I've been reading here and in the computer forum and I cant find a definite answer. I understand that the LT1 at WOT is in PE mode and not reading the O2's. How does the ECM know to add fuel while injecting the n2o? There will be a difference in intake manifold pressure as the engine revs faster but that will only afect the FPR which isnt gonna help much. The ECM needs to increase the injector pulse width to add enough fuel I would think. That only leaves the MAF sensor. I have not seen anyone running the n2o in front of it and dont see how the ECM would correct for it (accuratly) only reading the NA air. So is a dry shot really too dry?

 

The typical way to increase fuel flow when spraying a dry shot is to increase the fuel pressure, not the injector pulse width. The NOS 5176 dry kit uses a small, pressure regulated nitrous line to the FPR to bump the fuel pressure up when the nitrous solenoid opens. By adjusting the fuel pressure increase, you can kind of "tune" for the shot size.

Some people have tried spraying dry nitrous directly through the MAF sensor on the LT1, and have reported good results. You might want to do a "search". The sensor will pick up the added mass of the nitrous, and adds extra fuel. Problem is that the stoichiometric A/F ratio with fuel/nitrous is not the same as it is with fuel/air, and the O2 content of the nitrous, and specific heat of nitrous (used by the MAF sensor to calculate mass flow) is not the same as air..... so it comes down to a hit-or-miss situation.... maybe all the "errors" in the system cancel each other - I don't know..... never tried it.

You can't go into the PCM and "tune" for nitrous, because the PCM has no way of knowing when nitrous is flowing.

 

Thanks Fred, I didn't know for certain that the LT1 dry kits came with provisions to connect to the FPR. From what I have seen and read so far the install instructions are to inject right infront of the throttle body. So I guess it was someone being creative to inject through the MAF. From what you explained about the MAF reading the n2o, it would add more fuel and not less just not sure how much. Makes more sense why some people prefer a wet system, there is a more straightforward control of the added fuel with the fuel jets. Thanks again.

Dan