AAN into Ur quattro, 400-450 Bhp Target

[DJones]

Exactly so you'd need a new housing to step down to .63 as your old housing wouldn't fit over the new bigger wheel

The other option is having the old one machined

Agreed. The old housing is actually only .6 not even .63 so I just wouldn't bother.

It's actually a k24 housing machined to accept the wheel.

[Jamo]

I'm changing the wheel size to fit the new housing, see picture above. Hence 2 steps not 1.

Exactly so you'd need a new housing to step down to .63 as your old housing wouldn't fit over the new bigger wheel

The other option is having the old one machined

[DJones]

If your changing the wheel size the old housing wont fit

I'm changing the wheel size to fit the new housing, see picture above. Hence 2 steps not 1.

Edit...

I think I know what you mean! No it would mean another new housing not the one just removed.

[Jamo]

If your changing the wheel size the old housing wont fit

[DJones]

The plot thickens! Not a nice feeling is it, I wondered for a while whether I had somehow been shipped the wrong turbo!

Its funny the opposing problems we have had too, too savage, and not savage enough...

It does kind of clear things up though...

My only concern now is I will be taking 2 steps forward not the one I was thinking I.e. a bigger wheel and a bigger housing not just the housing. I will effectively end up with a 3071.82.

It will be interesting to see how it performs with my light car, light rotating assembly and shorter gears of the 5 speed.

If its to laggy I could always go 1 step back to the .63 housing...

Fun fun fun...

[URquattroGus]

The plot thickens! Not a nice feeling is it, I wondered for a while whether I had somehow been shipped the wrong turbo!

Its funny the opposing problems we have had too, too savage, and not savage enough...

[DJones]

Spoke to Craig at CR Turbos today, interestingly he said my MD357 has got the wrong wheel, the wheel fitted is not what the spec sheet indicates should be fitted.

He is going to swap it back to the standard spec for me then the new housing will fit. Hopefully that will help towards the aggression.

[URquattroGus]

Markings on the turbo where: MM002429 and then 700177-5022 which d doesnt seem to be listed.

The smaller turbine wheel is for an the internally gated version, so I would guess that most people here have not used it and that is one of the main differences with your car, that turbine put into an external housing.

[DJones]

Thanks, just printed it off.

So by comparing all the dimensions it would appear that the MD357 is a GT3071r Part No. 700382-3 (with the exception of the KKK housing) rated at 280-480 bhp. This model is fitted with the 56.5mm turbine wheel, which mine does to.

Your old one must be a GT3071r Part No. 756021-1, rated at 300-460 bhp which is fitted with the 60mm turbine wheel.

Interesting how they state the smaller turbine wheel (understandably) comes on to power sooner but then hold on for longer.

I guess this must be the differences we have felt between turbo reactions, notwithstanding other set up differences.

[URquattroGus]

Darren, my advice would be to go to the Garrett website and download the PDF catalouge as that has two pages that list all the garret turbos and their dimensions. That website could be slightly wrong, or just list one variant, also probably talking about an internally gated version of the 3071.

[Billman]

From the info I have the GT3071 comes with 3 different turbine impellers:

55/60mm (same as GT30R)
51.78/56.5mm
53.6/56.5mm

[DJones]

This confuses things a little more... see picture.

It basically states that my MD357 has the identical size wheels to a GT3071r and that the 55/60 turbine wheel you mentioned you had in your previous GT3071 belongs to a GT3076!

[DJones]

No, it has quite a lot of water injected at full boost which would of helped though.

[Jamo]

Thats smaller than a 28 wheel which is 53.8 mm iirc they state on the tech doc it's a 25 wheel

Have egt ever been measured in this turbo setup?

[DJones]

I'm not clued up on the dimensions of others so can't compare it, all I know is it's to aggressive and linnear in its power delivery and this certainly wouldn't help..