Vg30 Rear Housing On Gcg Rb25 Hiflow

[tuitahi]

Went in to GCG this morning with my GCG hi-flow and what I was lead to believe was a VG30 rear housing. He (can't remember name) had a real quick look at it and said it wasn't a VG30 housing, his opinion was that it is a standard RB25 housing... same as on my turbo already. He based this on the inlet side of the housing, saying it doesn't have squared off edges around the stud holes.

Believing the experts, I took his word for it and left. After getting home I had another look at them and I don't agree.

Here are some pics, it may not be a VG30 but its definately larger than the housing on there now.

You can see by what I have circled that the housing buldges quite noticably after the bolts.

Here are some more of the housing.

What housing have I bought???

[Bass Junky]

I'm not sure what the one with the round outlet it, surely never fitted to any skyline from factory.

The one with 45V is a T25 flange.

If you were to flip that full turbo over and take a pic, I could tell you whether it's a normal housing, or the one off a VG30

[tuitahi]

Thanks Bass,

The full turbo is from a R33 RB25, already hiflowed by GCG. I was hoping to get a larger housing for it ie, VG30 or R34.

Don't know why you say the one with 45V is a T25. I just went and checked the flange sizes again and they are definately the same size flanges.

[Bass Junky]

the dump pipe flange I mean.

[tuitahi]

Man I need to learn more about turbos...

If thats a T25 flange on the loose housing, then that means the "RB25 Hiflow" sitting next to it has a T25 flange as well, cause they are both the same size. I just measured them and both the dump and manifold flanges are the same.

I hope I didn't incorrectly buy a T25 turbo as well as a T25 flanged housing from two different people.

[Bass Junky]

ah, I'm a moron.

I was looking at the housings wrong

sorry

Take a photo of hte other side othe whole turbo. Like roll it over and post pic

Do same view with the bare housing....

please

I'll tell you which is which..

[Bass Junky]

The one at the top is VG30, bottom is RB25.

See the difference?

[tuitahi]

Well based on your photo, and the ones I just took I think it must be a VG30... they are a lil blurry though

I really didn't think GCG would get it wrong, if it is a VG30 I'll have to go and convince GCG what it is.

[Bass Junky]

There ya go

VG30

There's an extra 25 rwkw there!

[tuitahi]

Thanks Bass!

Back to GCG tomorrow morning now!

[Abo Bob]

Looks like the goods.

[CEF11E]

tuithai,

If it has 45V stamped on the exhaust housing it is not a VG30det rear housing. a VG30det rear housing has OP6 stamped on it.

Have a look at the housing that is currently on your turbo and tell us what is stamped on the exhaust housing in the same place as the 45V on the housing that is not on the Turbo.

I have had a rear housing that looked like that and it was from a plain bearing VG20det turbo.

I know this dosen't really help you much. but that is not an VG30det rear housing but it is deffinatly bigger than your current rear housing.

If you could cover up all the holes and measure the vulume of the housing by filling it with water and compare it to a VG30det housing that would give you a definitave answer.

Cheers

[666DAN]

You made me paranoid...had to go check my one, yes VG30 goodness

[tuitahi]

Man I'm confused... lucky I was running late this morning and didn't go and argue with GCG.

CEF11E, thanks for your input. I have the turbo in the car and will check it out at lunchtime.

If the loose housing is not a VG30 it definately looks the same, if it is from a plain bearing turbo like you think could it be used anyway?

Anyone else seen one of these?

If it has 45V stamped on the exhaust housing it is not a VG30det rear housing. a VG30det rear housing has OP6 stamped on it... but that is not an VG30det rear housing but it is deffinatly bigger than your current rear housing.

[kwazza11]

it can be used, but you'll need to machine out the guts to suit the massive turbine wheels gcg put in thier hiflows.

[tuitahi]

The housing on my hi-flow has 21U stamped on it.

kwazza11, are you speaking from experience? As the housing itself is larger does it need to be machined out? I know they'll need to machine parts of it but I didn't think it would be anymore than the stock housing was machined.

[MANWHOR3]

21U is an r33 rb25 stock housing. I'm 100% sure.

[Slide]

Hitachi made many different variations of the T3 Exhaust housings with the 5 bolt exhaust flange.

Alot of housings are confused as VG30 housings but were used on many other applications aswell .

The internal area difference is minimal.

And in some cases they may be bigger than the early VG30 housings.

There is alot of difference between the stock rb25 housing and the VG30 seen in this picture the spine is 1cm less on the T3 RB25 housing then that of the real VG30.

They are both bored out exactly the same way and in most cases has the same internal dimensions for the turbine.

2 Different "VG30" Housings 1 bored and the other not.

We have pallots of VG30 turbo's with exactly the same induction and dump pipe setup still left on the turbo and i would be lucky to find 1 out of 4 that are the same.

The dimensions inside the housing do vary.

This may be why GCG turned it away.

But i couldnt see why they would have had a problem.

[MANWHOR3]

with highflowing, imagine, what they do is they make that hole (the snout you look into) bigger so it can fit bigger wheels.

The idea with the vg30 housing, is that the whole snail itself is bigger. Imagine that round bit where the air goes around to make the wheel spin. It's bigger and flows more air.

machining is for fitting a bigger wheel. the actual snail being bigger doesn't have anything to do with the machining.

cheers

[tuitahi]

Thanks for the replies guys...

Slide, I'll have another try at GCG otherwise I'll be sending you a pm

MANWHOR3, thats how I understood it, so considering the housing itself is considerably larger and will bolt up. The machining they'll need to do wont be any different than they'd do on a VG30 or a stock R33 housing.

If thats the case it should be usable.