rb25 RB25 stock turbo

[erall0]

hey guys I'm running a rb25 turbo on my Nissan patrol diesel its been running 15-16 psi daily for about 1 year now 

what I'm wondering is how do I know wich turbo I have?

I know its got a good front wheel (not plastic) and I believe the rear wheel is steel also not ceramic I know it is a ball bearing unit

what I'm wondering is I want to increase my boost and my inlet temps are still nice and low as are my exhaust temps 

seeing as diesel exhaust temps considerably lower then petrol temps would 20 psi be do able on the turbo?

 

Thanks guys

[Griffin]

We found in early 2000's on diesel patrols and landcruiser that ceramic turbos will run 20 psi. It wasn't the psi that killed them rather the heat on the turbine. 

It's worth a try. Ones from a vg20 / rb20 size were great on 4.2 diesels.

Early fj20 , z18, rb30 we're crap.

Post pics.

[GTSBoy]

It's not the psi or the temperature* that's important.  It's shaft speed.  Even with boost the diesels don't make mush power, and even though they run very high air-fuel ratios compared to petrol engines, they still end up moving far less air on a diesel than they end up moving on a petrol engine at the same boost.  They end up at a different place on the compressor map on diesels.  Higher pressure ratio, lower air flow rate.  This in turn results in lower shaft speed.  It's shaft speed that is the killer.

* Yeah, OK, temperature helps/doesnt help, depending on which way your looking at it.  The lower temperatures in diesels almost certainly mean that the turbo will accept some higher shaft speed before you risk spinning the turbine off the shaft.

As to the OP......there are no RB single turbos with steel wheels.  If yours is not ceramic, then it's been fiddled with and we can't tell you what it effectively is.

[erall0]

thanks guys so bump her up to 20 u recon?

[erall0]

its got 21u on the back if that helps 415v3 on the front I think

[-S-]

21u = r33

[GTSBoy]

4 hours ago, erall0 said:

thanks guys so bump her up to 20 u recon?

If it's not ceramic you'll be gold.  If it is ceramic, you're just playing the lottery.  They can die at any speed.  The chances just get higher as you wind them up.

[GeeDog]

How sure are you that it's a ball bearing core?

[erall0]

100% ball bearing core I had it rebuilt when I put it on the patrol

[GeeDog]

23 hours ago, erall0 said:

100% ball bearing core I had it rebuilt when I put it on the patrol

Rebuilt with or without being highflowed?

Your original question said you were running a RB25 turbo, and you were wondering what turbo it was. A later post says it has a 21U on the back and a 415v3 on the front (so it's only part of an RB25 turbo), and a later post again says you had it rebuilt with a BB core.

What did the person who rebuilt it tell you it was? Did they convert it to BB, or was it already BB before it was rebuilt? Which bits are original RB25 - the rear housing only? How high you can turn it up will depend on what's in it - it obviously isn't a (stock) RB25 turbo.

[erall0]

I was wondering if it had metal or ceramic turbine that's what I meant when I had it rebuilt 1 year ago from mtq I think it was they said it was a stock ball bearing unit I didn't ask or get much more detail then that  I don't know much more then that sorry I planned to only keep the boost low but ive recently put the motor in my auto gu from the manual gq and would like the extra power from a bit more boost lol

[GTSBoy]

Well, the only sensible thing that can be said is that there is no such thing as a rebuilt Nissan Hitachi ceramic turbo that still has a ceramic turbine.  That is the very first thing that has to go when rebuilding them.