ECU base maps, and TDC offset finding

[talseg560]

Hey guys, this is basically a hail Mary since I've searched up and down the internet for an answer, but here goes:

So my team uses a two cylinder 500cc engine, Yamaha T max 500 (2007).
Among the many problems I've had figuring out the unknowns of this engine, the toughest so far has been finding the base OEM ignition, fuel and VE maps (since it uses speed density air modeling). So here is the deal:

I want replace our current ECU setup (piggyback powercommander III attached to the original engine ECU) with a standalone ECU. The thing is, to do that, I sort of need to have a base map to start from (and I've tried searching for it to no avail). Failing that, I'll have to set conservative timing for ignition, Fuel map of basically Lambda = 1 across the board, and VE table set with a single starting value for the whole table. Also, I won't be able to touch the engine until I can get it to a dyno and start tuning from there.
I guess my question is, How did you guys deal with installing a new, standalone ECU on your engine? Did you have the OEM base maps? If so, where did you find them? If not, what was your process? Did you do what I've written above, or was it different?

My second issue is finding the TDC offset to put in the ECU settings. I don't a timing light around at the moment, so I was wondering if there is a different way to find TDC offset without using a timing light. I've had a few ideas already, but unfortunately all of them fail because they require knowing exactly where the index tooth is (that is, it's zero crossing on the signal). Not to mention the loss of accuracy of doing it without a timing light. So basically, do you have any basic ideas on how to find TDC offset without a Timing light? (I'm afraid this question might be too general).

Thanks for whoever answers. The TDC offset thing is less of an issue, but the OEM base maps really have me stuck, seeing as I don't want to start the engine with a bad map, to have it destroy the engine.

Apologies if my questions are too general

[Claude Rouelle]

And you are?

[WestCoastFSAE]

Base OEM maps are hard to come by. As well, the restrictor / intake geometry will change those maps a good amount.

I would proceed with the mapping plan you have. With the change of the observed lambda, when doing this type of work I normally set it to around .85-.90 for a safety factor. Especially in the low speed / high load regions. I haven't worked with that specific engine before so it might have a decent knock threshold, but that is something you can find out after base maps have been created. Look up Greg Banish and read his second book. It will give you the tools to start this procedure on the dyno and how to iterate through it.

In terms of reference angle, the easiest way is to purchase a timing light. They aren't expensive and will save you time and a headache later. If you don't end up getting the reference angle, make sure you are watching your EGT's at first since you will be guessing where your combustion angle is.

For VE mapping, will you be using a MAF or O2 sensor?

[Jay Lawrence]

I would second that. Start off safe with ignition and lambda, and buy a timing light :)

For ignition, you basically want it to be as far advanced as possible until it starts to ping or it fights the piston too much and you lose power. To detect ping, the easiest method is to bolt something to the block and listen to it with headphones. Pinging is very obvious with this method

[talseg560]

Thank you very much, all who answered.

I indeed forgot to introduce myself, apologies. My name is Tal, I'm part of Tel Aviv University's FSAE team.

Back to the matter at hand:

I'll be getting a timing light in short notice.
About the VE mapping, I'll be using a Wideband O2 sensor (which we still need to buy). I also need to find the specifications of the injectors (which is another unknown) before mapping the VE, but an experiment to find these unknowns will be conducted shortly :)
I already read both of Greg Banish's books and they indeed helped me a lot, So I'm not completely clueless as to the actual tuning process, thankfully, though it will be my first time tuning an engine. Also, thanks for the advice on the starting Lambda value, I'll definitely take that safety margin.
Basically from your answers I gather my suspicions are confirmed. We'll just have to start the engine at the next Dyno session, seeing as we don't have any base maps to work off of.

Also, thanks for the advice on the Knock detection headphones. I'll definitely try to sort something like that out. I originally thought that knock should be audible anyway, but I guess the milder knocks are harder to hear than that... Doesn't help that I've never heard an engine knock before.

Thanks again!

[MCoach]

If you know which is cylinder 1, you can find TDC by removing the spark plug and inserting a piece of welding rod, stick, or anything relatively long and fits in the hole.
Rotate the crankshaft until the rod reaches the highest point, TDC. If you remove the valve cover you will see the camshaft lobes and valves. Rod at its highest point when the intake valves are open is TDC.
Valves closed (on a four stroke motor) will be 360 off from what you're looking for. Using this method, you can find the zero point on the trigger by finding the piston TDC and then rotating until your zero trigger point lines up with the sensor.
Fortunately, the triggers follow easy to divide angles. Example:

This is a 36-2 trigger wheel
http://cdn3.volusion.com/kryfq.xaupn/v/vspfiles/photos/DM3151-3.jpg?1427153762

With this one you have a count on the sensor every 10 degrees and two missing teeth to trigger a complete cycle. This can help make it easy to count and estimate how far off you are.
If you have an oscilloscope or your ECU is able to log the triggers, this can also tell you how far off you are by comparing to the MAP (intake manifold pressure sensor).
It's easier to find and compare to bottom dead center (BDC) using this method than looking directly at TDC. You can use this to verify timing before you ever attempt to fire the motor.

In terms of calibration, you can start with a base of 10 degrees advance across your spark maps and that should be good to get it started.
For fueling, start with an estimation of how much fuel you will use based on an estimated VE across the map. Translate it to ms of pulsewidth, VE, or whatever you're ECU wants.
For your crank fueling it may take 3 - 10x the amount of fueling you may think. Start low and keep throwing fuel at it until makes those glorious explosions you're looking for.
It may take several hours to days to get it started if mistakes have been made such as incorrect measurement of zero point, mixing up cylinder 1 and 2, spark plugs mixed, incorrect wiring, etc.

If you have the motor on a dyno stand, I would suggest using rubber, car insulation, Properly torqued assembly bolts, etc, and a very large muffler to quiet sounds if you don't have sensors to measure knock.
It made a large difference trying to find the knock limit with our snowmobile engine dyno. Light initial knock that was once covered by the sound of the exhaust and dyno rattling became much more apparent.
You can use an OEM knock sensor wired to a set of headphones to listen for knock. MBirt was a fan of this method.

Once you hear the sound of knock -- you will never forget it.
Enjoy.