miparrott
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Joined: November 2014
Posts: 4 
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Post by miparrott on Jan 29, 2015 20:07:42 GMT -5
Hey guys, I've been researching for a while, reading through these threads and other sources on the web. Before I start my project I'm building a SolidWorks model of the entire assembly, and the one point that I'm having trouble with is finding specific turbos and specific specifications for these turbos that I can work off of. The VT-50 seems to appear a lot and seems like a good option, but again I can't seem to find a spec sheet that I could build an external model from. Also, it seems a bit large, this will be my first project and I'm looking for a lower cost alternative that I can build my first one off of and learn from. Any suggestions are appreciated!
P.S - I have already done research and understand the functioning, have the formulas for sizing the flame tube, a program for determining flametube patterns estimating TOT, etc, so I promise I'm not being lazy and hoping someone will give me the answers, I just need help finding a place to start.
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Post by racket on Jan 29, 2015 23:41:07 GMT -5
Hi Theres very limited information available for most turbochargers , especially those for largish diesel engine due to the cosy arrangement between engine manufacturers and the turbo manufacturers to not let the public know about flows etc . The newer Garrett turbos are about the only ones that provide reasonably comprehensive information about some of their turbos www.turbobygarrett.com/turbobygarrett/turbochargersFor a first engine build you could use an automotive size turbo , but you need to find one that has a larger turbine wheel exit area bigger than the compressor wheel inlet area , most don't , thats why larger diesel engine turbos are generally a better proposition as they invariably have the required larger turbine exit . Cheers John |
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miparrott
New Member
Joined: November 2014
Posts: 4
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Post by miparrott on Jan 30, 2015 14:37:29 GMT -5
Ok, that makes sense! What minimum size would you recommend for the turbine wheel exit area?
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Post by racket on Jan 30, 2015 17:16:44 GMT -5
The turbine exducer needs to be ~20% larger in AREA than the comp wheel inducer , this generally produces a workable match where the turbine wheel can process the gases comfortably whilst allowing the compressor wheel to flow in its efficient regions, this in turn keeps turbine gas temperatures where they should be , but due to variations in turbine scroll A/Rs this can also influence the flow rates etc etc ............lotsa variable that all need to be balanced out if the engine is to perform to its full potential .
Cheers
John
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miparrott
New Member
Joined: November 2014
Posts: 4
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Post by miparrott on Feb 1, 2015 0:07:06 GMT -5
The turbine exducer needs to be ~20% larger in AREA than the comp wheel inducer , this generally produces a workable match where the turbine wheel can process the gases comfortably whilst allowing the compressor wheel to flow in its efficient regions, this in turn keeps turbine gas temperatures where they should be , but due to variations in turbine scroll A/Rs this can also influence the flow rates etc etc ............lotsa variable that all need to be balanced out if the engine is to perform to its full potential . Cheers John Thank you so much for the help, last question. Is there a minimum size that I should be watching out for in terms of dimensions? I found a turbo with an inlet size of 76mm, but this seems small compared to the large diesel turbos in a lot of the projects here. I know its not an exact science, I just don't want to build the entire assembly and have it not work, and not know whether it's because of a mistake I made, or because the turbo is too small. Thank you once again for the help! |
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Post by racket on Feb 1, 2015 0:48:20 GMT -5
A 76 mm wheel inlet is more than large enough , generally its turbos with less than 50mm that give the most problems as the attendant smallish turbine stages generally have poor efficiency .
Diesel turbos are concerned with overall efficiency as it aids the heavy vehicles fuel burn rates which are of great importance commercially whereas auto sized turbos tend to be performance orientated with less emphasis on the efficiency, performance sells more cars than efficiency .
Cheers
John
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miparrott
New Member
Joined: November 2014
Posts: 4
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Post by miparrott on Mar 15, 2015 16:29:14 GMT -5
A 76 mm wheel inlet is more than large enough , generally its turbos with less than 50mm that give the most problems as the attendant smallish turbine stages generally have poor efficiency . Diesel turbos are concerned with overall efficiency as it aids the heavy vehicles fuel burn rates which are of great importance commercially whereas auto sized turbos tend to be performance orientated with less emphasis on the efficiency, performance sells more cars than efficiency . Cheers John John, last question. I know that an internal wastegate is bad, but how about an external one, is it all-right to pick a turbo with an external waste gate, and remove it? |
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Post by racket on Mar 15, 2015 16:44:55 GMT -5
Generally a turbo with any sort of wastegate would/could have an "undersized" turbine stage , it would pay to check the turbine wheel exit area and compare it with the comp wheel inlet area , you want the turb wheel exit to be at least 20% larger in area
Cheers
John
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