Hi, Rusty.....I
purchased the short intake manifold from Dave Atkins. He claims he has
more than adequate power with his, and that idle is also good.
Look at all the race cars and racing motorcycles that have the carbs or
throttle bodies right next to the engine. They seem to generate a
lot of power that way. For what it's worth.
Paul
Conner
Paul is correct.
There are any number of intake configurations that will produce adequate
power for the RV-6. I am told that Dave Atkin's intake permits him
to generate approx 160HP which is certainly adequate for an RV and could
even provide thrilling performance in a low weight
RV
Now, I will be the
first to say, if you want to experiment or if you find for cost,
configuration or convience reasons you want to try some particular
intake configuration, please do so. I've been wrong before and I
am certain will be in the future - but, do it with your eyes open and
understanding of what performance might reasonably be
expected.
Best
Regards
Ed
Anderon
Hi, Ed.....thanks
for the post and education. I guess I was kinda thinking that if Dave
Atkins's RV performs that well with his short intake manifold, my
aerodynamically cleaner canard should perform equally to, or hopefully
better? The primary reason I liked his intake was because it is
truly "bolt on" and go. I tried to buy the wrap-over manifold from
Powersport, but their reply was...."sorry, we can't help you". I'm
sure that experimenters such as yourself, who know and understand intake
systems better than I, can tweak more power out of these engines.
The latest effort I am going to attempt is a wrap-over system similar to
Paul Lamar's, but with only two intake runners. The intake manifold I
ordered is cast so that the four intakes go into two almost immediately,
and from there I will make my aluminum tubing wrap over the top of the
engine (as close as possible for cowling clearance) and then terminate
with my TWM throttlebody with the built-in injectors. )(Also purchased
from Dave Atkins, because it was another "bolt on"). Did I
mention that I like bolt-ons? I truly appreciate the time and
effort you invest into improving these rotary installations for
aircraft. Thanks again. Paul Conner
Hi Paul,
Nothing wrong with your logic nor bolt-ons. Just having tried two
manifolds with shorter and bigger tubes, I just did not find they did
anything powerwise at the rpms we operate at.
Sounds like you
have a "Racing Beat Webber" style manifold with the four into two
configuration. I think you will find your latest thinking on your
intake more power productive than the former. My study of the DIE
process has convinced me that there were some reasons for Mazda to keep
the primary and secondary runners seperate on their engine. It has
also convinced me that those reasons are not really germane for aircraft
use. But, like so much - it depends{:>)
The current
induction design I am working on also has the four into two design
showing you at least I put my effort where my mouth is
{:>)
I don't recall the
configuration of your engine, whether a stock block, which style
block, or whether you have had any porting done. It all has an
effect.
If I knew the
secrets of induction magic - I would probably be inclinded to go into
business with it {:>). Heck, I don't even have a flow bench or
a dyno! I have studied and tried the "Organ Pipe",
"Helmholtz Resonator" and several others - all have some merit and all
tend to fall short when applied to the pulsating, changing airflow of
the Internal combustin engine. The one that I think provides
answers that correlate best with realitity is the Finite-Amplitude Wave
(FAW) theory. That seems to be supported by what I am finding
on software simulations of ICs. However, it is not a simple plug
and play equation like the other approaches, its an almost agonizing
iterative application of the FAW theory mainly to predicticting manifold
performance and then combined with other thermodynamic and combustion
models for total engine performance (simulated of course). From
what I have read the correlation with these more advanced models with
reality is very good and that some of the more successful racing teams
are buying these expensive simulations because they enable them to
quickly throw out some the bad ideas and then concentrate on the more
promissing ones. Before, it was mostly expensive cut and try with
hardware.
Well, enough, got
to get away from the computer and out to the
workshop.
Best
Regards
Ed