Tune Changes required when adding Holley Hi-Ram & Katech 103mm TB

[BDPhoto519]

I recently picked up a 105mm Holley Hi-Ram & Katech 103mm TB to round out my FBO setup on my 2018 Camaro SS.

Aside from some possible retouching on the MAF curve and VVE tables is there anything else I will need to tune with the new setup?

I have read a few posts about TB area scaling and manifold volume change in the tune, and they all seem to eventually lead to people trying various values, and others saying to just leave it alone as it has no effect?

Does anyone have any direct experience or advice with this pretty common setup?

Thanks!

[TriPinTaZ]

MAF and VVE will definitely change. You will likely need to adjust your idle. I suspect your idle timing will drop lower than you want it to be. WOT fueling will lean out some.

[BDPhoto519]

Thanks TriPinTaz,

I am expecting the fueling/air flow changes, but I didnt realy account for the idle stuff, thats a good point.

I'm just wondering on any other small details like TB and manifold volume size scaling or anything else that may need to be changed for the calculations to all be accurate still in the calibration.

[TriPinTaZ]

Volumes size SHOULD change but I can't say for certain that I've seen it make a difference in the tune. I believe volume size in the tune has an affect on transient fueling below the filtered MAF rpm point and maybe even torque calculations when airflow is turbulent. I haven't tuned for a Holley Hi Ram though so I can't say how the VVE will change. I'm sure there are more experienced tuners on here that have tuned one before. Maybe they will chime in on some pointers.

[HeavyChevy305]

Just adjust MAf and VVE.

[BDPhoto519]

I appreciate the advice gents...