I have a 2nd gen s4 t2. I bought my car from a friend that was computer savvy and already built the ms1. I want to add a boost control option which can't be done with the ms1 from some research I did.

Would all the pins be the same if I were to buy an assembled ms2 ?

I'm debating between buying a separate boost controller or seeing if I can get a ms2, plug in with basic wiring? I can do basic wiring like water meth injections, gauges, but building a computer.....I'm stumped

If I do just get a separate boost controller, does anyone recommend one? From my reading, it doesn't sound like all boost controllers were created equal

 

MS1 supports boost control as long as you have enough spare outputs. I've run open loop boost control on MS1s before.

Though upgrading to an MS2 is basically plug and play. Pop in the MS2 daughtercard in place of the CPU, run a few jumpers, and done. You'll still need to add the boost control hardware.

 

Hmmm, I never had an electronic boost controller. How effective is it in closed loop?

I've never soldered a computer before, I'm wondering now if I should just wire up a boost controller since it would be working all the time vs going through the trouble of having someone help me and only have it during WOT.

 

I've not used MS1 boost control in closed loop but stretching my memory back to that time, I did some research and found that it was very primitive. As the owner of the car only wanted a few more PSI, we just used open loop and left it at that.

I you don't have any experience soldering, then modifying the MegaSquirt isn't necessarily the best practice. In this case, using a seperate boost controller may be the best choice.

 

soldering and wiring is not my weakpoint. I know how to mig and tig. I know basic wiring and automotive electronics. Ohm's law etc. But I have never built my own computer, I would need someone there next to me. But yeah, if it's a big hassle to install and going to make my tune harder, I rather just add another boost controller

 

Soldering a "computer" is the same as soldering anything else.

The MegaManual has info on how to add the simple boost control circuit:
MSnS-Extra Hardware Manual

As for tuning, it really doesn't change your tune at all. You can leave the boost controller turned off and tune at wastegate pressure. Then turn on open loop boost control, increase boost, tune that increased boost. Then experiment with closed loop once you have a tune.

 

Won't tuning in open loop slow spool since closed loop will keep the wg from seeing pressure until desired boost is reached? I'd think this would be dangerous since you may have untuned cells where you weren't making boost before.

 

Close loop boost control will typically result in the best turbo spool because the controller is smart enough to keep the wastegate closed until (or just before) desired boost is reached.

Open loop simply uses a solenoid to bypass air from the wastegate (closing it up) according to either a set amount, or with some basic adjustment like throttle position and/or RPM. But the controller doesn't look at the result of its actions, so the final boost pressure really isn't regulated in any way and will vary based on air density, temperature, etc. Open loop is best used if you only want a few more PSI over wastegate spring pressure.