Hello Paul and all.
I complete the my first RX-8 13B p-port engine and I measured power and
trq. This short lenght of intake dont good for me. Engine had cca 210
HP /
9000 rpm. Then I used intake tubes cca 14.9 inch and engine had 257 HP /
7500 rpm, but at 9000 rpm engine had only 222 HP. We used EFI euro 4
computer. What should I do to that I have 300 hp / 9000 rpm? Because I
used
this engine in competition car. Thank īs.
Respectfully, Michal from Slovakia.
Do you have a wide band mixture monitor on it?
If so what was the mixture?
Looks like you have the stock RX8 exhaust manifold on there.
Try a header 32 inches long. About 1 meter.
If you want to get really trick try something like this.
Make the outer runners 32 inches long and the inner runner
16 inches long. The theory is the center RX8 exhaust port
pulses twice as often as the outer exhaust ports.
Paul Lamar
Hi Michal;
What is the size and timing and shape of your Pports?
Intakes size?
Paul already asked about the exhaust stack. You probably want to tune
the 3 runner lengths, join the exhaust runners for scavenging as
straight out of the engine as possible, followed by a transition or
megaphone and a free flowing exhaust.
Lynn Hanover has posted details of his race setup in various web sites.
Cheers
Cary
Did Lynn run a P-port RX8 engine? I don't think so.
I think Michal copied our RX8-P-port youtube video.
He is getting about the same power at 7500 RPM we got
on the Mazdatrix dyno.
http://www.youtube.com/watch?v=NKJ00JsnS8A
Paul Lamar
No RX-8 stuff.
As with the British Leyland tractor engined stuff we thought was so cool in
my youth, the center exhaust port was shared by the two center cylinders.
Similar to the
RX-8 engine. This provides an unfortunate odd shaped cavity right at the
worst spot in the system. For the British stuff, it was found that a header
using shorter runs for the end cylinders, and double that length for the
center (shared) runner produced the best torque everywhere.
This would give you a more compact system, and compact is lighter. You are
trying to recover from a poorly designed system rather than make up some
great HP advantage.
Like the gate in a transistor, imperfections close to the chamber where you
have high velocity, and high temperature will have a big effect. Once
through the last collector, piston engine rules apply.
Unlike British Leyland and Datsun, years ago, Mazda has no well done book
available at the parts counter about racing their engines. You know Mazda
have investigated all of the stuff we want to know about, but guard it like
nuclear secrets, instead of sharing. Their ancient "competition manual" is
comically vestigal. What a shame.
Lynn E. Hanover
Well I don't entirely agree with the lack of Mazda info on racing.
There are a dozen or more Mazda written SAE papers on the subject
and some can be downloaded from here.
http://www.rotaryeng.net/ in the TECH PAPER DOWNLOAD SECTION
on the front page.
True there is near none on tuning the RX8 engine.
Paul Lamar
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