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I just happen to have a pair of Hitachi ceramic turbined BB turbos in the cave , one is an RB20DET one and the other is the correct VG30 single ball bearing turbo .

Will take a few pics after dinner just so you can see the differences .

Cheers A .

probably

stop asking

ROFL after reading that, i remembered that i did notice the same person asking in about 6 threads the same question haha.

Why dont you take the turbo to a turbo specialist and ask them? Its pretty hard to see from photos. And will take no time at all waiting for replies that you arent getting, and saves spamming everyone elses VG Turbo thread with your question.

how can you tell?

1. Experience

2. It has the 'fat' centre bearing area typical of a BB turbo

3. Despite all the glad wrap, I can see the 10mm hex head bolt (6mm thread) next to one of the water fitting banjo, which I've only ever seen on Nissan turbo's with a BB centre.

Looking at the amount of corrosion and general poor condition of the external surfaces, I'd also say it's probably done a lot of k's or had a hard life.

Neither is a T25 , T25's are made by Garrett and those two are Hitachi turbos .

If you look at the center sections they are basically the same and note the small hexagonal bolt head adjacent one of the water holes .

Been a long time since I've had a housing off these style turbos but I'm reasonably sure that the wheels are same/V similar . Externally the turbines look identical .

The RB20 one is actually the better of the two RB20 ones IMO because it has the slightly larger compressor wheel and if you look closely inside the comp housing snout you can see the anti reversion groove .

My main interest in the VG30 one was its larger ratio turbine housing , this one has "OP6" on it but people say that they don't all have it .

I'm hanging onto it because if I ever had the std turbo off my R33 I'd use it , may use it on a GCG Hi Flow if I go that way .

IMO these would be a dog of a turbo on an RB20DET because they need some boost low down if not to feel like a low compression ratio two liter six too far up into the useful rev range .

Compared to the std BB RB20 turbo the R33 25's one is a little larger in the turbine housing a quite a bit larger in the compressor housing . It is the logical next factory style turbo step for an RB20DET .

I think RB25DETs are better able to cope with the large three liter OP6 type turbine housing because they have ~ 20% more capacity , higher compression ratio , more valve and port area .

A .

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