soooooo in my ve i should be targeting around 200ve at 1 bar of boost for a reasonable base? also is my injector data correct? and ive done some changes in my tune and i get low 10s on my wideband under full boost. is my pe and be settings too rich? what is a safe target for both of those tables?
or should i dial my ve table in atmospheric only then use pe and be to handle my additional fueling under boost
You should work from the VE table you have. Because your engine did not start at 100% efficiency on the VE, it can't possibly hit 200% at 1bar of boost. Let's say you start at 95% maximum VE naturally aspirated. Doubling the pressure would give you a theoretical 190%, but not in reality. You are still pulling all that extra air through the same filter and intake tract, and pushing it out the same exhaust. You are also heating the air, making it less dense than twice the NA density. These inefficiencies all add up.Originally Posted by IamKuahn
As for your fuel injector data, it does not exactly match a data set that I have on file, but there are several data sets floating around, and I have no idea of which is more accurate. I would leave it as you have it unless it shows obvious problems. PE and BE are multipliers based on your VE table being correct. If you target, for example, 11/1 air fuel with them, you would set that target and adjust the VE until your wideband shows 11/1. That 11 is just an example number. Your boost level, compression, and fuel type will determine what enrichment amount you actually want to use under load.
Awesome thanks for the suggestions and guidance
What are you considering full boost? In the log your getting to 150kpa or so at 125 percent VE listed in the VE table and you say your are showing 10:1 AFR. In the BE table your are targeting 12.5:1. In order to get rid of the additional fuel, assuming the engine and it's support systems are in correct physical condition, your going to need to reduce the VE table.
Have you looked at your plugs? I'll bet they are black and your on the edge of washing the cylinders down with every attempt at a boosted pull. I'll also bet, if you cut your VE table down to a max of 110 percent VE you will still be too rich, based on what ever gauge you are referencing. As of now, the NBO2's are certainly showing it's significantly more rich than your target. Not sure why you would target 12.5:1 AFR while in boost but that also proves the point, something is wrong.
Why would you or any others suggest you move the VE table more toward the rich side as you are saying you are already extremely rich, maybe even at the bottom of the gauge reading and you don't know how extremely rich it is?
Learn to tune in Lambda rather than AFR so there is less confusion as to what fuel is doing what to the AFR. There is a saying, Lambda of 1 is always Lambda of 1 regardless of the fuel used. That applies in this error as you never really know how much ethanol is in pump fuel unless you have a lab to test the fuel every time you pump it.
I'm not typing any of this to belittle anyone and if you think I'm completely wrong, show me the proof. Do yourself a favor and go look at your plugs, then think about what is happening.
I just realized his EGR airflow and spark adder tables are still populated. Those need to be zeroed.
Injectors are characterized properly, they are ID1050x. Not spraying meth. No part of the tune is scaled.
mischief 169 leaned out VE added to ol start up DFCO BRAF TCS.hpt
Are you guys getting hung up on comparing VE of a N/A engine at obviously atmospheric psi, then assuming it must be close to 200 percent VE when you double the atmosphere? The VE table is taking into account you are unnaturally aspirating the engine and showing you a basic table of how efficient it is at the given forced induction. This is obviously only for unscaled tunes.
Are you also saying, when you guys tune boosted setups, you are ending up with a VE table that the VE mimics the amount of boost you are putting to it, and is proportionally equal to the boost? IE: 155kpa would end up near 150 percent VE?
If you want to do it visually, look at a VE table in a .HPT file and start at the 100kpa row. Let's pretend this given engine is 100 percent VE at the 100kpa row from 2000 rpm and up. Now go to the last row for a 2 bar COS and enter 200 percent, then interpolate between the 100kpa row and the 210kpa row and you tell me if that is what you guys are ending up with or even if that looks remotely normal or acceptable.
This is what the OP VE table looks like to me. He guessed at what his table should look like based on a misunderstanding of what will happen to the VE table when he makes his engine unnaturally aspirated. The evidence is in your logs and on your WBO2 gauge. look at your plugs and this will confirm the other two, it's too rich. I would be changing the oil asap also.
To the OP, you would be in a much better starting point if you copied the rows out of the boosted VE table I posted then where you are now. No matter how you chose to do it, you should not just go stand on the loud pedal and see what happens. You should sneak up on the tune. By this I mean, load the engine in small increments by running it up to 1 or 2 psi of boost and let off. Go check the log, make adjustments, and repeat. When you have the first couple pounds of boost dialed in, move up to 4 psi of boost and let off. Read the logs and continue to repeat the process until you have the whole table filled out. If your doing this on the street, it deff. helps to have a co-pilot to signal when to lift.
Last edited by abc; 4 Weeks Ago at 08:10 AM.
You're good dude, with my understanding of ve beforehand I figured ve needed to be well above 100... I guess my first thoughts were wrong. And my plugs are for sure rich. They were that way when I gapped them a couple logs ago. And as a beginner only tuning on gas, it's easier to wrap my head around afr for now. Everytime I read a lambda reading I'm trying to convert it to AFR in my head anyways. But I'll pull a lot of fuel out of the table and edit my pe and be settings to target 11.5 or so and go from there
Yeah you are exactly right on what I assumed... I didn't realize that the ECU is taking into account that it's unnaturally aspirated and that the ve table shouldn't be much more over 100%. In any case changing the oil for sure soon and going to use part of your ve as a starting point. I appreciate the help alot
I feel ya on the lambda thing and I know it can be tough, similar to going from standard to metric measurements. In the long run you will be better off reading in Lambda and the sooner you start the sooner you will be comfortable with it. If you start with memorizing a few key points in Lamba, you then can start to fill in the blanks along the way. Such as, 1 lambda is stoich or 14.7 for 100 percent gasoline, which is not widely available anymore. (hence the reason for tuning in Lambda) Stoich for E10 is 14.2 or 1 Lambda, so if you went by AFR in this case and your shooting for 14.7 at idle, your end result is too lean or on the leaner side.
Key points: 1 Lambda is stoich or 14.7 as you know it.
.85 Lambda is 12.5:1 AFR as you know it.
1.1 Lambda is 16.1 AFR as you know it and likely more lean than you will ever want to be. You will likely feel a significant drivability change at/near/and above 1.1 Lambda.
.78 Lambda is 11.5:1 AFR as you know it and is a good starting point for boost above 2 psi.
The formula is simple: What ever stoich is for the given fuel, times Lambda readout will give you your AFR number. IE: 14.7 times .85 Lambda is 12.5:1 AFR. A quick note as to why this is important and/or an explanation, Stoich for E85 is 9.7:1 AFR. If you are in a PE area on a N/A engine and are shooting for a safe power AFR you deff. don't want to be at 12.5:1 AFR, you will want 9.7 times .85 equals 8.25 AFR. The point is you get the same Lambda number in PE no matter the fuel or combination of fuel used. This is one of the reasons if you tune to AFR on a rowdy, boosted street driven engine, (already tuned on the lean side) go to fill it up one day and unknowingly get E20 out of a E10 pump. The engine leans out, melts a piston and nobody seems to know why.
One last thought, tune your engine to what it needs, not what you think it needs. If you think your lost, pay attention to what the spark plugs are telling you.
Another thought, slightly on a tangent, the stand alone, aftermarket ECM's will give you the option to view the VE table in pound per hour of fuel desired for the given cell. Even though in loose practice, it takes twice the amount of fuel to make twice the power, when you convert the VE table back to VE percent, the VE table will still show you a number near 100 percent VE. I think this is just a feature they put in to mimic the OE ECM's that started air flow based tuning, rather than the simplified version of fuel based tuning. Basically, just another angle to view it from, no different than standard vs metric. Now of course they are torque based tuning and so the trend continues.
Ok sweet. Thank you again for everything. I wonder how the o2s still even read lambda with different fuels and different stoich numbers
Know/remember this, O2's do exactly that, sense the presence of O2. They don't care what else is there with the O2. They are designed to output a specific amount of voltage at a specific amount of O2 content. The different readings come in via a controller so you can decide what formula/conversion you want to view it in. The O2's are they to monitor how much O2 the combustion events use or don't use, they don't care what type of fuel or how much was used to consume the O2.
There are many ways an O2's can mislead you. Use it only as a tool. If you think it's lying to you, it probably is, find a way to test and verify it. Things like exhaust leaks, excessive fuel psi, leaking injectors and so on can wreck a good closed loop tune.
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