bump what? JohnBradley's breakdown is as broken-down as it gets. Read into this a little further and learn what all of the terms he's using are and it makes perfect sense. Ultimately it comes down to efficiency of the entire engine (and all associated parts).

 

You're kidding me, right? You post at 11:00PM, then JohnBradley, who has a life, doesn't get back to you in two hours, so you bump your post at 1:30AM?

Answer #1, and answer #2.

(Ye ghods, I hate "bumping".)

 

So let me ask you guys a question...I've been going back through my RPM VE tables, and I'm looking at the curve of the table vs. the maf curve. I think I'd like to set my MAF values to one set constant and retune the RPM VE to avoid any odd inconsistencies. What would be the best way to go about resetting the VE since MAF logs are obviously out of the question this time?

 

You should do it for both MAF tables then. But, it should be pretty easy. Just set them so that they show a percentage.

Your SD VE is going to be RPM VE*Map VE*maf scaling*maf smoothing (If I am remembering correctly...you can verify with a quick search).

Anyway, with that you should easily be able to set your maf tables to a constant that you want and adjust your RPM and/or map VE to get back to the same ultimate VE value.

 

Not that it totally worries me, but do I have someone on global ignore? I cant see anywhere where someone said "bump"? LOL

 

Thank you! I'm going to leave the map VE where it sits since it seems to work rather well how it's scaled, I just want to adjust rpm VE accordingly since the way it looks right now is pretty much a mirror image of my MAF scaling table and at times it's been troublesome for me to get the correct VE for a certain range (even harder now that my laptop erased all my previous maf logs ).

 

It appears there is an awesome moderator going in an sniping pointless posts out of this thread, which is pretty cool! It was just some guy asking OT q's.

 

For the SD load calc, only RPM VE and MAP VE are used. The base fuel pulse contribution multiplies load by MAF scaling and MAF compensation.

 

This probably won't work exactly as you are hoping. There will be more involved, but I think in the end, it produces a more realistic way to manage the engine. Instead of putting in values that just make the car run, you end up with values that actually seem to reflect what I would expect from a real engine.

I have done exactly what you are after. The first thing I did was to look at the total effect of the MAF tables. Think of the tables as a scalar in the end.

Scalar = (MAF Characteristic Scaling+MAF Offset)*MAF Compensation Scaling

The chart below shows the factory MAF curve.


I wanted two things to happen. I wanted my WOT stuff to change very little and I wanted my MAF Compensation table to be 128 across the board. Doing the later allows me to use that table to trim up any airflow related problems I may encounter (which I have).

The peak value of the stock table is 45617. To get there, you can use 216 in the MAF Scaling and then 128 in the compensation scaling. This produces a value of 45568 which is a 0.1% error.

I think you’ll find that you can get the MAP and RPM tables very well tuned in, but then your idle will be very rich. This is where the MAF Comp below 75 Hz comes into play…

 

I have been thru these threads and trying to keep up, but I was wondering is there a step by step guide to set this up considering I already have an IAT and 4bar map sensor in place and working properly on MAF. If there is one anyone have a link. I searched for one did not find it.

 

I think as soon as somebody comes up with a surefire way to tune the car and iron out all the little issues, you'll see a complete write up.

IMO, there are still a lot of little things to straighten out. Most won't even be noticed, particularly if the car is operated in closed loop.

 

Thanks for the info 03whitegsr. What you pretty much covered about the airflow differences at certain rpm's is the main reason why I want to try it, and perhaps be able to straighten out why I can't seem to bring my LTFT Low and Mid below -8%. Currently my VE for those ranges is sitting between 75-83%, and when I first apply the changes in VE, my o2 feedback goes nuts trying to compensate, and then after a while seems to settle the Low and Mid back to around the -8 to -11% mark. It's starting to get annoying, and I can physically see my throttle enrichment disappear every time I lower the VE values even more. In all reality it ran the best with Low and Mid sitting at -12 to -14%, but any large transitions in o2 feedback are killing my mpg.

 

I've noticed a similar pattern.

I've been pursuing a couple different methods to tune though and I've noticed each has good and bad aspects. I think in the end, either you are going to use a very basic setup like JCSBanks originally intended, and then let the closed loop system straighten out the small issues, or you are going to end up very deep down the rabbit's hole with little light to see what the hell is going on.

The more tables you change, I think you'll start to see the more issues you run into. Much of the ECU is setup around certain parameters under certain conditions. If you change the tables that control those parameters, it starts doing very interesting things.

 

Lol I think you are very right. Personally mine ran the best with a -12 to -14% LTFT Low and Mid, and every time I try changing something around to get me where I need to be, I just end up opening another can of worms and another odd issue to deal with. I'm going to just set the RPM VE back to where it ran the best and let the closed loop control do its thing until another solution might be found.

 

So has anyone else had any issues with SD while the car is semi-warmed up? Mine gets to the point where boost control isn't limited to wastegate pressure and will allow full boost, but the engine breaks up horribly until it's fully and completely warmed up now. Once it's completely warmed up, then everything works just fine. It seems to get worse as it gets colder (currently 28* here), so I'm wondering if IAT correction is coming into play.