Max Boost The Standard R33 Turbo Can Deliver?

[The Mafia]

I am still amazed that some people think that the compressor wheel is nylon.

Its a f**king alloy. Last time I checked, Nylon was a plastic. The turbo wheel on a Series 2 turbo IS NOT PLASTIC. IT IS AN ALLOY.

How do I know? I have a Series 2 turbo. The wheel was metal..

*shakes head*

[siksII]

I am still amazed that some people think that the compressor wheel is nylon.

Its a f**king alloy. Last time I checked, Nylon was a plastic. The turbo wheel on a Series 2 turbo IS NOT PLASTIC. IT IS AN ALLOY.

How do I know? I have a Series 2 turbo. The wheel was metal..

*shakes head*

Sorry mate, later model GTS-T definitely have plastic compressor wheels.

Recently replaced a series two turbo with a another series two turbo and have had a look at another one years ago off my old car too. At first glance it does look like alloy but trust me, it is black plastic.

Saw heaps of them at a wrecker recently too, all the later ones had the black plastic compressor wheel.

[siksII]

In fact.. here is a picture of the first turbo I mentioned from back in 2006 - you cant clearly see but that wheel is black plastic, not alloy.

[bubba]

I am still amazed that some people think that the compressor wheel is nylon.

Its a f**king alloy. Last time I checked, Nylon was a plastic. The turbo wheel on a Series 2 turbo IS NOT PLASTIC. IT IS AN ALLOY.

How do I know? I have a Series 2 turbo. The wheel was metal..

*shakes head*

Dude, I have held a series 2 compressor wheel, in pieces, in my hand, and it is most definitely NOT metal.

For everyone else, here's the dyno sheet:

[Harey]

Very nice, the extra 2psi makes a good consistent increase everywhere on the RB20! Great job

My expectation is that on the RB25 it might make more power down low-mid but drop off to the same max power as the turbo runs out of efficiency.

Edited July 8, 2010 by Harey

[bubba]

Very nice, the extra 2psi makes a good consistent increase everywhere on the RB20! Great job

My expectation is that on the RB25 it might make more power down low-mid but drop off to the same max power as the turbo runs out of efficiency.

I doubt it would nose over up top but it would certainly come on boost a fair bit sooner, giving you better midrange.

Different story on the 3L though..

Split the difference and that's where an RB25 with stock turbo would be.

Edited July 8, 2010 by bubba

[mad082]

i should try and get the dyno sheet off my mate some time of when he ran his 33 on the dyno in back to back runs at 13psi and 16psi. from memory 16psi made 25hp more.

[The Dan]

+1 for S2 turbo and R34 GTT turbos both have Nylon(or could be baker-lite) compressors

[R33 Sleeper]

whats safe on a hiflowed stock turbo?

[Galois]

http://www.skylinesaustralia.com/forums/Hy...ce-t261613.html

i bet it's in there somewhere. this thread has been on my to-read list for a long time

[bubba]

whats safe on a hiflowed stock turbo?

Whatever the turbo builder says..

Should be somewhere up around 19-20psi, at least that's what mine is supposed to be good for.

[Rolls]

whats safe on a hiflowed stock turbo?

Totally depends on who built it, highflow doesn't mean anything, it just means its been ground out and had different wheels/bearings put in it, could be anything.

[Torques]

This Dyno finally answers my question

(The question this thread was initially about)

As you can see from the 2 boost curves in the picture, the turbo is running out of steam at 14-145PSI.

While at the slightly lower boost level the pressure is more or less constant, at 14+PSI the boost eases off gradually.

See my own attached dyno and compare to the one in this post.

Don't get confused about the 300HP figure, it's calculated from rear wheel power.

Conclusion: The standard turbo can not sustain boost over 15 PSI.

Edited July 8, 2010 by Torques

[jrm]

But that's an RB20DET with an R32 turbo, no? Where-as your car is an RB25DET with an R33 turbo - you're not really comparing apples here.

[Rolls]

rb20det with an rb25 turbo, however 14psi with a 25 turbs on a 20 det is more like 10-12 psi on a 25 as the 20 doesn't eat as much air as the 25.

[R31Nismoid]

^ Exactly.

Clearly shows if anything, what these pages have said for years.

Running more than 12psi on a RB25 Turbo (on a RB25) is utterly pointless unless you WANT to kill the turbo, there is no justifiable power increase for the added stress.

[Torques]

But that's an RB20DET with an R32 turbo, no? Where-as your car is an RB25DET with an R33 turbo - you're not really comparing apples here.

Yep ... but as per lower post the RB25 eats up more air (higher flow rate), so it's even harder for the RB25 Turbo to keep up on the larger engine.

So I have no boost leak, my boost controller is fine, and setting higher values than 13-14 PSI does not do anything since the Turbo is running out of its efficiency range.

Clearly: It's all in the dyno graphs!

Cheers,

Andrew

[Torques]

rb20det with an rb25 turbo, however 14psi with a 25 turbs on a 20 det is more like 10-12 psi on a 25 as the 20 doesn't eat as much air as the 25.

AMEN!

[Torques]

^ Exactly.

Clearly shows if anything, what these pages have said for years.

Running more than 12psi on a RB25 Turbo (on a RB25) is utterly pointless unless you WANT to kill the turbo, there is no justifiable power increase for the added stress.

I am glad we have sorted this out ..

I was quite sceptical about the posts saying the turbo can deliver 20PSI+ on the RB25 but did not have enough hard facts to make my statement.

Now with that independent other dyno and mine as a comparison there is not much room for speculation.

The RB25-Turbo simply can not deliver that kind of airflow/boost (and it would have surprised me if it could)

The universe is sound again ..

Edited July 8, 2010 by Torques

[R31Nismoid]

It can deliver it, we've established that already. If you welded the wastegate shut, it would easily go past 15psi.

However, as established also, the turbo might spin upto that boost, however once you go past efficiency of the turbo there is no point.