ECU

Info provided by Calvin of Nivlac57 Youtube Channel

Stock GM ECUs

The Vortec 4200 came with 3 different ECUs from the factory. The P10, P12, and E67. See below.

If you are running Naturally aspirated, any of the 3 ECUs will support your needs. The P10 and P12 also provide transmission control, which is something to consider if you are running a 4L60e. The E67 has a separate transmission controller (likely a T42).

P10

The P10 (left) would only be good for swaps where the motor is being left relatively stock. They definitely give you some room to get a little extra power, as Power enrichment is basically turned off, and the stock VVT tables targets 12 degrees of cam angle at wide open throttle. The part that will kills it is in HPtuners, they do not allow you to enter injector characteristics if you choose to change injectors. Additionally, they don't let you change any idle characteristics other than the target engine speed. This is not great for those that may want to install larger injectors and reground cams. You could always go the decapped injector route though and hope the idle settings are up to the task. There is no flex fuel support, and there is no support for boosted applications. Honestly it would be my ECU of choice for naturally aspirated combos simply because they allow you to adjust the VVT settings. It also is ideal for those that want to use it in a piggy back scenario, and just want the ECU to control the VVT. 

P12

The P12 (middle) is widely considered the go to stock ECU for boosted applications. The reason the P12 is the go to is it has a MAF sensor, and the appropriate scale on the spark table to provide safe spark timing at varying boost levels. Since there is no way to expand the Speed Density Fuel table on the P12, all enrichment in boost must be done with use of the MAF sensor. This can be a bit touchy, but is very doable, until you run out of the accurate range of the MAF sensor. The spark table uses Cylinder Airmass on the Y axis which is required. In a nut shell how stock ECU tuning works is you are trying to fool the ECU into doing what you want. We can more easily fool Cylinder Airmass into having relevance in boost than if the table had MAP on the Y axis, when we do not have the ability to rescale/expand the tables.  One thing I do not like about with the P12 is that with HPtuners you cannot adjust any of the VVT settings. Therefore, you may get unpredictable VVT response, and will be leaving power, and possibly spool time on the table. Another thing I do not like is you cannot adjust any of the idle characteristics other than target engine RPM. This may be limiting for those that want to run cams, but the MAF sensor will likely dash any high power goals before cams are necessary.

E67

The E67 will support boosted applications! The E67 is the preferred choice if you must retain the Stock ECU. Unfortunately they only work on 58x crank patterns, so you'll have to run a 08-09 engine or add an external trigger wheel and convert to a 08-09 exhaust cam sprocket.

For those looking to have a stand-alone harness made, Lime-Swap is the way to go. They will build a harness for you that is very easy to hook up. They can also do ECU reflashes/VATS deletes. Here is a link: http://www.lime-swap.com/home 

VVT

So let's talk about VVT. The ideal response for the VVT in a NA combo is to just give it about 22 degrees (with stock cams) at anything above say 2500 RPM. There are no benefits to varying it across the rev range. 

With boost however, you can do a lot with the VVT. Ideally it should looks something like this (Note: This is just an example of the general shape. It has not been optimized for any particular combo. See sample tunes for that)

We have found it most successful to give it lot of angle at lower boost, and ramp it out as boost increases. Basically what the VVT does is change Lobe Separation Angle. So at lower boost you give it lots of angle (lots of overlap) to get the turbo to spool, and then you take it back out to maximize power. We optimized this strategy on multiple combos and it is repeatable. 

Now which ECUs are capable of providing this type of response? Of the stock ECUs, only the E67 can accomplish this. Any good aftermarket ECU that has control of the VVT, should be able to provide this control.

Aftermarket ECUs

Megasquirt

In performance applications, I strongly recommend people go to an aftermarket ECU. Microsquirt is a very cheap entry level option that is very simple to wire. Tuning can be a little difficult with this ECU, and I generally recommend people stay away from super large injectors with a Microsquirt. Running a Microsquirt will require a switch to a cable driven throttle body. Here is a complete wiring guide to making your own harness. Please note that you must run a 08-09 crank position sensor with any aftermarket ECU, because the older VR sensors don't work well with aftermarket ECUs. 

I recommend running ethanol with any boost application, so having an aftermarket ECU allows you to run a flex fuel sensor, and run any blend of gas and ethanol that you want. Additionally Aftermarket ECUs give you features like:

If you want more IO and Sequential fuel and Spark Control, I recommend a Goldbox, or MS3pro ECU. They support closed loop VVT control. They are wired very similar to the Microsquirt, but the Fuel and spark outputs will have individual outputs from the ECU rather than sharing outputs. Here is a wiring list for a Goldbox to get you started:

It's a lot easier once you start digging into it. Don't be scared of it. The EFI source manuals are excellent. Refer to them for all of your other questions.

Holley EFI

Many have asked if the Holley products will work on these engines. They do not support the 02-07 GM7X triggers. They will work with the 08-09 58X/4X triggers. You can always run an external trigger wheel if you want to run an earlier engine. Please be aware that they do not support VVT control, but you can always setup an output to run it open loop. It would be wise to run the cam sensor on the intake cam if running sequential fuel/spark as you will be moving the exhaust cam with the VVT. This will require some custom fabrication.

The only way that I have devised that you could get functioning VVT with a Holley is if you buy one of their GDI boxes on top of a Terminator X, and configure the engine as a Gen V LTX engine without the Direct Injection. They do support VVT control with the Gen V engines, but unfortunately the output pin for the VVT solenoid is on the GDI box and cannot be remapped. This is certainly not recommended by Holley, and may not even work. The only reason it has any shot at all is that the Gen V engine still has 58x/4x trigger. Also, you have to hope that the built in VVT PID algorithm would just work on the 4200, because they don't let you adjust that either.

Maxxecu

For those wanting to do a serious race application, I recommend a Maxxecu. They are very hard to beat for the price. They recently added support for the Vortec 4200. I am using one on the Wagon. Been a personal best of 9.90 at 134 on only 12.5psi. The more I use the Maxxecu, the more I like it. It's just better.

ECUmaster

Trevor from Motion Auto TV is using an ECU Master EMU Black ECU on his project. I don't know how well it works, but it natively supported the Vortec 4200 trigger pattern. This is probably another great option.