Off beat idea for rotor housings.

[Whizbang]

Now i dont think i am the only one on here you has heard of this or has run this idea.

Instead of porting the cast iron exhaust sleeves, Just remove them and shape the exhaust port accordingly on the inside. Now it sounds bonkers, but my last TII apparently was like this and i drove it for a few thousand miles, a guy before me drove it for longer, etc. Spooled fast and ran damn good. And there was 100 percent NO sleeve to be found.

Now why i think it works? Because aluminum when exposed to a decent amount of heat forms an outer layer of aluminum oxide which has some similar properties to iron in terms of its ability to withstand heat. Additionally, i think that ceramic coating the sleeveless hole would also reject heat from the coolant.

I am going to give this a try on my NA temp motor for the hill climb car and see what happens.

[Jeff20B]

rotarygod says it's ok to run sleeveless. Some R5 rotor housings only had a ring near the outlet of the port leaving a cavity/expansion chamber from the inlet right up to the ring. I assume this was for noise control before Mazda came out with the diffusers in NA FC rotor housings.

[Whizbang]

i mean it worked fine in my Turbo II for about a year. I think i will have to make a header with a flange with a larger diameter port for the exhaust though.