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Old 02-17-2013, 06:21 PM   #225 (permalink)
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Blueberry - '17 Mazda Mazda3 GS
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Originally Posted by MetroMPG View Post
Did you try a Google Image search? A quick search revealed this gasoline turbo BSFC map:

via: Turbo and BSFC - CleanMPG Forums

Not particularly helpful without seeing the comparable non-turbo though.
hey metro just wanted to add that chart i made above that you linked is not actually based on real world testing. it was based on honda i-vtec BSFC charts and A/F ratio tables for my car. after some recent real world testing i have found that chart to be inaccurate. It seems that turbocharged engines, specially mine, tend to run very rich above 70% engine load and/or 3000rpm. for example at 2500rpm and 80% load my RDX hits 13:1 AFR. At 90% load it's 12:1 rich and beyond 3000rpm full rich. anyway here is a much more accurate BSFC i found (i did not make this). it basically confirmed my suspicion that moderate loads (60%) and little to no boost are best for turbo BSFC:

Mazda 2.3L turbo:

and the AFR chart:

in comparison NA hondas do not enrich mixture too much below 3500rpm, some like my subaru stay stoich no matter what unless you're operating at high engine speeds. Turbocharged engines are more eager to enrich mixture to prevent knock. little to no boost along with low RPMs are best for turbo engines because as you can see from above charts AFR is actually related to BSFC.

Last edited by ever_green; 02-17-2013 at 06:41 PM..
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