R33 Rb30 Conversion

[Sydneykid]

RB30E (non turbo) with RB25DE head, everything internal standard, new rings, bearings gaskets and seals and all of the up & down and round & round stuff balanced. Made 475 bhp on the engine dyno, still going nearly 5 years later. Proves that if you keep the boost down (1.1 bar) ,service it regularly and tune it properly, it will last a long time.

[sky^rkt]

awesome. well i have a turbo head from my engine outa my other car. u think i shuld hunt down a turbo block or go for an n/a block ? sydney kid would you be able to pm me an avergae price and exact thigns you got done. im not after insane power. as i shall have that in my other car. (yes i know i shuld spend more money etc on it but *** it )

[Alf]

awesome. well i have a turbo head from my engine outa my other car. u think i shuld hunt down a turbo block or go for an n/a block ? sydney kid would you be able to pm me an avergae price and exact thigns you got done. im not after insane power. as i shall have that in my other car. (yes i know i shuld spend more money etc on it but *** it )

Go for an na block as the comp will be more suitable for more low down torque. But if you do find a turbo block change the pistons to na ones to get a decent comp.

It's easier to find an na block with the oil n water lines tapped like in na s2's.

[sky^rkt]

so pretty much i shuld go for an n/a series 2 block

[TTT]

Bingo

[Sydneykid]

awesome. well i have a turbo head from my engine outa my other car. u think i shuld hunt down a turbo block or go for an n/a block ? sydney kid would you be able to pm me an avergae price and exact thigns you got done. im not after insane power. as i shall have that in my other car. (yes i know i shuld spend more money etc on it but *** it )

I don't care how much money you spend, if you have read this thread you will find I mentioned a guy I know who buys used RB30 bottom ends, whacks new rings, bearings and seals in it for an all up cost of ~$1200. He then sticks his good top end and turbo on it and goes racing. He usually ends up with around 500 rwhp, and he just races it till it blows up. He has been doing it for around 5 years and is on his 3rd bottom end. Around the same time I built a forged bottom end RB31 that cost me $6K, so he is still 2 engines worth ($2400) ahead.

He buys standard VL Commondoor parts, rings, bearings, gaskets and seals. Hones the bores, decks the block and gets the up & down and round & round parts balanced. That's it, no secrets, just a standard rebuild of an RB30E, any machine shop can do it.

The real "secret" is tuning and knowing the limits. He doesn't "sneak a bit more boost in", "rev it a bit higher", try for "just another 20 hp". It gets service regularly, uses good oil and the tune is checked often. It isn't tuned on the limit for fuel or ignition, the tune is a bit conservative everywhere. I mentioned "tune" 4 times, not by accident.

Hope that is of some help:cheers:

[sky^rkt]

awesome thanx!, well on the w.e im takin out my old engine and ill let u know how everything goes!

[mopar_nl]

I've read this thread once, but I can't find it anymore...

You can use the series 2 n/a block and the r31 block, right?

If you can use an r31 block, how do I know it's a r31 block?

thanks

[StockyMcStock]

okay 93 pages is a bit much for me, need a quick answer for this one:

i am looking at purchasing an R33 RB25DE head, supposedly with VCT.

1. did they come with VCT?

2. is the presence of different cams the ONLY difference between this head and an R33 RB25DET head?

[Cubes]

All R33 RB25 Heads have VCT.

As far as I'm aware the R33 RB25's have the same cam specs. Lobe centers and all.

The only difference is the VCT is engaged at a higher rpm on the N/A heads, this is controlled via the ECU.

The N/A heads do run softer valve springs which may cause a valve float at 1bar+ boost.

[StockyMcStock]

brilliant, good answer. thanks dude! i won't be running more than 1bar to reach 450hp so that'll do me just fine.

odd, though, that the turbo and n/a cams would be the same...... nissan must have got lazy and started mass-producing them cheaper.

this head is still a direct bolt-on (after i re-route the VCT feed of course, and blank off the hole in the head for it) to an RB30 block isn't it?

[Cubes]

If the cam specs (lobe centers) are different for the N/A's it really doesn't cause any problems. I got the cam specs from the Tomei website.

There are a few discrepancy's with the specs on the table, so the specs they list for the r33 rb25 may not be 100% accurate.

If anything the N/A will be setup with a little more overlap which is good for top end breathing, this will benifit the 3ltr.

The head is a direct bolt on after the VCT mods.

I would still get the heads valve seat pressure checked out if anything at all.

Some heads I have seen have lacked seat pressure.

You need seat pressure to cool the valve.

Without in spec seat pressure you 'may' drop a valve.

[StockyMcStock]

yeah i see what you're getting at with the cam, either way it doesn't worry me. cams are one of the last things i would change to reach my target power. just wondering now if i should bother getting my rods cryo treated and shotpeened or just leave em........ ah i dunno.

the head i am looking is dissassembled completely, has everything there though. been crack tested, pressure tested and cleaned, the valves need re-seating but are fine apart from that. also wondering how much a head specialist would charge to do this..... might throw in some isky springs while i'm there, or can you add a shim to increase the seat pressure?

[Cubes]

You can add shims to increase the seat pressure but this won't affect the springs tension and will still valve float at the higher boost levels.

If you are thinking about cryotreating rods etc then obviously you want 280rwkw+.

Go with the isky valve springs.

While your there let me know what they are worth as I will eventually be needing a set.

The stock rods are quite strong and don't see the as much side load as the rb20/25/26's.

I would think 300rwkw is a fairly safe number for a street driven RB that doesn't need to run stupid amounts of boost (due to det head) or over 6500rpm.

[StockyMcStock]

sorry, yeah i didn't think about that too much before i typed it.

my target is 350-400 ponies at the wheels (300kw or so) and i simply don't need any more than that. from all my calcs, i am pretty sure i'll only need about 14-15 psi at the most to achieve this (not from a turbo) so i should be right with stock cams etc. the rods i have are 300,000km old though, i am just not certain if i should get them cryo-treated (for stress relieving) and shotpeened or if i should just leave them.

the isky springs are $300-$350 a set i believe.

[StockyMcStock]

oh and from people who have actually done it, give me your opinions on whether or not it's worth re-routing the VCT and getting it working. bear in mind that i will be running an aftermarket ECU, stock cams and a blower which will have no lag so off-boost driveability is not a problem at all. (off-boost doesn't exist with this motor)

[Alf]

sorry, yeah i didn't think about that too much before i typed it.

my target is 350-400 ponies at the wheels (300kw or so) and i simply don't need any more than that. from all my calcs, i am pretty sure i'll only need about 14-15 psi at the most to achieve this (not from a turbo) so i should be right with stock cams etc. the rods i have are 300,000km old though, i am just not certain if i should get them cryo-treated (for stress relieving) and shotpeened or if i should just leave them.  

the isky springs are $300-$350 a set i believe.

I hope ur not using one of those toyota whipple blowers. :Bang:

[StockyMcStock]

me too, because toyota don't make whipple blowers.

[Alf]

me too, because toyota don't make whipple blowers.

They came on the 2L 6 cyl soarers.

[StockyMcStock]

right, so i am to believe that toyota is in fact the producer of whipple blowers, not lysholm in sweden, and that the SC-14 twin-vane roots blower off the 2L soarers is in fact a whipple twin-screw supercharger? that cleared it up heaps for me thanks!