APP requested load / req'd load gear limit relationship

[lincsmps6]

Hi, I'm just playing around with the load tables and noticed that at WOT the APP req'd load figures are slightly higher than the load limit figures (lower BAT) tables.
I don't understand that, why would it be set that way- if the req'd APP load can't be achieved because the per gear load limits are slightly lower?
Can you also explain what the overload table is for and again why is that identical to the normal APP req'd load table. I understand the knock table that is obvious.
I am trying to push my car just a little harder so I am raising my APP req'd load figures at WOT only by 0.1 or so, but noticed that the per gear load limits are already slightly lower so surely its pointless? Would understand the higher BAT tables been lower for knock protection, but not the lower BAT tables?
Running the high load tune BTW with no issues.
Cheers...

[Steve @ VersaTune]

The ECU uses the APP Requested Load as the primary load target. It is subject to the following limits: Per Gear Requested Load Limit, Load Limit by RPM, Load Limit Overall, and Load Limit Barometer. The Load Targets table and the MAP Targets tables are not used. They are used in development by the OEM when the other tables have not been defined yet.

The ECU will use the lowest of any of these table lookups as the requested load base. It will then apply some modifiers to come up with the actual requested load.

Generally you will want to match your overload and normal tables. It is an option in the ECU code to allow detuning when the load target is exceeded. In the stock tune, they match so they have chosen not to do that.

[manselainen]

So I think we want to limit number of variables from this logic how load targets are formed (at least I would like to...).

In Load Targeting section, I would disable following:

Requested Load Limit Overall = 3 already
Requested Load Limit RPM = 3 already
Requested Load Limits Baro specific - Could I set these high as well (2,5 or 3)? I'm just 100 meters above sea level.
Requested Load - x Gear Limit Low BAT - Could I set these high as well if I don't want to limit e.g. 1st or 2nd gear loads?

Then these above mentioned tables would not play a role here. Load targets would be solely defined by:

APP Requested Load Normal and
APP Requested Load Overload

These I would modify and keep them identical.

Does this make any sense?

[lincsmps6]

^^^^ That is a good question/point.^^^^ Would be nice to simplify things a little.

I must say, I'm very impressed with the software, its capabilities and the support provided by the Versatune team!

[Steve @ VersaTune]

You could do that, however you would not have any high BAT load reduction then and would probably knock badly in hot weather or when heat soaked.

Most everyone uses the per gear requested load tables to define the max load and the APP requested load to control the APP to load relationship.

If you want all gears to be the same, simply copy the same values to every gear.

If you don't regularly climb mountains with your car, you can push the barometer load limits up high so that they will never limit load.

When creating base tunes for use by everyone, VersaTune has some of the same limits as the OEM. We need to create tunes that work at sea level and altitude and in hot and cold weather.

[skiptownmcat]

I use the gear tables reduce the loads in 5th and 6th, you end up hitting silly psi if you don't.

[manselainen]

It's good to ask before doing anything, thanks for comments! Actually I was to keep the high BAT gear limits, forgot to mention those.

So new theory version would be to define load targets and APP to load relationship by
- APP Requested Load Normal and
- APP Requested Load Overload
(same values in both tables)

But keep limits
- Requested Load - x Gear Limit High BAT (untouched)
- Requested Load - x Gear Limit Low BAT (used as needed, e.g. gears 1-2 and 5-6)

Not to use limits (set them high enough)
Requested Load Limit Overall
Requested Load Limit RPM
Requested Load Limits Baro specific

[Steve @ VersaTune]

That's how most do it.

[mrQQ]

I don't change APP tables all that much. I do some smooth climbing, and then just target 3 after certain level. That way, WOT runs are limited solely by x Gear, however, PT driving is still smooth.

[MPS2NV]

Another silly question (hoping it comes out in a way it you understand) following on from above load per gears, what effect does this have with your WGDC in other gears if lower loads are requested than what the WGDC was set up on?
Im pretty confused at what Im typing but if each gear can have different load targets adjusted why is there only one WGDC and not WGDC per gear?

Completely complexed question one of my best! or worst!

Thanks!

Mitch