Stryk3r

Hi guys i have a Pivot wide band installed in my FD3S, and i am running .81 boost, i wanted to know that there are numbers from 1 to 20 on my pivot gauge so what do those number coresspond toe.g if it shows 14 on the gauge does that mean that my ratio is 14:1 or something else and what would be a good ratio above 12 or below it please advise?

ksource

If I'm not mistaken it's better to be running richer, and 14:1 is Air:Fuel? Then 12:1 and lower would be better since there is less air per amount of fuel = richer.

Don't quote me on that because I'm not sure.

yonner

14.7:1 is a perfect mixture i think but an x7 runs a bit ritcher im shure mabe 13:1 i quite fancy getin and afr guage

j9fd3s

under full load it should be richer than 11:1, cruising it should be 14.7+/-.5

wolfgang

That is true, assuming that you can get perfect atomization of fuel, which is almost imposible. The only time you will likely see that is when the engine is at steady state (ie, crusing on a flat at a steady speed, idling at 1500 rpm for a while, etc). You will prob. have normally above 12:1, and under hard accelleration it will drop (I have seen 9:1 on my S4, but at that point it was just dumping fuel into the intake as fast as it could, and was not a good thing...time for a rebuild....). You want to get this number as close to ideal as posible for ideal fuel usage, but be aware that the reason that rotaries normally under stock ecu, run a little rich, so that some heat is disapated into the fuel.



Things normally done to improve your SMR are....

1: make your intake and exhaust as smooth as possible inbetween your maf / map and your O2 sensor. Ie. increase turn radius's, switch to smoother pipe..... This requires hours with a dremel / air grinder, or new pipes. This is a really good idea to do!!



2: Increase the PSI in your fuel system. Whenever you increase the pressure of a liquid that you are trying to force threw a small hole (ie. your fuel injector) it will shear itself into smaller particles. You can do this with a fuel pressure regulator, and if you change it you will have to recalibrate your ECU to the new line pressure. (total fuel is aprox equal to PSI X Injector size X duration of opening)



3: Decrease the size of the injector holes. Again smaller opening = higher PSI. You will also have to increase the number of holes in the injector so the total surface area is the same as before.



4: Find some way of disrupting the airflow around the fuel injection point. Mazda does this on stock S4 fuel injectors by putting a screen just downwind of the injector. This is the idea behind the tornado devices, which have not been proven to work. Basic concept is if you drop a drop of food coloring in a stirred bowl of water it will dilute faster than a standing bowl of water. Same deal except use fuel instead of food coloring and replace the water with air.



5: Get a more advanced ECU that can react to the changes quicker than stock. I noticed quite a bit more power, and got better MPG when I upgraded from my stock '86 dinosaur ECU to a megasquirt (www.megasquirt.info). Other ones are from haltech, etc...



6: Hook your wide band to your ECU so the ECU can use the new more accurate information. This may require switching ECU's to one that can understand all of the new WBO2 info. There is info on how to make a wideband O2 be electrically compatable to a regular O2 at the megasquirt site.

Stryk3r

hi agian guys thanks for your replies but i was wondering i am still confused would a 12:1 ratio be richer or leaner than 14:1 and so on lets say i am at 16:1 so which of the above 3 gigues shows lean and which shows rich mixture????

ksource

12:1 is richer than 14:1. 16:1 is leaner than 14:1.

yonner

think of it this way more air to 1 part fuel is leaner



les air to 1 part fuel is ritcher