I swapped pulley, anyone have experience?

[JohnDeere506]

Long story short I did the 103mmTB, ported stock blower, and 2.3in pulley, no tune as many shops suggest. It ran good ish and had good blower whine, but it started pulling spark at 5-6k rpm. It was not smooth, could feel seat of the pants then on dyno could clearly hear it pull spark and lots of sooty black smoke, Put the 2.5 back on and its VERY happy. Still picked up 50-55rwhp and everything looks good on the screen when monitoring. I did NOT however change the plugs from stock. Do you think this could have made the difference if I run 1 or 2 heat range colder brisk or NGK plugs? Id at least like to try a 2.4 and plugs and see if its happy.
It will get a maggie or whipple with tune this winter but its a brand new car so was trying to be patient through this first summer

 

[blkout]

Its typically recommended to swap plugs to one or two steps colder when increasing boost depend on how much. With a ported blower and 2.3, I would say one step colder would be almost guaranteed.

 

[JohnDeere506]

Yeah Id say you are likely correct, and what Ive read also. We didnt do that but Id like to try 2 steps colder and see if it even makes a difference. Ive seen some dyno charts from well known tuners that were posted online and you can clearly see the torque and HP drop of around 5-6k rpm with the 2.3 pulley and was likely pulling spark same as mine. Im not sure how that could be something you sell when the chart looks like that and it feels far less than ideal in the car... I thought about trying 2 heat ranges colder and a 2.4 pulleya nd maybe thats where it stays for now if that works

 

[blkout]

Yeah Id say you are likely correct, and what Ive read also. We didnt do that but Id like to try 2 steps colder and see if it even makes a difference. Ive seen some dyno charts from well known tuners that were posted online and you can clearly see the torque and HP drop of around 5-6k rpm with the 2.3 pulley and was likely pulling spark same as mine. Im not sure how that could be something you sell when the chart looks like that and it feels far less than ideal in the car... I thought about trying 2 heat ranges colder and a 2.4 pulleya nd maybe thats where it stays for now if that works

Two steps colder won't be necessary at that boost level. I had a 2021 Camaro ZL1 before my Blackwing that made 700whp on 93 octane, FBO, ported blower and 9.45 lower pulley making right at 15psi of boost and the plugs were one step colder and worked just fine.