NefMoto

So I am part way through unravelling the various ME7 labels for fuelling - trying to help someone with a supercharger project using C5 RS6 injectors (BCY motor) into another Audi V8 application with the BBK motor - B6 S4). Both ECUs are ME7.1.1 so hoping for good amount of consistency between them.

With help from some map packs found here and other online crumbs of info elsewhere I have the main injector constant (KRKTE) and latency (TVUB) info extracted from the RS6 binary and I know how to translate that to the slightly differently sized BBK engine.

I also found the KVB byte needing to provide more accurate fuel consumption info on the cluster. There is some detail about that which was weird but thats subject of another thread.

What I cannot find is any reference to the TEMIN or TEMINVA values in the RS6 map pack.

I just want to check that the TEMIN values (essentially the smallest width injector pulse permitted) on the BBK setup is not going to force the bigger RS6 injectors to run richer than desired at the very small load levels for idle. I suspect its not as the difference from BBK injectors (230ccpm) vs BCY injectors (390ccpm) is not so huge - those are nominal figures for petrol at 4bar. I just want to check and confirm that TEMIN/TEMINVA is good.

Firstly can someone explain the difference between TEMIN and TEMINVA ?

Does anyone have a more complete map pack of any sort for any C5 RS6 ECU variant that I can look into ?

Just adding some further findings from another dig... the TEMIN & TEMINVA bytes in the documented map pack for the BBK engine are right alongside the 5x1 latency table (TVUB) so I was able to find what value has been set in the RS6 binary - again all assuming scales are the same etc.

Assuming the value is 16-bit LoHi X 0.002667 then I saw TEMIN for the BBK is around 0.666ms (from 0xFA00)
Doing the math for anticipated TEMIN on the RS6 injectors i.e multiply by 230/390 for the different flow at rail pressure then I would expect around 0.4ms. Divide that by scaling gives 150 (0x0096 or 0x9600 in LoHi form).

Looked at the RS6 bin where the TEMIN values might live and sure enough - there she blows at 0x147B4 = 0x9600

Thats all great but whats weird is the RS6 (like the V6T on the B5S4) shows a value of ZERO for TEMINVA while on the B6S4 (BBK) I see that TEMINVA is roughly half of TEMIN... so what on earth is "VA" all about ?

Search the FR for rkuk and B_va

basically, iirc, when the wall wetting model is showing a very large negative(?) correction, switch to the other TEMIN.

I could be wrong on this, its off the top of my head.

Thanks, I always get lost in the FR but I had a look and some googling to translate a few things. There is reference to a "wall wetting model" in there but without the bigger context of what that means it remains challenging.

B_VA ==> bedingung verzögerungsabmagerung (anzeige)

that gets translated as "condition of deceleration emaciation (display)" which doesn't help either.

Roughly, decel leaning (pull fuel) condition (indicated)

Basically, on decel, wall wetting may require a correction which the normal TEMIN may prevent.

So why not just pull TEMIN_VA to 0 ?

TEMIN_VA is 0 on the B5S4 and C5RS6, but its half of TEMIN on the B6/B7 S4 so is wondering if its some different requirements on a turbo engine version NA - or something to do with layout of the inlet manifold ?

Great question! No idea :) Stock values are often mysterious, and the OEM calibrators often take shortcuts and even make mistakes.

BTW here is a good summary of TEMIN (I really need to add this to the wiki)

https://www.audizine.com/forum/showthread.php/402750-The-Great-Maestro-7-Tuning-Suite-Thread?p=8509073&viewfull=1#post8509073

Yeah I am going to get some logs for what injector time looks like in decel/liftoff condition.

As I type that, I cannot remember if VCDS (or the ME7logger) includes the latency (TVUB) aspect of pulse width or if its just the raw "TE" (effective time) the injector needs to be actually in flow.