# R34 GTT Engine Differences



## Mitz (Nov 12, 2017)

Hi Guys, 

I'm looking to buy an R34 GTT, but noticed that depending on the model you get, you can get either an RB25DET engine or the RB25DET Neo Straight 6 engine.

Can someone please help explain the differences between both engines, and which of the 2 engines are easier to modify in terms of increasing the cars power and performance?

Cheers,
Mitz


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## f5twister (Feb 5, 2013)

r34 gtt only has a neo in it.


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## 9TR (Aug 12, 2012)

Yes I'm pretty sure that is the case too.


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## Mitz (Nov 12, 2017)

Maybe I'm getting it wrong then, but I thought there were 2 different engines they came with (see attached photos):


















Keen to hear your thoughts...


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## Trev (Nov 1, 2003)

Top one is an RB25 found in the R33GTST - bottom one is the RB25 with Neo found in the R34GTT.


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## Mitz (Nov 12, 2017)

Thanks for the clarification Trev. 

So the R34 GTT's that have the RB25 engine that can be found in the R33GTST, is that a bad thing? (as I have seen quite a few R34 models using that engine).

Any ideas on which of the 2 engines are better for the R34 GTT model, and which engine from both is easier to modify in terms of increasing the cars power and performance?


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## integra (Jan 29, 2013)

Neos arguably better as its just abit more modern....


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## e30h26 (Mar 9, 2013)

@Trev that is incorrect.

They are both the same engine, the only difference is the bottom one has the engine cover fitted.

The R34 GTT only came with the Neo engine.


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## f5twister (Feb 5, 2013)

e30h26 said:


> @Trev that is incorrect.
> 
> They are both the same engine, the only difference is the bottom one has the engine cover fitted.
> 
> The R34 GTT only came with the Neo engine.


Thats correct the intake and cambelt covers are a death give away that it is a neo.


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## Trev (Nov 1, 2003)

e30h26 said:


> @Trev that is incorrect.
> 
> They are both the same engine, the only difference is the bottom one has the engine cover fitted.
> 
> The R34 GTT only came with the Neo engine.


Yes, my bad - I somehow missed the part on the manifold inlet.


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## sparkso (Nov 4, 2011)

Big tell tale is the traction control unit on the throttle body there. As said both neos, top one is without cover and bottom one is with cover


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## K66 SKY (Jan 25, 2005)

sparkso said:


> *Big tell tale is the traction control unit on the throttle body there. As said both neos, top one is without cover and bottom one is with cover*


And the Factory strutbrace too! 

_Don't know why but you don't seem to find R33 GTS-t Owners fitting the R34 GTT items to their vehicles for some unknown reason?!_


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## Mitz (Nov 12, 2017)

Thanks everyone. 

So if I am following this correctly, both engines are identical (just that one has the new engine cover on it)?


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## f5twister (Feb 5, 2013)

Mitz said:


> Thanks everyone.
> 
> So if I am following this correctly, both engines are identical (just that one has the new engine cover on it)?


Yes but every gtt came with a engine cover so the one in the picture has his removed.


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## sparkso (Nov 4, 2011)

Rods in the rb25det neo are the same as RB26 rods and the pistons are different as well. The neo runs higher compression than the non neo engine. They have solid lifters instead of hydraulic lifters in the head.

Internally the neo and non neo are quite different engines


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## Spiidfriik (Sep 9, 2015)

I would say biggest difference is the Neo has variable cam.


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## joshuaho96 (Jul 14, 2016)

Spiidfriik said:


> I would say biggest difference is the Neo has variable cam.


Intake variable cam is a big deal. However the intake cam is a simple on/off advance of 15 degrees. Nothing really that impressive, basically the bare minimum to pass emissions/improve response at the time.


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## sparkso (Nov 4, 2011)

Spiidfriik said:


> I would say biggest difference is the Neo has variable cam.


Not strictly true either, the non neo rb25det has nvcs aswell. It's not unique to the neo. 

Parts I posted above are unique to the neo only engine, pistons, rods, camshafts, lifter arrange.

They also use a different power steering system and slightly differ turbo. 

Everything else is the same between neo and non neo rb25det's


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## fastfu (Mar 28, 2011)

joshuaho96 said:


> Intake variable cam is a big deal. However the intake cam is a simple on/off advance of 15 degrees. Nothing really that impressive, basically the bare minimum to pass emissions/improve response at the time.


Not at all the 33 rb25 had variable valve timing and that was the on/off switch type, The Neo vvt is different in that it is constantly adjusting the timing.


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## fastfu (Mar 28, 2011)

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