View Single Post
Old 01-27-2012, 09:29 AM   #9 (permalink)
320touring
Master EcoModder
 
Join Date: Jun 2010
Location: scotland
Posts: 1,434

The Mistress - '88 Bmw 320i Touring SE
Team m8
Last 3: 27.17 mpg (US)

Germany Beadle - '91 Mercedes 300td (estate, N/A)
90 day: 24.63 mpg (US)

The Bloodylingo - '05 Citroen Berlingo Multispace Desire
90 day: 39.77 mpg (US)

Shanner Scaab - '03 Saab 9-5 estate Vector
90 day: 26.19 mpg (US)

Clio 182 - '05 Renault Clio RS 182 182
90 day: 31.73 mpg (US)
Thanks: 90
Thanked 95 Times in 79 Posts
Quote:
Originally Posted by Olympiadis View Post
I haven't seen everything, but I have yet to see an adaptive fueling routine that couldn't compensate the pulse-widths by at least 25%.
That is during closed-loop though.
The problem is I have never seen a system that applied fuel trims to the cranking fuel, so you could run into problems there.

The new design injectors are supposed to be more efficient, and I'd like to see some really well done tests to show this.
Generally for efficiency (as in ecomodding/hypermiling) you want to size the injector on the small side and run higher pressure.
You want to increase your fuel pressure until you see negative fuel trims in most of your load cells.
The reason you want negative trims is because positive fuel trims, while they have to subtract fuel to bring you back down to stoich in closed-loop, will often be applied to the fueling values as calculated in other modes of operation like PE Power-Enrichment and AE Acceleration-Enrichment. The other modes of operation are almost always too rich already, on the order of 10 to 15% more fuel than needed. If whatever load cell you are in when you invoke one of these modes has a positive fuel trim, then it gets this extra fuel applied. Negative fuel trims do not normally get applied to anything but normal closed-loop operation.
Thanks for the info.

The car runs NO knock sensor, only a crank sensor for timing, and has no ability to advance/retard ignition, hence my concern regarding it's abilities to alter pulse widths..

Also, with some more thinking it occurred to me that the lbs for the engine are devided by 6 (6 injectors) so I need to look at SMALLER capacity 4 cyls, rather than ones with comparable bhp/displacement.

i.e. possible replacement injectors from a 1.4/6 rather than a 1.8/2l
__________________
My Blog on cars- Fu'Gutty Cars
http://fuguttycars.wordpress.com/

US MPG for my Renault Clio 182


---------------------------------------------------
  Reply With Quote