Hi guys, Just hoping to get a few answers that may help me in the future. I want to fit a RB25DEt head to my RB30E, I heard the final compression is then 8.3:1 or 7.5:1 (anyone know the accurate compression ratio?).Anyway my question is what sort of boost level would be safe using a t3/4 hybrid and AVO stage 2 intercooler with 3" zorst? I would prefer to keep the boost at 1 level constantly rather than play around with it.I was hoping to be able to run 14 - 15psi all day every day, does that sound alright? Also will the standard internals from the Rb30E na hold up?

Sorry 1 last question, I heard that the RB20 ECU can be remapped would this be ok to use in my situation?

Quote: Originally Posted by CyberCrim Hi guys, Just hoping to get a few answers that may help me in the future. I want to fit a RB25DEt head to my RB30E, I heard the final compression is then 8.3:1 or 7.5:1 (anyone know the accurate compression ratio?). ... Also will the standard internals from the Rb30E na hold up? If you're starting with a n/a RB30 (9:1) you get 8.3:1 compression. BTW, I don't think there is any such thing as an RB25DET head; it and the n/a head are the same AFAIK. I haven't done it myself, but others on the board have said that with modern turbos and fuels the standard (9:1) internals will hold up, but I understand the series II n/a block is stronger and identical to the turbo block.