Neo Head Vs Rb26 Head

[maximajim]

Has anyone flow benched the R34 RB25 head?

For some reason I think a Neo head with GTR ITB's and cams will perform almost aswell as the rb25 head. Is there any real difference between the bare heads?

[Sydneykid]

Has anyone flow benched the R34 RB25 head?

For some reason I think a Neo head with GTR ITB's and cams will perform almost aswell as the rb25 head. Is there any real difference between the bare heads?

There isn't any real difference between the RB25DE, RB25DET, RB25DET Neo and the RB26DETT bare cylinder heads, the castings are almost identical. The advantage of the RB26DETT cylinder head is in the hardware (valves, springs cams, followers, inlet, exhaust etc) attached to the cylinder head, not the head itself.

cheers

[maximajim]

There isn't any real difference between the RB25DE, RB25DET, RB25DET Neo and the RB26DETT bare cylinder heads, the castings are almost identical. The advantage of the RB26DETT cylinder head is in the hardware (valves, springs cams, followers, inlet, exhaust etc) attached to the cylinder head, not the head itself.

cheers

AHA I knew it. I saw the head pics in your signature that's why I thought of making this post .

[Abo Bob]

My engine builder told me that my exhaust valves were 1mm bigger than the RB26 ones.

That is all I have to add.

[Wobbz]

My engine builder told me that my exhaust valves were 1mm bigger than the RB26 ones.

That is all I have to add.

Ok I'm wanting to revive this thread....

So sydneykid, if, for example someone were to build up an RB30DET (going full house, if you will), there would be more or less no benefit of using the 26 head over the neo25? wouldnt the neo therefore be a better option? variable cam timing...

I mean, if you're changing out the valve springs, retainers, intake manifold etc... is it really worth forking out the extra money for the 26 head? I know the neo has solid lifters (and probably less worn than any 26 head you'll get your hands on, being from newer cars)...

I ask this because im looking at the options for my 32 GTR... it needs an entirely new motor... no i don't have the old one anymore (therefore no 26 head)

What about valve sizes? port sizes? head stud sizes?

Cheers guys (and sydneykid !),

Christian

[drgnball34]

i had to decide which head to use for my rb30 build, NEO or rb26. I went with the neo mainly being that it hadn't been done bar one person i knew of at the time. Another deciding factor was that it had similar solid lifter desgin to a rb26. I have changed to aftermarket springs/retainers, GTR cams, guides, plenum etc... Its also had a port and polish. Currently still in the workshop so can not add anything more. Interesting to hear that it has larger exhaust valves. Can anyone confirm this? I also was told that it has titanium exhaust lifters instead of steel? Could mean the neo was not a bad choice after all.

[Wobbz]

i had to decide which head to use for my rb30 build, NEO or rb26. I went with the neo mainly being that it hadn't been done bar one person i knew of at the time. Another deciding factor was that it had similar solid lifter desgin to a rb26. I have changed to aftermarket springs/retainers, GTR cams, guides, plenum etc... Its also had a port and polish. Currently still in the workshop so can not add anything more. Interesting to hear that it has larger exhaust valves. Can anyone confirm this? I also was told that it has titanium exhaust lifters instead of steel? Could mean the neo was not a bad choice after all.

Can I ask how much you sourced the bare head for?

I'm still in the process of contemplating putting in a plain-jane 26 (ie. stock), or building an rb30 with neo25 or 26 head... the 26 is costing me $4k (it is in good condition, and has a guarentee)... I figure I can build an rb30 (which would be single turbo) for not much more...

Don't get me wrong, I'm not planning to build a thousand HP competition motor... but I figure, even a rebuilt rb30 on "the cheap" (i'd be doing the build myself... so alot of labour is saved there) would be stronger than the majority of second hand (ie. r32 and 33 rb26's) floating around...

Leaning towards the 30 build, as I've already got quite a bit of shit for a single conversion... bosch 044, greddy type r BOV, Tilton triple plate clutch/flywheel etc...

Car has alot of goodies too... 17x9's all around... coil-overs (kei office), braided lines, new discs... too much to list!

[R34GTFOUR]

Can I ask how much you sourced the bare head for?

I'm still in the process of contemplating putting in a plain-jane 26 (ie. stock), or building an rb30 with neo25 or 26 head... the 26 is costing me $4k (it is in good condition, and has a guarentee)... I figure I can build an rb30 (which would be single turbo) for not much more...

Don't get me wrong, I'm not planning to build a thousand HP competition motor... but I figure, even a rebuilt rb30 on "the cheap" (i'd be doing the build myself... so alot of labour is saved there) would be stronger than the majority of second hand (ie. r32 and 33 rb26's) floating around...

Leaning towards the 30 build, as I've already got quite a bit of shit for a single conversion... bosch 044, greddy type r BOV, Tilton triple plate clutch/flywheel etc...

Car has alot of goodies too... 17x9's all around... coil-overs (kei office), braided lines, new discs... too much to list!

the rb30 in a gtr isnt a simple as most make it out, or as cheap. I sat down the other day and did a few calculations for my car and was in abit of shock ahaha (im still doing it lol)

remember with the rb30 you'll defiantely need an awd adaptor (proengines is around a grand), you would rebuild it since its most likely 200k km old, and while your there you'll probably go silly and put some forged goodness in there, thats not including the turbo, manifold etc needed. All of a sudden the engine is costing you over 10k when you can get a used 26 for 4k complete and bolt it in, albeit its not going to be a "fresh rebuild" but theres a reason rb26 are well like, they make great power and are pretty much bulletproof when driven right.

[toffy]

the rb30 in a gtr isnt a simple as most make it out, or as cheap. I sat down the other day and did a few calculations for my car and was in abit of shock ahaha (im still doing it lol)

remember with the rb30 you'll defiantely need an awd adaptor (proengines is around a grand), you would rebuild it since its most likely 200k km old, and while your there you'll probably go silly and put some forged goodness in there, thats not including the turbo, manifold etc needed. All of a sudden the engine is costing you over 10k when you can get a used 26 for 4k complete and bolt it in, albeit its not going to be a "fresh rebuild" but theres a reason rb26 are well like, they make great power and are pretty much bulletproof when driven right.

thats the thing mang, as it has been argued before, that 4k rb26 may only last as long as the $200 rb30 bottom end un-rebuilt, yes they're a strong motor but most have been used for their purpose if you get me . imo if you were going to rebuild full stop you might aswell go rb30 , the price would be similar to rebuildong an rb26 i suspect

Edited March 20, 2008 by toffy

[Wobbz]

the rb30 in a gtr isnt a simple as most make it out, or as cheap. I sat down the other day and did a few calculations for my car and was in abit of shock ahaha (im still doing it lol)

remember with the rb30 you'll defiantely need an awd adaptor (proengines is around a grand), you would rebuild it since its most likely 200k km old, and while your there you'll probably go silly and put some forged goodness in there, thats not including the turbo, manifold etc needed. All of a sudden the engine is costing you over 10k when you can get a used 26 for 4k complete and bolt it in, albeit its not going to be a "fresh rebuild" but theres a reason rb26 are well like, they make great power and are pretty much bulletproof when driven right.

I understand everything that is involved

I'm not clueless! I wouldn't buy an adaptor - i'd get one custom made myself... getting steel laser cut is cheap as hell... f**k paying $1000 for a glorified adapter plate. You could get your own made for < $300. I'm just tempted to build a 30/31 as the there is an equal chance that a rb26 will last as long as a $200 rb30 bottom end as stated above... hell, i'd be looking at putting in forgies at a minimum (cheap), and getting the factory rods prepped and checked... new bearings etc. Cams could always come later, they're easy to install...

And yeah I understand all the ancillaries that are required are "extra" (ie. turbo, manifold)...

If you build a motor yourself, a $10k long block will give you an rb30 that will handle 1000+hp... forged pistons, rods, oil pump, waterpump, springs, retainers etc...

[Adriano]

I understand everything that is involved

I'm not clueless! I wouldn't buy an adaptor - i'd get one custom made myself... getting steel laser cut is cheap as hell... f**k paying $1000 for a glorified adapter plate. You could get your own made for < $300. I'm just tempted to build a 30/31 as the there is an equal chance that a rb26 will last as long as a $200 rb30 bottom end as stated above... hell, i'd be looking at putting in forgies at a minimum (cheap), and getting the factory rods prepped and checked... new bearings etc. Cams could always come later, they're easy to install...

And yeah I understand all the ancillaries that are required are "extra" (ie. turbo, manifold)...

If you build a motor yourself, a $10k long block will give you an rb30 that will handle 1000+hp... forged pistons, rods, oil pump, waterpump, springs, retainers etc...

Yeah, good luck with the $300 adapter, i made one myself, and its not the cutting or the steel plate that is the expense, its the fasteners, and the 50 odd holes that have to be within about .25mm for it to fit properly. Even if you charge out your time at $20p.h. you are better off buying the kit.

[shanef]

I understand everything that is involved

I'm not clueless! I wouldn't buy an adaptor - i'd get one custom made myself... getting steel laser cut is cheap as hell... f**k paying $1000 for a glorified adapter plate. You could get your own made for < $300. I'm just tempted to build a 30/31 as the there is an equal chance that a rb26 will last as long as a $200 rb30 bottom end as stated above... hell, i'd be looking at putting in forgies at a minimum (cheap), and getting the factory rods prepped and checked... new bearings etc. Cams could always come later, they're easy to install...

And yeah I understand all the ancillaries that are required are "extra" (ie. turbo, manifold)...

If you build a motor yourself, a $10k long block will give you an rb30 that will handle 1000+hp... forged pistons, rods, oil pump, waterpump, springs, retainers etc...

Yeah, good luck with the $300 adapter, i made one myself, and its not the cutting or the steel plate that is the expense, its the fasteners, and the 50 odd holes that have to be within about .25mm for it to fit properly. Even if you charge out your time at $20p.h. you are better off buying the kit.

adriano youve hit it on the head

the r&d for mine has cost me in the vacinity of $4000 (i was getting them laser cut and tapping/countersinking them by hand, but now have changed to a full cnc process)

[Wobbz]

adriano youve hit it on the head

the r&d for mine has cost me in the vacinity of $4000 (i was getting them laser cut and tapping/countersinking them by hand, but now have changed to a full cnc process)

Ahhh excellent, didn't realise the Pro Engines kit came with all the fasteners and oil pickup in the kit! that's pretty well priced for what it is then... I thought the original cost was just for the adapter plate - in which case you'd have to be smoking crack to pay $900 for it.

Out of interest, how much for your plates shane? do they come with any fasteners ?

Cheers guys,

Christian

Edited March 20, 2008 by Wobbz

[drgnball34]

complete head (all vavletrain) minus the cams set me back $750.

[122]

what is a bare rb26 head worth, considering its in good working order?

i've got some rb30 blocks lying around and would like to make this engine combination up as its sounds to be the way to go these days.

[STR8E180]

the neo RB25 cylinder head isnt no where near as good as the neo VVL cylinder head in the SR20VE so dont get it miss taken

some people think they are both the same but they arnt

the neo VVL cylinder head found in the SR20VE's run a very similar system to the honda vtec

the cam shaft has a extra set of lobes which it switchs over to at a set RPM the RB25 neo cylinder head does not do this

[neo32]

why would a sr20 head have any thing to do with a rb25neo topic?

the neo RB25 cylinder head isnt no where near as good as the neo VVL cylinder head in the SR20VE so dont get it miss taken

some people think they are both the same but they arnt

the neo VVL cylinder head found in the SR20VE's run a very similar system to the honda vtec

the cam shaft has a extra set of lobes which it switchs over to at a set RPM the RB25 neo cylinder head does not do this

[Marco-R34GTT]

Not just that.. But how could you possibly incorporate it into an Rb2*/30 build when the head of off a 4 cylinder....

[STR8E180]

why would a sr20 head have any thing to do with a rb25neo topic?

im just saying alot of people think the neo RB25 cylinder head runs the same neo system as the SR20V engine but it doesnt

[Marco-R34GTT]

Oh... Ok...

Damn, duel stage cams would be awesome on the neo...