>   >> At least for short term performance. Still skeptical about the
    thing
    >   >> taking long term heat.
    >   >>
    >   >> >>
    >
    http://www.rx7club.com/showthread.php?t=752927&highlight=aluminum+rotor
    >
    <http://www.rx7club.com/showthread.php?t=752927&highlight=aluminum+rotor>
    >   >>
    >   >> They made 830ish on a turbo 2 rotor with the aluminum rotors.
    >>
    > Videos on
    >   >> youtube.
    >   >>
    >   >> Rob Woods
    >   >>
    >   >> Yes the trick is making them hollow to cut the weight and
    having >>
    > cooling
    >   >>
     passages.
    >   >>
    >   >> Paul Lamar
    >   >> --
    >   >>
    >   >> They say that that they weigh 3.2 kg loaded. 7 lbs.
    >   >>
    >   >> Rob Woods.
    >   >>
    >   >> That is a two pounds savings. Not bad for a solid aluminum
    rotor.
    >   >> An exact copy less the one pound gear would be about 2.64
    pounds.
    >   >>
    >   >> Paul Lamar
    >   >>
    >   >> -- >
    >   > Paul,
    >   >
    >   > I shifted through the RX-7 comment and found the following post by
    >   > CrissSpeed. Someone BTW who, over the years I have been found to be
    >   > quite accurate and experienced in his drag racing field.
    >   >
    >   > But after reading the following comments I can't help wondering
    why the
    >   > turbocharger or even the engine breathing, in off boost rpm
     range
    would
    >   > improve with a lighter rotor and approx. the same torque. The
    lighter
    >   > drive train mass can be accelerated faster but that is not the same
    as
    >   > measuring steady state power.
    >   >
    >   >
    >   > "Allrighty then!
    >   >
    >   > Here's a quick run down on the initial testing done by E&J
    and Alex
    >   > Lopez using their 'Billet Aluminum' rotors.
    >   >
    >   > I was told by Alex that the motor is a street ported S-4 T2 with
    just
    > the
    >   > basic stuff. Nothing fancy was used other than a couple of extra
    dowels
    >   > and his ALS apex seals.
    >   >
    >   > First off just on free rev the motor picked up 7 psi in boost over
    >
    > what it
    >   > did before. It had no problem finding the limiter at 10.5k.
    >   > First run on the dyno yielded a 67 hp increase
     over what it made
    >   > previously at the exact boost pressure. The good thing about the
    >   > increase in power was that it was through out the entire power band
    and
    >   > averaged about 60 hp from 6K to 10.5k rpm.
    >   >
    >   > Even the off boost area was up 10-15 hp. The torque remained approx
    the
    >   > same as before. I guess that's a positive!
    >   > At 39 psi dropping to 36 psi by redline the motor made 860whp.
    >   > They made at least 6-7runs on the dyno to verify power and it
    remained
    >   > about the same.
    >   >
    >   > So there you go the rotors that many said could not work all ready
    have
    >   > made almost 900hp. The motor is going to be opened up tomorrow for
    >
    > inspection. "
    >   >
    >   > I still believe the titanium rotor is the better choice for
    aircraft
    >   > engines interested in good
     BSFC.
    >   >
    >   > Doug in Japan
    >
    >   > Obviously somebody is measuring things incorrectly. No engine can
    >  > make more HP with the same torque output and at the same RPM.
    >   >
    >   > Paul Lamar
    >
    > I think they have just highlighted the difference between different
    > types of dyno measurements.
    > (quote dyno type, calibration and ambient corrections or run away)
    > Without some sort of cooling, these things are probably not good for
    > anything more than short dyno runs.
    > The reduced drive train mass and increased acceleration would be good
    > for racing. (with proper cooling)
    > Anodizing or hard anodizing might help with wear issues although I'm
    > sure that introduces other
    > problems...have to look it up.
    >
    > ~Cary
    >
    > Cary,
    >   I think you missed Paul's point. If torque didn't change and
     RPM
    > didn't change you have the SAME HP.
    > I think we need to revisit the definition of HP. I hope the rotors work.
    > That said, One of the numbers
    > would have to change. the reason for a super lightweight rotor is to
    > allow a much higher SAFE RPM at
    > the same torque, equalling more power obviously.
    > Bill Jepson


        So does anybody have a drawing or better yet 3D model of standard rotor? If

    not than we'll have to wait for Paul to produce one.
        Thank You
        Ted

    Does anybody know how to calculate the radius of the rotor face?

    Paul Lamar



Hey all,

Here is the excel file I have been working on. It is not finished and I
am still sorting out a couple errors here and there but it is getting
there. Eventually the thing will be all correct and allow you to change
the variables and do all sorts of neat stuff. I just got laid off
recently from Delphi (note: F*%k the American auto industry) and have
been busy with finding a new job so I will get back on it when I get the
chance. Paul, note that the rotor equation never nets a constant radius.
This data while representative of the the points cannot be used in a
machine shop environment. This is where my questions of Solidworks 2009
came from as you would need to graph the sketch of the equation and not
a spline of a number of points. I checked with NX3 platform and SW2009
and it looks like they are too simplistic to do what pro-e does. Who has
pro-e that we can test out? I can gpo more into it at depth but will
only do so if there are serious questions about it. Here are a couple
things that will show you whats up with what I mean. I am working
diligently to get this worked out because if my plan for a lightweight
all steel brazed rotor works out then I can move to the next step which
is increasing the capacity of the engine and and having the weight of
the rotor as the cast iron version for the larger capacity engine be the
same as the 13b/renesis. 8500rpm to 10000 rpm limit on a 1 liter rotor.
That sound intersting to anybody?

http://www.profilesmagazine.com/p33/marsalek.html

http://esoxrepublic.com/blog/category/geometry/splines/

http://www.adras.com/SW2009-Equation-Driven-Curves.t8302-83.html

Rob Woods

If I am understanding  you correctly you are saying the face of the rotor is a not a circular arc?

Paul Lamar