372 Cylinder head.

[Darryll]

On the 500i, the most notable quality of the chamber is the squared transition from squish to dome. I assumed that was a product of manufacturing but maybe it was intentional. Does the squared transition created more turbulence? Does it distribute force to the piston better? Also, it will have an effect on chamber volume.

I think the R&D guys have clauses in their contracts that don’t allow them to discuss this stuff. I could see them occasionally reading to inform their own ideas though. They probably do laugh at us stumbling along.

Having a probe that would quickly and accurately measure area and angle sounds amazing. Jealous.

I guess when I started this thread I was hoping someone had already been down this road and had all the answers. That may well be the case but unless you have a Dyno and went to the trouble of building different combustion chambers designs and testing them you wont have any definitive answers. What we do have is our observations and I'd like to think they have some value.

I have found in recent days a guy who has done that with a small moto x bike on YT. His findings indicate a wider squish will make slightly more power and make it slightly boarder on top. He also suggested a small radius in the transition from the squish band to the combustion chamber.

Is any of that relevant to us? I guess I will find out.

You have some nice tooling I assume you get into this kind of detail also?

 

[Moparmyway]

2 stroke stuffing ??

 

[Darryll]

2 stroke stuffing ??

No, some other guy. He got pretty deep into it. It was dyno results that interested me.

 

[Woodwackr]

I know…old thread…
Anyone know what the compression should be on a stock 500i?
I can’t find much in the way of specs for them.
I picked up a used one, older model, that seems low to me, 155#.

Thanks.

 

[Ketchup]

That seems dead on stock to me.