Today's Message Index:
----------------------
1. 08:24 AM - Auto Engine - compression ratio vs. octane (Brad Maynard)
2. 09:18 AM - Re: Auto Engine - compression ratio vs. octane (steve korney)
3. 09:34 AM - Re: Auto Engine - compression ratio vs. octane (jrc)
4. 09:53 AM - Re: Auto Engine - compression ratio vs. octane (Monty Barrett Sr)
5. 09:59 AM - Re: Auto Engine - compression ratio vs. octane (teamgrumman@aol.com)
6. 10:13 AM - Re: Auto Engine - compression ratio vs. octane (Hinde, Frank George (Corvallis))
7. 10:35 AM - Re: Auto Engine - compression ratio vs. octane (LarryMcFarland)
8. 12:14 PM - Re: Auto Engine - compression ratio vs. octane (Hinde, Frank George (Corvallis))
9. 02:53 PM - Re: Auto Engine - compression ratio vs. octane (Ed Anderson)
10. 04:12 PM - Re: Auto Engine - compression ratio vs. octane (Andrew M)
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| Subject: | Auto Engine - compression ratio vs. octane |
----------- Would someone have a rough idea of what c
ompression ratio I could run on my chevy auto
Conversion if I run 100LL- instead of regular unleaded?
Specs for my 3.4 V6 are 9.0:1 for regular.
-
Thanks,-- Brad=0A=0A=0A
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| Subject: | Auto Engine - compression ratio vs. octane |
At least 10:1 with 100LL
Best... Steve
From: bk_maynard@yahoo.com
Subject: Engines-List: Auto Engine - compression ratio vs. octane
Would someone have a rough idea of what compression ratio I cou
ld run on my chevy auto
Conversion if I run 100LL instead of regular unleaded?
Specs for my 3.4 V6 are 9.0:1 for regular.
Thanks=2C Brad
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| Subject: | Re: Auto Engine - compression ratio vs. octane |
Theoretical limit is 11.2:1 with premium autofuel. I don't think I'd go
that high. I do know from experience that 9.5:1 is OK on premium with
28 degrees advance on an O-200, but I have trouble on shutdown with
regular.
JimC
----- Original Message -----
From: steve korney
To: engines-list@matronics.com
Sent: Wednesday, May 13, 2009 10:16 AM
Subject: RE: Engines-List: Auto Engine - compression ratio vs. octane
At least 10:1 with 100LL
Best... Steve
-------------------------------------------------------------------------
-----
Date: Wed, 13 May 2009 08:17:42 -0700
From: bk_maynard@yahoo.com
Subject: Engines-List: Auto Engine - compression ratio vs. octane
To: engines-list@matronics.com
Would someone have a rough idea of what compression
ratio I could run on my chevy auto
Conversion if I run 100LL instead of regular unleaded?
Specs for my 3.4 V6 are 9.0:1 for regular.
Thanks, Brad
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| Subject: | Auto Engine - compression ratio vs. octane |
I don't think I would use 100 LL in an auto engine for a couple of
reasons.
1. Avgas burns at a slower rate
2. One of the products of combustion with leaded fuel is lead bromide,
which is somewhat corrosive and abrasive.
Aircraft lubricating oil has an additive package to deal with lead
bromide whereas motor oil does not.
an interesting side note. I rebult a Ford Flathead for a 46 Coupe I
have and the engine is considerably pumped up. I ran it on the dyno
here in the BPE shop and ran it on 100 LL. mixture was not quite right
and during the process of straightening out power valves, jetting, etc.
I also tested with 91 Oct mogas. The CR on this engine is 9.25:1 which
is quite a bit for a flathead. The engine made slightly more power on
mogas with the timing not changed. FYI
Monty Barrett
Barrett Precision Engines
-----Original Message-----
From: owner-engines-list-server@matronics.com
[mailto:owner-engines-list-server@matronics.com] On Behalf Of Brad
Maynard
Sent: Wednesday, May 13, 2009 10:18 AM
To: engines-list@matronics.com
Subject: Engines-List: Auto Engine - compression ratio vs.
octane
Would someone have a rough idea of what compression ratio I
could run on my chevy auto
Conversion if I run 100LL instead of regular unleaded?
Specs for my 3.4 V6 are 9.0:1 for regular.
Thanks, Brad
Message 5
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| Subject: | Re: Auto Engine - compression ratio vs. octane |
If compression were the only consideration, it would be so simple. It
isn't that simple.
Cam design plays more of a roll in detonation limits than compression
alone. You can easily make 8.5:1 compression produce 145 pounds
cranking pressure if you know what you're doing. Likewise, 11:1 can
produce less than 140 pounds with the right lobe separation angle.
I recommend measuring the cranking pressure. 145 pounds cranking
pressure is easy with 100LL. 155 would be a little on the edge.
Anything in the 130 range (125 to 135) is a piece of cake.
-----Original Message-----
From: jrc <jrccea@bellsouth.net>
Sent: Wed, 13 May 2009 9:34 am
Subject: Re: Engines-List: Auto Engine - compression ratio vs. octane
Theoretical limit is 11.2:1 with premium autofuel. I
don't think I'd gothat high. I do know from experience that 9.5:1 is
OK on premium with 28 degrees advance on an O-200, but I have trouble
on
shutdown with regular.
JimC
----- Original Message -----
From:
steve
korney
To: engines-list@matronics.com
Sent: Wednesday, May 13, 2009 10:16
AM
Subject: RE: Engines-List: Auto Engine -
compression ratio vs. octane
At least 10:1 with 100LL
Best... Steve
------------------------------------------------------------
Date: Wed, 13 May 2009 08:17:42 -0700
From: bk_maynard@yahoo.com
Subject:
=2
0 Engines-List: Auto Engine - compression ratio vs. octane
Would someone have a rough idea of what compression ratio I
could
run on my chevy auto
Conversion if I run
100LL instead of regular unleaded?
Specs for my 3.4 V6 are
9.0:1 for regular.
Thanks,
Brad
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| Subject: | Auto Engine - compression ratio vs. octane |
Interesting..And seems to be evidence that mogas is better for an aircraft
engine too, assuming its not a turbo'ed 540.
I know my IO 360 loves mogas and runs well even with 10% Ethanol blends...A
lthough I have not flown it above 15000ft so cannot attest to vphase sepera
tion, water fallout predictions.
Frank
________________________________
From: owner-engines-list-server@matronics.com [mailto:owner-engines-list-se
rver@matronics.com] On Behalf Of Monty Barrett Sr
Sent: Wednesday, May 13, 2009 8:41 AM
Subject: RE: Engines-List: Auto Engine - compression ratio vs. octane
I don't think I would use 100 LL in an auto engine for a couple of reasons.
1. Avgas burns at a slower rate
2. One of the products of combustion with leaded fuel is lead bromide, whi
ch is somewhat corrosive and abrasive.
Aircraft lubricating oil has an additive package to deal with lead brom
ide whereas motor oil does not.
an interesting side note. I rebult a Ford Flathead for a 46 Coupe I have a
nd the engine is considerably pumped up. I ran it on the dyno here in the
BPE shop and ran it on 100 LL. mixture was not quite right and during the
process of straightening out power valves, jetting, etc. I also tested with
91 Oct mogas. The CR on this engine is 9.25:1 which is quite a bit for a
flathead. The engine made slightly more power on mogas with the timing not
changed. FYI
Monty Barrett
Barrett Precision Engines
Message 7
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| Subject: | Re: Auto Engine - compression ratio vs. octane |
Hi Frank,
I've used 87-octane with 10% ethanol for the last two years and only on
one occasion did "phase separation" occur. The aircraft had set for 4 months
with less than a gallon in the tank after the pre winter annual
inspection. The small amount of fuel did look nearly opaque and gray. I
drained the remaining
and added new fuel when flying weather returned. No telling how long the
gas had set in the retailers tank before I got it.
Larry McFarland 601HDS at www.macsmachine.com
Hinde, Frank George (Corvallis) wrote:
> Interesting..And seems to be evidence that mogas is better for an
> aircraft engine too, assuming its not a turbo'ed 540.
>
> I know my IO 360 loves mogas and runs well even with 10% Ethanol
> blends...Although I have not flown it above 15000ft so cannot attest
> to vphase seperation, water fallout predictions.
>
> Frank
>
> ------------------------------------------------------------------------
> *From:* owner-engines-list-server@matronics.com
> [mailto:owner-engines-list-server@matronics.com] *On Behalf Of *Monty
> Barrett Sr
> *Sent:* Wednesday, May 13, 2009 8:41 AM
> *To:* engines-list@matronics.com
> *Subject:* RE: Engines-List: Auto Engine - compression ratio vs. octane
>
> I don't think I would use 100 LL in an auto engine for a couple of
> reasons.
> 1. Avgas burns at a slower rate
> 2. One of the products of combustion with leaded fuel is lead
> bromide, which is somewhat corrosive and abrasive.
> Aircraft lubricating oil has an additive package to deal with lead
> bromide whereas motor oil does not.
>
> an interesting side note. I rebult a Ford Flathead for a 46 Coupe I
> have and the engine is considerably pumped up. I ran it on the dyno
> here in the BPE shop and ran it on 100 LL. mixture was not quite
> right and during the process of straightening out power valves,
> jetting, etc. I also tested with 91 Oct mogas. The CR on this engine
> is 9.25:1 which is quite a bit for a flathead. The engine made
> slightly more power on mogas with the timing not changed. FYI
>
> Monty Barrett
> Barrett Precision Engines
>
>
>
> *
>
>
> *
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| Subject: | Auto Engine - compression ratio vs. octane |
Good input Larry..Sounds like the remaining fuel absorbed the water from condensation.
Fit for the lawnmower only after 4 months is a certainty now..:)
Thanks
Frank
-----Original Message-----
From: owner-engines-list-server@matronics.com [mailto:owner-engines-list-server@matronics.com] On Behalf Of LarryMcFarland
Sent: Wednesday, May 13, 2009 10:35 AM
Subject: Re: Engines-List: Auto Engine - compression ratio vs. octane
--> <larry@macsmachine.com>
Hi Frank,
I've used 87-octane with 10% ethanol for the last two years and only on one occasion
did "phase separation" occur. The aircraft had set for 4 months with less
than a gallon in the tank after the pre winter annual inspection. The small
amount of fuel did look nearly opaque and gray. I drained the remaining and added
new fuel when flying weather returned. No telling how long the gas had set
in the retailers tank before I got it.
Larry McFarland 601HDS at www.macsmachine.com
Message 9
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| Subject: | Auto Engine - compression ratio vs. octane |
Given that the lower the octane rating, the more energy a specific volume of
gasoline has, I am not surprised that with auto fuel you got more power than
with 100LL. The higher octane fuel has less energy content and only real
purpose is prevent detonation with high compression engines. Many believe
that higher octane means more power than lower octane fuels, but only if you
are able to run higher compression or forced induction systems (which in
effect increase compression ratio).
100LL contains approx 120,000 BTU/Gallon whereas 87 Octane contains approx
125,000 BTU/Gallon or about 4% more energy.
Ed
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
<http://www.andersonee.com> http://www.andersonee.com
<http://www.dmack.net/mazda/index.html>
http://www.dmack.net/mazda/index.html
http://www.flyrotary.com/
<http://members.cox.net/rogersda/rotary/configs.htm>
http://members.cox.net/rogersda/rotary/configs.htm#N494BW
http://www.rotaryaviation.com/Rotorhead%20Truth.htm
<http://www.dmack.net/mazda/index.html>
_____
From: owner-engines-list-server@matronics.com
[mailto:owner-engines-list-server@matronics.com] On Behalf Of Monty Barrett
Sr
Sent: Wednesday, May 13, 2009 11:41 AM
Subject: RE: Engines-List: Auto Engine - compression ratio vs. octane
I don't think I would use 100 LL in an auto engine for a couple of reasons.
1. Avgas burns at a slower rate
2. One of the products of combustion with leaded fuel is lead bromide,
which is somewhat corrosive and abrasive.
Aircraft lubricating oil has an additive package to deal with lead
bromide whereas motor oil does not.
an interesting side note. I rebult a Ford Flathead for a 46 Coupe I have
and the engine is considerably pumped up. I ran it on the dyno here in the
BPE shop and ran it on 100 LL. mixture was not quite right and during the
process of straightening out power valves, jetting, etc. I also tested with
91 Oct mogas. The CR on this engine is 9.25:1 which is quite a bit for a
flathead. The engine made slightly more power on mogas with the timing not
changed. FYI
Monty Barrett
Barrett Precision Engines
-----Original Message-----
From: owner-engines-list-server@matronics.com
[mailto:owner-engines-list-server@matronics.com] On Behalf Of Brad Maynard
Sent: Wednesday, May 13, 2009 10:18 AM
Subject: Engines-List: Auto Engine - compression ratio vs. octane
Would someone have a rough idea of what compression ratio I
could run on my chevy auto
Conversion if I run 100LL instead of regular unleaded?
Specs for my 3.4 V6 are 9.0:1 for regular.
Thanks, Brad
href="http://www.matronics.com/Navigator?Engines-List">http://www.matronics.
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| Subject: | Auto Engine - compression ratio vs. octane |
In that case is there an aviation oil including the additive that can be
run in auto conversion engines? Or can the additive be bought and added
when filling up with 100LL? If you're flying into places w/out mogas it
sounds like you need it.
-Andrew
From: owner-engines-list-server@matronics.com
[mailto:owner-engines-list-server@matronics.com] On Behalf Of Monty Barrett
Sr
Sent: Wednesday, May 13, 2009 10:41 AM
Subject: RE: Engines-List: Auto Engine - compression ratio vs. octane
I don't think I would use 100 LL in an auto engine for a couple of reasons.
1. Avgas burns at a slower rate
2. One of the products of combustion with leaded fuel is lead bromide,
which is somewhat corrosive and abrasive.
Aircraft lubricating oil has an additive package to deal with lead
bromide whereas motor oil does not.
an interesting side note. I rebult a Ford Flathead for a 46 Coupe I have
and the engine is considerably pumped up. I ran it on the dyno here in the
BPE shop and ran it on 100 LL. mixture was not quite right and during the
process of straightening out power valves, jetting, etc. I also tested with
91 Oct mogas. The CR on this engine is 9.25:1 which is quite a bit for a
flathead. The engine made slightly more power on mogas with the timing not
changed. FYI
Monty Barrett
Barrett Precision Engines
-----Original Message-----
From: owner-engines-list-server@matronics.com
[mailto:owner-engines-list-server@matronics.com] On Behalf Of Brad Maynard
Sent: Wednesday, May 13, 2009 10:18 AM
Subject: Engines-List: Auto Engine - compression ratio vs. octane
Would someone have a rough idea of what compression ratio I
could run on my chevy auto
Conversion if I run 100LL instead of regular unleaded?
Specs for my 3.4 V6 are 9.0:1 for regular.
Thanks, Brad
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