Quote:
Originally Posted by Chrisyphus
Thanks for the kind words!
Great question about the Alusil, but it is a common misconception that the Alusil is a coating. The entire block is cast from Alusil. No matter how much material is removed from the cylinder wall, there are still Silicon crystals to be exposed. The primary issue with Alusil reconditioning is that very few shops are willing to do it, and even fewer have the necessary tools to do it correctly.
The process is, essentially, bore to near desired diameter, diamond hone to the final desired dimension, then use a felt pad and the appropriate abrasive paste and reode the Aluminum away without eroding the Silicon crystals which were surfaced via the diamond hone.
In the end, from the piston ring's perspective, it only ever touches Silicon.
Meeting the correct roughness specs is critical because if you do not erode enough of the aluminum, the piston rings will scrape the Silicon and gall the walls, leading to a catastrophic failure, and if you erode too much, the Silicon crystals will not be adequately supported by the Aluminum substrate and be scraped out by the piston rings, filling your oil with Silicon particualates, and allowing the rings to come into contact with the aluminum leading to catastrophic failure.
We are firm believers in retaining the Alusil surface for any and all NA builds we do and for all but the most extreme FI builds.
Man, the G8x cars are incredible machines. I rode in one around VIR during IMSA, and it was... mind-bending. Awesome lap you had there!
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Thanks for the detailed explanation. It's good to learn new things from the horses mouth than internet rumors. Consider me educated on Alusil!
I'd love to hear any and all updates regarding your 4.6L package when they are available. I'd like to keep my options open and Partee seem to be doing great things. I know the ITBs close at 8500 RPM on the stock ECU, yet the thought of a dry sumped 4.6L S65 revving to 9000 RPM keeps me up at night....
As for the G8X, they are insanely fast machines that are easy to drive and forgiving on the limit. Completely different ball game than a manual E92 and I'm glad they both exist.