Posting for a friend Quote: it maybe a re-post and if it is could you please point me in the right direction i can get a cheap RB25 convertion (well i think it is cheap) around $2000 with everything i need, what i was wondering, would a standered bottom end hold up with DOHC and min mods, cooler boost exh ext.....usuall ****?? Thanks heap

So a search - heaps of indepth info, also check the skyline australia forum. It will be totally fine. Some original photos have not been recovered yet.

good for 230 rwkw + sau is your place to ask there is a 120 page thread on the conversion and plenty of dyno results

u got a link to this 120 thread buddy? and what is sau?...

SAU = Skyline's Australia www.sau.com.au (http://www.sau.com.au)

You can run tons of power through the stock bottom end, a guy on the SAU forum has 318rwkw or so with his RB30DET conversion. Some original photos have not been recovered yet.

I would bother reading that thread its too full of crap, i dont mean wrong information but it would take ages to read... there is a PDF file written by cubes on SAU that explains the conversion its pretty simple and too the point, i think it could have more on it but everyone is pretty happy with it...

the info that isnt in the pdf can be had by asking in that thread or reading the thread

Quote: Originally Posted by platinum You can run tons of power through the stock bottom end, a guy on the SAU forum has 318rwkw or so with his RB30DET conversion. you saying you can run tons of power through the NA bottom end??? Coz the title says RB30 NA Block...... that means 9.0:1 compression ratio.... plus the rb25 dual cam head PLUS turbo..... U sure the NA bottom end with standard NA internals, will hold up??? Jim Some original photos have not been recovered yet.

Yup. The n/a bottom end on the 25 head produces about 8.3:1 compression (or there abouts). Most high performance workshops from what I've read these days, will use pistons that aim for 9:1 on their RB2x/30 converions - the standard VLT c/r is very very crappy. The n/a internals are basically exactly the same as the turbo internals, the pistons are the only difference. Some original photos have not been recovered yet.

so wats wrong with the NA pistons???

Quote: Originally Posted by DJ Mitzi so wats wrong with the NA pistons??? They are higher comp than the turbo ones.

260rwkw here on totally stock bottom end. Has been thrashed.....err driven....to work every day for 18 months now.

That is so good. I wish I converted to DOHC before I bought all my gear. It still sounds like a cheap enough option to convert the heads and get new manifolds rather than build a forged bottom end to make that power.

Quote: Originally Posted by MonstaS4 260rwkw here on totally stock bottom end. Has been thrashed.....err driven....to work every day for 18 months now. Is that Stock NA bottom end or Turbo??? GUYS CAN U PLZ STATE WHEATHER OR NOT U ARE RUNNING NA OR TURBO BOTTOM ENDS!!! thnx Jim

if you put a twincam head on a turbo bottom end, leavin the stock pistons in you would have some serious dramas.

wat about the NA bottom end??

Yes it is a stock N/A bottom end. Youd be crazy to use a turbo bottom end as you end up with somewhere around 7.5:1 compression ratio.

Quote: Originally Posted by MonstaS4 Yes it is a stock N/A bottom end. Youd be crazy to use a turbo bottom end as you end up with somewhere around 7.5:1 compression ratio. Let me get this straight Now... Your running a Stock NA RB30 bottem end with stock pistons, a rb25det head.. and your compression ratio is between 8.5 and 9:1.. And the bottom end is still good???

Spot on. Well it's actually a RB25 non turbo head out of an R33 (with VCT). RB25 head chamber volume is about 63cc compared to the RB30's 57cc, hence the change in compression ratio from 9.0:1 down to 8.3:1 while using the NA bottom end.