Idea for better staging
 

Here is the problem, I am running 850 1300 on an REW motor with the stock seq system.

It builds boost so fast and so easy that I inevitable bounce off the staging bar any time I am pulling away from the line, with even 20% throttle, as low as 2K rpm (where there is no power).

I know that a good tuner could make it far less noticible, but it will allways be wasting some fuel that it doesn't need to when bouncing off the staging bar.

So the idea:

Use a fast switching electronic solenoid and an RPM switch off the ECU set at about 5K RPM (or 4K or whatever to be calculated based upon max possible injector duty cycle at a given RPM) to controll the +12v signal to the secondairy injectors.

That way the secondairy injectors don't open up unless the staging bar is hit and I go past that pre determined RPM.

Second use the output of the solenoid to the injectors as a second input into the 2 step switch that I currently have set at 5K RPM, so that if the solenoid fails, then the engine bounces off the 2 step.

I really wish haltech would:

1 include a staging RPM, as in do not stage before (like stock ecu)

or 2 add a 2D map with load and RPM that vary's the staging bar (at 3K stage at 20PSI, at 3.5 stage at 15 and so forth) I guess this might make it harder to tune because of the interpolation that would be nescisary along the staging bar part of the map.

Opinions?

I honestly believe it can be all tuned out.

You can adjust when the stagging occurs (what bar) and that might help.

I've had to use this when converting a 3bar map to a 2.5 bar map.

If you have a wb you can easily tell what it's doing at the transition.

Take a look at some maps that have those size injectors and look at the stagging points for ideas.

Where is the staging bar?
If it's in vacuum, it would help to put the staging bar on the boost side of the map.
With the 850's you're running with the stock twins, you should be able to run it at least 2 bars past "0".


-Ted

does this go with TII's also?

It can be tuned perfectly. That's one advantage Haltech have. You can actually tune on the staging bar and get perfect AFR's. The way to do it is to put it on an eddy curent dyno so you can load it to the required load point on the map. Doing it this way will give you a perfect AFR and make it a lot safer than trying this on the street. Also using that type of dyno you can nail your AFR's on every load point of the map especially in the low load areas in a very short time.
The staging setup on earlier Haltechs did not have this feature and staging had to be a compromise sometimes in different parts of the map. With the present software Haltech enables you to acheived a perfect staging setup.
I have setups that stage the injectors at 12psi and get perfect AFR's below, at and above this load point.

I don't have the benefit of an eddy current dyno, or the money to tune on one

The staging bar is set at the first bar above 0

I hit 4-6 PSI at 20-30% throttle under 2K rpm, this is where I am finding it impossible to stage, anything over 3 to 3.5K rpm doesn't have a problem

It just seems that if the staging had either an RPM or throttle % "qualifier" that it would work better, perhaps a TPS switch based upon the TPS setting, after all the secondary throttle doesn't open until long after the primary throttle is open

So what's exactly the problem at 2K rpm?
At that load and rpm the primary injectors can handle the fueling so make the required adjustments to suit. With 850cc primaries you could move the staging bar a little higher.

Around 2-3K there is lots of variance when crossing the staging bar depending on throttle and load, If I have it set up so that at full throttle in first gear it stays pretty stable when staging, it will go real rich and even stuble when the throttle and load is greatly reduced, and the opposite vice versa.

You either don't have the right AFR's at 0psi and the staging bar is not correct.
What AFR's are you trying to acheived at that load level?

11.5

The issue is only when staging at lower rpms, but short of moving the staging bar to 5-6 psi there is no way to keep it from staging so low.

You're way to rich at that rpm. You don't need to be that rich at such a low load vs rpm.

If I try to tune for 13-1 I get a bad lean stumble.

I have found that one of my primary injectors is bad (Impedance).

So I am going to install a set of fresh, 550 primaries that I have and try and re tune with it in primary hold mode.