That's great data Tig and Al, thanks for sharing it!
We run 8 O2's on pretty much everything. EVERY single 4 intake has issues with distribution. Why they make carbs with circuits to help correct that, if one knows what thye are doing. You can also can use individual cylinder timing to help. Dont matter WHO ports it there is an issue, some better than others but I have yet to see one that does not have that issue.
![[Linked Image]](https://i.postimg.cc/BnLghG2p/E9-AF0944-A08-C-475-C-9-BC0-7988-C2-C6-FED6.jpg)
Appreciate sharing the plot too, always interested in plots like this. And it makes sense any single 4 is going to have distribution issues.
I calibrate diesels as my day job and we have many degrees of freedom to adjust issues like that. One thing that has always struck me as interesting, in a boosted application the distribution changes based on manifold pressure and engine speed. We measure the cylinder pressure in real time and also will measure individual and bank average exhaust temps. At different boost levels the correction needed for each cylinder is different, and it changes with altitude too.
