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All good points Dean, and a few I hadn't considered. My car is a T7 9-3, and at present I have no plans to mod it. Right now I basically just enjoy the hobby of figuring out how everything works. My motivation for the post was to see where I could get a number of torque curves so that I could experiment with a simulation spreadsheet I've been working on. However, I hadn't modeled the lag, and now that you mention it, what you say with respect to dynamic vs. steady state conditions makes a lot of sense.
How exactly does T5 regulate boost pressure? Does it not take into account temperature, relative humidity, altitude (i.e. air density) effects, all of which I understand T7 to consider in determining the mass flow? It seems like T7, in adjusting for a target torque has pretty much already assumed the "best case" airflow, thereby providing certain limitation. If T5 just shoves air in until the sucker starts to knock, then theoretically if you go to some really cold, dry , low altitude place, you could get better than "best case" output, even with stock components. Naturally you could alter components to shove more air in too. T7 on the other hand will only shove air in until it thinks it's shoving enough in to generate its preprescribed max torque. Then again, I assume it's running without feedback on the actual torque generated, so you could conceivably trick it somehow into spitting out more.
Another passing thought...maybe with some accelerometers hooked up to the car you could effectively do a dynamic dyno test. Do the problem backwards and back out the engine output from the acceleration data. This would be a big task in estimating all the relevant variables (i.e. tire friction, air density, inertial effects, etc.)...but if you could get a nice calm, windless day out on the salt flats.... This might provide you with the capability to at least roughly correlate a published steady-state dyno run to a real world dynamic one.
Have you by chance been following the thread on the 9-3 board re: "old" vs. "new" 9-3? Would be interested in your thoughts.
Cheers,
'Roo
'89 900S 5spd
'01 9-3SE 5spd
posted by 12.13.238...
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