Fuel injected 2 step?

[art leong]

What do you do to the fuel map during the 2 step function?
Trying to get it smooth at 3200 but in gear it's rough.
Can't use data because it shows real lean because it randomly kills 25% of the cylinders. So it has a lot of unburned oxygen.

[Ed Wright]

Originally Posted by art leong

What do you do to the fuel map during the 2 step function?
Trying to get it smooth at 3200 but in gear it's rough.
Can't use data because it shows real lean because it randomly kills 25% of the cylinders. So it has a lot of unburned oxygen.

Art, you don't do anything to it. If you can duplicate WOT at that RPM with no 2 step just dial the air/fuel ratio in that way & forget it. An engine dyno can load it WOT and hold it there. That is how I did mine. it wasn't far off. I did it before by setting the 2 step down to 2000. That gave me a look at it as it went past 3200 hitting on all cylinders. It was very close to the engine dyno data.

[art leong]

Ed I'll try to set the 2 step that low then use the quick tune function to get the afr to around 12.8. Not sure if I can set it that low, But I'll try it tomorrow.
Thanks
I have a function that can adjust the fuel when I have the button pressed. It seems to want to be pig rich when on the 2 step. leaning it out seems to make it very cranky. But I'm
afraid of making it to rich and washing the cylinders

[Ed Wright]

Art, 4 cylinders probably sound a lot rougher than an 8. 12.8 is where I run mine. If your ECM is fast enough that should get it. You tap the L key on mine to make it learn. Takes more than once. If you can set the Gain for the learn function kinda low it won't be as likely to over shoot the target. Mine tends to do that, go too far first time. I just log it and make a change, then run & log it again. I can usually hit second time if not the first.

[art leong]

Originally Posted by Ed Wright

Art, 4 cylinders probably sound a lot rougher than an 8. 12.8 is where I run mine. If your ECM is fast enough that should get it. You tap the L key on mine to make it learn. Takes more than once. If you can set the Gain for the learn function kinda low it won't be as likely to over shoot the target. Mine tends to do that, go too far first time. I just log it and make a change, then run & log it again. I can usually hit second time if not the first.

I have a quick tune function., that I can pick a box map/rpms And type the afr I want then type the actual afr and it adjusts automaticly. It is very accurate if you are within .5 of what you want. If you are getting readings of 11.0 and you want 13.0 it takes a couple of trys to get it right.
The motor is making plenty of power. But my short times are off by 4 to 5 tenths (not hundreths).. If I can get the darned thing to launch even like last year (low 1.70's). I'm looking at some respectable times.
I will go back to the trans brake if needed (1.60's) but I've been breaking a lot.

[Ed Wright]

To get a good look at it that low try foot braking it from very low with no 2 step. Might be worth a try.

[art leong]

Originally Posted by Ed Wright

To get a good look at it that low try foot braking it from very low with no 2 step. Might be worth a try.

The problem with that (I've tried it) is as soon as the throttle gets open enough to get to 100kpa's. It pushes past the brakes big time. I had a "looser" converter made and it was actually much tighter. The one in the car flashes to 5200 the "loose" one flashes to 3500.
My thoughts are it needs to be richend up a lot (2 step seems to act better when richer) when on the 2 step but I'm afraid of hurting something.

[Tim Lisson]

I'm going to try a 2 step with my car this year. One thing with my set up, the O2 sensor reads nothing at my preferred starting line RPM due to its location and with my crossmember, I can not add a collector extesion to help the situation. I did try 2 stepping one time and it was so overfueled it barely stayed running, then left like a slug. For foot braking it likes more fuel in those cells. I will pull a bunch of fuel out of those cells when I try it this spring.

Ed, you posted sometime ago regarding percentage of AFR change, equaled? What was that again?

Tim

[Ed Wright]

If the V.E. table & injector flow rate are set up correctly the V.E. around the torque peak should be around 100%, then if you want to lean from 12-1 to 13-1, subtract 10%, should be really close. To go the other way add 10%. 13-1 to 12.5, add 5%, etc.
Works with FAST XFI & Big Stuff3, DFI, should work with any system. Your results may vary. LOL

[art leong]

I think my problem is semi solved. Still does the herky-jerky on the brakes.
I went back and used the standard launch control program (non advanced mode)
But it doesn't go to 2000 and die there.
We will know tomorrow.