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Something a little different from the usual:
Looking at raising the CR of my engine to build a decent-ish NA engine. Options are: shaving the head 20thou (any ideas on how high this will raise it to?), or if anyone can recommend any pistons that would suit to bump it up a bit, I'm trying to get maybe around 10.5:1. This will be matched with a nice port and polish, and a Camtech CT503 517 cam. Aiming for around 130atw, although more would be nice, possibly going to go nistune and slightly bigger injectors. Thoughts, ideas, and what I should expect?
Cheers boys and girls
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I think SYK086 did a high comp N/A RB30 motor for his car and there was a purple/silver VL Calais with an N/A RB30/26 combo. I'd wait for them to reply or speak with a tuner e.g. Maatouks as i know they do Hi Comp N/A RB30 motors now
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any ideas what power figures they made? I'd like to stay sohc, but twin cam isn't out of the picture.
---------- Post added 09-11-12 at 22:29 ----------
been having a read of this:
http://www.skylinesaustralia.com/for...omp-sohc-rb30/ (http://www.skylinesaustralia.com/forums/topic/282640-high-comp-sohc-rb30/)
informative, but a bit inconclusive. Anyone have any more details on using rb25 pistons for example? I don't want to spend much money if possible, and it's NA so no need for forgies.
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anyone? How much will shaving the head increase my compression by, I went to a shop and they said 20thou should be safe, anyone got anything to add to/say about this? If I get decent compression just by shaving I won't bother changing pistons, just want a bit more
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you could calculate it, someone might know exactly but if you know the cc of the combustion chamber standard then subract roughly the area at 20 thou in mm, decent head gaskets tell you the the cc of gasket at 1 and 1.2mm
not much help but just an idea
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that thing sounds mental, much want! Yeah I've been googling it a bit, my cam will be quite nice for what I want, a little above gts2 spec without needing too many revs and being a hassle. I'm planning on doing a nice polish job, inside of plenum, runners etc as well as a bit of porting, nothing dramatic. So you say 25det pistons will give me around 10:1? Can anyone back that up? Might be worth a shot, and I'll deck the head to give a bit more probably. See how much I can push the good old 30e without going twin cam, it's weird I know but I have a bit of an attachment to sohc and I like to have a car that's a bit surprising
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