RB25 neo Turbo question

[Infinity238]

ok, im not sure about this one so I'm going to see if anyone knows. Both are R34 RB25 neo turbos one is the steel garrett unit, the other is the nissan stamped housing. The question I have is that they both seem to be rocking different actuators. Are they essentially the same? or is one better then the other? Because I cant really find any info other than the fact that one is bigger then the other.

[Dragon Humper]

Grab a fish scale and see which one has a stiffer spring....or take them both off, tie the actuator rods together. Pull on the cans and see which one pulls first...use the one that stays put...its stiffer. The larger can should give you better/faster control over the smaller one but the stiffer one will allow more boost to be screwed into it.

EDIT: Now that I think about it some more, the spring on the larger can actuator is going to be stiffer because the can is bigger. Im sure if you put 10psi of air to the cans the rods will move the same amount. If that is the case, use the larger can for reasons mentioned above.



Jon.

[Infinity238]

Grab a fish scale and see which one has a stiffer spring....or take them both off, tie the actuator rods together. Pull on the cans and see which one pulls first...use the one that stays put...its stiffer. The larger can should give you better/faster control over the smaller one but the stiffer one will allow more boost to be screwed into it.

EDIT: Now that I think about it some more, the spring on the larger can actuator is going to be stiffer because the can is bigger. Im sure if you put 10psi of air to the cans the rods will move the same amount. If that is the case, use the larger can for reasons mentioned above.



Jon.

Excellent, I'll give this a good testing in the morning before they go back in. Thanks for the response Jon!

[beacher1B0]

If these are both stock could you for the community do some bench testing/research/picture taking?
Points to prove:
Turbine(Exhaust) Wheel magnet testing with pictures of both turbos. Just to prove or disprove all stock RB25 turbos are ceramic Exhaust wheeled.
Turbine Housing Pictures. OP6?
Centre cartridges pics if they have ID tags.
Compressor(Intake) Wheel magnet testing with pictures. Which turbo has Nylon wheel and which has steel?
And anything else you can think of.

Its possible that one of those actuators u have in the original post is RB20 actuator which is a couple psi higher or maybe even an auto vs manual actuator.

[Infinity238]

ok, here we go. For starters a simple pull on both actuators and the larger one is much stiffer spring. Anyone know if its stock or not as its not stamped nissan like the other one. So in the pics bellow I have already swapped them around.

As far as I know the magnet test wont work as the blades will be non magnetic regardless if there metal or not, but the Garrett is full steel ball bearing unit as where the rb25 neo is a nylon/ceramic unit. Also from what I have gathered from heavily researching this is that nissan was bad for mixing and matching parts on the R34's. So you will never know what turbo you have until you pull it and have a look.

Stock turbo from my 98 R34 GTT 45 V1 with single blades

Factory Garrett R34 Turbo from series 2 GTT with a two blade design

Stock Rear stamped OP6 with an F stamp above it (not sure what that indicates)

Garrett unit stamped OP6 with a B stamp

Stock unit stamped OP6 again with the numbers 514A

Garrett stamped OP6 and 8278 or 827B cant really be sure


now the 2 actuators.

Larger unit off my 34

Nissan unit off my garrett

[beacher1B0]

Thanks.
I was hoping for absolute proof of an steel exhaust wheel from an Rb25 turbo. Too much tunnel vision info out there. Your "op6 B stamp" photo looks like a ceramic exhaust wheel.
As far as I know/researched NO RB20/25 engines came with steel exhaust wheeled turbos. Only certain early vg30det have steel exhaust wheels.
An OP6 exhaust housing is the biggest of the Exhaust housings on RB25 turbos.

Sorry to take it off topic. If your gonna stay stock boost control find yourself an Rb20 actuator and slap it on.

[Infinity238]

Thanks.
I was hoping for absolute proof of an steel exhaust wheel from an Rb25 turbo. Too much tunnel vision info out there. Your "op6 B stamp" photo looks like a ceramic exhaust wheel.
As far as I know/researched NO RB20/25 engines came with steel exhaust wheeled turbos. Only certain early vg30det have steel exhaust wheels.
An OP6 exhaust housing is the biggest of the Exhaust housings on RB25 turbos.

Sorry to take it off topic. If your gonna stay stock boost control find yourself an Rb20 actuator and slap it on.

Yeah, As far as I know the only RB25 turbo with steel exhaust wheel the one stamped garrett and those didnt come around until the series 2 R34 GTT. I do have a boost controller which is the main reason for swapping the turbos but it was my understanding you still want the better/stiffer actuator. Which was the main reason for my post.

[Skym]

1.) Remove internal wastegate actuator from turbo.

2.) Hook up vacuum hose to internal wastegate actuator bulb nipple with compound gauge (mechanical boost gauge) T'd in the middle of vacuum hose.

3.) Apply compressed air to vacuum hose carefully and note at what boost level (on compound gauge or boost gauge) the internal wastegate actuator arm starts to move.

In knowing when the internal wastegate actuator arm moves, you'll have the spring pressure or basically the lowest boost level you can run via a boost controller.

[nick-nismo]

Hmm looks like that garret turbo still has a ceramic exhaust wheel. The white coloring to it should be a giveaway.
A steel wheeled unit should be black in color. Also not sure of the red on the stock unit, if that's discoloration from the camera or a different type of ceramic exhaust wheel.

Oh and I have a steel wheeled rb20 turbo, must be a rare one.

[Infinity238]

Hmm looks like that garret turbo still has a ceramic exhaust wheel. The white coloring to it should be a giveaway.
A steel wheeled unit should be black in color. Also not sure of the red on the stock unit, if that's discoloration from the camera or a different type of ceramic exhaust wheel.

Oh and I have a steel wheeled rb20 turbo, must be a rare one.

Yah, i was wondering about this too but these garretts have always been listed on nissanparts as full steal ball bearing units. The thing was running 16psi on my r32 like nothing so id assume this is true. Any other way to test it other then this magnet test myth? Since the wheels on a proper steel turbo are usually a non magnetic alloy.

As for the color, the ceramic ones that have seen some miles seem to go a reddish orange color the steel ones are more a dark grey.

A stock rb20 steel turbo? nick-nismo are you sure it hasn't been rebuilt/high flowed? ether way sounds awesome.

[Dragon Humper]

You could do the tap test.

Take a small chistle and use the blunt end to gently tap on the end of the turbine wheels. Start with the known ceramic wheel then move to the other one, the ceramic and the alloy should make very different sounds. Make sure you use a hardened metal like a chistle and tap just hard enough to hear a noise and that should do it.


Jon.

[Skym]

A stock rb20 steel turbo? nick-nismo are you sure it hasn't been rebuilt/high flowed? ether way sounds awesome.

The exhaust, intake wheel will be bigger on a hybrid turbo if you put stock, hybrid turbo next to each other. Hybrid RB20 turbo gives 20hp more at same boost level over stock RB20 turbo and power band goes right to the rev limiter (7500rpm).

High flowing is porting, polishing housings, back cutting blades.