Re: Re: Re: 85 vs 87 Octane
 

On Sun, 2 Sep 2007 22:01:24 -0500, "Mindy"
<drranchtx@nospamearthlink.net> wrote:

>sooo, if I increase my octane to 87 at say 9,000 or so altitude, I will gain
>some power back ?? my jeep is a 2001 grand with the straight 6, 4.0
>engine...


Possibly, if is worth a try. It is not because fuel has more energy
but because it has a better burning curve in a high compression
engine. My wife has a 2000 Cherokee that we bought new and it is a
stripped 4cyl with a stick and A/C that she uses to go to work and run
around. It has been a good trouble free car and has over 80K now but
even it runs a lot better on 89 or better octane in warmer weather at
the 1000 MSL where we live. It gets better overall MPG too. (it
average 19 to 22 MPG in city/urban driving (no highway) using A/C too.
On highway it gets 23 to 25 with A/C depending on speed. We bought it
as a cheap knock around vechile that could carry outsized cargo and
such and it has served well for this. We have a bigger vehicle for
really long trips that is not used in daily cycle.
-----------------
TheSnoMan.com

Re: Re: Re: 85 vs 87 Octane
 

On Sun, 2 Sep 2007 22:01:24 -0500, "Mindy"
<drranchtx@nospamearthlink.net> wrote:

>sooo, if I increase my octane to 87 at say 9,000 or so altitude, I will gain
>some power back ?? my jeep is a 2001 grand with the straight 6, 4.0
>engine...


Possibly, if is worth a try. It is not because fuel has more energy
but because it has a better burning curve in a high compression
engine. My wife has a 2000 Cherokee that we bought new and it is a
stripped 4cyl with a stick and A/C that she uses to go to work and run
around. It has been a good trouble free car and has over 80K now but
even it runs a lot better on 89 or better octane in warmer weather at
the 1000 MSL where we live. It gets better overall MPG too. (it
average 19 to 22 MPG in city/urban driving (no highway) using A/C too.
On highway it gets 23 to 25 with A/C depending on speed. We bought it
as a cheap knock around vechile that could carry outsized cargo and
such and it has served well for this. We have a bigger vehicle for
really long trips that is not used in daily cycle.
-----------------
TheSnoMan.com

Re: Re: Re: 85 vs 87 Octane
 

On Sun, 2 Sep 2007 22:01:24 -0500, "Mindy"
<drranchtx@nospamearthlink.net> wrote:

>sooo, if I increase my octane to 87 at say 9,000 or so altitude, I will gain
>some power back ?? my jeep is a 2001 grand with the straight 6, 4.0
>engine...


Possibly, if is worth a try. It is not because fuel has more energy
but because it has a better burning curve in a high compression
engine. My wife has a 2000 Cherokee that we bought new and it is a
stripped 4cyl with a stick and A/C that she uses to go to work and run
around. It has been a good trouble free car and has over 80K now but
even it runs a lot better on 89 or better octane in warmer weather at
the 1000 MSL where we live. It gets better overall MPG too. (it
average 19 to 22 MPG in city/urban driving (no highway) using A/C too.
On highway it gets 23 to 25 with A/C depending on speed. We bought it
as a cheap knock around vechile that could carry outsized cargo and
such and it has served well for this. We have a bigger vehicle for
really long trips that is not used in daily cycle.
-----------------
TheSnoMan.com

Re: Re: 85 vs 87 Octane
 

On Sun, 02 Sep 2007 22:26:01 -0500, c <c@me.org> wrote:

>I have a 350 in my S10 truck that runs on 89 octane with a true
>blueprinted 10.7 compression ratio and cast iron heads, but it also has
>a cam with quite a bit of overlap and the combustion chambers are highly
>polished. The quench distance between the top of the piston and the head
>is .038" which is the tightest recommended distance, but also the best
>for reducing detonation. I do not have to compromise my ignition timing
>with this setup. I am running 12 degrees initial timing and 24 degrees
>mechanical.

I would run more octane and a bit more spark too. I used to race SB's
years ago and 38 to 40 degress total advance is sweet spot for SB. You
want to start mech advance at about 1200 to 1500 and have it fully in
by about 3800 RPM. (1900 distributor RPM) You have a fairly nice build
but it would do more with better fuel and more timing tweaks.
-----------------
TheSnoMan.com

Re: Re: 85 vs 87 Octane
 

On Sun, 02 Sep 2007 22:26:01 -0500, c <c@me.org> wrote:

>I have a 350 in my S10 truck that runs on 89 octane with a true
>blueprinted 10.7 compression ratio and cast iron heads, but it also has
>a cam with quite a bit of overlap and the combustion chambers are highly
>polished. The quench distance between the top of the piston and the head
>is .038" which is the tightest recommended distance, but also the best
>for reducing detonation. I do not have to compromise my ignition timing
>with this setup. I am running 12 degrees initial timing and 24 degrees
>mechanical.

I would run more octane and a bit more spark too. I used to race SB's
years ago and 38 to 40 degress total advance is sweet spot for SB. You
want to start mech advance at about 1200 to 1500 and have it fully in
by about 3800 RPM. (1900 distributor RPM) You have a fairly nice build
but it would do more with better fuel and more timing tweaks.
-----------------
TheSnoMan.com

Re: Re: 85 vs 87 Octane
 

On Sun, 02 Sep 2007 22:26:01 -0500, c <c@me.org> wrote:

>I have a 350 in my S10 truck that runs on 89 octane with a true
>blueprinted 10.7 compression ratio and cast iron heads, but it also has
>a cam with quite a bit of overlap and the combustion chambers are highly
>polished. The quench distance between the top of the piston and the head
>is .038" which is the tightest recommended distance, but also the best
>for reducing detonation. I do not have to compromise my ignition timing
>with this setup. I am running 12 degrees initial timing and 24 degrees
>mechanical.

I would run more octane and a bit more spark too. I used to race SB's
years ago and 38 to 40 degress total advance is sweet spot for SB. You
want to start mech advance at about 1200 to 1500 and have it fully in
by about 3800 RPM. (1900 distributor RPM) You have a fairly nice build
but it would do more with better fuel and more timing tweaks.
-----------------
TheSnoMan.com

Re: Re: 85 vs 87 Octane
 

On Sun, 02 Sep 2007 22:26:01 -0500, c <c@me.org> wrote:

>I have a 350 in my S10 truck that runs on 89 octane with a true
>blueprinted 10.7 compression ratio and cast iron heads, but it also has
>a cam with quite a bit of overlap and the combustion chambers are highly
>polished. The quench distance between the top of the piston and the head
>is .038" which is the tightest recommended distance, but also the best
>for reducing detonation. I do not have to compromise my ignition timing
>with this setup. I am running 12 degrees initial timing and 24 degrees
>mechanical.

I would run more octane and a bit more spark too. I used to race SB's
years ago and 38 to 40 degress total advance is sweet spot for SB. You
want to start mech advance at about 1200 to 1500 and have it fully in
by about 3800 RPM. (1900 distributor RPM) You have a fairly nice build
but it would do more with better fuel and more timing tweaks.
-----------------
TheSnoMan.com

Re: 85 vs 87 Octane
 

SnoMan wrote:
> On Sun, 02 Sep 2007 22:26:01 -0500, c <c@me.org> wrote:
>
>> I have a 350 in my S10 truck that runs on 89 octane with a true
>> blueprinted 10.7 compression ratio and cast iron heads, but it also has
>> a cam with quite a bit of overlap and the combustion chambers are highly
>> polished. The quench distance between the top of the piston and the head
>> is .038" which is the tightest recommended distance, but also the best
>> for reducing detonation. I do not have to compromise my ignition timing
>> with this setup. I am running 12 degrees initial timing and 24 degrees
>> mechanical.
>
> I would run more octane and a bit more spark too. I used to race SB's
> years ago and 38 to 40 degress total advance is sweet spot for SB. You
> want to start mech advance at about 1200 to 1500 and have it fully in
> by about 3800 RPM. (1900 distributor RPM) You have a fairly nice build
> but it would do more with better fuel and more timing tweaks.
> -----------------
> TheSnoMan.com

Well, in my case the added timing doesn't help. I've run my truck at the
strip, and did lots of testing with it. Anything more than 36 degrees
and it slows down in the quarter mile, even with higher octane fuel.
Most of the engines I've built in the past ran best with 38 degrees, but
they were much more race oriented than this engine one is.

Chris

Re: 85 vs 87 Octane
 

SnoMan wrote:
> On Sun, 02 Sep 2007 22:26:01 -0500, c <c@me.org> wrote:
>
>> I have a 350 in my S10 truck that runs on 89 octane with a true
>> blueprinted 10.7 compression ratio and cast iron heads, but it also has
>> a cam with quite a bit of overlap and the combustion chambers are highly
>> polished. The quench distance between the top of the piston and the head
>> is .038" which is the tightest recommended distance, but also the best
>> for reducing detonation. I do not have to compromise my ignition timing
>> with this setup. I am running 12 degrees initial timing and 24 degrees
>> mechanical.
>
> I would run more octane and a bit more spark too. I used to race SB's
> years ago and 38 to 40 degress total advance is sweet spot for SB. You
> want to start mech advance at about 1200 to 1500 and have it fully in
> by about 3800 RPM. (1900 distributor RPM) You have a fairly nice build
> but it would do more with better fuel and more timing tweaks.
> -----------------
> TheSnoMan.com

Well, in my case the added timing doesn't help. I've run my truck at the
strip, and did lots of testing with it. Anything more than 36 degrees
and it slows down in the quarter mile, even with higher octane fuel.
Most of the engines I've built in the past ran best with 38 degrees, but
they were much more race oriented than this engine one is.

Chris

Re: 85 vs 87 Octane
 

SnoMan wrote:
> On Sun, 02 Sep 2007 22:26:01 -0500, c <c@me.org> wrote:
>
>> I have a 350 in my S10 truck that runs on 89 octane with a true
>> blueprinted 10.7 compression ratio and cast iron heads, but it also has
>> a cam with quite a bit of overlap and the combustion chambers are highly
>> polished. The quench distance between the top of the piston and the head
>> is .038" which is the tightest recommended distance, but also the best
>> for reducing detonation. I do not have to compromise my ignition timing
>> with this setup. I am running 12 degrees initial timing and 24 degrees
>> mechanical.
>
> I would run more octane and a bit more spark too. I used to race SB's
> years ago and 38 to 40 degress total advance is sweet spot for SB. You
> want to start mech advance at about 1200 to 1500 and have it fully in
> by about 3800 RPM. (1900 distributor RPM) You have a fairly nice build
> but it would do more with better fuel and more timing tweaks.
> -----------------
> TheSnoMan.com

Well, in my case the added timing doesn't help. I've run my truck at the
strip, and did lots of testing with it. Anything more than 36 degrees
and it slows down in the quarter mile, even with higher octane fuel.
Most of the engines I've built in the past ran best with 38 degrees, but
they were much more race oriented than this engine one is.

Chris