Megasquirt Project, .....IT RUNS ! Options

[Michelj13]

Hi,

Although I have been a member for a while (since I purchased my 914), I have not posted much. I still love my 914 and it's is interesting how this car drives like an absolute go-cart.

Anyway, my engine is a carbed 2270 that I built up with the help of many including Jake, and I am now embarking on a Megasquirt project. As many know, megasquirt is relatively inexpensive for a programmable FI system. I find, however, that there is too much information out there that it is nothing short of confusing. I want to share my progress so that at the end of the day, some may learn and may become less intimidated. Hopefully I will be successful....we'll see.

I have so many questions that I will post, along with some things that I have already learned. ANY and ALL comments appreciated.

I made a youtube video of my progress up to date. Enjoy!

http://www.youtube.com/watch?v=RoJfMZ9YgQc

Michel (IMG:style_emoticons/default/smile.gif)

[Michelj13]

This weekend, I had chance to spend a couple of hours tuning, but, no real progress to report. I played aroud with the ignition timing, VE generator, AFR table.

I think there is something really wrong somewhere. At 1200 RPM, with measured timing of 15 degrees (with respect to TDC fan marking), the engine has no torque to pull the car forward even slipping the clutch is 1st gear. If I bump the timing reference at trigger wheel 10 degrees, which raises RPM to 3000, there is then enough torque to pull car forward.

To answer wndsrfr 's questions.

1. I think it was around 12.5, but, I need to recheck
2. I set my advance like your SDS system with no variation WRT load
3. I think it was 120%, but, will need to check that also

The cam is a Jake Raby 9530. Not sure how wild it is and it did not come with a card. Jake told me, the 9530 cam nets .465 lift at the intake valve, and about .450 on the exhaust.

I will get more accurate info and I also need to figure out how to use the log feature of TunerStudio.

I am thinking, that I may need to give full advance by 2000 rpm for this to work!

[JamesM]

Step 1: Make sure you are firing on all 4. No point in trying to tune anything if you have a clogged/bad injector or bad coil.

Step 2: Make sure the timing table you are starting with makes sense. Even better, post it here. I find it easiest to start with a table that ignores all vacuum advance/retard and then work from there. Just map out what a mechnical advance only dizzy would do, say idle starting at somewhere from 0-10 deg and progressing up to 27-28 deg around 3-3.2k, that should be a good place to start.
Step 2b:SANITY CHECK, in Tuner Studio, make sure ALL sensors are reporting expected values. IAT and CHT should show roughly ambient temp before starting, TPS should reflect throttle position

Step 3: Tune idle for max vacuum. Play with the fueling and take note of the changes it is having on manifold vaccum, and shoot for the higest vaccum you can get. This should help with your torque off idle.

Step 4: Auto tune is your friend here. Set up your target AFR table IGNORE EVERYTHING you have read in MS documents abount AFR target numbers, starting out all your AFR targets are going to be between 13.5-12.5:1. You can play with leaning these out later, but to start this is where you want to be. Once the targets are in place start up the car, let it warm up as much as it can, turn on autotune in TS and then tune the no load section of the table. Basically from idle slowly rev up the engine and hold it at different RPMs while autotune does its thing. If it is missfiring due to being to lean or rich you may need to tweak it manually as the O2 sensor wont know whats going on. Do this until you can hold the engine at any RPM in neutral and it runs smooth as butter, most likley somewhere in the mid 13:1 AFR range.

Step 5: From here do a sanity check on your fuel map. Looking at the cells that have already been tuned using auto tune, as load and RPM increase so should the fuel. If for some reason you see the fuel values in the higher load bins to be less then the ones you just tuned then you can pretty much assume they wont work well. If nothing stands out as being obviously wrong then move on to the next step of running autotune at light loads the same way you just did no load, and repeate the process. Autotune - sanity check - Autotune slightly more load - sanity check -etc

obviously there is going to be a lot more to getting it fully dialed in, but this should get you a good driveable base map to start from.

Post your current MSQ and/or some datalogs and we can see if anything is standing out as being off.

-James