BTW for the new people the Lemans engine ran for 24 hours
using this full throttle engine speed distribution for the RPM. It
spent 28% of the time between 7500 and 8000 RPM. They disassembled
the engine after the race and could not measure any wear.
Also BTW the Lemans engines is no longer considered a full blown
race engine as some people I know are running them only between
8000 and 10,500. They start were we leave off. The turbo race
people are getting as much as 400 HP or more per rotor.
Paul Lamar
....snip
Well 400 hp per rotor - is that for road race or 1/4mile racing?
I assume we can all but forget about 1/4 mile tech for our application.
Even if these guys run their engines all year, they never do it for more
than a few seconds at a time (at all out power...).
Road/Rally/CircleTrack is a different story, especially if it is long
duration races 6/12/24 hour endurance...
Thomas J.
"Still wondering about any difference between the 6-port and 4-port Renesis
exhaust :)"
400 HP per rotor is drag racing.
In road racing the rules are rather restrictive. In most cases
p-ports are outlawed. The guys are lucky to get 110 HP per rotor.
Even at 10,500 RPM. In the 80's the 13B p-ports engines had over 300 HP
They dominated 24 hour endurance road racing until they were severely
handicapped. They won the IMSA championship five years in a row.
My guess is there is no difference in the RX8 exhaust ports.
Paul Lamar
Paul,
Congratulations. What a great start. Did you happen to get any accurate
BSFC data at the peak torque level or near 6000 rpm?
P-porting the Renesis engine is starting to look like a future project
after I am finished with the turbo 13B. However I am not totally convinced
it would be any better. As far as I can tell there appears to still be a
overlap of the port timing and of course the Renesis's side exhaust may not
be as robust to drive the turbo compared with the 13B.
Doug in Japan
We got lots of BSFC data but I hesitate to list it because a carb
is really bad about controlling BSFC to a fair thee well. It gets
you in the ball park but it cannot hope to match EFI when it
comes to precise fuel control.
It was in the range of .5 to .6 which is a bit lower than I expected.
An air cooled aircraft engine full rich full power BSFC can be up to .65.
These are also full power runs and a cruise fuel setting leaned
out will be much lower. Down around .47 I expect.
Here are some data from the OBD II
in my RX8 to document that statement. Notice the mixture is
stochimetric = 1 (14.7:1) within +/- .01 or so. From this
data one can calculate the steady MPG. Mazda does not, and probably
cannot, lean the engine at low power (like we do) due to NOX emmisions
problems. When you do the math the RX8 does about 25 MPG at 70 MPH.
Paul Lamar
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