[John.M]

Installing this into an NA chevy silverado with cold intake, headers, and exhaust. I'm thinking of getting the universal S2. My question is: What parameters do we monitor to dial the system in? I have a real time OBDII software package to use.

Also, what does this system do to the O2 fuel feedback loop? Is the O2 system going to perform the same?

What settings can you recommend for best performance?

FYI: I'm an Aerospace guy, Autos are a hobby only.

Thank you

[Mike]

Check out the nozzle calculator to see what size you need then take it from there. Tune it according to dyno if you're looking for power. The Fuel Injection System goes open loop (Rich) at Wide Open Throttle so the 02 sensor feedback is ignored.

[John.M]

I'm aware that the ECU goes open loop during WOT. I'm going to be using this system at TPS positions well below wide open. I'm interested in cooling the intake air and (mainly) cooling the combustion cycle so I can run a bit leaner without the NO buildup and overheating issues.

That said, I'm aiming for injector operation during 2300-3000rpm approx. I will likely be using the absolute minimum nozzle.

My questions still stand: What ECU parameter should we be monitoring for tuning? What are the ECU symptoms of an engine running with a bit too much Alc/Wtr injection so I know what to look out for. Warning light, EGT temp ??

Thanks Mike, I needed to clarify.

[Mike]

Sorry I mistook "best performance" to mean outright power. I guess if you're aiming to reduce IAT's then you'll be monitoring that sensor? Ditto for the EGT's if you want cooler combustion etc etc.

Someone more experienced will have to answer what the effects of too much will do at part-load settings. Sorry I can't be of more help, I'm still learning myself. Good luck.

[Ondonti]

Since the progressive nature doesn't follow rpms but map voltage, and your vacuum will pretty much read zero the moment you go WOT, you gain nothing with progressive control.

Running it off TPS would probably work since most TPS have about 3-4 volts at WOT so thats well within the tuning range of the unit.

Thats more intelligent then pure RPM basis because maybe you arent pushign the throttle very hard but the RPMs are high.

Take a few PSI out of the base fuel pressure and hopefully your ECU isnt adaptive.

For lean burning, I would suggest similated narrowband that can change the switchover point. Zeitronix widebands can do this, so you can have your switchover point at 16:1 or higher/lower. So it will send the 14.7 switchover point that the ECU normally uses but send the signal at the wrong afr (the one you set it too).

Then you could keep fuel pressure the same, and leanburn the engine under load with meth to prevent knock at leaner mixtures (maybe you could go 18:1?!?! or higher). Thats pretty cool stuff that I never really thought about. Ive thought about leanburn but never a way to make it leaner and safer.

Since you probably have and after cat o2, that makes things more difficult to leanburn. Its easy to trick catless cars, but running super lean I dont know.

[John.M]

I'm thinking that I'll have to adjust the outputs of the PRE-Cat O2 sensors by adding .2-.3vdc to the timing circuit. The PRE-Cat O2 are the only ones that matter for EFI systems. This should trick the ecu into thinking that it is in a rich condition and attempt to lean out the mix. I'll have to plot it on a graph with EGT to figure that one out.

The rest of your comment I can't say I follow you. Remember, I'm an aerospace guy.

Please describe the effect of lowering the fuel pressure. In my uninformed opinion this sounds bad. Doesn't fuel pressure help the injectors atomize the fuel?

For lean burning, I would suggest similated narrowband that can change the switchover point. Zeitronix widebands can do this, so you can have your switchover point at 16:1 or higher/lower. So it will send the 14.7 switchover point that the ECU normally uses but send the signal at the wrong afr (the one you set it too).

You'll have to dumb it down for this country boy. What can a wideband do? It sounds like you are adjusting (lowering) the AF ratio. Is it as simple as that?

I'm an engineer and this is my little side project. My plan is to run the system at Temperature, RPM, and Speed consistant with highway travel. I want to get some data that will describe torque, temperature, AF ratio, O2 readings during injection operation. Basically I'm testing and plotting set curves for a "freeway travel mode" where I run lean and use the injection system to keep the torque curve consistant and prevent the combustion cycle from heating past 1500F where NO gas is created. My goal is lower emissions and slightly higher gas mileage in FTM.

[Ondonti]

I have run 31psi base fuel pressure and MPG staged the same on 1000 mile trips.

Atomization starts suffering below that.

The problem with changing fuel pressure is that your computer will probably modify things so your air fuel ratio is the same.

When you are in open loop, the computer constantly goes between 14.4-15.0. 14.7 air/fuel = "switchover" on your narrowband sensor. 14.7 is where the CAT burns the most efficiently and gives the cleanest emissions.

With Zeitronix, you hook a wideband in and then use the "narrowband output" wire (simulated) from the zeitronix unit and send that to your narrowband wire to trick the computer into thinking it still has a narrowband. Then, with software, you tell your zeitronix to change the "switch" point from 14.7 to whatever you want it to be. Your ECU will try to always being around the switch point to make the CAT happy. It doesnt konw that the signal it is getting is not accurate.

This way you can make your car cruise a few points leaner (whatever you want). It will run lean so under load, the alcohol injection would prevent knock (load, up hills etc, is when n/a cars usually knock) even with the lean mixtures.

Wiring alcohol to the TPS voltage (throttle position) would give you load based alcohol spray. it wont follow RPMS but it would work well with leanburn setups.

[dvldoc]

The controller works fine with GM 1bar map sensors, All the controller knows is voltage.

The GM 1bar sensor reads from 30in of vac to 0 so it is works great as a input source for a progressive kit. YOu would just order the voltage faced controller and use that with your system.

Many vehicle run this set up, to include High compression N/A engines the need premium fuel but rather run alcohol for the extra timing.

We do have a EGT signal converter as well that is not out in the store yet. You can PM rocket468 about that unit.