I have been useing 93 High octane in my XJ. Do I really need it or am I wasting money???

 

You're wasting your dough.

 

I put 91 in when i get paid and i usely only put in 87 and i cant tell a difference i guess in my mind it cleans my engine alittle bit

 

yeah only need low grade

 

From factory it came with 87 and says in owners manual to run 87... now if you want to spend the money on something more then it's up to you. From what i have seen if it's meant to run on a specific octane then you don't need to use anything else, well... it helps to run higher octane a little when towing.

 

agree w/ the other members. 87 is definitely good enough!

 

x2. Race fuel should be used for a few extra ponies. just playing.

 

Agreed with everyone else. I have heard anything above 87 just burns hotter or something to that effect; good for cleaning the gunk in the cylinder but not mpg gain.. I actually get WORSE mileage when I use anything over 87

 

I notice when I use 91, I get about 2mpg better that with 87 or 85.

 

In my experiences, running 91 and 97 octane fuel through my Jeep just made it backfire a lot and made some pretty cool flames but didn't increase power or fuel economy enough for me to be able to tell. I primarily run 87 or 89 octane, depending on the gas station. Where you get your gas will however effect power and fuel economy greatly. I used to run Hess gas all day every day because the station was right down the road from my house and cheap but I ran through it like water. One day I needed gas and the only gas station around was a shell charging outrageous prices for their gas. I bit the bullet and bought their gas to be utterly amazed at the 2-3mpg increase. I now run Shell gas, and only Shell gas through my Jeep. Tried Sunoco once and the Jeep hated it; idle surged, spit fire, didn't want to start... Never making that mistake again.

 

I've got lots of ExxonMobil stock......if you are NOT using 101+ octane AV gas, you'll ruin your XJ.LOL

 

I think avgas is leaded so you prolly dont want to run that.

 

you can get 100 low lead but still does have lead in it. all the lead does is mess up your cat so all you none cat running guys are fine to use av gas.


the higher grade gas only helps mileage on the renix era jeeps, from what my readings have said. something about hte renix era engines knock sensors or some sensor keeps the engine at just under the leanest usable mixture to keep it from knocking and the newer dodge ecu just runs from a map that the tps and map sensor give the inputs for.

 

cheapest

usually 87, but i have encountered 85 octane and it runs no different

 

I run 91 just because here the premium does not contain ethanol.. Me no likey ethanol..