This is a multipart message in MIME format.
--===============2702396419330967851==
boundary="----=_NextPart_000_0389_01DCCE9A.CF356260"
Content-Language: en-us
This is a multipart message in MIME format.
------=_NextPart_000_0389_01DCCE9A.CF356260
charset="utf-8"
Content-Transfer-Encoding: quoted-printable
Bill,
=20
It is the compression ratio of the engine, not the cylinder compression, =
that is related to octane rating.
=20
Generally, the higher compression ratio, the more need for high octane =
fuel.
My Healey has a 10:1 compression ratio, so I add an octane booster to =
each tank of gas.
My TR3 engine has whatever the factory compression ratio was, so the =
octane rating is not that important. But, I still put =
=E2=80=9CPremium=E2=80=9D gasoline in it because that is all that is =
available near me that does not contain corn.=20
=20
All that said, in theory, most engine will perfume better with higher =
octane fuel, and they should get better fuel milage as well.=20
Non ethanol gas will result in around 10 percent better fuel milage.
But if you are running gas with ethanol, I doubt the additional cost of =
=E2=80=9CPremium=E2=80=9D fuel it is worth it for =
=E2=80=9Cnormal=E2=80=9D driving.=20
=20
Check the owner=E2=80=99s manual for the TR4 and see what it recommends =
for fuel octane rating.
Ron
=20
From: Triumphs <triumphs-bounces@autox.team.net> On Behalf Of Bill =
Beecher
Sent: Friday, April 17, 2026 5:07 PM
To: Randall <triumphs@autox.team.net>
Subject: [TR] PSI vs Octane
=20
Good evening all,
I have always run regular 87 octane in my TR3(=E2=80=9866 TR4 motor), no =
knocks or pings. Don=E2=80=99t know what got me to thinking but there =
has to be a relation between compression psi and the octane rating I =
should use. My compression across all four is 175-180, would I be =
getting improved performance from a higher octane gas? Or just wasting =
$$ ?
All the best,
Bill B
TS30766L
=20
=E2=80=9CThe harder I work, the luckier I get=E2=80=9D H. Ford
------=_NextPart_000_0389_01DCCE9A.CF356260
charset="utf-8"
Content-Transfer-Encoding: quoted-printable
<html xmlns:v=3D"urn:schemas-microsoft-com:vml" =
xmlns:o=3D"urn:schemas-microsoft-com:office:office" =
xmlns:w=3D"urn:schemas-microsoft-com:office:word" =
xmlns:m=3D"http://schemas.microsoft.com/office/2004/12/omml"; =
xmlns=3D"http://www.w3.org/TR/REC-html40";><head><meta =
http-equiv=3DContent-Type content=3D"text/html; charset=3Dutf-8"><meta =
name=3DGenerator content=3D"Microsoft Word 15 (filtered medium)"><!--[if =
gte mso 9]><xml>
<w:WordDocument>
<w:DontUseAdvancedTypographyReadingMail/>
<w:DontUseJustificationAdvancedTypographyReadingMail/>
<w:DontUseHyphenationAdvancedTypographyReadingMail/>
</w:WordDocument>
</xml><![endif]--><style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Aptos;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
font-size:12.0pt;
font-family:"Aptos",sans-serif;}
span.EmailStyle18
{mso-style-type:personal-reply;
font-family:"Arial",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;
mso-ligatures:none;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext=3D"edit" spidmax=3D"1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext=3D"edit">
<o:idmap v:ext=3D"edit" data=3D"1" />
</o:shapelayout></xml><![endif]--></head><body lang=3DEN-US =
link=3D"#467886" vlink=3D"#96607D" style=3D'word-wrap:break-word'><div =
class=3DWordSection1><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Arial",sans-serif'>Bill,<o:p></o:p=
></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Arial",sans-serif'><o:p> </o:=
p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Arial",sans-serif'>It is the =
compression ratio of the engine, not the cylinder compression, that is =
related to octane rating.<o:p></o:p></span></p><p =
class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Arial",sans-serif'><o:p> </o:=
p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Arial",sans-serif'>Generally, the =
higher compression ratio, the more need for high octane =
fuel.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Arial",sans-serif'>My Healey has =
a 10:1 compression ratio, so I add an octane booster to each tank of =
gas.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Arial",sans-serif'>My TR3 engine =
has whatever the factory compression ratio was, so the octane rating is =
not that important. But, I still put =E2=80=9CPremium=E2=80=9D gasoline =
in it because that is all that is available near me that does not =
contain corn. <o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Arial",sans-serif'><o:p> </o:=
p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Arial",sans-serif'>All that said, =
in theory, most engine will perfume better with higher octane fuel, and =
they should get better fuel milage as well. <o:p></o:p></span></p><p =
class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Arial",sans-serif'>Non ethanol =
gas will result in around 10 percent better fuel =
milage.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Arial",sans-serif'>But if you are =
running gas with ethanol, I doubt the additional cost of =
=E2=80=9CPremium=E2=80=9D fuel it is worth it for =
=E2=80=9Cnormal=E2=80=9D driving. <o:p></o:p></span></p><p =
class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Arial",sans-serif'><o:p> </o:=
p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Arial",sans-serif'>Check the =
owner=E2=80=99s manual for the TR4 and see what it recommends for fuel =
octane rating.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Arial",sans-serif'> =
<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Arial",sans-serif'>=C2=A0=C2=A0Ron=
<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Arial",sans-serif'><o:p> </o:=
p></span></p><div><div style=3D'border:none;border-top:solid #E1E1E1 =
1.0pt;padding:3.0pt 0in 0in 0in'><p class=3DMsoNormal><b><span =
style=3D'font-size:11.0pt;font-family:"Calibri",sans-serif'>From:</span><=
/b><span style=3D'font-size:11.0pt;font-family:"Calibri",sans-serif'> =
Triumphs <triumphs-bounces@autox.team.net> <b>On Behalf Of =
</b>Bill Beecher<br><b>Sent:</b> Friday, April 17, 2026 5:07 =
PM<br><b>To:</b> Randall =
<triumphs@autox.team.net><br><b>Subject:</b> [TR] PSI vs =
Octane<o:p></o:p></span></p></div></div><p =
class=3DMsoNormal><o:p> </o:p></p><p class=3DMsoNormal>Good evening =
all,<o:p></o:p></p><div><p class=3DMsoNormal>I have always run regular =
87 octane in my TR3(=E2=80=9866 TR4 motor), no knocks or pings. =
Don=E2=80=99t know what got me to thinking but there has to be a =
relation between compression psi and the octane rating I should use. =
My compression across all four is 175-180, would I be getting =
improved performance from a higher octane gas? Or just wasting $$ =
?<o:p></o:p></p><div><p class=3DMsoNormal>All the =
best,<o:p></o:p></p></div><div><p class=3DMsoNormal>Bill =
B<o:p></o:p></p></div><div><p =
class=3DMsoNormal>TS30766L<o:p></o:p></p><div><p =
class=3DMsoNormal><o:p> </o:p></p><div><p =
class=3DMsoNormal>=E2=80=9CThe harder I work, the luckier I get<span =
style=3D'font-size:19.0pt'>=E2=80=9D H. =
Ford</span><o:p></o:p></p></div></div></div></div></div></body></html>
------=_NextPart_000_0389_01DCCE9A.CF356260--
--===============2702396419330967851==
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
** triumphs@autox.team.net **
Archive: http://www.team.net/pipermail/triumphs http://www.team.net/archive
--===============2702396419330967851==--
|