Rb26 Compression And Build.

[RB30 Ceffy]

Hi all! I am building a few engines at the moment in Canada. I've spoke to a good friend in aus and a good friend in Canada who both build good engines and from what they both have said had got me a little mixed up on what compression to run. I am building these engines for use in Canada and the best gas that we have access to is only 91 OCT. I want to build street RB26's to be able too run 450hp on 91 oct gas on reasonable timing with about 12 psi daily driving and 15-20 psi racing. Now a friend in aus said to me for every 14.5 psi you have on a engine you go up 3 compression ratio's. Does this make sense? I was just thinking with a 8.5:1 compression on a RB26 with est 18 deg timing and over 15 psi I would get detonation. I’ve had a friend who built RB's with as little as 7.2:1 compression built for our shit gas but I have never herd these engines run so wouldn’t know if that would be any good for driving everyday. Anyhow I’ve searched on this forum already about what I want to do and have had no luck through have read and learned lots more on other things so I know you guys are pretty smart.

This is what these engines have already:

-R32 RB26's

-JUN oil sleeve

-34 N1 Pump

-std water pump

-refreshed cyl head/std cam's

-1.2 head gasket

-oil restrictor

-86.5mm over bore

-ARP head studs

-ARP rod bolts

They are pretty standard but what I want to do is advertise these to be able to slap on a bigger turbo(s) injectors and eprom and have plenty of power that will be reliable. These engines will be street used everyday and weekend drag, grip, and drift. One RB26 is in a GTS-T so it will see drift more than the other so I might add an oil pan baffle. Other than that they’re pretty much the same. If I need anything else let me know as well or if I am doing something unnecessary let me know.

p.s. I had had another thread about me looking for factory Nissan clearances or a service manual but have had no luck finding it anywhere. Some of you said you’ve seen it so if you could please point me in the right direction that would be good! I also am looking for RB26 bearings, Main and rod. We can get ACL here in Canada though no part numbers are listed in out books for any RB so a part number would be great. I am not grinding the crank as they are all in good shape so just std size I would think. Or even if a Nissan bearing set if that would do. Pretty much just a part number for what would be best for me. Thank's guy's a million!!!!!

Edited July 6, 2006 by RB30 Ceffy

[CRACKD]

If you improve on the combustion chambers you are able to run farily decent compression and boost on pump fuel, but I have no idea on the quality of your fuel other there so I can't comment on how much you can run.

As far as the psi vs CR, i was told once that every point (0.1) of compression is worth approx 4 psi of boost.

[RB30 Ceffy]

Ya your equation is much different than mine. I’m also not sure how you guys measure the quality of your gas or I just can’t remember right now anyway. We measure our gas in octane "oct" the gas we have at the pump is normally 87oct for regular, 89oct for middle grade and 91oct for high performance but its still really crap. If we run a mixture of VP race gas and 91 it really makes out RB's run much better and smoother in Canada but that’s more toward the 98-102oct gas depending on mixture and is very expensive as we already pay over $1.07 for our 91oct. Not sure on your guy’s fuel prices.

I also plan to keep combustion chambers factory unless it is a must. Let me know if you guys think that’s a good idea for what I am doing.

Edited July 4, 2006 by RB30 Ceffy

[CRACKD]

For our top fuel Optimax Extreme which is a 98+ ron with ethanol we pay $1.50 a litre