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Jeff Waltermire wrote:
Hi Guys (and
gals),
I'm new to the group. I am building a 4 place Bearhawk. I am an
A&P but I am really interested in the auto conversions as I am a
tinkerer.
Welcome Jeff.. I'm a fairly newbie too.. 6 mos or
so in here...
I won't slam
the aviation engine manufacturers too hard ..(SNIP). What are some
pointers?
Let someone else be the guinea pig
<grin>... I mean that in a constructive way, actually.. In my
case, I am learning from the mistakes of others so I don't replicate
them independently. For instance, cooling and intakes seem to be the
main issues, and I am looking to the guys who are actually flying to
see what works and what doesnt. There has been a lot of ingenuity with
regards to putting things together (some working, some not... Air
conditioning evap cores moonlighting as oil coolers for instance).
While I dont know about any other flying Bearhawks (and hence no
airframe specifics) a lot of the essentials are the same.
In order to get 180-200hp out of a 13B, does one just need to do street
porting? Is it worth the cost getting things flow tested after porting
or is it not worth the expense? To get 250hp out of a 13B do you do
more wild porting or put on a turbo? Does reliablity go way down if
you try to get that much out of a 13B or is it about the same if you
can keep it cool? You don't have burnt valves to worry about!
I will defer to Lynn about these sorts of
numbers.. he's the racer out of the bunch, and has seen lots with
regards to high hp applications in cars. Seems the bad stuff I've heard
about reliability is up in the HIGH turbocharging range... breaking
apex seals n such.. or running it out of oil. It seems that compared to
a piston, the rotary has a lot in its court with regards to
reliability. I can't speal with personal authority on how reliable or
not. We dont have ours running yet.
Will the renesis be a better option? I guess we are all waiting to see
how the renesis is going to do. Would a little mild porting get you up
to 250-260hp with the renesis without hurting reliability? Are the
street rodders or anyone else tinkering with the renesis yet? What's
the difference in the two versions of the renesis (one power rating for
the automatic transmission and another for the manual tranny)? Does
the higher hp version have different porting or just different
intake/exhaust manifolds? Is it just in the ECU? I think it's fair to
say we are fortunate for people like Tracy who are willing to
experiment then also share their experiences.
The Renesis seems to make a lot of its magic
(from what I've heard) from a tuned induction and high compression
normally aspirated rotors. Chris and I wanted to go with a Renesis, but
cost and availability factors pushed us into using a 2nd gen engine. At
this point I've disassembled, ported and substantially reassembled one
(of the 3 engines we bought for $700) for a total cost approaching
$1600. The PSRU should be arriving from Tracy Crook in the near future,
and I am actuvely shopping for the peripherals. If you want a new
renesis, you can still get one for a fraction of a lycomings cost, and
it should be a great NA engine. With the high compression however, I
would be hesitant to do more than turbonormalize it. As for
experimenters.. My hero is John Slade.. Since I want to turbocharge our
engine (lightly, more of a normalization).. The score.. Turbo's 2,
Slade 0... but my money is on John to go the distance.
Thanks for letting me "bend your ear" and ask the newbie questions. I
look forward to meeting some of you possibly at Sun-n-fun this coming
year. I haven't been there in years but I was into ultralights the
last time I was there. Since I have lived out of the US I haven't been
able to go there but now I want to see the different auto
conversions. I am going to try to do my best to get there. Are any
of you in OH, MI, PA, or IN?
Thanks,
Jeff Waltermire
Regards,
David Staten
Houston, TX
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