Turbine A/R

D

DIESEL_POWER

NGM Diesel
Joined
Jul 8, 2006
Messages
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OK question.

If you are making desired boost and drive psi is lower than boost, and there is a wastegate in the system, will a higher A/R Turbine housing make any more power with all else being the same?
 
Yes, especially if you are gating less, but probably at narrower rpm band.
 
Your Monday morning skill testing question? I guess if you can maintain the same boost curve, while reducing parasitic drive pumping losses, there should be a gain.
 
Pressure is the only thing here that is directly relevant to HP losses or gains, if im not missing something.

Gate controls pressure as long as its open, so
With that said, drive psi is lower than boost and boost is at the desired level, so a bigger A/R would not drop drive psi because the gate would naturally close up its flow due to less psi and volume would remain the same untill the point of gate flow is shut off or compromised. does that make sense?


does it matter if its single or dual scroll? t3 or t4?
 
There is no way to answer this with certainty, but from what I have seen; the larger exhaust housing will not increase power, and typically in diesel applications they tend to make better power with a divided scroll, whether T3 or T4 would depend on the size of the turbocharger.
 
DIESEL_POWER said:
OK question.

If you are making desired boost and drive psi is lower than boost, and there is a wastegate in the system, will a higher A/R Turbine housing make any more power with all else being the same?
Click to expand...

On A/R alone larger will slant towards potentially producing more boost at lower turbine inlet pressure. Smaller A/R slants to better low end response and lower boost potential at a higher turbine inlet pressure. Where and how hard your gating will determine if a housing jump is in the books.

DIESEL_POWER said:
Pressure is the only thing here that is directly relevant to HP losses or gains, if im not missing something.

Gate controls pressure as long as its open, so
With that said, drive psi is lower than boost and boost is at the desired level, so a bigger A/R would not drop drive psi because the gate would naturally close up its flow due to less psi and volume would remain the same untill the point of gate flow is shut off or compromised. does that make sense?


does it matter if its single or dual scroll? t3 or t4?
Click to expand...

A waste gate cannot lower the turbine inlet pressure required to drive the turbine. Therefore at higher flow rates a smaller A/R is bound to have higher turbine inlet pressure for the same compressor flow.
 
DIESEL_POWER said:
Pressure is the only thing here that is directly relevant to HP losses or gains, if im not missing something.

Gate controls pressure as long as its open, so
With that said, drive psi is lower than boost and boost is at the desired level, so a bigger A/R would not drop drive psi because the gate would naturally close up its flow due to less psi and volume would remain the same untill the point of gate flow is shut off or compromised. does that make sense?


does it matter if its single or dual scroll? t3 or t4?
Click to expand...
less wastegating makes turbine more efficient which makes boost/backpressure ratio better. Ofcourse you need to fine tune to get most out of that change. Optimise injection timing, camshaft timing, boost to fuel ratio etc.
 
Ok fellas same situation but in this case let's talk turbine wheel. Bigger wheel but less drive than boost psi. Wastgate. Any Benifits?
 
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