So a lot has happened in the past 6 / 7 years. I did actually end up making a flow bench, but rather than follow the traditional constructions of using a manometer and orifice plates as outlined in the PDF above, I decided to design and build a system that uses automotive MAF sensors. I also went one step further and released it as an open source project.

After many experiments and several iterations I ended up with a system based on the ESP32 micro controller and designed a custom PCB 'shield' that integrates the necessary pressure and environmental sensors on one board.


Some early tests


Initial versions used an LED display


V1 Prototype PCB


The interface is now web based and accessed from a browser

All of the work to date is available under the GNU open source license and is available for free. So you can build your own flow bench for relatively little cost if you have some patience and some basic soldering skills

You can download the project files via my GitHub account. There is more info in the Wiki on the GitHub page and also on the website. I also created a Facebook page way back when I started this project, but whilst initially created to support the project it had now morphed into a community with over 8,000 members and covers a wider range of flow benches.

The main project is still a work in progress and I am hoping to finalise and release the V3 PCB along with updated interface code some time this year.

Wow been 6 years since I posted this up. I'm still slowly chipping away at making my own supersquish style pistons. I did reach out to John at ACN a few years back, to see if he would be prepared to do a run of standard sized pistons, but the lack of demand made it prohibitive (unless I wanted to purchase multiple sets). So, somewhere on the horizon I will eventually make something akin to a supersquish for the Okrasa engine I'm building.

Here's where I'm at...



I've scanned the combustion chambers of the heads, this has given me a 'plug' of the chamber shape. This shape needs to be refined so that there is a void at the plug locations. This will force the charge towards the plug and confine it ready for the ignition event.



Once the shape has been finalised I can then go ahead and machine the pistons.

Which leads me to my next challenge - upgrading my desktop CNC. Whilst it would just about machine the pistons, it's not really enough guts to produce the kind of results I need. So I really need to pull my finder out and get my CNC mill finished off.