ct26 with 62mm trim

[Spidey]

Can I ask what power it's rated at/up to ?

What was the upgrade done to it ? on compressor side only or turbine side clipped ?

Thanks
Rob

[Spidey]

Also, is there an uprated actuator ? what is this rated at ?

How much are you looking for ?

Thanks
Rob

[Fats]

Alright mate, it has a T04 compressor wheel and modified compressor housing, it has a standard actuator so lower boost levels could be maintained, looking at the turbine side theres no clip, the turbo it self is good with the slightest amount of play obviously for oil pressure, the turbo owes me £400, i never got round to fitting it so its being boxed for about 3 months, £350 but collection would be the best option unless you want to pay the postage cost (heavy). I was going for around 350bhp with forged internals, rev3 cams, fuel system upgrade and ecu. I posted this turbo on the forums about 3 months back asking for peoples opinions on the power out put, mark edwards was suprised with the size of the compressor wheel. It was imported from america

Cheers
Andy

[MR2Mania]

Basically, you're saying - Size Matters !

No, *I* didn't say that, although someone else might.

But what I didn't fully follow was your conclusion about the external wastegate ? I'm not a turbo tecchie but is the advantage of the external wastegate that it leaves more room for a bigger housing ?

Basically, with an internally gated turbo, the entrance to the turbine housing has to flow both the "wastegated" gas and the gas that actually drives the turbine wheel. There'll come a point when the turbine housing can't support enough flow for both of these together, and hence a restriction occurs, which causes back-pressure, and it's this back-pressure that stops the gases escape from the engine, meaning this has a knock on effect on intake temps, regardless of what the intercooling is doing. Also, the back-pressure will be costing you power, hence why it's so difficult to get an internally gated turbo to flow well enough to support over 400fwhp.

With an external wastegate, the gases are released BEFORE they get to the turbine housing, and the inside of the housing only has to flow the gases that will be driving the turbine wheel. Hence, you can actually get a smaller housing (which will give you better spool up) without affecting the flow at high RPM. Also, a turbine housing that is designed to be NOT have an internal wastegate (ie needs an external wastegate) has a much better flow path to the turbine wheel itself.

[MR2Mania]

Alright mate, it has a T04 compressor wheel and modified compressor housing, it has a standard actuator so lower boost levels could be maintained...

Andy, what size is that compressor wheel?

Also, it's a mistake to think that a standard actuator (ie 6-7psi) will work well on a hybrid for 2 reasons:
1) hybrids tend to boost spike at the top end if you try and run low boost, because you're still spinning the turbine wheel at the same speeds, yet larger compressors don't need to be spun so quickly (not to mention the issues with the turbine housing, ie the amount the wastegate ports can flow).
2) A low-rated actuator can allow the wastegate to be blown open way too early if pressure builds up in the turbine housing.

This ain't a problem though, as it's not that expensive to get an uprated actuator. I'd say you should be looking for a 1bar actuator to use with any decent hybrid. The most popular actuator to use is a Garrett -34, and then adapt that to fit.

[Fats]

Alright, this is the problem i don't know the size with out stripping the housing off

[MR2Mania]

Alright, this is the problem i don't know the size with out stripping the housing off

Andy, if you get a set of calipers and measure the visible side of the compressor wheel, this is all you really need, as it's the most critical dimension in terms of power.

But from the look of it (ie the taper left on the inside of the inlet to the compressor wheel), it looks big enough!

[Spidey]

Basically, with an internally gated turbo, the entrance to the turbine housing has to flow both the "wastegated" gas and the gas that actually drives the turbine wheel. There'll come a point when the turbine housing can't support enough flow for both of these together, and hence a restriction occurs, which causes back-pressure, and it's this back-pressure that stops the gases escape from the engine, meaning this has a knock on effect on intake temps, regardless of what the intercooling is doing. Also, the back-pressure will be costing you power, hence why it's so difficult to get an internally gated turbo to flow well enough to support over 400fwhp.

With an external wastegate, the gases are released BEFORE they get to the turbine housing, and the inside of the housing only has to flow the gases that will be driving the turbine wheel. Hence, you can actually get a smaller housing (which will give you better spool up) without affecting the flow at high RPM. Also, a turbine housing that is designed to be NOT have an internal wastegate (ie needs an external wastegate) has a much better flow path to the turbine wheel itself.

Thank you for all this info - I am getting a crash course in turbo education. Some is still gone over my head and I'll have to read up a bit but I've learned a lot over the last two days. And in hindsight, what you've told me nearly makes "common sense" !

Thanks
Rob