air fuel ratio's

background info

- d16a3 engine, 4speed auto
- ram intake, 2" catback
- approx 650-700km of driving per week

due to the amount of travel that i do, and the increase in petrol prices, i want to squeeze every km/litre that is possible.

i've got an old school SAFC lying around, waiting to be hooked up. i can adjust at 5 different rpm set points. i also have a jaycar digital air/fuel display.

questions
- should i still get it tuned on the dyno?
- am i able to tune it using just the air/fuel display?
- what should be the optimum air/fuel ratio in terms of consumption, performance etc
- will i need to have different settings if i use unleaded, premium or 98ron?

sorry for the loads of questions. thanks in advance

without a wideband o2 sensor, the a/f display on it is completely worthless... don't try to tune with it, it won't do you a bit of good.

Honestly, you're really not going to be able to make any gains that way, and you don't really have any mods that justify a significant fueling increase

true. however out of the factory, the majority of ecu's are programmed to run richer than they should. and going by a dynograph produced by the same engine with similar mods, its tending to run quite rich at the high end. and because i do a lot of freeway driving, it means that i'm in this zone quite frequently

most dynos show a/f at higher rpm at higher load... fueling is different at higher rpm and light load.


What sort of a/fs are these dynos showing?

mind you, this is all based on an assumption that this is how all d16a3 engines perform. of course, i won't know how mine is running until i get it on the dyno

courtesy of fat_85_civic's civic with a d16a3
http://www.redpepperracing.com/galle...Stock+Dyno.jpg

wow... crazy rich indeed...

I have a very difficult time believing that that's how honda intended things


for reference sake, if that's how it should be, your a/f ratio will not be like that whille at the same speeds/rpm if you're not giving it full throttle

yeah, i doubt that honda would have planned for it to run like that. but either way, its something that needs rectifying. i'll get my car dyno'd, using a wideband o2 sensor. that'll confirm wats going on with my air fuel ratio's

Something is definately astray there, without knowing what the owner has done to that car (ie what ecu, mods etc), all comparisons are really useless.

the engine on the dyno is stock, aside from a k&n panel filter

yeah, and what engine manaement is he running, including add ons(Vafc), vtec controllers etc etc

d16a3, 1.6l DOHC non-vtec. no engine management upgrades, no add-ons

very strange, i'd put that one down to a bad O2 sensor

what sort of fuel ratio's should be aimed for?

approximately