Wideband and tunning questions

[talon187]

ok im new at tunning im running an safc2 a maft and aem wideband im wondering what should the a/f ratio be? i know at idel the af is lean. i havent driven the car yet i will tonight when i pick it up my dump tube is being made at the moment. if my car is lean at idel should i try to richen up on the maft or the safc2 ? or do alittle on each ? any input would be great thanks guys

 

[silvreclips]

You dont want your car to be lean at idle. It should idle around 14.7 A/f. The ECU controls your fuel and tries to keep a 14.7A/F untill it goes into open loop mode. If you have larger injectors you will want to lean your car out to try and have the fuel trims around 0. The ECU is going to try and keep a 14.7 ratio by altering your fuel trims. You want to have these close to 0 so that the ECU can either lean or richen the mixture up as need.

When you try and tune the car at WOT tune the AF to between 11.1-11.5 and you should be fine.

 

[talon187]

hrmmm i dno why but my idle is only around 11ish

 

[91talon27]

That means you are running rich. Try taking out some fuel out of the Safc at the 1000 rpm ne point. Don't take out a lot at first gradually do it maybe 5% at a time. After you take out 5% wait approximately 20-25 seconds before making another adjustment. This gives the ecu time to react to the change you made.

 

[talon187]

i got the idel to be about 15 ill leave that for now as far as higher rpms its going alittle to lean over like 3500-4k rpms

 

[turboglenn]

How lean? If you're seeing 12:1 or leaner under wide open let off and richen those areas up and fade some of the change into the RPM zones around the lean area too. Say it's going lean at 4k you would richen 4K, 3500 and 4500 to where they are all near each other. Mainly what i'm trying to get at is Your fuel curve on the AFC should look rather smooth. If you are -8 @ 4000 and it's okay, then 4500 & 3500 areas shouldn't be too far off for % taken out, only a couple percent at the most. If you are finding yourself raising one particular area too much, change the ones around it with it.

I hope that makes sense, it's easy to explain in person when you can point or draw pictures

 

[talon187]

i k inda understand i richen it up at idel on the maft and it made it eaiser on the safc im going to play with it on the way home tonight little 91talon27 said 11.1-11.5 was ok so are you saying 11.1-11.5 is still to lean ?

 

[talon187]

this may go eaiser once i get a chip into my ecu as well im thinking of geting a chip for 550s take away fuel cut and up the rev limiter with a sutter box but im not sure yet

 

[GVR4592]

Air fuel metering


Basically you want as close to 14.7 as you can get at idle and cruising, and around 11:1 at wot. The lower the number the richer the mixture.

 

[talon187]

ok thanks i see 10 i was seeing 10 at woot when i started to get on it i let off once it got there ill have to take alittle fuel out then

 

[GVR4592]

Are you monitoring knock, or just tuning with the wideband?

 

[turboglenn]

i k inda understand i richen it up at idel on the maft and it made it eaiser on the safc im going to play with it on the way home tonight little 91talon27 said 11.1-11.5 was ok so are you saying 11.1-11.5 is still to lean ?

No that is rich, tht is for when you're wide open only. At idle is should be hovering around 14.7 that is what's called stoich or perfect mix for a clean burn. The stock o2 sensor should actually cycle up and down from .200 to .800mv constantly when you have the idle and cruise fuels right. Then when you step into wide open you want it to go to 11:1 - 11.5:1 and stay there, that will ensure you're safe on AFR.

 

[talon187]

so what should the a/f be if im riding around and the cars not under a load?

 

[spyderturbo007]

so what should the a/f be if im riding around and the cars not under a load?

Scroll up and re-read Luke's post. You'll see that the answer has been here for 2 days just waiting for you to find it.

 

[1992awdlaser]

It should be at 14.7:1 when at idle or cruising. I tune for 11:1 at full throttle on pump gas and 11.7:1 on race gas at full throttle.