How to identify correctly a rb25 turbo!

[frankydodo]

Hi everybody! I was just wodering how do i correctly identify a rb25 turbo because i will be buying one soon to put on my rb20 ! I want to do a little setup on my skyline next summer!

Turbo from rb25
Fmic
Boost controller
Injector 440cc
Fuel pump 255lph
Full 3" exhaust from dump to muffler
Aem wideband

My whp goal is 250-275!

So! I dont want a jdm shop to sell me not the right turbo!

I have seen a lot of number on housing like

45v1
45v3

But wich one is the right one for a rb25? And is the a difference of number between s1 and s2 ?

Hope you guys will be able to help me! And if somebody has tip or advice for my setup , positive or negative feel free to tell me!

Thanks!

[Voodoo_ChildR32]

The main difference I noticed on my 25 turbo was that the compressor housing is visibly larger than the 20.


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[frankydodo]

Ok thx and can someone tell me what to look at, i know that there is the shaft play that need to be as minimal but what should i check too?

[bellis_GTR]

Check for scrapping around the walls, look at turbine and compressor to make sure they are not broken or have chips. You can check shaft play by moving shaft side to side and up and down. It needs to be as minimal as possible. You can spin the turbine and compressor and make sure it spins freely and with out making any chatter sounds. Another thing is check the actuator and the opening in the back to make sure it opens freely and fully. Make sure that the actuator is opening fully so you dont have weird boost spikes or no boost at all. If the turbo is in the car still check for signs of oil.

I'm not sure about identifying an RB25 turbo other than looking for serial numbers. I know from a stock R32 GT-R turbo and RS580 turbo and the main difference is compressor housing size. If you have the both the RB20 turbo and RB25 turbo put them together to see.

Hope this helps.

edit: here are some helpful videos.

How to test actuator

How turbo works and internals

[MKIV]

I made 264whp on the exact same setup.

The tune is key.

Good luck!

[Skym]

RB20DET turbo has say 16v5 Nissan (Nissan logo) Motor on compressor housing and a nipple on main scroll / round part of housing for internal wastegate actuator. RB25DET turbo has 45v4 Nissan on compressor housing and no nipple for internal wastegate actuator (need to weld a nipple onto intake piping after turbo or drill, tap stock compressor housing to fit screw in nipple near outlet of housing that goes towards intake piping).

Series 1 R33 RB25 turbo, R32 RB20DET turbo have twin blade design on compressor wheel. Series 2 R33 RB25 turbo has single blade design.

R32 RB20DET internal wastegate actuator (auto, manual use the same internal wastegate actuator) = 11.36psi-12.78psi

R33 RB25DET manual internal wastegate actuator = 7.059868421psi-7.833552631psi

R33 RB25DET auto internal wastegate actuator = 4.835552631psi-5.60921052631psi

[frankydodo]

Thanks thats exactly the answer i was lokking for! Still 2 question haha:P

How the hell did you call the nipple for the vacuum?
Cause im french lol and im searching fornthe real word :P

And you made 264 whp @ xx? Psi MKIV?

Thanks!

[rak123]

The picture amnash posted is an rb20 turbo which is branded 16v
S1 rb25 is branded 45v1 and uses a ceramic exhaust and steel turbine wheels.
S2 rb25 is branded 45v2 on the turbine housing and 4iu on the exhaust housings and uses ceramic exhaust wheel with a nylon compressor wheel.
Rb25 neo #1 is branded 45v2 on the turbine housing and op6 on the exhaust housing and uses ceramic exhaust wheel and a nylon compressor wheel. (same as a s2 rb25 turbo but with a bigger Exhaust housing).
Rb25 neo turbo #2 is branded Garret on the turbine housing and is steel exhaust and turbine wheels.
And if u happen to come accross one branded 45v4 that is a vg30det turbo which uses steel wheels also.
S1 and rb20: capable of 14psi safely
S2 and neo #1: capable of 12 psi due to the nylon wheel
Neo#2 and vg30det: capable of what ever u want throw at them I'd imagine due to steel wheels but don't know when they run out of effiency.
Hope that helps
-Ryan

[frankydodo]

Ok!! so i will be searching for a 45v1 ou 45v4 or a neo2!



EDIT

And hey...if i drill/tap a hole on the compressor housing or the rb25 turbo inlet pipe with something like this

http://www.veneersupplies.com/products/Brass-Barb-Fitting-14-NPT-Male-to-12-Barb.html

or

http://fittingsandadapters.com/pusbarmalpip.html

Is it the right kind of fitting/size?

Thanks!

[frankydodo]

Saw a couple people with the hks 2530... Damn looks like a really good turbo . Bolt on on a rb20! Yep more expenaive but way more possibilities with it.. Will definitly think about it :P

[beacher1B0]

Yep u could use something like those. Cant remember off hand what size the vacuum line tho. Take the vacuum hose off and go to Can Tire or wherever with it to get your vaccum nipple fitting,
If u tap the spot on the 25 where it is on the 20 you might want to use an elbow fitting. You might even be able to unthread and reuse the elbow fitting from the 20 turbo.

I tapped and threaded in a Brass fitting like the veneersupplies on the turbo outlet pipe.