P59 Scaling for better timing table resolution. Maxed at 5psi

[2004gtols1]

Did a google search multiple ways, youtube search for videos, and multiple searchs using the forum search feature yet still can't find my answer so here we are.

Car is a 2004 GTO P59 3 BAR OS SD only no MAF and it's been maxing out the timing table at 1.20 Grams by about 5psi of boost for years now. On kill I run the car on 24-25psi so timing at 5psi and 25psi is the same LOL. I would like to get a little better resolution for some finer tunability in the lower boost ranges as well as some more control on the upper end.

That being said do I just cut the Injector- Flow rate vs. KPA table in half as well as my entire VE table and send it?

If this accomplishes my goal does it have any effect on other tables in the tune aka do I need to cut anything else by 50%?

[murfie]

yes half the fuel flow rate, half the VE table, and that should half your cylinder air mass while keeping the fuel ratio the same. Make sure you prescale your timing table, or you could end up at a higher timing value than expected. Values at 1.2 to .6, .8 to .4, .72 to .36, etc. Fill the higher values with a low starting value. When you do this you should notice you are losing half the rows on the bottom and gaining twice the rows on top, thats the shift in resolution.

The other thing would be to double the fuel Qc factor of the torque model. This is to say half the air/fuel mass will make the same heat/ torque.

Halving the VE is going to halve the estimated mass airflow. Idle base airflow and park position airflow could be halved to help IAC with engine decel and return to idle.
With the increase resolution, you will probably find you need to adjust things slightly, rather than just a straight multiply and send it.

If needed you can go more than half, just multiply all the values by .4 or .3, instead of .5. The fuel Qc factor would get divided by that value.

[2004gtols1]

Okay I cut the VE and fuel flow table by 50% already haven't tried it yet. Double the QC Factor? Not sure I know what that is lol

EDIT* Nevermind found the fuel QC factor. So double that as well as cutting the VE and all that in half?

The QC factor is at 18,960 already, double exceeds the limits. Limit is 32,768 double is 37,920

[2004gtols1]

Okay so I tried to cut everything by 50%. VE, fuel flow rate, base running airflow, IAC park position airflow and the QC factor set to max. It does not stay running lmao. Starts fine like normal and air/fuel looks the same as before scaling 50% then it dies about 5 seconds in. This car normally will cold start on E85 close to 0*F on the first try like it's on pump 93 in the summer time lol so definitely something else missing here.

Tried putting the Qc factor back to normal as well as base running airflow and IAC park airflow and it does the same thing so idk must be missing something else. In the idle-airflow tab there are quite a few other tables that use airflow....maybe those need scaled too I would assume?

[murfie]

Did you do the cranking VE tables as well? Did the RPM flare or come on slowly? If cranking VE was twice what it should have been, it correcting down to the new base idle airflow, may have been to large of a difference causing the IAC to over react and stall the engine during the transition.

Most everything else in the idle tab is related to error correction, and allowing the IAC to open/close more. Scaling that would just reduce how much error the ECU control could correct RPM and idle airflow too.

[2004gtols1]

Did you do the cranking VE tables as well? Did the RPM flare or come on slowly? If cranking VE was twice what it should have been, it correcting down to the new base idle airflow, may have been to large of a difference causing the IAC to over react and stall the engine during the transition.

Most everything else in the idle tab is related to error correction, and allowing the IAC to open/close more. Scaling that would just reduce how much error the ECU control could correct RPM and idle airflow too.

I did not half the cranking VE but it fires up perfectly fine. Idles like normal for 4-5 sec or w/e then just straight dies lol