SAFCII Settings, No Correction on 550's???

[Cool Mr Steve]

I have 550's on my car along with an SAFCII. I have been running the setup for a good long while now but I have had this issue from the beginning. Why would my car need no fuel correction after I installed my 550's? I have 0 correction at idle, and at some points I'm adding fuel to correct my fuel trims.

 

[FastGS-T]

-18% on your SAFC with the 550s, is the equivalent of 0% with your 450s.. remember when looking for a new base line on an AFC

(old injector size / new injector size) - 1 = % correction for new injectors

 

[Cool Mr Steve]

I'm not sure you understood my question... I am aware that there should be correction and that it should be around -18%. If I tuned it to -18% though, my car would be getting 18% less fuel than it needs to run ideally. 0% correction is making it run correctly. It's like I installed stock injectors, but they are clearly RC 550's.

 

[FastGS-T]

Well when I was running my 550s with a ported b16g I had the same situation, turned out I had boost leaks and ended up messing my motor up. Washed out a cylinder with fuel. I would just put it to -18 and check for boost leaks and then re tune. Your car shouldn't be running fine because at wot you shouldnt ever be adding fuel bc you should be taking %ages out of larger injectors

 

[larsenracing]

Mine is the same way my low throttle setting is all at 0-1% and my high points are all about 17-18% roughly. The shop that dyno tuned my car had said when i asked him about it he said that the computer will correct for the little difference. He had tuned it for low and high throttle and that is about the right correction for my car. It ran the right air/fuel mixture I looked at the graph to make sure it was right. PS> the guy that dynoed it is very good with DSMs that is his main business and he has a great name for it so I guess I will trust him. He has dynoed it many times and its pretty much the same tune.

 

[EclipseTrbo420A]

Mine is the same way my low throttle setting is all at 0-1% and my high points are all about 17-18% roughly. The shop that dyno tuned my car had said when i asked him about it he said that the computer will correct for the little difference. He had tuned it for low and high throttle and that is about the right correction for my car. It ran the right air/fuel mixture I looked at the graph to make sure it was right. PS> the guy that dynoed it is very good with DSMs that is his main business and he has a great name for it so I guess I will trust him. He has dynoed it many times and its pretty much the same tune.

I was messing wiht my fuel trims after my afpr and I have 1K -5% , 2K 0% , 3K -14% I dont see why it would just jump from 5 to 0 then to 14 but they say there with in 10 from 0 I dont get it...so really I have kind of the same problem as the thread starter. Ill do a boostleak test tomarrow and check that situation.

 

[Cool Mr Steve]

Hey, I just wanted to update... My corrections are at about +8% at idle, but I am taking out the proper amount of fuel at upper RPM's. And I believe I found out why I am having to take out fuel at idle

You are tuning out your deadtime with your injectors. RC engineering injectors are known to have high dead times. What you are doing is the only way to tune it out with pigglyback. DSMLink would get you a much better tune, becasue you tell the ecu to include extra deadtime when calculating the duty cycle. But, nevertheless, you're doin gright and that makes sence that you have to do this.

So if anyone else is having this issue, that is probably why. Don't make the same (stupid) mistake I was making and have no correction throughout the powerband... I was hitting fuel cut at about 3500rpm because of it. Hope that helps someone...