[F500] 493 - 494 dyno curves

[McAbee, Chuck]

Dave - 

I believe if you dynoed all the participants at the Runoff's you would find
more than 5.8% between the best and the worst engines in the field.
Progress moves forward, not backward.  No one in their right mind is going
to offer an engine that is inferior to what we already have.  What would be
the point, who would buy it?

I believe the 40mm carbs probably account for the peak between the 7750 max
for the 494 and the 8000 max for the 493.  Hopefully, Mike Moench
(Sidewinder Mike) or someone else when the dyno the engines will compare
apples and apples and test both engines with 38mm carbs.  The differences
between the 494 and 493 are probably as near equal as we will ever get any
two engines.    

No one has any dyno figures for any of the 494 RAVE configurations, and they
have the recommendation for Board approval....For all we know, some 494 RAVE
configuration might have a 10% improvement over the stock 494....Let's get
the 493 legalized and get on with the fun of racing instead of the agony of
bitching about engines.
  


Chuck McAbee
SEDIV #16


-----Original Message-----
From: dogill80 at charter.net [mailto:dogill80 at charter.net]
Sent: Saturday, January 31, 2004 10:56
To: f500 at f500.org
Subject: Re: [F500] 493 - 494 dyno curves


Chuck,

I cannot agree that a 5.8% difference in horsepower on the top end is
"remarkably similar" and I predicate my judgment on the "remarkably similar"
horsepower figures of the AMW and Rotax, Kawasaki and AMW, and Chapparal and
Kawasaki.  If Helio (Castro Neves), Mark (Martin), Ron (Fellows), or Kimi
(Raikonnen) believed they had that much horsepower advantage over their
competitors, they'd soil their knickers every time they strapped in.

I realize the caliber of competition at our levels is quite simplified,
several orders of magnitude lower in economic input, and less pivotal in our
daily lives.  However, if we are going to compete, we need to try to do this
one ( as opposed to the AMW vs. Kawasaki and Rotax vs. AMW) a bit better.
If applying 38mm Mikuni's to the 493 effectively evens the power output, I
will get on the 493 bandwagon but, first, I need some assurance that this
new motor will not instantly obsolesce the existing engine configuration.

dg


----- Original Message ----- 
From: "McAbee, Chuck" <Chuck_McAbee at csx.com>
To: <f500 at f500.org>
Sent: Friday, January 30, 2004 9:57 PM
Subject: RE: [F500] 493 - 494 dyno curves


> Jay -
>
> One question....Was the 493 run with it's stock 40mm Mikuni's or with
38's?
>
> The 494 is stock with the 38mm Mikuni's.
>
>
> I agree the data shows the engines to be remarkably similar.
>
>
> Chuck McAbee
> SEDIV #16
>
> -----Original Message-----
> From: Jay Novak [mailto:jnovak6 at wideopenwest.com]
> Sent: Friday, January 30, 2004 22:49
> To: f500 at f500.org
> Subject: [F500] 493 - 494 dyno curves
>
>
> OK guys, I have been trying to get dyno data from Rotax for a couple of
> weeks.  I just got it last Monday by fax.  I finished putting together a
> graph comparing the data of the torque & hp of PRODUCTION STOCK 493 &
> non Rave 494.  The data that I received was in metric units, Nm torque
> (Newton-meters) & engine rpm (also had Kw, fuel flow etc).  The faxes
> were Rotax data sheets.  I copied the data to Excel, converted the
> metric torque data to ft-lbs & then calculated the SAE hp.  Take a look
> at graph at the link below & I think you will see that we have two very
> similar engines.  I put lots of notes on the graph defining some of the
> variations in the 2 engines.  I think that they are amazingly close
> above 6000 RPM for being totally different designs. (Reed vs. rotary
> valve).  It is pretty clear to me that the performance will be VERY
> similar in the cars.  Remember these 2 curves represent the engine's
> performance with production exhaust systems & not your typical Aaen pipe
> setup.  It seems to me that with our Aaen pipe setup we have been right
> at 8000 rpm in any case, so the HP on the race track might even be
> closer.
>
> I hope that this helps to clear up some issues for many of us.
>
>
> http://www.f500.org/rotax/
>
>
> Thanks ... Jay Novak
> NovaRace Inc.
>
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