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Discussion Starter #1
Well I finally got the blower, lid, and j-tube back from paint.....Took a bit longer than planned but it is back. All I need to do is assemble the blower and do a few minor things. I would expect to see it on the truck and running in two weeks or so. Silver Birch looks good on the ole Magna Charger!

Some pics so you can see what I am up too:






For those of you that have removed or looked inside your inlet, this pic will be a nice comparison to the older MP112 housing:
 

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Im guessing thats color matched to your truck. Looks very nice indeed. Last pick is cool.
 

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Discussion Starter #3
Oh4GTO said:
Im guessing thats color matched to your truck. Looks very nice indeed. Last pick is cool.
yep, colot match the truck.....should be cool once its installed.
 

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Discussion Starter #5
phobos512 said:
So is this an update to the regular MP112?

More like an upgrade, I should have it installed in the next few weeks (work load is heavy right now). Once it is installed I will be sure to report back with my findings. The IAT data from 24V's 122HH was right inline with the characteristics of a High Helix supercharger, so I am excited about what I we might find with the 112HH.
 

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phobos512 said:
So is this an update to the regular MP112?
It is the High Helix Rotor for the "old" blower ... I'm not sure if this is an experiment or a future offering.
 

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Discussion Starter #7
Btlfed1500 said:
It is the High Helix Rotor for the "old" blower ... I'm not sure if this is an experiment or a future offering.

this is a new high helix 112 that should be available soon. It has been tested by EATON and Magnuson both, now its time for me:gears:
 

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GTO no more baaah!
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Does this require a whole new blower case or just replacing the internals?
 

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^^^^^^^^^^
ditto
 

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phobos512 said:
Next stupid question would be, will it fit? :)
Externally, it is the old housing.
 

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So it's a rotor upgrade in the standard housing??

So us GTO guys want to know. Is it a send ours and and the guts are swapped out??

Whats the difference??
 

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Now this IS a M112 with the High Helix?

I just want to make sure it wasn't a typo and you meant M122.




Never mind I guess I need to read more carefully.

So will there be a price difference between the M112HH and the M122HH?
 

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Ok so what little I could find online seems to indicate that the high-helix is a more efficient design than a standard Roots blower setup, and that it is an "attempt" to emulate the characteristics of a Lysholm type twin screw setup...yes? :)
 

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Discussion Starter #18
phobos512 said:
Ok so what little I could find online seems to indicate that the high-helix is a more efficient design than a standard Roots blower setup, and that it is an "attempt" to emulate the characteristics of a Lysholm type twin screw setup...yes? :)

negative, a twin screw is a male and a female rotor that compresses the air in the rotor housing. This is still a roots style, better known as a "hybrid" roots supercharger.
 

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Discussion Starter #19
Andy94SC said:
Now this IS a M112 with the High Helix?

I just want to make sure it wasn't a typo and you meant M122.




Never mind I guess I need to read more carefully.

So will there be a price difference between the M112HH and the M122HH?

yes a MP112, no typo.
 

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lanceygto said:
Telling you what I read. I am no authority here. Originally the Roots blower had rotors with two lobes and then three lobes which were linearly parallel to each other. That evolved to our present design, which incorporates the helix is called "the fourth-generation design of the involute, three-lobe Eaton rotor, which has a 60 degree twist and a special acrylic coating." The Lyshholm design, which is called a screw type design, not twin screw like I have seen posted, is different as it has one rotor with concave lobes and the other with convex lobes. The Eaton and the Lyshholm operating principle is nearly opposite the Roots.

Apparently the Lyshholm was designed in a spiral before the Roots ever was and in that sense both phobos and me were confused in thinking that the helix was introduced into the Eaton design emulating the Lyshholm. A bit of research here has enabled me to correct my misinterpretation. In both cases the spiral design has the cuantitative effect of increasing surface area within the same lenght and adds some direction to the air being compressed due to the directional spiral effect. On the other hand, if there was a change in lobe design where one lobe was smaller than the other to allow more twisting and to function with a smaller lobe against a larger lobe of differrent shape then in fact it would have been a Lysholm emulation. I thought that might have been the case because in the photo above the right hand rotor lobe looks different than the left hand rotor lobes. BC has corrected to say that this is just an optical illusion as both rotors are the same.

Seems to me like the M112 HH by having more helical twisting then the lobes may be smaller to accomodate in the same linear space. There might be some gain in surface area due to more spiralling but at the same time some loss due to smaller lobes. How that translates cuantitatively is up to Magnuson to announce. I suspect this is nothing a smaller pulley cannot take care off in each case. My personal and limited perception is not expect a dramatic improvement over our M112's to warrant a costly upgrade to the M112HH.
In a nutshell, increasing the rotor helix angle changes one very important characteristic of a Roots blower, it lowers the rotor Mach number. The rotor Mach number refers to the rotational speed at which the rotor tips go sonic, or are turning at the speed of sound (i.e., Mach 1). The resulting shock waves disrupt smooth air flow around the rotor tips. When the rotor tips rotate at Mach 1, around 12,000 rpm (for competiton 14-71 sized blower rotors), volumetric and compressor efficiencies take a beating, or, the blower "lays over." This usually happens when the engine is turning high rpms. By increasing the helix angle, supersonic rotor tip speeds can be pushed up to a higher rpm (one that the engine and rotor don't reach during a typical 1/4 mile run or does so for less time) resulting in a smoother flow of air inside the blower. Further, by restricting the outlet port they are able to increase compressor efficiency. When the entire rotor is exposed to the high-pressure plenum air it must constantly work against this boost pressure. By sealing the bottom of the case from the plenum except for a pie-shaped port at the front it reduces the high-pressure backwash. Consequently, it takes less power to turn rotors. Less air leakage is also a beneficial result. The smaller outlet opening doesn't cut down on the amount of air deposited in the plenum either. Because of the added twist and shape of rotors, most of the air is pushed toward the front of the case. These benefits are in addition to the already very efficient modified roots design by Jerry Magnuson:patriot:
 
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