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Series 1 R33 turbo has normal compresser wheel and ceramic exhaust wheel.

Series 2 R33 turbo has nylon/plastic compresser wheel and ceramic exhaust wheel.

R34 GTT turbo is same as above but it might have different guts.

I'm not so sure the turbo is the reason it makes 206kW, Joel. They've got cams with more lift (from memory) and continuous VVT as opposed to the stepped VVT on the R33. Having said that, I have no idea whether the turbo was actually changed :). I just reckon there are enough differences to explain the extra power.

I've heard of them failing on stock boost when they hit the track.

I think turbo's failing (ceramic) has more to do with Exhaust Gas Temp's than anything else.

Pressure probably has a little bit to do with it..

I'll let you know if it is when I get the RB20t turbo cranked up on the RB30DET.

It looks like its going to make at stock boost (11psi) what it made on the rb20det at 1bar. (164rwkw)

I'll dig up this thread if it pops when I try to push a little more boost through it. :)

Yeah on the track your EGT can certainly get up there and stay up there. My gauge was showing 1100 degrees when I was on the track once. I have no idea where the temp probe was for it though or if that is a high/low reading but it definitely hot enough to kill a turbo I reckon.

An RB20 turbo on an RB30DET will be insane btw. That'll be on boost the second you touch the accelerator.

One other thing - because you have 50% more displacement now, does that mean that the turbo has to flow 50% more air to get the same boost level? So running the same boost will actually be working the turbo harder?

An RB20 turbo on an RB30DET will be insane btw. That'll be on boost the second you touch the accelerator.

One other thing - because you have 50% more displacement now, does that mean that the turbo has to flow 50% more air to get the same boost level? So running the same boost will actually be working the turbo harder?

It sounds strange as you let out the clutch and you hear the turbo begin to whistle away before you have even started accelerating... :)

Its not really related to the displacement but more so the head.

The head is what allows air in to the pots and what essentially creates the restriction that creates the measure of pressure.

As the RB25 inlet valves overall are 10mm bigger they obviously allow a higher flow of air before pressure is required to force the air in.

I have noticed with the rb25 that as soon as it makes like 1psi you can feel the extra power. With the RB20 it required around 4-5psi before you really felt anything.

But yer.. the turbo will be spinning harder at a lower psi when bolted on to the rb25 head compared to the rb20t.

This is why Rb20t' need so much boost to make decent power. They have small valves and really look it when you put them side by side to the rb25 valves.

For the noobs like me out there, what's the tell-tale sign of a failed turbo other than the obvious no boost??

I'd like to know why the GTT turbos fail so often.

Is the failure in the nylon impeller?

It's easy to see how high EGT could transfer heat via the shaft, to melt the nylon impeller.

You can always check the turbo for shaft play - this is movement in the shaft of the turbo. You can do this quite easily - remove the intake piping, and then remove the intake pipe going onto the turbo. Check for movement in and out, and side to side. Other tell tale signs can include the turbo being noisy - making loud drilling/spooling noises (we all know a stock turbo shouldnt do this) hitting boost but not being able to hold boost. With the R33 gts-t turbos, they wont last long if run at higher boost levels. With the R34 GTT there seems to be a string of people experiencing turbos failing at .7 bar so probably a good idea to look at replacing the turbo if wanting to run more than stock boost as the standard turbo's dont stand up to that much abuse. Its better to replace the turbo for say $1500 rather than blowing the turbine and risking damaging the engine.

For the noobs like me out there, what's the tell-tale sign of a failed turbo other than the obvious no boost??

I read everything R34 and I don't know where you people are getting this idea that the GTT turbo's are crapping themselves left right and centre.

The ones that I have heard of failing have been the exhaust wheel delaminating and 'ending up in the cat'.

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