View Single Post
Old 06-25-2008, 08:51 AM   #10 (permalink)
Daox's Avatar
Join Date: Dec 2007
Location: Germantown, WI
Posts: 11,040

CM400E - '81 Honda CM400E
90 day: 58.68 mpg (US)

Daox's Grey Prius - '04 Toyota Prius
Team Toyota
90 day: 49.53 mpg (US)

Daox's Insight - '00 Honda Insight
90 day: 64.33 mpg (US)

Swarthy - '14 Mitsubishi Mirage DE
90 day: 56.69 mpg (US)
Thanks: 2,389
Thanked 2,435 Times in 1,469 Posts
Open loop is when the engine stops using the oxygen sensor and (almost always) makes the engine run rich. Some engines can dump up to 25% more (possibly even more) fuel while in open loop. This negates pretty much any benefit you would have seen from accelerating properly. On modern OBDII engines you really only kick into open loop upon very agressive acceleration. On my Matrix I literally have to put the pedal to the floor to get it into open loop. If you just accelerate at about half throttle (still pretty brisk acceleration) and keep the rpms at about 2000-3000 (under vtec engagement I assume) you should be doing pretty good.
Current project: Adding regenerative braking to the Mirage
  Reply With Quote