IIRC the jeep used for the test had a cat back and intake....But Wayne could tell us for sure.
The only time I could see the bigger TB being of bennefit is if there is head/cam/displacement changes. Such as a stroker or other mods that would require more volume in.
At the time, the vehicle was stock except a turn down after a higher flow muffler - and of course tires, lift, etc. Granted, the larger tires will make a change here, but it would effect any TB installed. We literally ONLY changed the TB between tests. We did not want any other results or factors to play in here..
I still stand pat on that I have noticed a difference in installing my bored throttle body. I don't have the hesitation off of idle or a rolling stop anymore. It also helped with pinging on the trails.
The one thing that I wish we would have done was run it with a aftermarket cold air cleaner setup - like a K&N or etc becuase the stock aircleaner could have been the choker here.
I think the biggest thing that it does is match the TB to the intake, and I think that was the gain we were seeing - not actually the size of TB hole that was making the difference. Everyone knows that gasket matching on the intake side of the cylinder is a good thing, and I think that was the numbers we were seeing.
It's just one of those deals that if you have lots of money and time, you can spend several days on the dyno changing and checking stuff.