how are your air/fuel ratios?

Mine seems to being running lean. It went very close to 14:1

On my VAFC, I added 10% fuel across the board and that made no difference on the air/fuel ratio Anyone know what might be causing that?

Pulled my sparkplugs and they look normal. Don't hear any knocking from the engine either.

Anyone know the FMU ratio is that comes with the SC kit?

 

Are you running one degree colder plugs?

 

Yes, I am. I'm running the NGK Racing plugs you guys recommended.

 

most time between 13.1 and 13.5 on my Vortech with ProFlow TB.

Where did you put the WB probe ?

 

My first dyno had my AFR in the mid 13s with just a peak at 14 at 6000 rpm. A later dyno with a different sensor had it in the low 14s all the way up to 8500 rpm. This is with the readings taken from the tailpipe.

Various sources seem to indicate that the FMU is set to 10:1. You can change it to 12:1 with a cheap upgrade from Vortech, but I don't know if the injectors can take the extra pressure. It's also hard to know if the FMU is really doing 10:1 (unless you test with a fuel pressure gauge) given all the boost pressure taps on the line that goes to it. I think there are like three or four different things tapped into this line like a christmas tree. The FMU might like one direct line better.

MG

ps - I might do a dyno run with the 12:1 FMU mod just to see what happens.

 

If you do it in the tailpipe it will show 14.5 - 14-7 because the cat is burning the excessive fuel. I used the first O2 and it shows max 13.5 but in the second o2 (cat) it shows 14.6-14.7 .
The only way to do it right is using a testpipe.
Make sure your WB02 is calibrated.

 

First we tested the air/fuel at the tailpipe, then wideband O2 Sensor was put into the cat. Both had same result.

 

Let me know how the 12:1 FMU turns out on the dyno.

 

[QUOTE]Originally posted by S2K
[B]

First we tested the air/fuel at the tailpipe, then wideband O2 Sensor was put into the cat.

 

We spent hours on the dyno getting mine just right with the VAFC. I live at 5500ft elevation and I run the ND Irridium's 1 step colder. My A/F measured at the tail pipe average 13.5 but never spike above 13.7. My tuner indicated 14 would be too lean. As you can see it builds big power! I have my dyno sheet and would love to post it, but I would have to fax it to someome who can scan it. Any takers??? Phil