Rb26 Inlet Manifold And Adaptation To Rb25 Heads .

[R.I.P.S NZ]

This thread was linked from another where a guy asked about doing this.

I've read the whole thing and man what alot of mucking round for what is such an easy job.

We've done lots of RB26 itb's and plenims (or just the plenim with a single front TB) on R33 RB25 heads and its pretty easy and we charge only nzd600 if the customer supplies their stock 25 plenim base to use as a starting point.

It bolts straight back up, your side feeds go straight back in along with the rail and you keep vct etc.

Rob

Edited September 30, 2009 by R.I.P.S NZ

[discopotato03]

Hi Rob , can you give us any more details or even pics without giving any secrets away ?

I like the idea of a modified primary RB25 inlet manifold section that mounts the throttlebodies etc just like the inner RB26 section does .

Can you tell me if R33 GTR IAC and TPS is electrically compatible with 96 S2 R33 GTS25T loom etc ? Computer is PFC BTW .

I have all the R33 GTR inlet manifold system and if I can run it with the 25's rail and Nismo side feeds thats real good news .

Thanks for your input , cheers Adrian in Sydney .

[R.I.P.S NZ]

Hi Rob , can you give us any more details or even pics without giving any secrets away ?

I like the idea of a modified primary RB25 inlet manifold section that mounts the throttlebodies etc just like the inner RB26 section does .

Can you tell me if R33 GTR IAC and TPS is electrically compatible with 96 S2 R33 GTS25T loom etc ? Computer is PFC BTW .

I have all the R33 GTR inlet manifold system and if I can run it with the 25's rail and Nismo side feeds thats real good news .

Thanks for your input , cheers Adrian in Sydney .

E-mail me [email protected] and I'll send you pix.

Your rail and inj etc can all go straight back on.

Rob

[crack]

This thread was linked from another where a guy asked about doing this.

I've read the whole thing and man what alot of mucking round for what is such an easy job.

We've done lots of RB26 itb's and plenims (or just the plenim with a single front TB) on R33 RB25 heads and its pretty easy and we charge only nzd600 if the customer supplies their stock 25 plenum base to use as a starting point.

It bolts straight back up, your side feeds go straight back in along with the rail and you keep vct etc.

Rob

how much if you supply the stock 25 plenum base?

[discopotato03]

Am in the process of e mailing Rob with the same question , possibly not economic to send one to NZ from Australia depending on the cost there .

A .

[discopotato03]

I did get RIPS to E mail me pics of his modified RB25 inner manifold section with the RB26 TB's and plenum bolted to an engine and it looks the part .

Rob mentioned that they don't use the air bypass on their engines and I've asked for details but not gotten a reply . I gather he means the cold start heated extra air bypass valve and I'm not sure why they wouldn't use it .

Can anyone familiar with R33 RB25 and R33 RB26 inlet manifolds add anything about this ?

Also for the 20th time can anyone confirm if an R33 GTR's IAC solenoid is electrically compatible with an R33GTS25T (S2) loom and PFC .

Cheers A .

[discopotato03]

A bit more .

http://forums.nicoclub.com/zerothread?id=179864

A .

[discopotato03]

I think I'm going to go with the RIPS modified RB25 lower manifold to run the GTR throttles and plenum chamber .

Robs wants $125NZ to supply the lower 25 manifold section and it's probably not economic to buy/post one over - or is it ?

If anyone in Sydney can sell me an R33 RB25DET S2 unmodified (non port matched) lower manifold section cheaply please let me know .

Also for the record are the gaskets in RB26 manifold sections reasonably easy to get ?

Cheers Adrian .

[Mr GTS4]

hey guys i have one similar to that rips nz was doing.

only difference is that i will be running GTR injectors with a top feed rail.

pics attached.

[discopotato03]

This just gets harder to do "factory style" .

I manage to search around and found a pic of an RB26 with the plenum and throttle plates removed so I could see the air chamber that is fed from the plenum chamber on one side and feeds through front and back facing hoses to two steel tubes runing up to an air log above the manifolds inner section .

I'm not sure that this could be re created on an Rb25's lower manifold section but RIPs would be the one to know . I'm guessing that it may foul on the 25's side feed injector rail etc .

All my 26 manifold stuff is burried under a wrecking yard ATM and I can't dig it out today , does anyone have pics of the RB26's inner manifold section bare ?

RIPS has said that they don't bother with any of this stuff because with the computers they run they don't have a problem . I can't see how it would start cold real well without the Auxiliary Air Valve or how its going to idle at a constant speed without the Idle Air Control Valve - let alone when the Air Con cuts in . I want to run with an R33 PFC and side feed injectors but I don't see how it can all fit together like Nissan would/should have had it .

Any ideas ?

Cheers A .

[dano4127]

This just gets harder to do "factory style" .

I manage to search around and found a pic of an RB26 with the plenum and throttle plates removed so I could see the air chamber that is fed from the plenum chamber on one side and feeds through front and back facing hoses to two steel tubes runing up to an air log above the manifolds inner section .

I'm not sure that this could be re created on an Rb25's lower manifold section but RIPs would be the one to know . I'm guessing that it may foul on the 25's side feed injector rail etc .

All my 26 manifold stuff is burried under a wrecking yard ATM and I can't dig it out today , does anyone have pics of the RB26's inner manifold section bare ?

RIPS has said that they don't bother with any of this stuff because with the computers they run they don't have a problem . I can't see how it would start cold real well without the Auxiliary Air Valve or how its going to idle at a constant speed without the Idle Air Control Valve - let alone when the Air Con cuts in . I want to run with an R33 PFC and side feed injectors but I don't see how it can all fit together like Nissan would/should have had it .

Any ideas ?

Cheers A .

I have a Rips plenum without the Auxiliary Air Valve or Idle Air Control Valve and was running it with a PFC no problems and it was not too bad on cold start, I really dont think its an issue

I spoke to Rob about it and they preety much exclusively run Link computers in all the cars they build I have now got a Link G4 and will be tuned soon so it will be interesting to see how it goes

[discopotato03]

Yeah I just like the idea of being able to control idle speed hot or cold and not have to resort to screwing around with throttle plates .

I have E mailed Rob so it will be interesting to see if he has an answer to this air by pass issue . Maybe he can fab something a bit more compact than Nissans system on the RB26 inner manifold and I can place the chamber and valves somewhere a bit more accessable than under the manifold .

I went through the multiple SU and Weber carburettors thing years ago and don't want to go back with fuel injection .

In time , cheers A .

[dano4127]

or just get a Lin-Pec and enjoy a better ecu for next to no change over cost if you already have a PFC+Z32 to sell

At the end of the day I dont think it would be a problem for rips to fab something up but I reckon what I'm doing is the way to go

Keen to know what Robby recommends

[discopotato03]

I got an E Mail back from Rob -

Anything is possible, its just time and money.

We don't use idle valves ourselves but your best bet would be to remote mount a RB20 units and run hoses to them, not too hard to do at all and they'd fit under the 26 plenim.

Does anyone have pics of the RB20 AAC/IAC housing so I can have a bit of an idea what they look like , and are they anything like the R33 RB25 one ?

Cheers Adrian .

[Cjmartz2k]

My intake with the IAC housing and adapter plates (blitz I think) is in a box and on the way over here from japan, but I won't get it until the middle of December. I'm pretty sure I used the 25 IAC though with some creative bends in the vacuum tubing.

[badhairdave]

Does anyone have pics of the RB20 AAC/IAC housing so I can have a bit of an idea what they look like , and are they anything like the R33 RB25 one ?

Cheers Adrian .

I don't have a pic but the main difference between the 20 and 25 det IAC valves is the 20 only has the 1 plug and solenoid to control idle where as the 25 has the second solenoid for idle step up with AC. They are very similar lay out wise other than that.

AAC valves are the same between the 2 models, maybe a different plug.

I blocked off the AAC on an rb20 years ago after a hose to it split and i refused to pay the $50 plus asking price from nissan for a replacement. In terms of cold start and drivability the car was fine other than it used to stall on return to idle at the same spot every morning. It would only happen in the first couple of minutes of driving. This was still stock ecu long before i swapped to a 25 and pfc.

I reckon with a tunable ecu you could have tuned that issue out. My s13 had all the cold start stuff removed from the throttle body when i got it and it cold started and ran better than my skyline ever did, even with the big cams and light flywheel. Both with PFC.

Edited October 22, 2009 by badhairdave

[boostn32]

Here is a 26 manifold and 6 itb's on my RB20, not yet finished, but will hopefully have dyno results soon.

[STATUS]

I did get RIPS to E mail me pics of his modified RB25 inner manifold section with the RB26 TB's and plenum bolted to an engine and it looks the part .

Rob mentioned that they don't use the air bypass on their engines and I've asked for details but not gotten a reply . I gather he means the cold start heated extra air bypass valve and I'm not sure why they wouldn't use it .

Can anyone familiar with R33 RB25 and R33 RB26 inlet manifolds add anything about this ?

Also for the 20th time can anyone confirm if an R33 GTR's IAC solenoid is electrically compatible with an R33GTS25T (S2) loom and PFC .

Cheers A .

with map sense all this can be tuned around, afm is a bit more involved but can be done to give acceptable results.

[discopotato03]

I'm not interested in doing this unless it can work completly like a GTR does and I think thats only possible with the sandwich adapter plates or an RB26 head , neither appeals to me .

I have toyed with the idea of twin TB's on a std RB25 plenum chamber but you'd still have the plumbing over the cam covers .

No I think the economics go with a GReddy type manifold on an RB25DET .

Multiple throttling is nice but I can't see it being worth the cost and complexity of doing it to an R33 GTS25T , blame Nissan because they went to the effort to make it this difficult .

A .

[dano4127]

So you going with a Greddy? Make sure you put on a decen TB when you do it

these guys make good stuff: http://www.throttlebodies.com.au/