Nissan skyline r34 gtt Rb25det neo plenum install questions

[adam wicks]

Hello RB lovers I'm currently installing a plenum for my r34 and have a couple questions. Firstly

 

1. What hoses go to the iac?

[GTSBoy]

Water and air.

[adam wicks]

The iac has 3 little ports and 1 big one, the big goes between the throttle body and cooler, what 3 little ports do I use and block ?

[adam wicks]

Water and air.

The iac has 3 little ports and 1 big one, the big goes between the throttle body and cooler, what 3 little ports do I use and block ?

[adam wicks]

[discopotato03]

I imagine the cold start portion of the IAC assembly , wax pellet part , will stay open and the idle will stay high .

You need to run coolant through them for it to work as intended .

Originally it gets coolant from three places . The standard manifolds cast in water log , the fitting into the lower drivers side rear of the head , the rear of the original manifolds throttle body .

The GTt's IAC housing is meant to be a high point in the original cooling system which is why it has the air bleeder bolt .

A .    

[GTSBoy]

Just to expand Adrian's post.....

The little one furthest to the right in your photo goes to the fitting on the top of the cast, ribbed, water gallery that runs along the length of the stock inlet manifold just above the runners adjacent the head.  The fitting that it connects to points straight up, and the hose that joins them is only a few inches long because it's not far away.

The next little one closer, the one in middle, connects to the small fitting on the rearmost of the two heater hoses, down pretty much immediately below the stock location of the IAC valve.  That hose is a little longer.

The third little one, closest to the main body of the IAC valve, connects to the rear port on the water path through the throttle body.  If you were not to have that, then on the other side of the throttle body that line continues on to the front bleeder, which has a few small coolant hoses connected to it.

You really can't neglect any of these connections.  I don't know if those useless Freddy manifolds have an equivalent of the stock manifold's water gallery.  If it doesn't, then I don't know what to tell you.

[adam wicks]

This is the plenum and throttle body I'm using

[adam wicks]

Just to expand Adrian's post.....
The little one furthest to the right in your photo goes to the fitting on the top of the cast, ribbed, water gallery that runs along the length of the stock inlet manifold just above the runners adjacent the head.  The fitting that it connects to points straight up, and the hose that joins them is only a few inches long because it's not far away.
The next little one closer, the one in middle, connects to the small fitting on the rearmost of the two heater hoses, down pretty much immediately below the stock location of the IAC valve.  That hose is a little longer.
The third little one, closest to the main body of the IAC valve, connects to the rear port on the water path through the throttle body.  If you were not to have that, then on the other side of the throttle body that line continues on to the front bleeder, which has a few small coolant hoses connected to it.
You really can't neglect any of these connections.  I don't know if those useless Freddy manifolds have an equivalent of the stock manifold's water gallery.  If it doesn't, then I don't know what to tell you.

You don't have any photos so I'm sure I have it connected correctly?

[adam wicks]

Just to expand Adrian's post.....
The little one furthest to the right in your photo goes to the fitting on the top of the cast, ribbed, water gallery that runs along the length of the stock inlet manifold just above the runners adjacent the head.  The fitting that it connects to points straight up, and the hose that joins them is only a few inches long because it's not far away.
The next little one closer, the one in middle, connects to the small fitting on the rearmost of the two heater hoses, down pretty much immediately below the stock location of the IAC valve.  That hose is a little longer.
The third little one, closest to the main body of the IAC valve, connects to the rear port on the water path through the throttle body.  If you were not to have that, then on the other side of the throttle body that line continues on to the front bleeder, which has a few small coolant hoses connected to it.
You really can't neglect any of these connections.  I don't know if those useless Freddy manifolds have an equivalent of the stock manifold's water gallery.  If it doesn't, then I don't know what to tell you.

Okay I understand now I'm just unsure about where the last one connects as my throttle body doesn't have coolant going through it ?

[GTSBoy]

So it would ideally need to connect to the same general area as the front bleeder does, which is no doubt a mixture of the thermostat housing and possibly the water gallery on the manifold.  I haven't got access to my car to have a look right now.  Why don't you google up some pictures of R34 engine bays and have a look see at that area?

[discopotato03]

I mucked around lots recently with R33 RB25/N14 Pulsar GA16DE/S15 SR20DET IAC valves . Make note that the Pulsar N14's GA16DE version uses a smaller internal shuttle valve size , R33 RB25 and S14/15 SR20DET are same . 

That aside , generally people use an adapter plate to fit R34 GTt IAC valve assemblies on the cast GR/Fredy manifolds intended for R33 RB25 . 

With a bit of a rejig you could probably mount an R33 or S14 or S15 IAC assembly because none of these use the water heated cold start valve (AAC) .You can change the air pipe tube over between these last three IAC units to get R33's T shaped junction tube . There is a mounting pad on R33 and R34 RB25DET water pipe that bolts underneath any of these inlet manifolds . This is where the R33's AAC or cold start bypass valve mounts .

I tend to agree that these aftermarket manifolds often create as many problems as they solve and most reckon the R34GTt's OE inlet manifold is pretty adequate anyway . The sad fact of life is that no aftermarket RB25 inlet manifold lets you put the cold start/idle stuff where it needs to be . 

I once thought removing the factory crossover pipe was a major PITA but once its been off a few times no biggie . 

[adam wicks]

Thanks for the help guys I live in far North Queensland Australia and it doesn't get cold here at all so it wouldn't really matter about the cold start correct ?

[discopotato03]

Well with the GTt setup you'd have to find a way to close that cold start side or use an adapter plate and possibly an R33 or SR20DET type IAC assembly .

If aftermarket your ECU may allow you to adapt an alternative IAC valve assembly that's big enough to do cold start and idle speed control electrically .

Aftermarket manifolds are never easy and many people reckon that in a road driven car performance can be less except right up high . Something to weigh up . 

[adam wicks]

Well with the GTt setup you'd have to find a way to close that cold start side or use an adapter plate and possibly an R33 or SR20DET type IAC assembly .
If aftermarket your ECU may allow you to adapt an alternative IAC valve assembly that's big enough to do cold start and idle speed control electrically .
Aftermarket manifolds are never easy and many people reckon that in a road driven car performance can be less except right up high . Something to weigh up . 

Okay thanks I'll put it together and drive it for abit and let you guys know how it runs

[adam wicks]

Also on the intake side on the rocker cover there is a plastic nipple with a hose that connects to it can that just be blocked ?

[iruvyouskyrine]

I run no IACV at all and my car cold starts fine and idles fine. About 10 seconds after cold start it is absolutely fine, before that idle will stumble a little under revs only. I live in Newcaslte NSW and it gets down to less than 10deg here. I just couldn't be bothered plumbing it in and i'm happy i didnt.

[adam wicks]

I run no IACV at all and my car cold starts fine and idles fine. About 10 seconds after cold start it is absolutely fine, before that idle will stumble a little under revs only. I live in Newcaslte NSW and it gets down to less than 10deg here. I just couldn't be bothered plumbing it in and i'm happy i didnt.

Sweet good to know what did everyone do with this ? Just run a hose down to nothing so it can breath ?

[adam wicks]

Also this has 2 spots for vac hoses do they both go to the manifold ?

[iruvyouskyrine]

12 minutes ago, adam wicks said:

 

 

Sweet good to know what did everyone do with this ? Just run a hose down to nothing so it can breath ?

 

 

No that is you PCV. that needs to run back into the intake manifold after the throttle body.