From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Re: timing on renesis engines
Date: Sat, 6 Jul 2019 07:16:27 +0800
References: <list-12737906@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-12737906@logan.com>
Message-Id: <9F0B24DE-0E6D-4317-BAD0-19B7B92DB92E@gmail.com>

Thanks Bobby and Lyn.

According to Tracy=E2=80=99s code -  2.6 mSec RX8, 3.5 mSec RX7, 4.0 =
mSec LS2, 4.3 mSec LS1.
I also wondered about the timing difference between the various coils =
trigger circuit actually firing.
Now I suppose that difference might be a few uSec and insignificant, but =
if its 100uSec=20
then the timing difference between various coil types might become =
significant.

@ 7000 RPM=20
1 rev takes 8.6mSec
So each degree of EShaft rotation is 24uSec.

Thanks again for the help.

Steve


> On 6 Jul 2019, at 2:52 am, Bobby J. Hughes bhughes@qnsi.net =
<flyrotary@lancaironline.net> wrote:
>=20
> Lynn,
>=20
> Default is what ever Tracy set it to. The CAS location is not =
adjustable so default is set in his code.=20
>=20
> Bobby
>=20
> Sent from my iPhone
>=20
> On Jul 5, 2019, at 12:43 PM, lehanover lehanover@aol.com =
<flyrotary@lancaironline.net> wrote:
>=20
>> What is the "Default" advance? Is that checked with a timing light? =
Easy starting can be up to 15 degrees of advance. For full power use up =
to 27 degrees of advance is good up to 10,500 RPM. Boosted engines =
require less advance as boost increases. Because the effective =
compression ratio as well as charge temperature is going up. Very high =
boost my have advance closer to zero. Advance is used to allow full =
combustion
>> of the charge before the exhaust port opens. At higher pressure and =
temps the flame front speeds are increasing. So, less time is needed. =
Thus less advance is needed. Lowering intake air temps with an =
inter-cooler and adding water spray can allow higher boost.
>>=20
>> Boosting to maintain sea level performance would probably not shorten =
engine life. Boosting for additional performance does shorten engine =
life. The kids get over 600 HP with boosted drag racing engines. This is =
fine if you only need the engine for 9 seconds. You have to know what =
the actual advance is to make any decision.  Mark the flex plate or =
flywheel teeth with paint so you can check actual advance during any =
RPM.
>>=20
>>=20
>> It is difficult to detonate an NA engine. It is not difficult =
detonate a boosted engine.
>>=20
>> Lynn E. Hanover
>>=20
>>=20
>> In a message dated 7/5/2019 10:22:44 AM Eastern Standard Time, =
flyrotary@lancaironline.net writes:
>>=20
>> Steve,
>> I=E2=80=99m running default timing or maybe 1 degree advanced. Early =
on I experimented with 1-2 degrees advance for many flight hours and did =
not detect any noticeable change in engine performance. I did push the =
engine to what I believe was detonation during a ground tuning session. =
I was tuning under boost (44=E2=80=9D MP) , 7000 rpm with a wideband O2 =
on each runner and adjusting Mode 9 and Mode 4. With F/A balanced =
between each rotor and EGT=E2=80=99s under 1600F I was trying to see if =
increasing timing would lower EGT=E2=80=99s. F/A was in the 11=E2=80=99s. =
This was at the end of the session and the engine and supercharger were =
already hot. I think I had added 4-5 degrees advance with no noticeable =
EGT decrease when I encountered a mild bang or misfire. This condition =
was well above my 38=E2=80=9D MP limit I sometimes use for takeoff.
>>=20
>> I=E2=80=99m curious about the dwell time setting difference between =
LS1 and LS2 coils. I switched to LS2 coils sometime back with no =
failures to date. I remember seeing an option setting in some of the =
code you or Finn posted. Internet research indicates LS2 coils require =
less dwell time than LS1. Possibly 0.5-1 ms less.
>>=20
>> Bobby
>>=20
>> Sent from my iPad
>>=20
>> > On Jul 5, 2019, at 12:58 AM, Stephen Izett stephen.izett@gmail.com =
<flyrotary@lancaironline.net> wrote:
>> >
>> > Hi there Guys
>> >
>> > Of the guys with Renesis engines using EC2/3 can you comment on =
your timing settings.
>> > I=E2=80=99ve to date left the timing at the default setting =
figuring its set by the location of the CAS.
>> > Not sure if the various coil options have different trigger timing =
latency.
>> >
>> > Thanks
>> >
>> > Steve Izett
>> >
>> >
>> >
>> >
>> > --
>> > Homepage:  http://www.flyrotary.com/
>> > Archive and UnSub:  =
http://mail.lancaironline.net:81/lists/flyrotary/List.html
>>=20
>> --
>> Homepage:  http://www.flyrotary.com/
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