My Rb30dohc Build

[HR31DRFT]

Hey guys my name is Craig .

I'm building the RB30dohc

Was wondering what inlet plenum would be best suited 4 this setup other then goin custom ?

Even turb setup, injectors manifold etc pls

96 R33 RB25 head.

Edited July 9, 2007 by HR31DRFT

[TurboX]

You dont say which "DOHC" ?

Easiest would be to go with the orig std setup, but as someone who has built a custom Intake plenum I would say it may not be worth the expense for the gain in performance.

I was never able to quantify the results from mine unfortunately as I fitted it with many other mods at the same time, but I dont think it made much diference except in looks and presentation.

Though it did enhance the FMIC fitting with no unesessary longer I/C pipes etc.

[Bliksem]

As turboX said which head are you using?? RB25, 20, 26?

turboX your plenum looks pretty intersting any links to the build??

[Cubes]

Definitely look at a R26 head and its std plenum.

Rb25 head for ~$1000 + ~$700-900 for a decent plenum.

That 2k can go a long way in buying a good rb26dett head and its std plenum and better factory cams.

[HR31DRFT]

  Cubes said:

Definitely look at a R26 head and its std plenum.

Rb25 head for ~$1000 + ~$700-900 for a decent plenum.

That 2k can go a long way in buying a good rb26dett head and its std plenum and better factory cams.

Got this 25de head 4 $400

Was gona go 26 but found it hard 2 get complete. Covers etc this stuff can be a bitch 2 get in parts.

I dont mind goin the greddy plenum, 10k has been put aside 4 the engine build, already have block + head, rods, N1 water + oil pump.

N still have 10k hehe, i kind of like keeping 10k in my bank 4 as long as i can

I was gonna go Borneo setup, but alot of custom work what will be a headf*k.

I only want around 300-350 atw but 4 a while

[Cubes]

$400 is a bargain.

[TurboX]

  MintR33 said:

As turboX said which head are you using?? RB25, 20, 26?

turboX your plenum looks pretty intersting any links to the build??

Just follow the link on my sig below and go to my website listed at the bottom -there's about three pages on it.

[HR31DRFT]

  Cubes said:

$400 is a bargain.

Thats it hey.

Gives me more 2 spend on other things like plenum i spose :-)

[scandyflick]

heh, hope you got your suspension and rear end sorted nicely.

with a 300kw+ rb30 in an HR31 youre going to be spending more time with your ass on the ground then driving properly.

[GTS4WD]

  HR31DRFT said:

Got this 25de head 4 $400

now somoene please correct me if im wrong..

By using a DE head.. you will have NA compression.. So.. about 10:1.

Because your going turbo.. you will have an turbo engine with a 10:1 comp ratio.. so.. you wont be able top push alot of boost though it.. engine longitivity will be greatly sacraficed.. and chances are.. your going to blow your head (hahaha)

Does the engine get its comp ratio via the head or the pistons/cylinders?

just a passing thought..

[HR31DRFT]

Car is fully decked out in suspension love.

Kaaz 2way hehe fun times.

Its actually 300-350 hp not kw

Car is awesome now, dont need anymore power from the rb20 but i want 2 build a engine.

RB30dohc POWER

This bitch is gonna be sick.

[HR31DRFT]

  GTS4WD said:

now somoene please correct me if im wrong..

By using a DE head.. you will have NA compression.. So.. about 10:1.

Because your going turbo.. you will have an turbo engine with a 10:1 comp ratio.. so.. you wont be able top push alot of boost though it.. engine longitivity will be greatly sacraficed.. and chances are.. your going to blow your head (hahaha)

Does the engine get its comp ratio via the head or the pistons/cylinders?

just a passing thought..

Lumpy is building the engine, i'll leave that up 2 him.

Compresion ratio's will be adjusted 4 optimum performance, but like i said thats 4 the gurus...

I dont like talkin about stuff i dont have a full quid on.

[GTS4WD]

good answere.. should say that to the other people that talk shit..

[GTS4WD]

  HR31DRFT said:

Lumpy is building the engine, i'll leave that up 2 him.

Compresion ratio's will be adjusted 4 optimum performance, but like i said thats 4 the gurus...

I dont like talkin about stuff i dont have a full quid on.

Nice answere.. should tell that to the people that like to talk shit..

Keep us updated!..

be fantastic to see how she runs!..

Good luck and keep the details comming!

[Cubes]

  GTS4WD said:

now somoene please correct me if im wrong..

By using a DE head.. you will have NA compression.. So.. about 10:1.

Because your going turbo.. you will have an turbo engine with a 10:1 comp ratio.. so.. you wont be able top push alot of boost though it.. engine longitivity will be greatly sacraficed.. and chances are.. your going to blow your head (hahaha)

Does the engine get its comp ratio via the head or the pistons/cylinders?

just a passing thought..

NA head is fine; it won't affect comp ratio as that is achieved by the domed pistons the N/A motor uses.

Drop the head on a N/A RB30E bottom end and you will end up with around the usual 8.2-8.3:1 comp ratio.

The N/A bottom end with the SOHC head achieves a 9:1 comp ratio; the DOHC lowers the comp from 9:1 to 8.2-8.3:1 because its combustion chamber is larger.

[HR31DRFT]

Yeh not rushing anything !!!

Building the engine in 2 parts...

Bottom 1st

All little bits like crank collar etc are goin 2 be used.

Using Mahle racing pistons

Head 2nd

Porting polishing work but really not much is required but doing anyway cuz i'm there u no.

Comp ratio's will be worked out so they are exact for fuel i'm using and what i'm doing with it.

But yeh havnt looked into it yet, just read and fully undestood the RB30dohc build guide.

As all says, a really good builder is assy the engine so i'm not gonna loose sleep over ratio's

I will blow the project out a couple of months if it takes, 2 get things exact or as close as poss.

No dead lines

Then paint lol

Thanks guys i appreciate the feedback

P.s i work at Coventry's so alot of gear is from here cutting costs big time.

U gotta cut at least 1 corner hey.

[SECURITY]

  HR31DRFT said:

Yeh not rushing anything !!!

Building the engine in 2 parts...

Bottom 1st

All little bits like crank collar etc are goin 2 be used.

Using Mahle racing pistons

Head 2nd

Porting polishing work but really not much is required but doing anyway cuz i'm there u no.

Comp ratio's will be worked out so they are exact for fuel i'm using and what i'm doing with it.

But yeh havnt looked into it yet, just read and fully undestood the RB30dohc build guide.

As all says, a really good builder is assy the engine so i'm not gonna loose sleep over ratio's

I will blow the project out a couple of months if it takes, 2 get things exact or as close as poss.

No dead lines

Then paint lol

Thanks guys i appreciate the feedback

P.s i work at Coventry's so alot of gear is from here cutting costs big time.

U gotta cut at least 1 corner hey.

a light polish is the way to go, ive seen more gains from mates who have done a mild polish than a major polish when aiming for lower hp.

i got most of my rebuild parts from coventry for my rebuild through my mate when he used to work there. it was probably the cheapest rebuild in history lol (just a std rebuld). i got pretty much everything but the rings from them.

goodluck with the build mate.

[HR31DRFT]

Thanks dude,

Head is gettin a light polish, we all need a polish every now n then

Will be a great package.

Will keep ya's posted.

Goin 26 head now thanks Richard

POWER TIME

Edited July 12, 2007 by HR31DRFT