Phyxius Posted July 14, 2005 Share Posted July 14, 2005 For fuel mileage, how lean is it safe to go on a turbocharged motor at highway speeds?...say 2000-2500 RPM under light throttle? just for cruising sake... Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 14, 2005 Share Posted July 14, 2005 Ask 1FastZ! he has set up his "low load" Kpa Bins to universally run 18:1 AFR in ALL rpm ranges. This is probably totally safe, as the old Chrysler Lean-Burn Emissions Engines ran 17.5:1, and some Hondas run close to 20:1 in some instances! As long as you aren't lean UNDER LOAD, you will be fine! With this kind of setup, Bryan is breaking over 30mpg on the highway with his MS-Powered 280Z. The GREAT thing about MS is that figuring out where "load" is couldn't be easier, the first two bins in the kpa column are a given. From there, it's a matter of what kind of driving manners you require from the engine, and what your EGT's are. For crusing at light load, that 18:1 is probably fine, and you can tailor the accel shot to make it transition without the typical "lean pop" like you would have if you jetted a carb that lean. Another reason to go EFI! (Yeah, I had a fire in the Mikuinis on the Black Car yesterday, and thought "only a few months and it will be cool, and I can convert these damn things!") Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted July 21, 2005 Share Posted July 21, 2005 almost got my car running-i need to get it going to use for a work car.becuase of gas milage-i will be happy if it runs over 26mpg Quote Link to comment Share on other sites More sharing options...
Drax240z Posted July 21, 2005 Share Posted July 21, 2005 My general guildline for turbo vehicles... Load vs AFR Flat ground: 15.5:1 Small hill: 15.5:1 Med hill: 14.7:1 Steep hill: 13.0:1 Max throttle: ~11.5:1 Quote Link to comment Share on other sites More sharing options...
Guest Loose_Screws Posted July 22, 2005 Share Posted July 22, 2005 I have heard you get really nasty emissions from running lean. Also, if you have CAT's, if you run too lean, I don't think there is enough fuel for 'combustion' in the CAT and could eventually clog it? Quote Link to comment Share on other sites More sharing options...
Phyxius Posted July 22, 2005 Author Share Posted July 22, 2005 where i live, there are no emissions tests...and i don't have a cat...hehe Quote Link to comment Share on other sites More sharing options...
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