school me on big turbos

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seeker1056

gear head
Joined
Aug 3, 2006
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I have searched and read many many threads on here and other sites in the quest to understand what a legal 2.6, or 3.0 charger means.

I can find no info on what size chargers they start life as?

ie are they of a size like an S488, with a cut cover or wheel, and and/or with a bushing installed? I seem to read that the HX60 is now the popular charger with many people

Can someone explain the difference between a non cut cover or protrusion wheel etc


Can someone shed light on what size chargers the upper levels of competitors are modifying and using?

or will this be another of those if i tell you I gotta kill you deals

thanks
 
Most are using hx60's, Precision(gt50) or the 96mm 1.32 S400. As far as i can tell they are clipping 80-85mm comp wheels down to 2.6 or 3.0. A protrusion charger requires the inducer of the wheel to protrude into the 2.6 or 3.0 bore. So you end up with a second larger inducer behind the step in the cover. This is where it gets tricky. By minipulating the shape and position of mwe groove you can pick up big gains in air flow. Keep in mind different organizations may require different placement and/or width of the mwe. Hopefully I have covered most of the pertinent details.
 
If you want something that lights quick and makes 600hp or more (depending on fuel)... i suggest a Holset Pro52
 
This should help, on the left is a 75mm "bushed" 2.6 charger the inducer right before the 75mm wheel is reduced down to 2.6" the right is the normal unbushed 75mm

CIMG0639.jpg



Better shot of it being reduced

CIMG0680.jpg


Example of an uncliped 80mm wheel


IMAG0247.jpg


here you can see the protrusion into the 3/4" straight bore

CIMG0686_zps90dbd4ea.jpg


clipped wheel, notice the step after the 1/8" protrusion

CIMG0687_zps484535b8.jpg
 
This is good information! Pics help a ton. My question is, will a protrusion charger net more power with the proper MWE groove vs. a clipped wheel? Is the housing on your bushed 75mm bigger than your standard 75mm? Or the fact that is a polished housing make it look bigger in the pictures?
 
Protrusion and clipped are the same. I think you meant clipped vs brushed. Yes a protrusion charger will make more power than a brushed charger of the same native bore.
 
RockinRam96 said:
This is good information! Pics help a ton. My question is, will a protrusion charger net more power with the proper MWE groove vs. a clipped wheel? Is the housing on your bushed 75mm bigger than your standard 75mm? Or the fact that is a polished housing make it look bigger in the pictures?
Click to expand...

The housing on my old bushed 75mm is the .66A/r race cover the unbushed is the std .63a/r thats why it looks bigger
 
What is the meaning of .66A/R? Also, what is this everyone talks about when they say they have a 1.32 exhaust housing?

I know I sound like a little kid asking these questions, but just would like to know more.


Thanks a bunch!
 
I imagine the numbers have to be some kind of ratio, but between what? Ha ha
 
think of the a/r as gear ratio..
1.32=3.55
1.10=4.10
.90=4.56
.84=4.88
.70=5.13
 
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