Jump to content
SAU Community

Recommended Posts

thanks CHris

Hey - how about compressor side. Is the compressor housing on the Rb20 the same beisdes the Pressure T coming off it?

I.e. could you use an rb20 compressor housing on an rb25 and not change the turbo characteristics?

thanks

i can't say i know first hand. but considering a lot of people upgrade to a rb25 turbo on their rb20's....i'd say the difference is the compressor housing because they upgrade for the larger flow. also i know for a fact that the compressor outlet attaches to a different size elbow for the two turbos. My thoughts -----> u'd b limiting the flow back down to an rb20 turbo standard basically.....tho not sure of this...someone back me up hahaha (if i'm right).

thanks CHris

Hey - how about compressor side. Is the compressor housing on the Rb20 the same beisdes the Pressure T coming off it?

I.e. could you use an rb20 compressor housing on an rb25 and not change the turbo characteristics?

thanks

sorry about the delay. Just finished exams today. Rb25 turbo comp housing is 45v, rb20 is 16v.

Nah, they're different. It changes teh characteristics. If you're having surging issues, perhaps you need a bigger a/r exhaust housing like the nissan op6 housing.

They're really rare though - my turbo is an op6 turbo.

The RB20 and VG30 compressor wheels are identical.

The cores are identical; that being the compressor wheel, center section and turbine wheel.

The Rb20 runs a small turbine and compressor cover to keep response up and spool down.

The VG30 turbo runs the larger OP6 turbine housing and larger 45v compressor cover.

The R33 Rb25 turbo runs a turbine housing that is apparently a little larger than the rb20's; be buggered if I was able to pick a difference apart from the markings. The RB25's compressor wheel is noticably larger and runs the larger 45v comp cover.

The R34 RB25 turbo is from what I've seen is the same as the R33 S2 turbo apart from that larger VG30 sized OP6 turbine housing.

The local turbo bloke here in Adelaide (ATS) told me the R32 and R33 turbine housings are a .6 and the VG30 and R34 OP6 turbine housings are a .7. There's nothing on paper stating their size but thats what he 'guestimates' without cutting one up.

In short the turbine housings are all interchangable. The Compressor housings are not; RB20 and VG30 compressor housings you are able to swap over

As for swapping comp covers on the R33/R34 RB25's, why one would want to do that is beyond me as they are the same size. :blink:

  • 5 weeks later...

Bit confused here matey

So is this 04u one the one on your car? or have you sourced another GCG highflow?

If the one on your car has the 04u housing, that could explain the compressor surge issue - too small exhaust housing.

Its hard to tell from the pictures, but does that turbo you posted pics of have a leaking oil seal?

Nah mate the one on my car is the 21U - you are right I have sourced another one. Apparently the oil seal is ok but it does look like oil is coming out the back. . I just posted another question regarding turbo balancing - I'm planning to use the smaller comp wheel on this one on my current one with the 21U housing.

It would have been better if I could have used this one since it is already machined.

Is there really any difference between the rb20 and rb25 housings?

I mean GCG use the Rb20/Rb25 housings interchangeably dont they?

Ah ok, makes sense now.

Well, I can tell for sure that the rb20 comp housing is smaller. It is smaller inside too - evident by the fact that people need to get an rb25 elbow.

In regards to the rb25/20 exhaust housing, the housing is supposedly larger. I didn't measure the 20 housing when I had one, but my friend did, and he said it is larger.

It could be an internal area difference (e.g. like inside the rb20 comp housing - smaller than the 25 comp housing). They might appear to be similar outside, but inside it might be different.

There definitely would be a difference, otherwise nissan wouldn't have used a different number housing

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • You won't need to do that if your happy to learn to tune it yourself. You 100% do not need to do that. It is not part of the learning process. It's not like driving on track and 'finding the limit by stepping over the limit'. You should not ever accidently blow up an engine and you should have setup the ECU's engine protection to save you from yourself while you are learning anyway. Plenty of us have tuned their own cars, myself included. We still come here for advice/guidance/new ideas etc.  What have you been doing so far to learn how to tune?
    • Put the ECU's MAP line in your mouth. Blow as hard as you can. You should be able to see about 10 kPa, maybe 15 kPa positive pressure. Suck on it. You should be able to generate a decent vacuum to about the same level also. Note that this is only ~2 psi either way. If the MAP is reading -5 psi all the time, ignition on, engine running or not, driving around or not, then it is severely f**ked. Also, you SHOULD NOT BE DRIVING IT WITHOUT A LOAD REFERENCE. You will break the engine. Badly.
    • Could be correct. Meter might be that far out. Compare against a known 5 ohm 1% resistor.
    • @Murray_Calavera  If I were an expert I wouldn't be in here looking for assistance.  I am extremely computer literate, have above average understanding on how things should be working and how they should tie together.  If I need to go to a professional tuner so be it, but I'd much rather learn and do things myself even if it means looking for some guidance along the way and blowing up a few engines. @GTSBoy  I was hoping it would be as simple as a large vacuum leak somewhere but I'm unable to find anything, all lines seem to be well capped or going where they need to be, and when removed there is vacuum felt on the tube.  It would be odd for the Haltech built in MAP to be faulty, the GTT tune I imported had it enabled from the start, I incorrectly assumed it was reading a signal from the stock MAP, but that doesn't exist.  After running a vacuum hose to the ECU the signal doesn't change more than 0.2 in either direction.   I'll probably upload a video of my settings tomorrow, as it stands I'm able to daily drive, but getting stuttering when giving it gas from idle, so pulling away from lights is a slow process of revving it up and feathering the clutch until its moving, then it will accelerate fine.  It sounds like I need to get to the bottom of the manifold pressure issue, but the ignition timing section is most intimidating to me and will probably let a pro do that part.  Tomorrow I'll try a different vacuum line to T off of, with any luck I selected one that was already bypassed during the DBW swap.  (edit: I went out and did it right now, the line I had chosen did appear to have no vacuum on it, it used to go to the front of the intake, I've now completely blocked that one off at the bracket that holds several vacuum lines by the firewall.  I T'd into the vacuum line that goes from that bracket to the vacuum pump at the front of the car, but no change in the MAP readings).  Using the new vacuum line that has obvious vacuum on the hose, im still only getting readings between -6.0 and -5.2.  I'm wondering why the ECU was detecting -5.3 when nothing was connected to the MAP nipple and ECU MAP selected as the source. @feartherb26  I do have +T in the works but wanted to wait until Spring to start with that swap since this is my good winter AWD vehicle.  When removing the butterfly, did it leave a bunch of holes in the manifold that you needed to plug?  I thought about removing it but assumed it would be a mess.   I notice no difference when capping the vacuum line to it or letting it do its thing.  This whole thing has convinced me to just get a forward facing manifold when the time comes though.
    • Update: tested my spark plugs that are supposed to be 5ohms with a 10% deviation and one gave me a 0 ohms reading and the rest were 3.9ohm<, so one bad and the others on their way out.
×
×
  • Create New...