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Yeah something I should have checked but oh well lol

I have a different front cover on mine to standard to block the anti surge slots off. Think this loses alot of flow when the standard anti surge holes are in there. It's not a big enough Turbo to warrant surge slots IMO and provides more cons then pros

Its much nicer to drive with my front cover on, fixed a few small issues. But it's not a great "fix" at the moment. Was hoping HKS would give me a Pro S front housing to try as I think this will improve it

But anyway, it's good enough for now

hmmmm, interesting. Though I've never done much reading on the 28's etc with anti surge etc to know pros and cons, but it's a bit of a strange one it would be better with it blocked :O

I had the GT3076 or the "GT3037"

0.6 Surge slotted comp cover

0.63 rear housing

Put the 0.82 rear housing on when I switched to the RB30.

I found the surge slotting was ok, especially when I had the BOV removed for a short period of time, and when in higher boost the factory BOV couldn't keep up and it created reversion.

Would have loved to try a non surge slotted cover, but I have heard stories of the surge slotting allowing more air in further down the blades, allowing the turbo to spool faster. Wouldn't have a clue if it does or not though, its something you'd have to try yourself.

Callan, what is your lag like?

On the RB25 I had 18psi by 3400 in third

On the RB30 I had 18psi by 3000 in third, maybe earlier. Hard to tell it moved that quick.

Surge holes like this?

cb3f61d2.jpg

The port shrouding on the Pro S housing is more typical on a turbo of this size. By the time the air has reached the rear of the surge slots there is some pressure there. And the other end of the holes are on the suction side of the turbo. Long physics lesson short, high pressure always wants to go to a lower pressure section. Pressure difference = flow. So therefore there will always be flow lost that would normally go into the engine that is now being recycled back through the blades

This is how I understand it anyway, what I know about physics makes me think I'm right and Stao from hypergear originally told me it would be the anti surge slots that are the issue. On a T04Z there is a benifit as such a large air flow might result in some surging. But a small GT30 series doesn't flow enough for me to think anti surge slots necessary.

This is what ive done

dc9cb18e.jpg

But as there is no actual seal in the snout of the Turbo to the housing, there is more then likely a leak between the two, again this will mean a slight loss in flow

This is how I See it anyway, hypergear will make me a new housing but want the whole turbo. Seen as it is my daily, I need the car so this isn't really possible right now

Surge holes like this?

cb3f61d2.jpg

The port shrouding on the Pro S housing is more typical on a turbo of this size. By the time the air has reached the rear of the surge slots there is some pressure there. And the other end of the holes are on the suction side of the turbo. Long physics lesson short, high pressure always wants to go to a lower pressure section. Pressure difference = flow. So therefore there will always be flow lost that would normally go into the engine that is now being recycled back through the blades

This is how I understand it anyway, what I know about physics makes me think I'm right and Stao from hypergear originally told me it would be the anti surge slots that are the issue. On a T04Z there is a benifit as such a large air flow might result in some surging. But a small GT30 series doesn't flow enough for me to think anti surge slots necessary.

This is what ive done

dc9cb18e.jpg

But as there is no actual seal in the snout of the Turbo to the housing, there is more then likely a leak between the two, again this will mean a slight loss in flow

This is how I See it anyway, hypergear will make me a new housing but want the whole turbo. Seen as it is my daily, I need the car so this isn't really possible right now

yeah thats the whole idea about the anti surge housings.

but i wouldnt think it would make that much of a difference.

its only if there is too much pressure so its squeezed out these holes.

i thought there was 2 blades on these turbos and the holes go ruffly to where the 2nd blades are.

maybe not and they are on the pressure side but then wouldnt it just be working twice as hard ??

air would be recirculating no ?

My 180 will be in Mky soon. It goes brum.

nice ride. gl wit it.

:lol: jokes this isnt boost.

Callan, whole heartedly agree with what you have to say about anti-surge. it is a good talking point really. ;)

I've heard about this sil80

Word is it's packin' heat! And getting tuned by mackay's finest?

you should be more worried about the 1 up your way.:P

i've heard a few things about the 1 your talking about, apparantly the owners mad c&*t :wave:

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