To Rb30 Or Not?

[Simon-S14]

im seriously considering going an RB30det.... i need someone on her to tell me its a good idea to go and blow some money on doing it.

Basically ive got an RB25det atm with a GT3071R making 265 rwkw on 16 psi or 1.1-1.2 bar ive got cams coming to improve the lowdown (i dont run VCT atm) and the car is used for drift which isnt all about peak power.

I am getting my hands on a spare 25det head and RB30 block. My plans for the block were to put ACL rings, brearings and so forth in it, freshen it up, 25det oil pump with the crank mod to give more drive area. once this was done i was going to put the 25 head on it with a stock nissan HG and my 254 8.9mm lift cams the aim of the game is to keep it simple and reliable... I do not plan on making much more peak power then i am now (FWIW i made 282 rwkw on my 3071r on 20 psi) but what i do want is a HUGE midrange and instant responce.

am i on the right track or should i just stick to the 25?

Im a mechanic, so will be getting parts on the cheap and building the bottom end myself. the cost all up for the upgrade is budgeted at around $1000. Thats 2-300 for the crank mod (would get someone to do that for me) then 500 for ACL race bearings, ACL rings, gasket kit, front and rear mains seals, and head studs.

discuss.

[Dale FZ1]

What pistons do you plan to run, and what static compression ratio?

Also what sort of rpm ceiling?

I may be slightly wide of the mark, but it seems that mild 30DET builds often produce similar maximum power figures to the donor 25DET, but at lower rpm. Their advantage is in torque, and with your spec 3071, I would say rapid response. Bigger torque would turn tyres easier, but is there any problem if you run out of revs?

[Simon-S14]

7500 is the current RPM limit... i would prob drop this back to 7000 for a 30DET in the aim of reliability. the fact that the 30det will make more torque earlier, and hopefully for longer means that if i do start to run out of revs all i need to do is shift up a gear.

As for pistons... i plan on stockers... unless someone suggests other wise... basically im just after a mild package. i really dont see myself going for a 400 rwkw package, All i want is to make the same peak power or maybe 10-20 rwkw more. but with a shitload more responce and torque throughout the revrange.

[Dahtone Racing]

after building my 3L i wouldnt bother with anything else from the nissan stables

[Simon-S14]

seems to be the general opinion from anyone who has done it lolol

[Simon-S14]

basically my questions are.

Will the stock pistons and rods do the job if the rev limit is kept to 7000 rpm? max power no more then 280 rwkw.

and

if not, where do i go from there?

[Dahtone Racing]

IMO they will be fine

[mr_rbman]

go for it simon, no regrets here.

i've been in joels with the same turbo as yours and it would be awesome for drift!

[Simon-S14]

i think joels is a larger turbo then mine.. but thats a moot point really.

one other thing, should i use a 25 or 26 oil pump?

Also, with the 25 head, i dont plan on running the VCT at all so its operation isnt needed, Do i still need to weld up the feed for it? or is there a way around it? If welding it up is the only way what is the correct way to go about it?

Edited February 19, 2008 by Simon-R32

[Dahtone Racing]

once again either will be fine, run a crank collar, oil restrictor, larger head oil drain and decent sump

[Craved]

i think joels is a larger turbo then mine.. but thats a moot point really.

one other thing, should i use a 25 or 26 oil pump?

Also, with the 25 head, i dont plan on running the VCT at all so its operation isnt needed, Do i still need to weld up the feed for it? or is there a way around it? If welding it up is the only way what is the correct way to go about it?

drill it out - tap it and usea grub screw - that way if ever you go back to rb25 or sell off the head it can still be used.

also no need to redeck the head - unless your doing that already

[Roy]

Why dont you want to run the VCT?

[-_-StRyDeR-_-]

run into issues with vct and these engine builds dont you?? something about where the added tensioner goes? or a oil gallery? il have to check again, but everyone says "dont use vct"... id also like a deffinate answer if anyone knows??

CJ

[Craved]

no issues, just need to drill and tap for a fitting into the oil gallery behind the cam gear (also covered in the rb30 thread with pics)

[STATUS]

HAHA screw the budget fit a 2.8 kit in the 25..... and keep the 8-9k rev limit. 3l over rated... even though im building a NEO / 3L hack for our tow car.

[-_-StRyDeR-_-]

wouldnt the stroker kit end up costing more then a 3L build??

[LTHLRB]

im also thinking a 3L bottem end if mine decides to shit bricks. But on the other hand thinking of prepping a 26 crank, getting steel rods, and boring my engine out to a 2.7ltr with a 9,000rpm limiter 25psi on the 3540 and hks cams.

[R34GTFOUR]

just bite the bullet and get the os 3L kit, dont be weak...

Edited February 19, 2008 by R34GTFOUR

[N1GTR]

Do it

Use a decent oil pump though if you plan on smacking the limiter a lot - get a JUN one

If you dont like it, refit the old RB25 with fresh rings (and whatever else)

Read the RB30 results thread, there are some big numbers in there for even stock 3L bottom ends

[Simon-S14]

thanks guys, yeah i have read through the RB30 thread, theres some 400 very informative pages but it makes finding what you want to know very hard lol. very impressive power figures being made too.

the grub screw idea sounds great, easy as pie too.

i dont want to run VCT since i have an RB20ecu remapped to run the 25 atm, no VCT control... besides ive got some cams coming anyway so i dont really need the VCT. if its less hassle i def wont bother rigging it up.