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Greddy Plenum On A R34 Rb25de Head

dori34

By dori34,
in Engines & Forced Induction

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dori34 Grand Master

dori34

Posted
Posted

I know the earlier models (R32 & R33) GTS can use the greddy plenum but on the R34 GT is completely different to the GTT.

has anyone ever attempted to fit a greddy plenum to a R34 GT RB25DE head?

if so, was it a direct fit & if not, what problems did you encounter?

as a r34 owner, you would all agree that the head design is a pain in the ass to do spark plug changes and overall makes the engine bay look so messy.

any help much appreciated :(

pics/links would be very helpful.

i've searched and only return results for R34 GTT & R33/32.

Trent from status, perhaps you may be able to shed some light on this.

Cheers

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R34GTFOUR Mentor

R34GTFOUR

Posted
Posted

The head stud pattern is the same so it would bolt up just like a r33 rb25.

The only problem i see is that:

1. The manifold is designed for side feed injectors and you would need to run a fuel rail to suit top feed as above, easily fixed with same spacers.

2. The idle control is different on the r34 so you would need to run a r33 AAC set-up an wire it up accordingly (haven't hit this hurdle yet, but I will when I'm closer to the build). Don't expect it to be hard to figure it out though.

3. The neo de head apparently has much smaller ports (just going off photos I've seen, but I'm going to double check this when my engine comes out), so the manifold will be far from "port matched".

4. The shorter runner style of the greddy will reduce down low torque and is more suited to FI, unless you're planning on really reving the old girl hard. I dont know about yours but the only thing that the neo DE has going for it is the lower down low torque compared to the non-neo DE, and this would work against that. Hopefully it would add to abit more top end as mind just dies in the ass after 6k rpm but I don't see it helping that much as I think the stock cams hold it back aswell.

It does look a lot cleaner though, and the extra time you would save from spark plug changes would pay for itself :thumbsup:

dori34 Grand Master

dori34

Posted
  • Author
Posted

thanks for the reply mate.

i also heard the neo rb25 has smaller ports too.. maybe bring out the grinder and give it a go? haha

my car is a de+t so its got better low end response already.

definitely worth looking into with abit of fiddling round, could work!

has anyone got a greddy style plenum that i can borrow for a day so i can see how much work is needed to fit?

will leave something of value so u know im not gonna run away with it lol

R34GTFOUR Mentor

R34GTFOUR

Posted
Posted

Depending on how long you can afford to have your car off the road, take the inlet manifold off and get a stock r33 inlet gasket and pop it on. You'll be able to see the difference in the ports from that.

From the pictures I've seen it looks more intensive then a die ginder job haha. I still can't believe its smaller than the turbo counterpart, the de and det heads on the r33's are exactly the same port wise I dont know why they would make them different on the 34's.

R34GTFOUR Mentor

R34GTFOUR

Posted
Posted
Failed? ill admit the na r34 is a slug but wat can you expect from a na 2.5L? In terms of intake runners or even exhaust manifold design nissan know what they are doing...

Yes and no. The neo head was designed to be more "emissions" friendly, so certain areas are leaning towards that and power/performance is sacrificed. Overall its not a bad engine, but I wouldnt say its much better than the r33 engine. If the ports are indeed as small as I've seen in the photos when compared to the DET head, then that would make it a big fail in my book.

  • 3 years later...
Sarumatix Veteran

Sarumatix

Posted
Posted (edited)

Massive thread Necro but.. I am working on putting an R34 RB25de + T into an R32. I have a high mount T67 and just realised (ouch big fail) that due to the de throttle setup there is no clearance. If I went with a turbo manifold setup I would be fine. My thought was to split the plenum bottom half from the top, hoping (probably wishful thinking), that the runners expand?

Even if they don't maybe it would be possible to port the bottom half to match a turbo top half and a damn sight cheaper than porting the head.

Damn you nissan and your smaller runners on the RB25de NEO! :(

Edited by Sarumatix

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