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Old 02-04-2020, 11:43 PM   #13 (permalink)
Master EcoModder
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spyder2 - '00 Toyota MR2 Spyder
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The OP is probably gone already, but I thought I would point out that that Dynamic Force 2.0L chart is definitely not complete. That engine produces around 200Nm of torque, not only 150. The new Toyota engines avoid enrichment up to a much higher load and speed so you can pretty much mash the pedal hard while driving.

A bit of history on best BSFC load:
In the late 90s and early 2000s, it was common for engines to run stoichiometric at all times below ~4000rpm. On these engines, near maximum load is efficient, with knock limiting efficiency at full throttle.

Then cars started running slightly rich at full load for all rpms to get more torque, and probably to help prolong catalytic converter life. On these cars, you want to avoid going rich, so you're limited to below 80% load or so.

In the latest engines, cooled EGR with better combustion speed/higher lean or EGR dilution limit has actually brought peak BSFC load down. I think this is a combination of pumping losses being negligible down to a much lower load, as well as the EGR gas increasing heat capacity (and decreasing cooling losses).
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