RB25 Head On RB26 Theory???

[grepin]

Possibly a silly question.

Considering I have a RB25 head with RB26 265 cams, solid lifters etc and all the manifolds, turbo etc that goes with it. Would it be conceivable to bolt it onto a RB26 bottom end if It could be bought at the right price (low km).

Would my current ECU still work with it?

[pnblight]

i dont think it would be worth the money

rb30 bottom end would be better value to you for the $$$

or sell the gear your got and go complete rb26ett

[R31Nismoid]

do you have a PFC?

[grepin]

i dont think it would be worth the money

rb30 bottom end would be better value to you for the $$$

or sell the gear your got and go complete rb26ett

How about if I said a $1000 RB26 bottom end that had 30000km on it. Considering my RB25 bottom end is starting to breath a little.

[grepin]

do you have a PFC?

Ok just to put things in perspective. The avatar is my motor. Head as described, 2835ProS, highflow exhaust manifold, Greddy plenum, Q45 throttle body, large sparco intercooler and all pipework to match, Z32 airflow, PFC (rb25), 3.5 inch exhaust from the turbo. 285rwkw. 550cc inj setup on current head.

Options:

1) Still have origonal head and all standard extras so if I remove my motor now I will have the full origonal stock motor as a defect motor.

2) 3L $5000-$10000 dollars. Plus loose some of my current pipework.

3) Build a 2.7L RB25 bottom end when mine goes.

4) RB26 Motor as sujested above. Need to buy all the turbos etc etc

5) RB26 Bottom end with my virtual RB26 head. Cheap option however is the bottom end any stronger than stock RB25 or should I say how long would it last running at say at a targeted 320rwkw.

[pnblight]

rb26 is a strong bottom end then rb25 (but rb26 rods will fit your block and arnt that $$)

rb26 bottom will handle 320rwkw no worries , if looked after (mine currnretly 395rwkw)

a little breathing doesnt necessary mean the motors shagged

$1000 for rb26 bottom end sound pretty cheap just hope all is in good knick

In my opinion i would think you best course of action would be to buy a set of rb26 rods ~$300 and new forged pistons ~$1250 for your current configuration ,cos even if you put rb26 bottom end in, there no guarantee it is in good knick but do a rebuilt like this and you know its money well spent.

sounds like a nice ride

pete

[grepin]

rb26 is a strong bottom end then rb25 (but rb26 rods will fit your block and arnt that $$)

rb26 bottom will handle 320rwkw no worries , if looked after (mine currnretly 395rwkw)

a little breathing doesnt necessary mean the motors shagged

$1000 for rb26 bottom end sound pretty cheap just hope all is in good knick

In my opinion i would think you best course of action would be to buy a set of rb26 rods ~$300 and new forged pistons ~$1250 for your current configuration ,cos even if you put rb26 bottom end in, there no guarantee it is in good knick but do a rebuilt like this and you know its money well spent.  

sounds like a nice ride

pete

Supposedly had only done 30000km and in good nick. Yeah was considering your sujestion however would prefer going to the rB26 Crank as well in the rB25 bott end - starting to cost. However this way its all there. Just not sure if the head would mate up oK. Surely it would be a good buy just for the crank later on if nothing else.

[Cubes]

Grepin,

If you were to go the RB25 head on the RB26 route you would have to modify the heads vct oil feed. Possibly weld.

You would then be required to tap in to the oil pressure sender oil feed then drill the head and tap in to the vct's oil galley in the head. Run the required hose and your done.

This is what they do for the RB30DET as essentially the bottom end (water/oil galleys are exactly the same as the rb26 bottom end)

Its a little bit of stuffing around but not to worry.

Those cams would go nicely with a rb30 sitting under there.

The RB30's don't need high rev's so an rb30 making the same power as an rb25 will last a little longer.

The PFC issue is nothing to worry about.

My rb20det pfc runs the rb30det (which runs the rb25 head) no problems. The base map even runs it well.

The only small issue with the base map is the warm starts are hard to get going.

[grepin]

Grepin,

 

If you were to go the RB25 head on the RB26 route you would have to modify the heads vct oil feed. Possibly weld.

You would then be required to tap in to the oil pressure sender oil feed then drill the head and tap in to the vct's oil galley in the head. Run the required hose and your done.

 

This is what they do for the RB30DET as essentially the bottom end (water/oil galleys are exactly the same as the rb26 bottom end)

 

Its a little bit of stuffing around but not to worry.

 

Those cams would go nicely with a rb30 sitting under there.

The RB30's don't need high rev's so an rb30 making the same power as an rb25 will last a little longer.

 

The PFC issue is nothing to worry about.

 

My rb20det pfc runs the rb30det (which runs the rb25 head) no problems. The base map even runs it well.

The only small issue with the base map is the warm starts are hard to get going.

The head has already had the VVt sealed up. Is that what you mean?

So being a RB26 I guess it can support more power, however I wonder if it would make more given the same boost etc as on the rB25 bottom end.

[Cubes]

The larger motors do tend to make a little more power and at a lower rpm.

Its not much, 5-10rwkw more with everything being the same. Boost, timing etc.

You do notice a little difference with the rb30 vs the rb25 but I am unsure if you will notice a difference with a rb25 vs rb26.

[R31Nismoid]

supposedly people do!

going the 2.7/2.8ltr kits on the RB26's.

Just talking to owners here of such vehicles in Vic.