Quote:
Originally Posted by Lagerpe  GaryG,
Many thanks for these comments. They were very interesting to read. I take it that this adaptive function is indeed made possible by the presence of a knock sensor, right?
I am almost ashamed to admit it, but I was not referring to MPG performance, but rather to bhp performance (horse power).
So, the question remains: will 93 octane gas give higher bhp and will the difference be noticeable?
Lagerpe |
In the '05 workshop manual, only the I-4 2.3L has a knock sensor. There is no knock sensor listed for the V6 3.0L engine. The adaptive system comes from feedback from the heated oxygen sensors located before and after the CAT converter. The PCM adjust the fuel mixture from the O2 sensors feedback.
In my younger days when I built race engines, high compression required high octane to prevent premature ignition (knock). The higher octane had a slower burn rate and allowed the fuel to be completely compressed so the spark plug would fire the explosion in the cylinder at the right time. This made for more power because the explosion wasn't premature before the piston reached the top of the compression stroke. The lower octane produces more energy and a faster burn rate (explosion) in the cylinders if premature ignition is reduced because of less compression and better timing control.
If higher octane would increase HP, it would also increase fuel efficiency in lower compression engines. In lower compression engines like your V6, high octane is a waste of money. I presently hold the record of 61.8mpg in the Ford Escape Hybrid at the '07 MPG Challenge. If 93 octane would have increased my efficiency with more HP, I would have ran with it.
If you haven't heard, the '09 3.0 V6 Ford Escape comes with 40 more HP and gets better mileage than the '08 V6 Escape. The new Escape also comes with a new 6 speed transmission. It runs on 87 octane also.
