Hi all -
Been lurking for a while, and finally am getting my 6 year project on the road..
Engine's a de-stroked, high compression, high-revving E85 build. 6.3L, 4.125" Bore, 3.622" stroke.. NC ported heads and big cam (BTR 33954143, 239/254 .624"/.595" 114+3). Intake is a ported LS3 piece (chokes it), and exhaust is a full 2" primary long-tube setup with dual 3.5" out (includes an X-pipe). Static CR is somewhere around 13.3:1.
I'm running an E67 ECM with the '07 CTS-V O.S. (12609051) due to some of the other vehicle/swap requirements.
This is the first engine I've ever built and tuned, and so far things have been working along nicely and this thing's a ripper.. EXCEPT, the damned thing hiccups in the mid/upper RPM band with partial throttle (most of the time) .
Managed to isolate one good sample of the event in the attached log file centered at 00:00:37.941. Event starts around 00:00:37.864 and finishes around 00:00:38:015.
The dynamic airflow / VE airflow inexplicably hits zero, and quickly recovers. Events seem to be isolated to 3K rpm or higher, and mid to upper load, but I don't understand enough about the issue to be able to trend when/why it'd otherwise be happening..
Would love any sort of insight as to whether this is a boundary calculation issue from the VE or perhaps it's a zone boundary calculation issue as the cam really comes alive... Not sure.. at a total loss. I've even tried looping the VVE stuff through Bluecat to attempt to let it auto-manage zone boundaries, but it seems to slap some of the zones REALLY close together (don't have a level of confidence in this yet).
Attached the tune / log and hoping someone can provide some love! I can also include a general driving tune if someone would like to see more data outside of a very isolated event.
Cheers!
Wagon-Tune-070420.hptHiccup.hpl