RB25DET build up for me cef

[DRFERO]

howsit

just done a compression test on me cef...turns out number 1 blows 75psi.number 2 blows 75psi and number 3 blows a big fat 0psi...so i decided to not bother testing 4 5 6..

so......

i brought a r33 rb25det block mint cond with only 49000 kms on the clock...

my decision lies within the head now....

which head will be the best for my application

RB20de??RB20det??RB25de??RB25det??

is there a big difference between the heads on rb20 - rb25??

are the combustion chambers any different??? are the ports any different???flow???

any help would be muchly apreciated

[DRFERO]

bump ***

[DRFERO]

does no one here know the differences

[l0nestar]

keep the 25 DET head on the 25 DET block.

There is a significant difference between the 20 & 25 heads. Don't even mess with the DE heads.

[DRFERO]

ok theres a signifficant diference??? how can u say that if you cant explain the difference???

ive herd 25de heads are better....more duration on the cams??? can anyone give me REAL information

[l0nestar]

.. think about it, the difference between a 2.0 and 2.5L motor.

The 20 has drastically smaller ports, runners, and combustion chambers. The 20 also lacks VCT. I don't know much about the 20 cams because I have a 25.

K.I.S.S. - Keep It Stock, Silly! Keep the 25 parts with the 25. /thread

*edit*Why would you even think of putting a poorer performing head (DE) on a turbo (DET) motor? Le Sigh.

[DRFERO]

ok...im not going to be running vct... so wats the point in putting a vct head on it???? and im going to be running my rb20det intake manifold as its a custom front facing one....so....

theory says the de head will flow better as a N/A engine drives off vacuum..ie the ports would flow better as theres nothing to force the air in...and the cams will stay open longer (duration) to let more air in once again as it hasnt got a compressed air forced into it..

so far ive had people answering my questions that people dont even know what theyre talking about...theyre just saying rb25det head cos they THINK its better..but have no knowledge wat so ever backing it up

some real knowledge please neone

[DRFERO]

and if the combustion chambers are smaller that means it would up the compression and therefore give more power right??? ur info contridicks it self

[Cjmartz2k]

The casting for the 25de and 25det that came in the 33's is the same (not the R32 RB25de's). The springs are weaker and the cams are same/smaller on the DE heads. If you are going to tear the whole head apart and put aftermarket guts in it, go ahead. RB20 heads have way smaller ports and just suck a** in general.

There is a bunch of internet bulls*** out there saying that the RB n/a cams are bigger. They aren't. That's the SR's that go like that, and somebody got confused, which got repeated over and over on the internet and now it's fact. I've looked up the specs.

If you are just trying to find a head to put on your new bottom end, what makes you think the one you currently have isn't any good?
Modified by Cjmartz2k at 1:05 PM 6/19/2009

[DRFERO]

it could be..will be finding out tomorow wen i rip it off...but since i will be running a rb20det intake manifold is there any point going to a 25 head with "bigger ports"???

[nismo8117]

goodluck trying to stick a rb20 im on a 25 head...unless you are going to go through all the hassle of cutting and welding.

[b00stinbmx]

seems like you already made up your mind with what you wanan do. put the 20 head on and let us know how it works out.

[DRFERO]

can someone give me rellavant info???? al u guys do is diss??? u dont actualy provide any facts??

will a rb20det head go on a rb25 block???

will a rb20det manifold bolt onto a rb25 head???

will the top half of a 20det manifold bolt to the bottom half of a 25det manifold???

[DRFERO]

r the turbo oil lines for rb20det any different to the oil lines on a rb25??

im looking at my block and cant see a drain or a oil feed hole???

[DRFERO]

just hada good look.has a oil feed hole but no drain...has anyone here drilled and tap'd the hole out???

is it safe to drill a hole in the sump and bronze a fitting onto it or is the oil level too high

[Cjmartz2k]

The bore size is different and I have no clue what effects that will have on a combustion chamber. Don't put a 25 head on a 20. The intake manifold from a 20 will not bolt up to the 25 head. Don't put a 25 head on a 20. There are different oil passages and stuff that will not line up or be used on the 25 head. Don't put a 25 head on a 20.

If you want more hp and better low end, buy a RB25. If not, or your budget won't allow, stick with an RB20.

And the reason people are being curt with their answers is the way you are posting is annoying as f***. Learn some internet forum etiquette and lay off the damn ?????????????? marks.

[l0nestar]

can someone give me relevant info???? al u guys do is diss??? u dont actualy provide any facts??

will a rb20det head go on a rb25 block??? no

will a rb20det manifold bolt onto a rb25 head??? no

will the top half of a 20det manifold bolt to the bottom half of a 25det manifold???no

You never stated in your first, or subsequent posts what motor was currently in your Cefiero. If I'm not mistaken, not only are the port diameters different, but also the flange configuration is different between the 20 & 25 heads.

So, with that being said, what motor is currently in your Cefiero?

[silviasgp06]

your being extremely F***ing disrespectful.

people are actually answering your question, and telling you NOT TO DO IT.Threads like this normally get ignored or locked after someone says search, so consider your self lucky for getting answers.

the relevant answer is that its not worth the headache. keep the right head on the right motor "if" your just looking to make power.

But sure "if not" and you want to try something different go ahead and make it work. It will work if you make it work..... cutting, welding, drilling, fabbing...... and a lot of $$$ later im sure it will work. But consider that that money might of been better spent on another motor a upgraded turbo and such.

http://en.wikipedia.org/wiki/Nissan_RB_engine

[DRFERO]

well i am being direspectful cos im getting answers like "theres a significant difference" and no one actually told me?

now someones actually telling me after i had a hissey fit..

so thanks i guess

and its kinda obvious that my cefiro has a 20det in it. as i keep asking questions about 20det stuff and my new 25de block

and y does that guy keep saying u cant put a 25 head on a 20?? i never said that

[Carl H]

most people dont even know what a ceffiro or laurel is here on this forum...we're US based so alot of the cars you guys can get here we've never seen...either way bore size is the main factor keeping the heads from bolting on, add in the machine work needed to match the block to the head and its just not worth it.

[Sil240]

I thought you were some kind of mechanic???Or are you just a Parts Changer?

People are giving you advice and answering your question. You are not choosing to accept their advice.

So.................. your a big boy.Try reading and researching on your own if you are not satisfied with the answers you are receiving.Then you can use your infinite wisdom and intelect to come to your own conclusion.

Also not to be a dyck, but why are you on a US forum. We welcome and accept everyone here at NICO.But.... were you kicked out of SAU or SDU????

If I were in NZ it would only be logical to troll around the Aussie forums. Also due to the fact that these cars are native.

Even though these engines are not native to the US, there is a wealth of infomation and knowledge here on NICO.

Try Reading and there will be lots of information and other BS that half @ssed people post up. But you need to learn how to differentiate the BS from the actual facts. (its not too hard because of the stickys....)

I don't speak for anyone but myself.But... if you don't wish to take the advice anyone has given or tried to HELP you.

Then keep if moving!!!!!!There are Lots of other forums out there.

Have fun sweet cheeks! :-)