Thread: Lambada Question
12-05-2009, 02:45 PM #1
If you purchase the Lambada upgrade can you let the ECU fine tune your ski from a base map and have a perfect AFR during changing weather conditions?
I guess another way to explain would be sort of like a target AFR graph that the ECU tunes to. This way tunning would be very easy to do.
Or can you build a map this way and save it and then run from it.
I am really thinking of buying one of these but don't want to be tunning it all the time because the temperature changed 10 degrees.
Where I live temps and humidity can change on a dime. i would also love to actually make MudBug and some other rides and doing this changes elevation, humidity, and temps so what exactly can this ecu do?
12-05-2009, 10:40 PM #2
12-06-2009, 05:35 PM #3
Ok here comes the big explanation, hope everyone can follow along with my mechanic way of explaining it.
All the mapping inside the MoTeC contains many fuel compensation tables.
A compensation table applies a trim to the main fuel table.
So these tables are working in the background to keep your tune right no matter what the air temp and no matter what the altitude.
There are 14 of these table in total so that should be enough to get the fuelling correct under all conditions.
The basic compensation tables that are in the start file should be reasonably close to what you want once of course you get the main table right.
The best way to get the main table right, out in the field is to log a few tests then make changes to main fuel map using the "lambda was” feature
Lambda Was Feature
This adjusts the fuel table value by an appropriate amount by comparing the value entered by you the user to the desired lambda value in the Lambda Table.
The lambda table is a 3D table of your aim lambda or your perfect AFR.
You fill this table out to the desired values. (your choice of the perfect AFR)
Again the start file should have reasonably close numbers to start with.
You then go to the main fuel MAP and go to the site where the engine was not running the correct lambda (AFR)
So in the case of an SHO that site might be 8500 RPM and 200 kpa. (14.7 PSI Boost)
Once on that site you type "L" for "Lambda Was" the software brings up a screen that asks you what was your lambda, you enter the lambda reading you obtained from looking at your logging.
Lets say it was lean and the reading "was" 0.92. (ouch) L
So you type 0.92 into the box, also on this screen the aim number from the lambda table is displayed to you, that should be something like 0.80
Once you have entered your "lambda was" figure the software automatically changes the number in the main fuel table and that’s it job done.
Go run it again and the reading should be very close to 0.80.
Obviously you can do more than 1 site at once, so it doesn’t take long to get the tune perfect.
Now once you have it perfect and you go some where and the engine air temp is say much hotter and you see that it is now rich, then you don’t correct the main fuel table you go to the air temp correction table and fix it there, once done at all different temps etc the tune should stay perfect always.
Now, all these comp tables have calibrations in them that should be fairly close so your tune once you get it right shouldn’t change too much.
By far the greatest problems that you guys are likely to face with varying lambda readings will come from 2 things,
1. Lack of Fuel Pressure, or should I say inconsistent fuel pressure.
2. Out of injector duty cycle (Injectors too small)
Fitting and logging a fuel pressure sensor will tell you how bad your fuel pressure is and there is even a fuel pressure compensation table that you can tune so that you can add fuel automatically should the fuel pressure fall for some unpredictable reason, same with fuel temp and on it goes.
What I want you to understand is that the M400 has the capacity to run an engine absolutely perfectly under virtually any condition.
Its just a matter of tuning it.
OEM's spend months if not years getting their tunes correct although they are chasing emissions as well as power.
Again thou the start files should be reasonably close.
Now all that said you can put the ECU into what’s known as “closed loop lambda”.
The ECU then uses the lambda sensor to measure the current lambda reading and compares that to the Lambda Table (your ideal AFR)
The ECU then trims the fuel on the fly so that you are always running perfect mixtures.
It does not however write permanent change to the main fuel Map, it just applies a live over all trim on the fly.
You get to program its limits for rich and lean and when it clicks in and out of closed loop.
But why does it not write to the program I hear you ask.
1. A lambda sensor is not the most reliable sensor, in electronic terms it reacts reasonably slowly so doesn’t give good information on transients.
2. It is susceptible to failures from leaded fuels and in your case water so can give false readings as it is on its way out.
3. It can read lean when its not, if the engine is so rich that it misfires then un burnt oxygen flows through into the exhaust and is then read by the lambda sensor (oxygen sensor) as lean
So in short the lambda sensor can not always be trusted and left unchecked could make a real mess of your fuel map.
There’s a tone more to it than that as well but that’s the basics and I hope I have answered your question.
12-06-2009, 05:36 PM #4
12-06-2009, 11:31 PM #5
12-07-2009, 12:16 AM #6
Yep you are out of injector.
More fuel pressure or bigger injectors.
What do you have the fuel pressure set to now?
Is it a rising rate regulator?
You really dont want to go over 75 PSI total as this is fairly hard on the std pump and in particular the factory wiring as the pump draws more current when pumping the higher pressure.
On top of that we have seen the voltage regulators struggle to keep up as well so everything points to keep the fuel pressure closer to stock and change the injectors.
12-07-2009, 08:04 AM #7
12-07-2009, 02:27 PM #8
You could be right in that the fuel pressure may be falling away, you need to either log that or at least eye ball the gauge at full throttle (good luck with that one)
If you do have good fuel pressure then that is actualy good news.
If you are using fuel then you are making power.
Anytime I go to retune an engine and I have to take fuel out to get the AFR right then that means less air, less air consumed means less power.
So what to do?
Sorry but it comes down to injectors, bang in either the 750 or 1000 injectors and forget about the problem for ever.
Anyone doing any mods now should go straight to those injectors at the beginning, one set for ever.
12-08-2009, 04:02 PM #9
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