I'm interested in the stock staging of the secondary injectors coming online. Is the stock staging dependent on rpm (3500 rpm) and load (atmospheric pressure I think) and is there another element??? The real question is, is there any other item other than rpm and boost sensor pressure involved? AFM??

I plug the source of vac to the pressure sensor and the secondarys come onat 3580 each time. Just curious if there is another element involved?

 

Secondaries will come on under the following conditions:
1. If rpm's are above ~5632
2. If rpm's are above the staging point AND there is positive
pressure in the manifold. "positive pressure" is the MAP sensor
(boost sensor) corrected for altitude. ie if your at altitude, the
secondaries will come on at a lower MAP reading than at sea
level.

-Henrik

 

is that only coming on w/ boost something that is happening on the stock ECU?
I know FDs bring on secondaries, and FCs at 3800, but never knew that t2s had any sort of positive pressure switch for the injectors
-Ben Martin

 

PUll your boost sensor vacuum line off and plug it. Go start the engine and rev it and you'll find the secondarys come online anytime over approx 3600 rpm. In other words atmospheric pressure is just about all you need to trigger it with the 3600 rpm. I'd suspect the FD's do the same.

 

bump

just wanted to confirm the secondary injectors are on ONLY if:
RPM above ~5632
OR
RPM above the staging point AND boost above 0 psi (including altitude correction)

The reason i ask is i ordered some 1000cc injectors and got to thinking. I want to use my 720's as primaries and need to be sure to where i need to correct for the 720/1000 combo. If i accidentally have it leaned out for 2ndaries on, when they are really off, that would be bad

so for secondaries on, the total fuel will be:
720*2+1000*2=3440
-15% correction with the 720/720 preset, total fuel would be 2924

Using the 720/720 preset with 720x4 actual, with no correction, total fuel would be 2880

I realize the fuel would never actually be that high (100% duty cycle), i just used that for comparison for before/after adding bigger injectors. So theoretically, it would still run a little rich with this setup with the full -15% correction applied. I also realize this is only an approximation of the stock map, so the ultimate deciding factor is feedback from the wideband along with a decent timing map. I would probably start with -5% correction (only where the secondaries are ON in the map!) and tune down from there, but does anybody foresee any problems i may run into? Hopefully im not missing anything and wont blow anything up