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Since the engine is out of the car, it is much easier for me to put up some finished pictures from below, which is where most of the action is. Particularly the water hoses and connections for the oil/water heat exchanger. I couldn't seem to find the Greddy instructions in this thread (it's probably there, I may have simply missed it), but just in case this is the link to the pdf file. It's in Japanese, but the drawings are very worthwhile.

http://www.greddy.com/img/PHP/products/pdf/1282.pdf

I noticed on some cars that the throtte cable angle was an issue. I purchased a Greddy throttle body adaptor from Nengun and it came with a bracket that goes between the standard throttle cable bracket and the mounting holes on the plenum. It straightens the throttle cable alignment. I will post up a picture of that as well.

I also noticed that some guys have used the water supply fittings for the turbo incorrectly. In order for water to flow through the piepwork and around the turbo core there needs to be a pressure differential between the source of the water and the return. That is usually accomplished by having the return plumbed in before the thermostat. The thermostat, even when it is fully open, forms a flow limiter and hence the water pump creates a partial vacuum on the radiator side of the thermostat. So having the water source and the return both plumbed into the rear of the block is not a good idea, as the pressure would be almost equal and very little water will flow. What I have done is to plumb the return into the fitting that comes out of the thermostat encasement on the block.

It also concerns me that most guys haven't re-used the air bleed, that standard is mounted at the highest point of the inlet plenum. This is also not a good idea as it removes the capability for the bleeding out of any air trapped in the cooling system. As everyone knows air in the cooling systems is not a good idea as it leads to hot spots at various places in the cylinder head which can cause cracking and/or warping due to temperature differential and also detonation due to localised heating. So I have plumbed the bleed vent and its 3 pipes back into the revised cooling system. One pipe goes to the throttle body cooling return, another to the turbo return (as mentioned above) and the third to the rear of the block. Hopefully the pictures will make it easier to understand.

As some may remember I purchased the inlet manifold/plenum to save some cost. So I could use top feed injectors (that I have plenty of) instead of side feeds (that I would have to buy). I thought I would be able to simply buy the alloy adaptors to fit the top feed injectors into the side feed holes in the inlet manifold. But apparently they are only sold (at $400 or so) with a Greddy top feed fuel rail, which I don't need as I have plenty of standard RB top feed fuel rails. So what I thought I would do is get our race team fabricator to machine up some adaptors out of alloy on the lathe. While he is doing it he may as well do a few more sets, so I thought I would ask if anyone else needs a set.

Cheers

Gary

incredibly intresting as i have hot spot issue's i think. sometimes my gauge spikes etc however its the wroung sender for my car *rb25 cefiro*.. also i get excesive knock on the powerfc at stupidly light throttle always at 3000rpm even with less then std timming. readings of 70...

would it be possibly for me just to hook up a hotspot reserviour for the cooling system and just by-pass the throttle body? as ive remooved the throttle preheats.... whats your thoughts?

p.s also could you get those pics up as i want to see how you did your cooling lines.

Edited by dead32
  • 1 month later...
As you may remember, the cylinder head was already extensively ported and larger exhaust valves fitted, after the over rev at the drags last year. So the manifold inlet runners had to be aligned with the head porting anyway. Only took a few minutes on each port with the die grinder. We also tidied up the water jacket porting a little, not much. All up less than $100 in time cost, so no big deal. Would have had to do it with any inlet manifold, same as we did with the exhaust manifold. It's standard engine preparation for us.

I haven't touched the plenum itself, the rough casting inside is good for airflow, separates it and stops laminar flow around the walls. We only worked up the ports enough to blend in the extra size required to match the head. It’s a smooth and straight transition and aimed at the back of the inlet valve, that’s all that matters.

As an asside, with the Tomei Poncams, valve springs, oversized exhaust valves and porting, it's the best RB25 head I have ever done. So it will be interesting to see how it works out with the VG30 housing on the GCG ball bearing hgh flow, response should be lightening fast. I know will have to spend some time getting the individual cylinder tuning right, but it should be worth it.

Cheers

Gary

Hi SK,

Wondering how you ended up getting on with the chinese plenum? I can make my own (As per photos in Fabrication forum) but this would be a crapload easier, especially since I can make test plates to pressure test/weld leaks my self.

Would one of these flow just as well as a greddy/so forth?

hey guys, i having trouble veiwing th picstures of the tute, i have recently bought one of these greddy copies, seens to be some burs on the inside, i'll just be filing them down n smoothing them out, apart from that the product looks good to me, smooth and should fit up nicely. Did anyone use a gasket or gasket goo when fitting one of these. i plan on doing the install soon. also could someone specify all the sizing of the nipples heater hose etc i need to buy. One more question.. with the ACC valve (thats the one on the left rocker cover, looking from front of the car right?) how did people block them off?

  • 4 weeks later...
As some may remember I purchased the inlet manifold/plenum to save some cost. So I could use top feed injectors (that I have plenty of) instead of side feeds (that I would have to buy). I thought I would be able to simply buy the alloy adaptors to fit the top feed injectors into the side feed holes in the inlet manifold. But apparently they are only sold (at $400 or so) with a Greddy top feed fuel rail, which I don't need as I have plenty of standard RB top feed fuel rails. So what I thought I would do is get our race team fabricator to machine up some adaptors out of alloy on the lathe. While he is doing it he may as well do a few more sets, so I thought I would ask if anyone else needs a set.

Not sure I follow what you saying, but this might be of use to some people.

I recently contacted Trust Japan regarding the installtion of top feed injectors (GReddy/Denso) into the GReddy 11.0mm fuel rail (the 10.5 mm only allows fitment of the stanard injectors). And they replied by stating that you need to buy the following Genuine Nissan parts:

1) 6pcs of O-Ring -----Code 16618-78A00

2) 6pcs of Insulator (Upper Side)----Code 16635-78A00

3) 6pcs of Insulator (Bottom Side)---Code 16636-V5000

hey guys, i having trouble veiwing th picstures of the tute, i have recently bought one of these greddy copies, seens to be some burs on the inside, i'll just be filing them down n smoothing them out, apart from that the product looks good to me, smooth and should fit up nicely. Did anyone use a gasket or gasket goo when fitting one of these. i plan on doing the install soon. also could someone specify all the sizing of the nipples heater hose etc i need to buy. One more question.. with the ACC valve (thats the one on the left rocker cover, looking from front of the car right?) how did people block them off?

I would think that gasket goo or even gasket paper would be a good idea.

An earlier post stated 6mm nipples.

To block off the ACC simple get a hose block off and hose clamp. Should be able to get this from a hardware or auto shop.

One more question.. with the ACC valve (thats the one on the left rocker cover, looking from front of the car right?) how did people block them off?

PCV

that is retained normally- but you can either get teh hole welded up, or use a plug on it from clark rubber or something.

  • 4 weeks later...

Just a quick note to those who are undertaking this, Total Tools has a large range of threaded brass nipples.

And in case it wasn't mentioned before remember to drain your coolant before doing this, and if you have thought about adding an oil relocation kit now would be a good time.

  • 3 weeks later...
  • 2 weeks later...
Can someone post up some pics of the water feed into a highmount turbo setup?

Or explain how to run it from the Greddy plenum to the turbo?

The turbo water feed doesn't come from the manifold. The feed is off the back of the block with the heater connections and the returbn is off the back of the thermostat housing.

Cheers

Gary

The turbo water feed doesn't come from the manifold. The feed is off the back of the block with the heater connections and the returbn is off the back of the thermostat housing.

Cheers

Gary

Im trying to work out how where the feed to the turbo comes from,aswell as where the water line from the turbo goes to.

Can someone post pics of there highmount setup with a greddy manifold?

Im trying to work out how where the feed to the turbo comes from,aswell as where the water line from the turbo goes to.

Can someone post pics of there highmount setup with a greddy manifold?

Whether or not it's high mount is irrelevant, the plumbing is the same.

Cheers

Gary

NOW, let's get to the cool stuff.

We're going to block this pipe off. Watch.

PlenumInstall%20015.JPG

I also noticed that some guys have used the water supply fittings for the turbo incorrectly. In order for water to flow through the piepwork and around the turbo core there needs to be a pressure differential between the source of the water and the return. That is usually accomplished by having the return plumbed in before the thermostat. The thermostat, even when it is fully open, forms a flow limiter and hence the water pump creates a partial vacuum on the radiator side of the thermostat. So having the water source and the return both plumbed into the rear of the block is not a good idea, as the pressure would be almost equal and very little water will flow. What I have done is to plumb the return into the fitting that comes out of the thermostat encasement on the block.

Cheers

Gary

I'm havin some problems finding the nipple for turbo water line hook up, i've found a bolt on the side of the block is this the spot? I was thinking of hooking it up to the water line shown above is this a good or bad idea??

SK, do you have any pics of where you put yours

Edited by m0rt

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