87 octane vs 89

Anyone here running or has ran 89 octane fuel? I was wondering if its good or bad for 3.5L

 

Neither. 87 is fine, buttdyno results demand that 89 is better. But neither is damaging the motor.

 

87 is fine, if you want to give your truck a "treat", get some non-gasohol from WaWa.

Usually the same price as premium.

 

Using a higher octane than the manufacturer specifies won't benefit you regarding power or efficiency. The higher octane gasolines do tend to have better detergent packages but that's not something I would bother with for the most part.

 

I'd best surprised if 89 ever made any noticeable changes except for cost at the pump.

I used to think it was its own sump and that it was old fuel so I never used it. Learned way later on that its a mix of 87 and 89 blended together. It just makes no sense. I think only the 300 hemi required it.

 

many pre-1990 stations had a separate tank for mid grade/89. but due to regulations, costs, and the limited profitability of a dedicated tank, most places capped it off to run a combo-87/91 blend, though some paid to clean it up and turn it into a diesel tank instead. i used to do the electrical work for a company that serviced the tank and pump system, as well as changed out the dispenser stands...

 

This may vary depending on where you live, but here there is a dedicated tank for 89 octane. The refineries don't make 89 octane. Tankers haul 87 and 91 octane. They mix the 2 when the fuel is delivered to the stations but there is no guarantee you are actually getting a 50/50 mix of 87 and 91 octane. There is very little demand for 89 octane. When the trucks are near empty, they just dump whatever is left in the truck into the 89 octane tank at the station.

A 3rd gen will run fine on either. I doubt there is enough difference between 87 and 89 octane to matter. You MIGHT see a slight improvement in power with 91 octane. Probably only noticeable when towing or loaded heavy. You won't see any difference in fuel mileage and whether or not the small improvement in power is worth it to you is a judgement call.

One more thing. You won't see any difference with a single tank. It will be your 3rd fill-up with 91 octane before you actually have 100% 91 octane fuel in your tank, and it takes time for the computer to adjust to the different fuel.

 

I have always ran at least 91 octane in my truck after dealers fill. Flashed my ECU with a premium tune about 4 years ago.
Currently running 94 Chevron.

Truck always drove amazing, stock or tuned. With a tune its a lot more fun to drive.

From my experience, all japanese makes that I had ran better and got better fuel economy with 91+

 

owners manual says 87, so 87 it is