CAN an RB26 twin turbo naifold fit an RB25?

[rich_the411]

After studying :confused: (yeah right) RB engines for a little while, i noticed a couple of years back, twin turbo RB25's were kinda popular, especially in VL's. So I was wondering if any of you intelligent humans know if the standard GTR manifold can fit the RB25, or is custom the only way to go? Any help would be greatly appreciated, cheers

[sproosy]

I think they fit but the bolt/stud patteren is different. Correct me if im wrong.

[Maxx]

it should fit with minor mod, as there is a RB25deTT silvia using RB26 manifold in magazine..

[Sydneykid]

The inlet and exhaust manifold stud patterns wers made deliberately different by Nissan to stop people from putting R26 manifolds on RB25's. They believed it would increase the exclusivity of the GTR and support its higher price.

[Mandingo]

Gee that only leaves 100000 other parts that will fit

[R31Nismoid]

this has been covered in depth before

search and you shall find

[Sydneykid]

Gee that only leaves 100000 other parts that will fit

By far, most of the parts that give the RB26 the extra performance are not interchangeable. Things like cams, valves, valve springs, followers, injectors, inlet manifold exhaust manilfold, inlet plenum, throttle bodies, turbos, dumps, engine pipes, inlet air temp sensor, ECU etc

Sure I can use the same spark plugs, oil filter, CAS, water temp sensor etc but they are hardly what I would class as "performance" increasers.

[Ronin 09]

There's a company in Japan that make a spacer that allows the 6 throttles / intake manifold to be bolted to a RB25 head...

[Maxx]

blitz i think?

[USRB25S13]

Now how about going the other way? I have an HKS cast manifold for my RB25. I am pondering the idea of getting an RB26 motor and was thinking how nice it would be if I could use the HKS manifold on the 26.

[GTRgeoff]

I fitted the twin turbos off the R34 GTR to my GTS25t track car. The manifolds fit after cutting and welding 2 of the flanges, then match porting. Everything then just bolts up like the exhaust. It's not easy or cheap.

[rich_the411]

Coolaid fellas, thanks for the advice!

[gtst25]

I fitted the twin turbos off the R34 GTR to my GTS25t track car. The manifolds fit after cutting and welding 2 of the flanges, then match porting. Everything then just bolts up like the exhaust. It's not easy or cheap.

Hi Gtr Geoff,

Just interested in how well the GTS25t went and what sort of power it made?

Did you use standard gtr turbos?

Cheers!

[discopotato03]

A lot of people look into this idea . SK costed out the cams buckets springs etc to mod a R33 25 head , buying the GTR head and manifolds is far cheaper .

I'm not disputing that Nissan made it difficult to fit GTR manifolds to any other RB head , but when comparing them too many things get in the way to make it practical . Obviously the RB20 pattern came first and the GTR type later . It looks impossible to fit the GTR inlet on the alternate pattern because there would be no access to the fasteners . The exhaust stud pattern has the same dramas for the same reason . The two flanges would have been changed to give access to the nuts and washers around the twin turbos .

Bang for buck using the complete RB26 top end (turbo/s optional) is best from a performance viewpoint if you can afford it . Being non VVT it solves the oil drain problems as well and another reason why I bought mine .

Cheers A .

[GTRgeoff]

It was feeling nice.

Unfortunately the stock (see ceramic turbines) front turbo decided to let go at 5psi and I now have 25psi compression on 1,2,3. This is appearing more common than I initially thought possible, but when the ceramic turbine let go on this setup (RB26 style) it is often ingested back into the 3 cylinders and scores the bores and stops the valves closing.

I would never do this again with the stock GTR turbos as they tend to be more prone to failure after being removed. That said, it would be too expensive to bugger with using expensive turbos. I think I will be dropping in a complete RB26 for a number of reasons, although they aren't as punchy low in the rev range.