I figure I'm running a shade over a 10:1 CR right now. I've got the -4.0cc flat tops with the GT40X's milled down to about a 60-61cc combustion chamber. My next heads will probably be the 58cc versions, which according to CHP will get me around the 10.3-10.4 range. I guess that's just a ballpark though, considering the XE274HR has a fair bit of overlap compared to most?
...and like yourself, I've got a purple bottle sitting in my living room right now waiting for the install. I'll probably spray it in the 75-100hp range, but I'm told this kit will handle as much as 150. We'll see. I'd kinda like to get some break in time on the engine first. Don't even have 1,000km on it yet.
I'd still like the option to used 87-octane every once and a while (yeah...cheap skate.
). I'm running my base timing at about 11-degree's right now and I'm just on the edge with the 91-octane. I'm actually thinking of pulling just a little more timing out of it, just to smooth things out a little. The car's a little bit jerky down low....like the timing is too far advanced. Might just be the nature of the camshaft though? I've still got to play around with a little more. Once I get all of the bugs worked out, I'll take her to the dyno for some fine tuning and see what kind of numbers it puts down.