{B8001} Normal VE Calculation

[limited cv8r]

Ok, is this what we have now instead of a VE table, if so how are some of the table values calculated eg [MAP Base],[RPM Base],[MAP Sq], there's some strange numbers in there. Is this what we need to adjust for speed density tuning now? Is the [VE Sum],which we can log with 'E38.SCALEDUNVE_DMA' the final number we need to adjust to get our fueling right compared to adjusting the VE tables in the LS1's?:nixweiss:

If this is completely wrong then could someone please correct me as the more I think about this the more my head hurts :bash:

[ringram]

http://forum.efilive.com/showthread.php?t=5716 :)

[limited cv8r]

read that post, seems there are a few people doing stuff,but not letting to much out of the bag.

[GMPX]

They are in there currently because there is a few users of our software that have been tuning E38's with HPT or LS2Edit so they are already familiar with altering those figures.

Although it might appear there is a secret E38 tuners club going on it's not really the case. What we (EFILive with the help of a number of tuners) are aiming toward is a pseudo VE table in the software that will automatically calculate those VE terms for you. We are pretty much 95% the way there with the maths involved to go back from a VE table to VE terms. We can certainly plot a VE table already based on the VE terms.
You really can't just enter in numbers to the VE terms blindly, it's quiet a complex calculation with each term having a flow on effect which is why it looks very wrong sometimes based on a single figure.

People have also suggested to us a custom OS with a 'normal' VE table. Whilst the concept makes sense when people are comfortable with VE table already it's a step backwards I think.
You will notice in the VE terms there is tables for cam position changes which are factored in using the current system GM have. If you were to do away with this does this mean you then add another VE table for the exhaust cam position etc. Once you get your head around what GM have done with the E38 it's actually a nice method of doing things.

I've attached a very simple VE calculator I was using before we were able to plot the whole graph. Here you can easily see how things are affected based on the values in the VE terms.

Just as an example, open up any E38 file.
Go to B8001, zone 30. highlight the entire row and copy.
Go to Excel with my spread sheet loaded and paste the values into the first entry [MAP Base] at D3.
Then look at the values in the yellow cells, this is the calculated VE figure (numbers look normal now)!.
Then you can go and alter each of the VE terms one at a time to see the results on the final VE values (in yellow).
You will see that some terms need a small change to make a big difference whilst others need a big change to make a small difference. There is a bit more to it than that as some tend to tilt the curve others lift the overall values when viewed as a graph.
There is other issues to with regards to which zone you are working in etc.
The PID 'E38.SCALEDUNVE_DMA' is reporting the exact same value the spreadsheet shows, this is how we have been able to confirm everything along the way.

Anyway, it's probably going to create more questions than answers ;)
The formula is listed in the VE Term tables for those who like maths.

Cheers,
Ross

P.S - Limited CV8r, you should increase the precision of the values in those tables beyond one decimal place, make it 5 or 6.

[limited cv8r]

I only made it one decimal place to fit more rows/columns into the screenshot. cheers for the reply

[GMPX]

I thought about that after I posted :) .

Cheers,
Ross

[TuneMaster]

Ross I was playing with this today. Our Holden's dont have IMTV so which VE table do we adjust? Open or Closed?? Did I miss something???

[GMPX]

Open.
There is a PID in the scantool that shows the IMTV state for those that are tuning engines with this fitted (V6's at this stage).

Cheers,
Ross

[Acer]

Just started having a look at table B8001 today & equations/calcs in e38 don't look too bad. Question I have though is how you determine the operating zone #? The table has zones 1-30 inclusive in the rows but the operating RPM Zones only range from 1-4 whilst Operating Map ranges from 1-5. Do you have to multiply the RPM & MAP zones to get the operating zone in B8001 or is only a small part of it used?

Thanks,

Acer

[GMPX]

You can simply log the zone # with the scantool. Look under the E38 section, there is a PID called "E38.ENG_ZONE_DMA1" or "E67.ENG_ZONE_DMA1" if logging an E67.

Cheers,
Ross

[Redline Motorsports]

What are the values in the RPM base and MAP based? How are they derived?

[GMPX]

It might seem like a dumb response, but they are just raw numbers, they really aren't any specific unit.
The base values influence the 'tilt' of the VE curve as the RPM (or MAP) goes up or down.

So a bigger value in the RPM Base will cause the VE numbers to increase as RPM goes up.
The tough part with all this is trying to figure it all out based on stock GM calibrations. It seems each calibration team had their own way of doing things, so looking at say the L92 V8, the MAP base in Zone 30 is 1.068398, yet in a 3.9L V6 you have a MASSIVE number like 143.150314. But there is the problem, cut/paste the whole Zone 30 row into the Excel sheet and the final number ends up about the same :Eyecrazy:

Cheers,
Ross

[Acer]

Hi Ross,

Thanks for the response but I am not logging an E38 or E67 PCM. Just trying to convert the E38 VE Formulas/Coefficients into a conventional VE table as a function of MAP & RPM. This requires an understanding of what the variables behind the Operating Zone #'s are. Guess the Operating Zone # would be a function of the usual MAP, RPM but perhaps other things?? Any thoughts/comments out there?

Thanks,

Acer

[GMPX]

Perhaps this pdf I whipped up might help explain it (hope I checked it thorough enough :doh:).

Cheers,
Ross

P.S - Imperial users, it's time to learn kPa for this stuff ;)

[TuneMaster]

I was logging on the dyno yesterday to work this out but you have just made it alot easier. Thank's heaps Ross. :master: :beer:

[Acer]

Thanks a lot Ross & looks plenty thorough to me at this stage :) .

Cheers,

Acer