Presenting Zero Clearance K04s!
12-19-2003, 07:25 AM
#141
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Here's my take. I'm not a Turbo "expert", but I think I'm a smart guy...if you disagree, shut up ;-p
I'll say this in simple terms...
I think the Zero clearance starts out at almost 100% efficiency, lets say around 97% for ****s and giggles. As the blades spin and expand during the first full runs at operating temps they set their "boundaries" within their housing. Because there is less turbulence inside due to less of a gap between blade and housing, the temperatures are overall lower...being easier on everything from the turbo itself to the oil to the motor...you name it. I don't think there is enough "slop" in the wheel to think the blades would hit anything once they've "seated" inside the housing. If a wheel exhibits enough play to hit the housing at this tolerance, I would be inclined to believe that its a faulty unit...and Zero-clearance or not, would fail prematurely from a factory defective bearing.
I know and understand all the concerns you and some others are having...its a lot of money to spend. But I think what Jacob said makes hits the spot....its "new", so its to be expected that initially there will be doubts and concerns that will need to be ironed out.
I think the Zero clearance starts out at almost 100% efficiency, lets say around 97% for ****s and giggles. As the blades spin and expand during the first full runs at operating temps they set their "boundaries" within their housing. Because there is less turbulence inside due to less of a gap between blade and housing, the temperatures are overall lower...being easier on everything from the turbo itself to the oil to the motor...you name it. I don't think there is enough "slop" in the wheel to think the blades would hit anything once they've "seated" inside the housing. If a wheel exhibits enough play to hit the housing at this tolerance, I would be inclined to believe that its a faulty unit...and Zero-clearance or not, would fail prematurely from a factory defective bearing.
I know and understand all the concerns you and some others are having...its a lot of money to spend. But I think what Jacob said makes hits the spot....its "new", so its to be expected that initially there will be doubts and concerns that will need to be ironed out.
12-19-2003, 07:59 AM
#142
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the shaft would be spinning at a lower rpm
because with the zero clearance, the turbo will be pushing more air per revolution of the compressor wheel. That plays off of the improved efficiency of the wheel.
12-19-2003, 08:01 AM
#143
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It is
when you initially put the turbo on the car the wheel is in contact with the compressor housing. That stimulates 100% efficiency. After start up and the compressor wheel seats itself, then the efficiency drops to its operating range of 94-96%.
12-19-2003, 08:09 AM
#147
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that "normal wear" is the break in period that we are talking about
but dont take me the right way, i'm not trying to flat out argue with you, just convey the product in its entirety
12-19-2003, 08:10 AM
#148
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so you're saying, that by slowing the shaft speed, you still get the same airflow...
if you still get the same airflow, then where does the power gain come from?
You need more air, to make more power. So, actually, you will get more air from the same shaft speed.
You need more air, to make more power. So, actually, you will get more air from the same shaft speed.
12-19-2003, 08:13 AM
#149
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Efficiency is how much of the turbo's energy is used to compress the air, versus heat the air....
So if you say 100%, then that means that outlet temp = inlet temp.
Do you break the laws of physics often?
Do you break the laws of physics often?
12-19-2003, 08:14 AM
#150
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one thing about compressor wheel heat.......
for those that think that the wheel is going to have thermal expansion enough to rain on our parade.
first, in the start up/break in period, the compressor wheel is going to expand due to thermal expansion as much as it ever will. This is included in the seating of the wheel.
second, think of his. when you touch the blade of a fan, even a very high speed one, it isn't hot due to fricion, its cool. Same principal with the compressor wheel. although its spinning at high speeds, at the same time its cooling itself with, idealy, ambient temperature air.
first, in the start up/break in period, the compressor wheel is going to expand due to thermal expansion as much as it ever will. This is included in the seating of the wheel.
second, think of his. when you touch the blade of a fan, even a very high speed one, it isn't hot due to fricion, its cool. Same principal with the compressor wheel. although its spinning at high speeds, at the same time its cooling itself with, idealy, ambient temperature air.