better/easier to tune larger injectors or gm maf first?

[brandnew161]

ok i have a set of 680cc precision injectors and a gm maf and maft ready to be installed and i want to be sure of the correct way to go about dialing in the settings since i have never tweaked a maft before. Basically my questions are;

-is it easier to tune the larger injectors first or the gm maf/maft first?
-OR do i install both at the same time, tune the maft, and then tweak the safc?
-Do i clear the tune i have now (hi-lo maps) in the SAFC and completely re-tune the car starting with the MAFT?

To me it just seems like a lot to do all at once but if thats the right way then so be it. I'm familiarizing myself with the safcII and i'm comfortable with doing it myself. My AEM UEGO and EGT gauge really help out a lot. Thanks for the help.

 

[redleader36]

Gorgeous Car!

I would think that leaving the SAFC alone would be easiest. Install the injectors and the translator at the same time. Then set up the translator for the 680s to accommodate for the extra fuel. That way you are only turning the knobs on the translator to punch in 680s as the tables in the owners manual suggest. you can leave the fine tuning to the SAFC. My reasoning for this is to keep the SAFC with plenty of adjustability on both the rich side and lean side. If you accomodate for 680s with the SAFC, you are pushing it closer to one of its leaner limits before you can even start to fine tune.

Anyone else agree or disagree?

 

[brandnew161]

Gorgeous Car!

I would think that leaving the SAFC alone would be easiest. Install the injectors and the translator at the same time. Then set up the translator for the 680s to accommodate for the extra fuel. That way you are only turning the knobs on the translator to punch in 680s as the tables in the owners manual suggest. you can leave the fine tuning to the SAFC. My reasoning for this is to keep the SAFC with plenty of adjustability on both the rich side and lean side. If you accomodate for 680s with the SAFC, you are pushing it closer to one of its leaner limits before you can even start to fine tune.

Anyone else agree or disagree?

Thanks! she looks pretty sitting there, now i want to get it running just as good

that make quite a bit of sense. So pretty much what do i change on the safc? I know that i'll have to zero out the hi-lo maps. But what about the other settings? For example, will the safc still be set up as karmen? I hopefully will get the maft in the mail today, i'm interested in seeing which f/w version it is. Thanks for the help

If anyone else has any tips, chime in!

 

[redleader36]

thats a good question. i don't think you will have to change much. it will just be some fine tuning because the translator will soon be sending a slightly different signal to the safc/ecu. The main difference will be the hz for the maf signal will be a bit lower frequency than before because the translator is accomodating for the larger injectors. I understand that the safc runs on rpms anyway, so there will probably not me much to change on the safc.

the translator completely emulates the stock karmen signal, so there is no need to change that on the safc.

I am not very familiar with the SAFC so i wouldn't mind a second opinion here.

 

[clockworktoy]

With the Maft set up to compensate for your longer injectors the only changes i would do on the afc are on the low settings to get your fuel trims in check (+-5%). Other than that you can start fine tuning your high settings for your desired boost/afr's. Neopoints, high/low and sensor input shouldn't need to be changed unless you haven't set that up before hand.

 

[brandnew161]

good deal. thanks for the second opinion. i'm planning on installing the injectors and the maf/maft on a day where i dont have to work at all so i can play with the settings all day.