I made some Singh grooves today after reading up and concluding that at the very least, it couldn't hurt, and at most it will be an awesome mod to add to the list of effective ecomods. Unfortunately I don't have any baseline info about this engine, so I guess I'll have to compare to other XFi people, and start off driving as "normally" as possible.
Here's a picture of the whole job, then a closeup of each one from left to right.
I made a couple of minor scuffs on the existing surface between the valves on the the center one and the left one. It was impossible to make the center cut in the center chamber anywhere near perfectly vertical because dremel discs don't come big enough for me to have accomplished that, but I think it came out good enough. I also decided to round out my edges a little with a pointed stone to try to avoid a "glow plug" effect with sharp metal edges and very high temperatures. Then I used a circular wire brush disc to make it nice and smooth. I didn't manage to find out what the science was behind the angles on the other two slits, so I tried my best to make them so an imaginary line extending from them would be able to cross the area between the valves (squish area?) without touching the valve seats, but while being tangent to both valves. Here is some material I read before doing this:
TeamSwift • View topic - Combustion chamber grooves=better economy?? ,
Somender Singh grooves in a Geo Metro!, and of course the original
Singh site....which appears to have been recently hacked. I'd love to see some useless corporate site get hacked instead.