabatic compression heating and compressor (in)efficiency.

Mike

 

Ok, so if I had the same size compressor on a supercharger than on a turbo then I wouldn't see much difference. But since my turbo compressor is smaller than a normal supercharger compressor it will cause more heat. That makes much more sense. Thanks for that little tidbit that I didn't see.

 

what are the specs on your turbo? If you're asking too much of it then yes, you will get a lot more heat. Size alone does not determine efficiency. Your goals and setup determine the head unit you should be using, which may, or may not, be the one you have.

 

I've currently got a 60-1 HI-FI I'm building the crossover pipe as we speak. This is my first attempt at anything like this welding and fabricating. Any tips would be helpful if you've got some.

I do realize that this turbo is too small for me, I was going to go twins but after I had someone build me one turbo header I couldn't figure out how to get the second side in there so I'm just building a cross over pipe makeing sure it works and then getting a bigger turbo.

 

Something else to consider is given that boost increases intake temps, boost on a turbo comes on full at full throttle while a blower applies boost in relation to the engine's RPM.

 

I dont think its a small percentage as you say it is.. heat transfers through solid quite well

check out the hotrodtv videos... they have a nice animation and they say just this...

 

True, the only methods to remove heat and cool the bearings is the oil and water cooling jackets. As well as an aluminum composition to radiate heat versus the cast iron to retain heat on the turbine side. Also, the incoming air would have some effect too. But all heat is not eliminated.