Rb26 Internals Into Rb25 Looking For Info.

[rasored]

I am sure this has been discussed on here but finding the thread is near impossible , can anyone point me in the right direction , or give me a quick run down on what is needed

block is 4 X 4 RB25 S1

Crank is Std. S1 RB26 with a JUN collar

Con rods RB26 uprated

Pistons are Std. RB26 .. deciding if i should spend out on forged

I have a NEO head that came off a N/A block and wondered if i could use that or just use the solid lifters in the RB25 head , or do i bang the RB25 cam`s onto the Neo head ?

I have a bolt on Garret internal Turbo that will be on full chat at about 3,500RPM

Q45 MAF

Adjustable FPR

FMIC is on

Greddy Blue E-Manage

Am i on the right track ???

any help gratefully accepted

[Aberax]

  On 23/07/2012 at 4:01 PM, rasored said:

Pistons are Std. RB26 .. deciding if i should spend out on forged

Standard size is 86mm, depending on the quality of the bores in the block you may be better off having it bored/honed and get new pistons to suit. That way you know all the tolerances are correct and the engine is good.

  On 23/07/2012 at 4:01 PM, rasored said:

I have a NEO head that came off a N/A block and wondered if i could use that or just use the solid lifters in the RB25 head , or do i bang the RB25 cam`s onto the Neo head ?

I have a bolt on Garret internal Turbo that will be on full chat at about 3,500RPM

The head design is slightly different with the NEO due to the emissions etc, so I think you are going to have issues using standard RB26 pistons.

You can't just pull the lifters out of a NEO head and place them into a non NEO Head, there would have to be some machine work, and maybe a whole lot of messing around. really depends what your goal is, maybe be easier to go for some straight drop in cams. Also due to the different lifters, the RB25 Cams aren't suited for a NEO head (designed for hydraulic lifters, not solid) , so either won't work, or won't work very well.

What turbo is it exactly, there are TONS of bolt on Garret turbo's, really all depends on what size it is.

Have a look at my build thread, I have just done a Forged 2.6l RB25 Build, link in Signature.

[Moodles2]

Q45 AFMs are terrible, they don't have the same resolution as a Z32 AFM and apparently hard to get them idling right, not to mention the on/off throttle issues. Also they are supposed to max out at 300kw, but as quoted from PaulR33's site:

"Please note there is lots of speculation around the Q45's in single or twin form. These seem to be a hit and miss. I think there are two models for the Q45 AFM. They have similar part # ranges and look the same, but we suspect they act very differently. We have seen a few examples of members who can't get past 230rwkw with a single Q45 so it's unclear which is correct. "

Throw away the adjustable FPR unless your injectors are maxed out, otherwise use the stock reg.

[discopotato03]

The story I get is that there are two different sensors in these Nissan MAFs and depending on which you get in which size body the results are different .

About to read the above 26 in 25 link , cheers A .

Edited July 25, 2012 by discopotato03

[GTSBoy]

Yeah, Neo NA head combustion chamber size would be quite small. Would need to make sure you had RB26 pistons that would not give you stupid high compression ratio.

[R32Abuser]

  On 25/07/2012 at 1:35 AM, GTSBoy said:

Yeah, Neo NA head combustion chamber size would be quite small. Would need to make sure you had RB26 pistons that would not give you stupid high compression ratio.

+1

Need to do your homework with regards to cc'ing the combustion chamber, checking the deck height, piston pin height etc. etc. Most of these details you can get off SAU but its always best to check your build.

If you just slap it all together and install it, you WILL run into issues i.e. detonation once its all going. Would suck to have to pull it all back out again and re-check. Engine building is an exact science and should be treated as such.

  On 24/07/2012 at 1:43 PM, Moodles2 said:

Q45 AFMs are terrible, they don't have the same resolution as a Z32 AFM and apparently hard to get them idling right, not to mention the on/off throttle issues. Also they are supposed to max out at 300kw, but as quoted from PaulR33's site:

"Please note there is lots of speculation around the Q45's in single or twin form. These seem to be a hit and miss. I think there are two models for the Q45 AFM. They have similar part # ranges and look the same, but we suspect they act very differently. We have seen a few examples of members who can't get past 230rwkw with a single Q45 so it's unclear which is correct. "

Throw away the adjustable FPR unless your injectors are maxed out, otherwise use the stock reg.

My Q45 AFM is basically maxed out on ~ 5.05V for 280 RWKW on on my RB25/30DET & GT3076R 0.82 A/R. Was somewhat disappointed in this, considering it would have been easier to get a Z32 all setup.

That said I did get it brand new for less than $100

Edited July 25, 2012 by R32Abuser

[AngryRB]

are you going to balance the motor? was watching a car show called gasolene last night, anyway, the guy was rebuilding an old classic V8 and he was weighing every piston and every conrod, bearing etc then showed the correct way to bore a block which is very scientific indeed then he span the crank on a machine ,

i think that was great to see and if i do a rebuild in future i will defintely look into having that done,

so i agree with birds, dont just get parts and slap it together, take your time and get things right, cause the end result will be a nice engine with a long life.....

research and make sure you use a good engine rebuilder to to the crucial parts...

[AngryRB]

  On 25/07/2012 at 4:19 AM, R32Abuser said:

+1

Need to do your homework with regards to cc'ing the combustion chamber, checking the deck height, piston pin height etc. etc. Most of these details you can get off SAU but its always best to check your build.

If you just slap it all together and install it, you WILL run into issues i.e. detonation once its all going. Would suck to have to pull it all back out again and re-check. Engine building is an exact science and should be treated as such.

My Q45 AFM is basically maxed out on ~ 5.05V for 280 RWKW on on my RB25/30DET & GT3076R 0.82 A/R. Was somewhat disappointed in this, considering it would have been easier to get a Z32 all setup.

That said I did get it brand new for less than $100

isnt that odd to max out that Q45 AFM? even my Z32 AFM isnt maxed out on an RB25DET, does the RB30 have that much more flow ?

[zebra]

  On 25/07/2012 at 9:26 AM, SliverS2 said:

are you going to balance the motor? was watching a car show called gasolene last night, anyway, the guy was rebuilding an old classic V8 and he was weighing every piston and every conrod, bearing etc then showed the correct way to bore a block which is very scientific indeed then he span the crank on a machine ,

i think that was great to see and if i do a rebuild in future i will defintely look into having that done,

so i agree with birds, dont just get parts and slap it together, take your time and get things right, cause the end result will be a nice engine with a long life.....

research and make sure you use a good engine rebuilder to to the crucial parts...

That is basic engine building 101

[rasored]

  On 24/07/2012 at 9:12 AM, Aberax said:

Standard size is 86mm, depending on the quality of the bores in the block you may be better off having it bored/honed and get new pistons to suit. That way you know all the tolerances are correct and the engine is good.

The head design is slightly different with the NEO due to the emissions etc, so I think you are going to have issues using standard RB26 pistons.

You can't just pull the lifters out of a NEO head and place them into a non NEO Head, there would have to be some machine work, and maybe a whole lot of messing around. really depends what your goal is, maybe be easier to go for some straight drop in cams. Also due to the different lifters, the RB25 Cams aren't suited for a NEO head (designed for hydraulic lifters, not solid) , so either won't work, or won't work very well.

What turbo is it exactly, there are TONS of bolt on Garret turbo's, really all depends on what size it is.

Have a look at my build thread, I have just done a Forged 2.6l RB25 Build, link in Signature.

86.5 HKS pistons on way = tolerance was on limit in block so bore and hone it is . Can`t find spec on Turbo at the moment ;

here`s a picture though

Chinese outer with Garret internals - on the hunt for the spec now ....

[rasored]

  On 25/07/2012 at 4:19 AM, R32Abuser said:

+1

Need to do your homework with regards to cc'ing the combustion chamber, checking the deck height, piston pin height etc. etc. Most of these details you can get off SAU but its always best to check your build.

If you just slap it all together and install it, you WILL run into issues i.e. detonation once its all going. Would suck to have to pull it all back out again and re-check. Engine building is an exact science and should be treated as such.

My Q45 AFM is basically maxed out on ~ 5.05V for 280 RWKW on on my RB25/30DET & GT3076R 0.82 A/R. Was somewhat disappointed in this, considering it would have been easier to get a Z32 all setup.

That said I did get it brand new for less than $100

there is a big difference between the RB combustion chamber in the head compared to NEO , NEO is 51cc and RB25 56 . Head only cost 100 bucks so no great loss , Maybe cams will be of use ? who knows ..

[rasored]

looks like Q45 is going on ebay then , thanks for input gents

[rasored]

  On 25/07/2012 at 9:26 AM, SliverS2 said:

are you going to balance the motor? was watching a car show called gasolene last night, anyway, the guy was rebuilding an old classic V8 and he was weighing every piston and every conrod, bearing etc then showed the correct way to bore a block which is very scientific indeed then he span the crank on a machine ,

i think that was great to see and if i do a rebuild in future i will defintely look into having that done,

so i agree with birds, dont just get parts and slap it together, take your time and get things right, cause the end result will be a nice engine with a long life.....

research and make sure you use a good engine rebuilder to to the crucial parts...

I will be using a torque wrench and not an air gun to build