>> 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

(echoing)

At 10k RPM, the torque should have changed by about 30 lb-ft if the hp
increased by 60..  At 6k RPM, the torque would have increased
something closer to 60 lb-ft if it gained 60hp.

Let's see the dyno curves (before and after)!


Matt-