Re: What kind of gas?
 

samos@sympatico.ca wrote:

>
> I have a new Wrangler/TJ Sport ... 6 cylinders, automatic transmission
> .... what type of gas should I be buying ... regular? medium?

You should be using the minimum recommended by the owner's manual, which is
87 octane and nothing more. Any higher octane is a waste of money unless
you're getting detonation and higher octane cures it.

Re: What kind of gas?
 

I disagree. I say use High grade all the time. I have to anyway on my
Wrangler, cause the mechanic who put the new carb on said the manual required
it.

My Firebird has a sticker on the filler door that says High Grade is
recomended. See Manual for details. So I checked. It said you can safely use
87 but will encounted lower performance, pinging, and hesitation expecially at
lower sea levels.

My mechanic said you should always use 93, in almost every vehicle. He's got a
2002 Grand Cherokee Limited, and a 1990 Cherokee.

We use our vehicles for beach driving. We go from here, 200 ft above sea level
to right down to sea level. Sometimes you have to pour 106+ octane booster in
carbed Jeeps just to get them to run without hesitation. Then when you get
back to higher levels, it runs with lots more power with the octane booster in
it.

Re: What kind of gas?
 

I disagree. I say use High grade all the time. I have to anyway on my
Wrangler, cause the mechanic who put the new carb on said the manual required
it.

My Firebird has a sticker on the filler door that says High Grade is
recomended. See Manual for details. So I checked. It said you can safely use
87 but will encounted lower performance, pinging, and hesitation expecially at
lower sea levels.

My mechanic said you should always use 93, in almost every vehicle. He's got a
2002 Grand Cherokee Limited, and a 1990 Cherokee.

We use our vehicles for beach driving. We go from here, 200 ft above sea level
to right down to sea level. Sometimes you have to pour 106+ octane booster in
carbed Jeeps just to get them to run without hesitation. Then when you get
back to higher levels, it runs with lots more power with the octane booster in
it.

Re: What kind of gas?
 

Mark12211 wrote:

> I disagree. I say use High grade all the time. I have to anyway on my
> Wrangler, cause the mechanic who put the new carb on said the manual
> required it.

....

> My mechanic said you should always use 93, in almost every vehicle. He's
> got a 2002 Grand Cherokee Limited, and a 1990 Cherokee.

Your mechanic is dead wrong. Octane is used to prevent detonation, not add
performance as many believe. It can add performance only if a lower octane
is robbing the engine performance. The only thing you can do to get better
performance by using higher octane (other than adding more compression) is
to advance the initial timing. The higher octane will prevent detonation at
more agressive timing settings and often a bump your timing will make it
run better and have more power, but going too far makes it more difficult
to start. Staying with the standard timing settings, and not increasing
your compression only requires the minimum octane required. Anything more
is just throwing money away.

Now, I've heard, though not experienced, people having detonation while
towing vehicles and more octane will certainly help for that.

Re: What kind of gas?
 

Mark12211 wrote:

> I disagree. I say use High grade all the time. I have to anyway on my
> Wrangler, cause the mechanic who put the new carb on said the manual
> required it.

....

> My mechanic said you should always use 93, in almost every vehicle. He's
> got a 2002 Grand Cherokee Limited, and a 1990 Cherokee.

Your mechanic is dead wrong. Octane is used to prevent detonation, not add
performance as many believe. It can add performance only if a lower octane
is robbing the engine performance. The only thing you can do to get better
performance by using higher octane (other than adding more compression) is
to advance the initial timing. The higher octane will prevent detonation at
more agressive timing settings and often a bump your timing will make it
run better and have more power, but going too far makes it more difficult
to start. Staying with the standard timing settings, and not increasing
your compression only requires the minimum octane required. Anything more
is just throwing money away.

Now, I've heard, though not experienced, people having detonation while
towing vehicles and more octane will certainly help for that.

Re: What kind of gas?
 

"Mark12211" <mark12211@aol.com> wrote in message
news:20030906105647.22670.00000391@mb-m23.aol.com...
> I disagree. I say use High grade all the time. I have to anyway on my
> Wrangler, cause the mechanic who put the new carb on said the manual
required
> it.

Octane is not determined by carburation, but by compression ratio. Most
newer vehicles are designed to run on 87. Higher octanes can cause carbon
build-up in low compression engines.
__
Steve
..

Re: What kind of gas?
 

"Mark12211" <mark12211@aol.com> wrote in message
news:20030906105647.22670.00000391@mb-m23.aol.com...
> I disagree. I say use High grade all the time. I have to anyway on my
> Wrangler, cause the mechanic who put the new carb on said the manual
required
> it.

Octane is not determined by carburation, but by compression ratio. Most
newer vehicles are designed to run on 87. Higher octanes can cause carbon
build-up in low compression engines.
__
Steve
..

Re: What kind of gas?
 

But that carbon build-up would just cause more pinging and/or knocking since
it glows after combustion and will prematurely ignite the air-fuel mixture
during the next compression stroke.

Jerry
--
Jerry Bransford
To email, remove 'me' from my email address
KC6TAY, PP-ASEL
See the Geezer Jeep at
http://members.cox.net/jerrypb/

"A.H. MacIntosh aka USERNAME" <chesshire_cat@nospam.net> wrote in message
news:82o6b.6519$cQ1.1856858@kent.svc.tds.net...
> Now there is a new way to raise compression. Get enough carbon encrusting
> the combustion chamber to bump it up a point or two. It's hell on the flow
> pattern though.
>
> "Steve Cowell" <scowell@sbcglobal.net> wrote in message
> news:ntn6b.1812$LB5.276@newssvr24.news.prodigy.com ...
> >
> > "Mark12211" <mark12211@aol.com> wrote in message
> > news:20030906105647.22670.00000391@mb-m23.aol.com...
> > > I disagree. I say use High grade all the time. I have to anyway on
my
> > > Wrangler, cause the mechanic who put the new carb on said the manual
> > required
> > > it.
> >
> > Octane is not determined by carburation, but by compression ratio. Most
> > newer vehicles are designed to run on 87. Higher octanes can cause
carbon
> > build-up in low compression engines.
> > __
> > Steve
> > .
> >
> >
>
>

Re: What kind of gas?
 

But that carbon build-up would just cause more pinging and/or knocking since
it glows after combustion and will prematurely ignite the air-fuel mixture
during the next compression stroke.

Jerry
--
Jerry Bransford
To email, remove 'me' from my email address
KC6TAY, PP-ASEL
See the Geezer Jeep at
http://members.cox.net/jerrypb/

"A.H. MacIntosh aka USERNAME" <chesshire_cat@nospam.net> wrote in message
news:82o6b.6519$cQ1.1856858@kent.svc.tds.net...
> Now there is a new way to raise compression. Get enough carbon encrusting
> the combustion chamber to bump it up a point or two. It's hell on the flow
> pattern though.
>
> "Steve Cowell" <scowell@sbcglobal.net> wrote in message
> news:ntn6b.1812$LB5.276@newssvr24.news.prodigy.com ...
> >
> > "Mark12211" <mark12211@aol.com> wrote in message
> > news:20030906105647.22670.00000391@mb-m23.aol.com...
> > > I disagree. I say use High grade all the time. I have to anyway on
my
> > > Wrangler, cause the mechanic who put the new carb on said the manual
> > required
> > > it.
> >
> > Octane is not determined by carburation, but by compression ratio. Most
> > newer vehicles are designed to run on 87. Higher octanes can cause
carbon
> > build-up in low compression engines.
> > __
> > Steve
> > .
> >
> >
>
>

Re: What kind of gas?
 

"Mike Romain" <romainm@sympatico.ca> wrote in message
news:3F59FD95.B051EBAE@sympatico.ca...
> Your mechanic has been ripping you off then or has no clue how to set up
> a carb engine....

thanks for beating me to it......you put it a whole lot nicer than i was
going to! :-)


--
Nathan W. Collier
http://7SlotGrille.com