SmithvilleD
Active Member
No doubt capable of making more boost & providing mass airflow levels beyond anything I'm interested in running thru my 6.5. Believe the compressor section is the same as the HX-40; Holset rates the HX-40 up to 350 hp. As it happens, the 6.7 Cummins in the latest Dodge trucks is rated at 350 hp.
It should be capable of a pretty low rpm boost threshold, but all that remains to be seen. In concept, it could be capable of blending some of the best traits of the stock turbo & the ATT.
From theory, I wouldn't expect to be able to get drive pressure levels quite as low as the ATT, because I'd expect this turbine wheel is smaller than the ATT's. But at the end of the day, it's only theory until it's been measured.
I do like the concept of being able to vary highway cruise boost & drive pressure on the fly. Not because I envision doing that in an ongoing fashion. More because I'd like to see if there are any changes in the fuel rate needed to maintain the same, level road, steady-state speed.
Because diesels can run at such widely varying air/fuel rates, you don't see much data/experimentation as to what yields the best fuel economy. Probably it's a compromise relating to how efficiently the turbo can supply additional air. Would expect the OEM's to consider this, but they'll have emissions & other concerns as well. Maybe GM has the 6.5 PCM commanded cruise boost levels dialed in for best economy, maybe not - I'd like to actually know.
It should be capable of a pretty low rpm boost threshold, but all that remains to be seen. In concept, it could be capable of blending some of the best traits of the stock turbo & the ATT.
From theory, I wouldn't expect to be able to get drive pressure levels quite as low as the ATT, because I'd expect this turbine wheel is smaller than the ATT's. But at the end of the day, it's only theory until it's been measured.
I do like the concept of being able to vary highway cruise boost & drive pressure on the fly. Not because I envision doing that in an ongoing fashion. More because I'd like to see if there are any changes in the fuel rate needed to maintain the same, level road, steady-state speed.
Because diesels can run at such widely varying air/fuel rates, you don't see much data/experimentation as to what yields the best fuel economy. Probably it's a compromise relating to how efficiently the turbo can supply additional air. Would expect the OEM's to consider this, but they'll have emissions & other concerns as well. Maybe GM has the 6.5 PCM commanded cruise boost levels dialed in for best economy, maybe not - I'd like to actually know.
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