Two Step and DFI
 

I have an Accel DFI Generation 7 with an stand alone two step function. I also have an MSD box with a two step. I'm not sure which one to use, or if I even have a choice, since the MSD box wires into the DFI.

Is one method preferred over other? Does one provide a softer limiter? Or, do I have one choice, and I have to make it work?

I appreciate anyone sharing their experience with this kind of set-up.

Re: Two Step and DFI
 

All the people I help use the MSD 2 step.

Re: Two Step and DFI
 

I have the crane cams HI6 box with the DFI and I have tried both two steps. The crane box two step is what I'm using now and it sounds way better than the DFI built in two step. The DFI built in two step would pop very loudly and didn't seem right. I would have thought it would have been better than the crane two step because the ECU "knows" it's on a rev limiter and would adjust it's fueling and timing accordingly. With the crane box controlling the rev limit, the DFI box doesn't really "know" because it is seeing 100% TPS and referencing the 102kPA fuel map and I believe it is throwing lots of fuel in the cylinders that are being canceled. My car puffs black smoke when I launch.

Re: Two Step and DFI
 

If you are leaving in Closed Loop, the oxygen in the exhaust from the misfires on the 2 step will drive the mixture very rich. Even if your not, you see a lot of EFI cars smoke a little black at launch.
If you are running it in Closed Loop, you might try setting the minimum RPM above your 2 step RPM.

Re: Two Step and DFI
 

Thanks guys. I figured most would use the MSD, but I thought that the DFI would be the better route, since it should be able to control the RPM as a system, not just at the ignition.

There's a launch mode in the DFI, which allows you to control A/F ratios, timing, and RPM, among other things. Have you tried that?

Re: Two Step and DFI
 

Nope. I use and work mostly with FAST XFI. I have never messed with that, with DFI.

Re: Two Step and DFI
 

We use an old MSD two step that was out of an old super gas car and it still works well without issue.

Re: Two Step and DFI
 

MSD it is, then. Thanks again for the replies.