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RB25/VG30 hybrid highflow Turbo?

riceline

By riceline,
in Engines & Forced Induction

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discopotato03 Grand Master

discopotato03

Posted
Posted

Cubes I've been down in the cave looking at an old RB25 housing and an RB20 turbo I have . I did a very rough rule measurement and both are similar at this point . What I did notice is that when I put two fingers (middle and index) down the turbine inlet flange they go slightly further into the RB25 housing . You can see a difference when looking into the inlet's just downstream of where the wastegate port comes in from the left hand side . The passage is slightly taller on the 25 housing .

Just to compare my 25 housing has 726B next to the T3 flange on the cartridge side in fine figures , and 2IU in bold figures nearby . On the dump side it has a "D" and the bold 2IU again . Just inside the turbine inlet flange on the LHS there is a number "2" rotated 90 degrees .

The RB20 housing has 123C on the core side and 04U in bold print , nothing inside the flange .

Cubes you may be able to tell me if the VG30 housing has a number inside the flange etc . I have not had a 30 housing for ages but it was very obvious that the passage downstream of the gate outlet was much bigger than the 25's , which itself was only a little larger than the 20's . What may tell the story is measuring the outside diametre of the housing as this goes up with ARR .

As has been mentioned before , factory stealth bitz ie VG30 housing on RB25 (R33/34) turbo is about as good as it gets provided you have cheap access to them and for a first try as they bolt on . Not a race std turbo but pretty passable first off .

Cubes Grand Master

Cubes

Posted
Posted (edited)

I've done lots of measurements..

The R34 GTT and VG30DET Turbo's I have here have 'exactly' the same turbine housing.

Everything measures up, feels and looks the same.

The cross section I mentioned to measure measures up as 50mm.

The RB20 turbo measures up as 45mm here.

On the turbine housing both have the Markins OP6.

The VG30 has a 6 stamped just inside the T3 flange where as the R34 turbo has a 5.

BassJunky bought a VG30 turbo only to find it had the same turbine housing as the R34 turbo he had. :D

What are your thoughts on a slightler larger comp wheel with a surge ring vs a slightly smaller without the surge ring? :O

Edited by Cubes
discopotato03 Grand Master

discopotato03

Posted
Posted

I would say that Nissan must have found a surge problem when using the larger compressors on RB25's with the relatively small ARR exhaust housings . I'd say the VG30's having a much larger ARR turbine housing with a smaller diametre compressor did not go into surge conditions at lower revs .

My RB20 turbo also has the anti reversion groove in its snout , probably because of its even smaller ARR turbine housing .

I'm curious to know why the GTt housing has the 5 and the VG30 the 6 . The only way to tell is to seal the sides of the housing and measure the fliud volume required to fill it up with the flange perfectly level , sort of like buretting combustion chambers .

Cheers A .

Cubes Grand Master

Cubes

Posted
Posted (edited)

Boostd,

I've spoke to ATS on marion road regarding the size of the turbine housings.

He said the RB25 turbine housing is most definaitely a .6 a/r and the vg30 a .7 or there abouts. He said its difficult to measure exactly unless they are cut down (as disco once said I believe also).

He also said there is no actual listing for the turbine housings so that too also throws out the idea of looking up specs.

He could be wrong though.. :P

I seem to think so especially after looking at a VLT turbine housing that is most definaitely a .6.

Edited by Cubes
Bass Junky Grand Master

Bass Junky

Posted
Posted

Guys, Keep this quiet.

Otherwise the price of busted R34 GTT turbos will go through the roof.

By all means, search for the VG30 and R34 turbos, but don't go mentioning to wreckers or parts suppliers that the R34 GTT turbo can support heaps more power than the R33.....

Let's keep it quiet!

BASS OUT

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