VE and AFR Table questions
 

Gents,

I've had some free time (and six planned events cancelled so far) and I've been doing some research. I also have a 75mm pulley coming to replace the 80mm. She makes about 9 psi now. I'd be happy with 10 max with my current intake setup, but I'm expecting the boost to come in sooner. I have seven rows of resolution in the boost area of the VE Table. Everything I read indicates I could go down to four, or even fewer so I could have more resolution in cruise since I still drive her to events. If I wanted to go to four rows in boost, does 120, 140, 160, and 180 rows sound reasonable? Could I go to three, say 125, 150, and 175? Would I need to make any changes to the AFR Table or Spark Table?

Also, the trubokitty base map for a 99-00 has 500 rpm as the first column, then 800 as the second. I assume 800 is where idle rpm is expected. With the supercharger, I chose 900 rpm as my warmed up idle, so I used 600 as my first column. Should that first column be something else, like 700 or 800? Do I even need anything left of 900?

I'm very happy with the way she runs, on and off track, except for very cold starts. I'm just bored.

Thanks,
https://cimg8.ibsrv.net/gimg/www.mia...640b1db4ff.jpg
https://cimg5.ibsrv.net/gimg/www.mia...fd045b43d9.jpg

Personally i would have more than 4 rows in boosted areas, you're only running 9-10 psi so you could probably get away with 5. I would stick with the 7 you have now for the ve table. 1-3 psi, I usually have mid/low 12s and higher creeps towards mid 11s. Having correct fueling in boost is more important that cruise, not to say they aren't both important.

I can’t speak to the AFR and I’m n/a, but for VE I spent a lot of time rebinning my table to add resolution at the non-linear sections of the rpm range. I had more columns near 4k rpms

That's not what I found in my research, but that's what I thought when I first set up the table.

Hope you know you can press the arrows where X and Y axis meet and change the row values there and it will automatically interpolate the bins for you. So you can play with this as much as you want. When I had idle hunting issues what I did was change those values and turns out the interpolated values in the idle area showed that what I thought was even constant ign timing, wasn't once I expanded that area a bit. Same with fuel. 10 degrees might actually be 10.5

Gentlemen,

All I'm looking for is someone experienced and smarter than me to tell me I need at least three, or at least four, rows in boost. Or... someone experienced and smarter than me to tell me not to bother.

Thanks,

You need rows in zones. There is no number of row required in boost or out of boost. You will want more rows in areas where the VE is changing as a function of manifold pressure as well as where you have rapid changes in the AFR target. Obviously, you need to turn Incorporate AFR target on.

Think about the modes of operation...
Idle
Tip in/accel
Cruise
WOT
Decel

It makes no sense to put a bunch of rows in partial boost if you don't operate there, especially at the cost of resolution in places where you do operate. With incorporate turned on, VE error as a % in regions with rich operation is much less problematic than it is in areas where you are running small pw with a stoich or lean target.

Now if you were trying to get maximum power with high cyl pressure ie 12.5 AFR(gasoline), then control of the fueling is more critical.

Bottom line, it doesn't really matter man. If you are having difficulty hitting target in a zone due to lack of resolution, add a row. With the interpolate function, moving breakpoints around is NBD.

You can look at where the VE versus load data is linear, and where it changes. That will suggest places you can reduce the row density. As said above, places where it is non-linear, or the linearity changes, are places you need more resolution.

I entered a few of your data points into excel, and got the following plots for a few rpm, a bit randomly chosen. You can see from the plot attached, that for all the rpm I selected, you have a very linear region between 120 and 160 kPa, indicating you could easily drop one or two of the rows in the 130-150 range. I would do this for the entire data set before reaching a firm conclusion, though. And you will need to decide which rpm data to weight most heavily in your decision.

https://cimg9.ibsrv.net/gimg/www.mia...e8238be5f0.png