1998 Grand 8 cyl 5.9
 

A few days ago I bought a '98 Grand Cherokee with 8Cyl 5.9 and now I
see that it might be necessary to use premium gas. Bad news but is it
true?

Re: 1998 Grand 8 cyl 5.9
 

Ed wrote:
> A few days ago I bought a '98 Grand Cherokee with 8Cyl 5.9 and now I
> see that it might be necessary to use premium gas. Bad news but is it
> true?

It's true. The 5.9 needs higher octane but only if your getting ping.

Run it on the mid octane and if you get any pinging then add the higher
octane till it goes away.

Works like this.

1/2 gal of 87
+ 1/2 gal of 91
--------------- is
1 gal of 88

octane works in direct proportion.

p.s. gasoline is gasoline, there is no "premium" just additives
and octane booster that contrary to what some say actually lowers
the combustibilty of the fuel.

I run (on average) 92 octane. Which I get by pumping in alternating
fillups of 93 and 91 octane fuel.


--
-- DougW -- 93 ZJ 4.0 http://revbeergoggles.com
HESCO Supercharger - 300W IASCA Stereo - Edelbrock IAS Shocks
Gibson Exhaust - rear DCpower - custom gauge install - Stillen Rotors
Banks Header - and BEER, in the fridge!

Re: 1998 Grand 8 cyl 5.9
 

Ed wrote:
> A few days ago I bought a '98 Grand Cherokee with 8Cyl 5.9 and now I
> see that it might be necessary to use premium gas. Bad news but is it
> true?

It's true. The 5.9 needs higher octane but only if your getting ping.

Run it on the mid octane and if you get any pinging then add the higher
octane till it goes away.

Works like this.

1/2 gal of 87
+ 1/2 gal of 91
--------------- is
1 gal of 88

octane works in direct proportion.

p.s. gasoline is gasoline, there is no "premium" just additives
and octane booster that contrary to what some say actually lowers
the combustibilty of the fuel.

I run (on average) 92 octane. Which I get by pumping in alternating
fillups of 93 and 91 octane fuel.


--
-- DougW -- 93 ZJ 4.0 http://revbeergoggles.com
HESCO Supercharger - 300W IASCA Stereo - Edelbrock IAS Shocks
Gibson Exhaust - rear DCpower - custom gauge install - Stillen Rotors
Banks Header - and BEER, in the fridge!

Re: 1998 Grand 8 cyl 5.9
 

Ed wrote:
> A few days ago I bought a '98 Grand Cherokee with 8Cyl 5.9 and now I
> see that it might be necessary to use premium gas. Bad news but is it
> true?

It's true. The 5.9 needs higher octane but only if your getting ping.

Run it on the mid octane and if you get any pinging then add the higher
octane till it goes away.

Works like this.

1/2 gal of 87
+ 1/2 gal of 91
--------------- is
1 gal of 88

octane works in direct proportion.

p.s. gasoline is gasoline, there is no "premium" just additives
and octane booster that contrary to what some say actually lowers
the combustibilty of the fuel.

I run (on average) 92 octane. Which I get by pumping in alternating
fillups of 93 and 91 octane fuel.


--
-- DougW -- 93 ZJ 4.0 http://revbeergoggles.com
HESCO Supercharger - 300W IASCA Stereo - Edelbrock IAS Shocks
Gibson Exhaust - rear DCpower - custom gauge install - Stillen Rotors
Banks Header - and BEER, in the fridge!

Re: 1998 Grand 8 cyl 5.9
 

I do a gas mileage and performance test.

I run a tank of regular and see what happens. In my CJ7's case the
sucker won't go over 65 mph, rattles like crap and only gets 250 miles
per 76 liter tank on regular. When I switch to premium, 3rd gear will
do 70+ mph, 4th buries the speedo and I don't have any urge to see what
5th will do. I then get 350 miles easy to a tank full. (I am comparing
tankfulls on long trips here, we put 3000 miles on the CJ7 this summer
on one trip)

With my Cherokee, it makes absolutely no difference at all.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

Ed wrote:
>
> A few days ago I bought a '98 Grand Cherokee with 8Cyl 5.9 and now I
> see that it might be necessary to use premium gas. Bad news but is it
> true?

Re: 1998 Grand 8 cyl 5.9
 

I do a gas mileage and performance test.

I run a tank of regular and see what happens. In my CJ7's case the
sucker won't go over 65 mph, rattles like crap and only gets 250 miles
per 76 liter tank on regular. When I switch to premium, 3rd gear will
do 70+ mph, 4th buries the speedo and I don't have any urge to see what
5th will do. I then get 350 miles easy to a tank full. (I am comparing
tankfulls on long trips here, we put 3000 miles on the CJ7 this summer
on one trip)

With my Cherokee, it makes absolutely no difference at all.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

Ed wrote:
>
> A few days ago I bought a '98 Grand Cherokee with 8Cyl 5.9 and now I
> see that it might be necessary to use premium gas. Bad news but is it
> true?

Re: 1998 Grand 8 cyl 5.9
 

I do a gas mileage and performance test.

I run a tank of regular and see what happens. In my CJ7's case the
sucker won't go over 65 mph, rattles like crap and only gets 250 miles
per 76 liter tank on regular. When I switch to premium, 3rd gear will
do 70+ mph, 4th buries the speedo and I don't have any urge to see what
5th will do. I then get 350 miles easy to a tank full. (I am comparing
tankfulls on long trips here, we put 3000 miles on the CJ7 this summer
on one trip)

With my Cherokee, it makes absolutely no difference at all.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

Ed wrote:
>
> A few days ago I bought a '98 Grand Cherokee with 8Cyl 5.9 and now I
> see that it might be necessary to use premium gas. Bad news but is it
> true?

Re: 1998 Grand 8 cyl 5.9
 

DougW wrote:
> Ed wrote:
>> A few days ago I bought a '98 Grand Cherokee with 8Cyl 5.9 and now I
>> see that it might be necessary to use premium gas. Bad news but is it
>> true?
>
> It's true. The 5.9 needs higher octane but only if your getting ping.
>
> Run it on the mid octane and if you get any pinging then add the
> higher octane till it goes away.
>
> Works like this.
>
> 1/2 gal of 87
> + 1/2 gal of 91
> --------------- is
> 1 gal of 88
^^---89
That is IF I actually could do math in my head. :/

--
Doug(mind like a steel trap. rusted shut)W

Re: 1998 Grand 8 cyl 5.9
 

DougW wrote:
> Ed wrote:
>> A few days ago I bought a '98 Grand Cherokee with 8Cyl 5.9 and now I
>> see that it might be necessary to use premium gas. Bad news but is it
>> true?
>
> It's true. The 5.9 needs higher octane but only if your getting ping.
>
> Run it on the mid octane and if you get any pinging then add the
> higher octane till it goes away.
>
> Works like this.
>
> 1/2 gal of 87
> + 1/2 gal of 91
> --------------- is
> 1 gal of 88
^^---89
That is IF I actually could do math in my head. :/

--
Doug(mind like a steel trap. rusted shut)W

Re: 1998 Grand 8 cyl 5.9
 

DougW wrote:
> Ed wrote:
>> A few days ago I bought a '98 Grand Cherokee with 8Cyl 5.9 and now I
>> see that it might be necessary to use premium gas. Bad news but is it
>> true?
>
> It's true. The 5.9 needs higher octane but only if your getting ping.
>
> Run it on the mid octane and if you get any pinging then add the
> higher octane till it goes away.
>
> Works like this.
>
> 1/2 gal of 87
> + 1/2 gal of 91
> --------------- is
> 1 gal of 88
^^---89
That is IF I actually could do math in my head. :/

--
Doug(mind like a steel trap. rusted shut)W