View Single Post
Old 03-10-2014, 05:07 AM   #9 (permalink)
serialk11r
Master EcoModder
 
Join Date: Jan 2012
Location: United States
Posts: 1,756

spyder2 - '00 Toyota MR2 Spyder
Thanks: 104
Thanked 407 Times in 312 Posts
Quote:
Originally Posted by oldtamiyaphile View Post
My turbo charged Fiat 500 stays in closed loop at WOT all the way to the rev limiter (as verified by SG). Most small Euro turbos are tuned for ecomony so I wouldn't be surprised if many of them do this. The Jeep and Merc also stay in closed loop at WOT, they may switch to open loop at well past sensible revs, neither would normally be revved anywhere near that point.

Given this I now simply accelerate at WOT which is a lot easier than aiming for 80% load or 14 inches on the vac gauge. The 80% load - stay out of enrichment idea seems gospel around here but in my experience it's not a blanket solution.
Newer cars are indeed closed loop through the whole rev range, except this closed loop is using a wideband O2 sensor. Because they have wideband sensors, almost all new cars are capable of running rich in closed loop and do so at WOT. Because of the 7 year (I think 7?) emissions equipment warranty requirements, modern cars actually can run very very rich (to cool the cat off with excess fuel), which is very bad for mpg. For example in the FRS/BRZ community people have seen noticable fuel economy improvements by optimizing the tune for power, which leans the engine out a bit at WOT. The fuel saved at high throttle positions can be significant.
  Reply With Quote
The Following User Says Thank You to serialk11r For This Useful Post:
vwecopower (03-10-2014)