# Compressor Wheels:Cast vs Billet - 11 full blade vs 6/6 split...what's the whole story ??



## GolfRS (Feb 4, 2006)

I have been looking at the new GTX series turbos, and especially their new compressor design.

Seems pretty impressive with a full 11 blade design, and Garrett claims a 10% more flow
over the previous GT series, BUT that doesn't tell the whole story, since before the
wheels were cast, and now are billet.Of course Garrett again has rushed to state that
the billet wheels offer no advantages over the cast ones, so that is also something to
note...

Now the question to those that know is ...

Is the full 11 blade design actually better ??If so, why wasn't it used from the start ??
It would make more sense for the turbo manufacturers to start with a full design many years ago
and seeing the advantages switching to a 6+6 split design (which is more complex btw) than
the other way around...

So once again, Garret claims the 11 blade design is more quiet and more efficient.Some say
only the first actually stands, and the true reason for switching.Others again say the
6+6 design is more efficient at high boost and the reason it has remained for so long...

So what are your thoughts on the above ??


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## GolfRS (Feb 4, 2006)

Also looking around i found the thread with the new EFR turbos...

Why didn't BW also follow the 11 blade route ??

Why keep (although billet) the 6+6 design ??


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## TTAdict (Aug 3, 2010)

I am subscribed to this thread and hope the tuning gurus enlighten us with their invaluable experiments. :thumbup:


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## GolfRS (Feb 4, 2006)

TTAdict said:


> I am subscribed to this thread and hope the tuning gurus enlighten us with their invaluable experiments. :thumbup:


Unfortunately you will wait a looong time....

This forum is more into selling stuff than any real technical info... :thumbdown:


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## $GTI07$ (Feb 29, 2008)

GolfRS said:


> Unfortunately you will wait a looong time....
> 
> This forum is more into selling stuff than any real technical info... :thumbdown:


You are so right.


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## Hendrik (Sep 13, 2008)

A pity!!!! 

Nevertheless, here is a nice link with some testings. Not 2.0T relevant but,...enjoy! I did...

http://forums.nasioc.com/forums/showthread.php?t=2110277 :thumbup:

- Hendrik


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## GolfRS (Feb 4, 2006)

Hendrik said:


> A pity!!!!
> 
> Nevertheless, here is a nice link with some testings. Not 2.0T relevant but,...enjoy! I did...
> 
> ...


Ohhh looks awesome. :thumbup::thumbup:

Gonna read it now... 

Thanks Hendrik

I wish we had more info and less advertising in here.It would be better for all (except the advertisers that is :laugh: )


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