Honda Power Unit Hardware & Software

[diffuser]

If you change combustion chamber geometry, you’ve now deformed and compromised the valve seats / effect the valve height, it has to work around the TJI unit and in-situ pressure transducer, all of that still has to support 250bar + of cylinder pressure, AND it can’t compromise cylinder sealing.

To even get 16:1 compression requires a very compact chamber to begin with. There just isn’t any room for this and imo is just not a viable theory.

Yeah, I didn't think so either but it doesn't mean that some expert doesn't figure out a way.

The highest heat is in the combustion chamber and anything that comes in contact with it, that is the heads and the pistons. Heads can be made of specific aluminum, which expands twice as fast of any of the steel alloys allowed for piston use.

Not you but I've see alot in this forum of people saying oh you can do this and you can do that to raise the CR and it isn't true. There are very strict rules around building the a ICE and the FIA have taken away as many tricks as they could think of to raise the CR.

[Hoffman900]

If you change combustion chamber geometry, you’ve now deformed and compromised the valve seats / effect the valve height, it has to work around the TJI unit and in-situ pressure transducer, all of that still has to support 250bar + of cylinder pressure, AND it can’t compromise cylinder sealing.

To even get 16:1 compression requires a very compact chamber to begin with. There just isn’t any room for this and imo is just not a viable theory.

Yeah, I didn't think so either but it doesn't mean that some expert doesn't figure out a way.

The highest heat is in the combustion chamber and anything that comes in contact with it, that is the heads and the pistons. Heads can be made of specific aluminum, which expands twice as fast of any of the steel alloys allowed for piston use.

Not you but I've see alot in this forum of people saying oh you can do this and you can do that to raise the CR and it isn't true. There are very strict rules around building the a ICE and the FIA have taken away as many tricks as they could think of to raise the CR.

The problem with expanding materials is as I said, you have two things (TJI) and a pressure sensor threaded in, and the valve seats are cut in / coated. It doesn’t take a lot to distort a valve seat and then your power drops like a rock as they don’t seal (or you hang up a valve). If the seat grows in, you also mess with the valvetrain geometry.

The hottest part in a chamber is the spark plug (in this case the TJI injector) and the valves, all are seeing temperatures well above the piston, especially the exhaust valve and often this is why they’re usually an inconel based alloy.

The combustion chamber is one of those things you want as stiff and inflexible as possible. I worked on an engine where we actually had to drill into the chamber, through a water jacket, and thread in screws that were ground flush with the chamber to support / bridge it, because it was failing.