How much air in terms of volume being flowed is only really dependent upon the engine's displacement, its volumetric efficiency at a given RPM, and the pressure ratio. What varies from compressor to compressor is how efficient the compressor is at that given flow point plotted on a compressor map in terms of pressure ratio vs. CFM, and therefore what mass of oxygen exists in that fixed volume of air, as the compressors vary from one to the next in terms of their efficiency level (essentially how well it compresses compared to the ideal temperature rise).
Also for those of you comparing much larger turbos should not neglect the difference in turbine size.. The TD04HL hot side I would say is a pretty large difference from conical to angle-outlet housing, and beyond that our larger GT-series turbines as well as a typical Stage 3 T3 turbine or even a TD05 would move your mid-high RPM volumetric efficiency up quite a bit. Then you're moving more volume at the same boost levels as you would be on the smaller turbos, in addition to probably moving up to much denser air thanks to the corresponding larger compressor.
We are often comparing a 15G to a 19T and a 13G to a 16T and so on and so forth. These turbos all share the same turbine wheels, and very often the same turbine housings. This means, that if you are upgrading from say a straight-outlet 15G to a straight-outlet 18T, and change nothing else, you are essentially *only* changing the compressor. And the differences you'll see in your setup will stem from only that difference in compressor efficiency at whatever boost level you are running.
However, if you go from say a conical-outlet 15G to an angle-outlet 19T, you are also going to be changing your volumetric efficiency quite a bit above maybe 3500 RPM. So you will not be at the same place on the compressor map from one turbo to the next, as with the previous example. You will also be pushing your point over to the right, as in more CFM at the same pressure ratio. Now, this obviously would be a much more drastic difference if you were to change from a conical 15G to a TD05-16G(big) or something even bigger. You'll continue to pick up more and more VE points at higher RPM the bigger turbine side you have. The downside of course is a loss in spool time, along with the fact that your stock rods like to pretzel really more or less just beyond what the 19T is capable of. (or just short of what it's capable of if you do not have a sufficient tune
)
Anyway, I'm starting to feel like a nerd so I'm done rambling for now.
Laird, you have some serious issues going on with the running state of your car, and I really can't begin to think of where to look other than cam timing and your tune. It looks like your ignition timing is all over the place, and there is no reason you should have boost fall-off with a 19T like that.. Both the torque curve and the power curve are very wrong, and the choppiness is almost worrying. Your peak torque should be about 1000 RPM higher, and your horsepower should be about 40-50 whp higher, both curves should look more organic by quite a huge margin and your power should continue to rise until maybe 5500 or so before it starts to plateau and then taper off. Hopefully RICA will get your dyno chart back along with your ECU and say "whoops, didn't mean to solder *that* chip in there" and then you'll get it back with the right tune and be delighted. From what I can see that's about the only possibility in my mind.
1984 244 GLT - blue rat rod (SOLD!)
1995 850 turbo - Turbonetics CBB T3/T04E, M56H, KW V2, VEMS Standalone, not as shitty as it looks! (I sell to you for good price?)
"Fish, I love you and respect you very much. But I will kill you dead before this day ends." -Santiago
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