JamesShort wrote:
I don't think the issue is necessarily the ringlands, but the tune required to keep the car ULEV2. The tune has some absurdly lean points in the rpm spectrum under WOT.
I guess they have to do that to squeeze the extra 40 hp compared to the WRX. The EJ255 and EJ257 have next to identical internals. The only difference is the doming on the pistons to make the compression ratios different. Other than the spun bearing problem the early 09 WRXes have, the WRX has been quite solid. I haven't heard of any ringland issues on them. I wonder if the STI pistons, due to the difference in geometry to change the compression ratio, has an inherent structural flaw because of it, which is causing weakness in the ringland which is compounded by the insanely hot/lean exhaust gas during the power stroke.
According to the people I have talked to, they think it's more along oil starvation from hard cornering, thus the reason why the #4 piston is always the one to break. This would be really bad in an autocross situation, especially when you factor in that higher g loads will just exacerbate the situation... aka the Christopher Carris syndrome.
The good thing is that Niles is holding on my bar selection until I figure out what I will do. The FSB is different for each US generation of STi's.
Yeesh. This sucks, but in the long run, I would probably be happy. I had considered a 370z, Audi TT, and others (yes, none of these fit the right criteria), but when it all boils down, the '06 STI is the right machine for the task. - AB