Gen 5 boosted target AFR
#1
Gen 5 boosted target AFR
Anyone mess with gen 5/LT4 stuff or looked at a stock tune? I'm trying to understand how direct injection impacts target AFTER I for a boosted setup. I couldn't find much info searching online other than people saying it's leaner than port injection. An example would be port injected 93 octane ls1 may target 11.2 under boost, an LT4 direct injection on the same 93 octane may target 12.0 under boost. My understanding is that its due to cooling efficiency and that more of the fuel stays a liquid in DI as opposed to PI. Learn me.
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#12
Launching!
The gasoline and spark plug don't really know it's DI vs PFI. You just get an extra cooling process inside the cylinder as the fuel evaporates, so think of it as running in a cooler ambient temp. I see a lot of village wisdom claiming that the DI engines need to run leaner under boost than the previous (LS3/7) engines and that's simply not true according to the tests I've run where we were able to keep conditions constant.
#14
FormerVendor
iTrader: (4)
The gasoline and spark plug don't really know it's DI vs PFI. You just get an extra cooling process inside the cylinder as the fuel evaporates, so think of it as running in a cooler ambient temp. I see a lot of village wisdom claiming that the DI engines need to run leaner under boost than the previous (LS3/7) engines and that's simply not true according to the tests I've run where we were able to keep conditions constant.
#17
Launching!
The link above shows us on the same dyno, but it isn't the Lambda sweep. It's all in the disc though.