RoughandReady wrote:
So I've read a few basic articles about MS, did some poking around on the google. I feel like I have a pretty good understanding of how the box itself works, but less so when it comes to an actual conversion. For my application, I'd be looking at replacing a K-jet system.
So how hard is it to set up MS? I've got a pretty good list of parts I'd need to replace the K-jet, and I know a guy that will make me a new engine harness for ~$150.
MS2 v MS3, would MS2 work well enough for replacing a K-jet system on a mid 80s 4 banger? What about Microsquirt? I like the size and the price, but read online that it's more for ATV's and the like. Can I set up MS to run only fuel and keep the stock ignition system?
Most of all I'm wondering, if there's someone who has already set up MS for my engine and I duplicate their set up, could their programing be transferred to my box? Is it a sort of thing that is tailored engine by engine, or is what's good for the goose good for the other goose?
The most important question: Can I setup MS for NA now and go turbo later?
Thanks in advance!
Check the forums for your particular car as there may be someone there that has done the conversion already. Also msruns.com might have some information on running cars and their settings. Adding a turbo or making further changes later is certainly possible, you have complete control over the ECU hardware and software configuration.
The simplest conversion is to run megasquirt in a fuel only configuration and leave the stock ignition solution in place. This will alleviate having to try and tune both the ignition and the fuel from scratch. Getting an MSQ or fuel table from someone else can help, but you'll still need to adjust them to your particular hardware as you may be running different injectors or other changes (cam, intake, etc.). If you can use a donor MSQ to also tune ignition then that is just gravy.
The hardest part (after sorting out the wiring and sensors) is getting the engine started and idling and that just takes trial and error. Don't forget that the start settings are temperature dependent so you'll want to start tuning these settings at different temperature ranges. Lots of info available on this on the web. Many tune by setting it to 1.0ms and adjusting from there by .1ms increments until it starts, note the ambient temp and place that in the appropriate range. Let the engine cool and verify that setting works the next day. No matter what you'll want a good battery and fresh starter before going this route.
Once it tries to start (runs for a second or two before dying) you'll have to adjust the After Start Enrichment to keep it running.
Make one change at a time. They are dependent on each other and changing them both at the same time can drive you absolutely bonkers if you go too far, which is easy to do.
Once idling, you can slowly start to tune the fuel map using the autotune feature in TunerStudio in combination with your wideband O2 (these are almost a requirement for tuning) by slowly revving the motor from idle and holding it in certain cell ranges in the fuel map to allow autotune to adjust those cells. If you're starting with a a table from someone else, then this may not take very long since it should be fairly close and you can skip straight to road tuning. If you're working from scratch you'll need to finish free revving to get the fuel map close so you can start slowly puttering around your neighborhood to further tune the fuel map with a load on it. The amount the fuel map changes in those initial cells should give you an idea of how far to scale the rest of the base fuel map to get it fairly close so you can finish fine tuning the map with Autotune.
Once that base fuel map is sorted then you'll want to work on Acceleration Enrichment (think of a power valve on a carb) to help improve throttle response. There is a great article on DIYAutotune.com about AE tuning. IF you can swing it, then tuning on a dyno can help a lot here since you can run the car at nearly any speed and throttle position without much hassle.
As for which version to use? I'm not sure Microsquirt is of any benefit except to those that don't have room to install the already relatively small MegaSquirt ECU box. If there is a MSPnP option available, that might make the most sense, check DIYAutotune.com for more info on that. MS1 is well documented and works well for most basic CIS conversions, plus they are fairly cheap. MS2 is slightly faster with more features and has become the defacto "standard" for many builds. The nice part is you can upgrade an MS1 to MS2 by replacing the CPU with a $100 CPU daughterboard and adding a couple of wires. MS3 is awesome and will do even more, but it is expensive and quite honestly is more than most need for a simple fuel or fuel and ignition conversion.
No matter what version you choose, make sure the wiring is properly configured and installed. Many, many problems with MegaSquirt are related to poor wiring connections. I would also go with the MSExtra code base to allow more options and available configurations. A Wideband is basically a requirement, choose your poison there, lots of options available. I would also pony up the money for TunerStudio/MegaLog Viewer, they really help with tuning, plus you can tune with your smartphone/tablet via Bluetooth or WiFI.
