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Thanks David

No worries.

Like I said that is an approximate. Know of several (four other members!) others who have cc'd their heads and got 62cc or there abouts. Its fairly accurate "approximation" to assume yours will be the same.

If you're shooting for 9:1, just make sure your builder/assembler knows this and machines the assembly accordingly.

I think its weird that its not more commonly known (the chamber volumes)

I guess it comes down to not many people touching the heads on RBs and simply throw a bigger turbo and more boost at it to make power.

This also relates to CP/Weisco etc labling the comp ratios for pistons straight out of the box.

No worries.

Like I said that is an approximate. Know of several (four other members!) others who have cc'd their heads and got 62cc or there abouts. Its fairly accurate "approximation" to assume yours will be the same.

If you're shooting for 9:1, just make sure your builder/assembler knows this and machines the assembly accordingly.

wildo, costing me enough as it is, dont want to risk phucking it up. . :thumbsup:

Rb25 & rb26 I've seen all varied from 62-67. Neo's from 52-56. The first 20 thou ground off an un machined 25 & 26 head removes exactly 2CC's and it always varies from there

piston to deck heights varied too,

rb30 with rb25/26 pistons 10 - 40 under

rb30de pistons 20 thou under to 10 thou above

5 thou above will usually add .25 to the comp ratio

a 1.8 gasket replacing a 1.2 can lower the comp by around 0.75

  • 2 months later...

My RB30DET is running,

modified r33 25 head, drilled oil returns, welded water and vct, 20 inlet cam, 25 exhuast cam, full reco and skim.

RB30 block, drilled oil returns, drilled & taped tensioner, 1.0mm oil restristors, deburred and honed.

RB30 crank, grub screwed & crank collar, linish and balance.

RB30E std piston and rod, new rings, acl race bearings,

Cometic 1.2 MLS head gasket, genuine nissan gasket set.

N1 oil & water pumps, dayco 94407 timing belt, 2x tensioners.

Garret GT3071r 3037s 56t .63. ebay hi mount, tial 38mm gate, nismo 750cc, Freddy, apexi pfc, 3x pumps.

Heaps of Torque & 12psi @ 2500rpm :whistling:

Next: E85, reposition wastegate & tune

Edited by RED513

So just as I finish sorting out all the teething problems of the new setup and was thinking of booking it in for a tune.. some dumbass P-plater tries to make the gap and failed hard :(

The old girls heart will beat again soon, hopefully in the body of a sexy young 34 :whistling:

post-31803-0-66439500-1324344558_thumb.jpg

post-31803-0-09321800-1324344625_thumb.jpg

  • 3 weeks later...

New engine has just been tuned. I have a nice 300rwkw tune for pump fuel as thats plenty for the street. And a 475rwkw E85 tune at only 24psi as that seems the be the limit of my exhaust system.

It makes 180rwkw @ 4000 and 360rwkw by 4500 so things get fun pretty quick.

Just need a 4" system and a less restrictive muffler and should make more but this will do for now :thumbsup:

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