Should I run 87 or 89 fuel in my 2017 Silverado 1500 5.3L?

[Bikemobile]

I run 85 here in Colorado at 7000 feet. Same as 87. Runs great.

[Nanotech Environmental]

I've always run 87 in everything, including my 06 1500 w/5.3 and my new 17. No issues. In Ontario, 89 is often as much as 10 cents a liter more than 87. I see no reason to pay that much more for no real tangible benefit.

 

Also, in most areas the 'off brand' gas is the same gas as the local mainline brands. It's bought from the same refineries and delivered by the same trucks. Almost all fuel refining is done by a very small number of companies, Valero being one of the bigger ones in that sector.

[Sean Neilan]

I ran 87 for the first year I had the truck with no issues. Then I took a summer road trip of 700 miles each way in the summer. Heard a something like a chattering noise while on the highway. Filled up with 91 for the return trip figuring it might be knock caused by pre-det cause of the heat (just an uneducated guess) and the chattering went away. I've been using 91/93 ever since. No difference in mpg but it feels like it runs smoother now but that can just be placebo effect. Whatever, another couple bucks a tank is worth piece of mind to me.

[JTodo]

No appreciable differences running either one. Just do 87

[Ozer]

I tried 91 non-ethanol in my truck, 2 tanks back to back then i went back to 87 E10 (normal gas with 10% ethanol) and ran that for 2 tanks back to back.

I got better mileage with the 87, call me crazy but 91 saw drop in mpg. It was the same route, same driving style and temperature wasnt really drastically different.

Im sticking with 87 top tier.

 

Turning off the grade braking helps, on a 1,5hr mostly highway some hilly road over the weekend i got to 23.7mpg with grade braking off ans same route before i knew about the grade braking i was getting 22 max.

Grade braking off - Hold the tow button down for 6-8 seconds and it will be off. Goes on after you shut it off, need to turn off each time you start the truck.

I tried 91 non-ethanol in my truck, 2 tanks back to back then i went back to 87 E10 (normal gas with 10% ethanol) and ran that for 2 tanks back to back.

I got better mileage with the 87, call me crazy but 91 saw drop in mpg. It was the same route, same driving style and temperature wasnt really drastically different.

Im sticking with 87 top tier.

 

Turning off the grade braking helps, on a 1,5hr mostly highway some hilly road over the weekend i got to 23.7mpg with grade braking off ans same route before i knew about the grade braking i was getting 22 max.

Grade braking off - Hold the tow button down for 6-8 seconds and it will be off. Goes on after you shut it off, need to turn off each time you start the truck.

[flms_pat]

i run 91 religiously in all our vehicles. The way I see it is the vehicle with the largest gas tank i own is 27 gallons and 27 x .20 is 5.40 roughly so i spend an extra 5 dollars at the pump no biggie for the long term piece of mind

[Ozer]

Yeah at 20 cents its no brainer but where i am there is a 40 cent (currently) difference between 87 and 91 so $10.80 more per tank would be felt in the wallet, especially if you fill up weekly.

I guess its best to try it in your area and see what happens, like i tried. Im getting good mpg with 87, others may not.

[NorCalSLT]

I just did tuning through BBP, the first thing they told me was to start running 89 octane rather than 87.

Yes 87 is specified in manual, but it does cause the engine to knock/ping.

Confirmed it using data logging on my tuner.

 

All 5.3 with or without tunes should run 89 was their advice.

Keep in mind that this information is based on actual data, not someone's impression that it does or does not provide a benefit.

[Donstar]

I just put in 75 litres at my local Shell station. 89 cost 10 cents more per litre than 87. $7.50 difference once every week or two is not impacting my quality of life. If my gas costs were creating issues for me, I would reduce usage, not octane!

[Silverado Steve]

Jeez, here 91 is about 70 cents more per gallon, so thats $14+ a week. I used to run 87 with no issues but now do 89 for 20 cents more per gallon. I found the throttle is a wee bit more responsive.

[fbachman]

Modern knock sensors are sensitive enough that incipient knock is detectable.

 

When your engine is operating under conditions where knock can/is occurring, the control retards timing to avoid/minimize knock.

 

The default calibration GENERALLY is good enough to avoid knock without intervention due to detected knock. Nothing, however, is fool proof, and, engines operate under a wide extreme of conditions (Temp/Pressure/Humidity/Load/RPM, etc.). If knock is detected, generally not much happens other than timing being pulled now-a-days, and, the results are transparent to all but the most seasoned.

 

Thus, running 87 causes no adverse effects. When, however, timing is pulled due to (incipient) knock, then, yes, power decreases due to the retarding of timing, all other things being equal.

 

That being said, if your truck is set-up for 87, then, running 87 is no issue. If, however, one chooses to run 91, instead, than you are providing the engine a little "insurance" relative to knock that timing won't be pulled as soon/quickly, as you are running a fuel with more pre-detonation resistance (high Octane rating).

 

These are the unemotional facts. That being said, how much difference does that make? Depends on how you are operating your truck, under what conditions, and ambient conditions. For 99% of us, it probably would not be noticeable, one way or another. Running 91 in an 87 engine just gives a little "head-room" against knock retard on timing.

 

I, personally, run 91, especially in the hot summer months. Does it REALLY matter? Probably not. I just prefer it that way.

[NWI Denali]

I recall seeing a tuner saying they logged significant knock and retarded timing running 87 in the 5.3's. The L83 5.3 is 11:1 compression ratio after all. I personally would probably run 89 for peace of mind for only a couple extra bucks a tank.

[Cowpie]

I would suspect that. Not as a bad thing, but a normal occurrence. The ECM is constantly adjusting the calibration. It will advance the timing till it hits a knock situation, then back off. Wash, rinse, repeat. If someone has premium in the tank, it will reduce these knock events, as the ECM will not advance enough to hit a knock event as often. As opposed to 87 being a bad thing, one is just experiencing normal ECM generated events. Of course, a bad load of fuel will accentuate this to where it actually is a problem.

[fbachman]

I recall seeing a tuner saying they logged significant knock and retarded timing running 87 in the 5.3's. The L83 5.3 is 11:1 compression ratio after all. I personally would probably run 89 for peace of mind for only a couple extra bucks a tank.

 

You reminded me of something I failed to mention. Not all fuels are created equal. I remember back in my tuning days, Shell caused unbelievable knock retard vs. other fuels. I wouldn't run Shell in a rented lawn mower.

 

Around here, the good fuels were BP/Amoco, Exxon, Marathon when it comes to knock performance. Not sure what the deal is/was with Shell, but it caused all kinds of pointing and scratching when looking at logs---other brands, however, showed no such behavior.

 

Dunno...

 

[SilveradoSaver]

I used to run 87 when I first bought the truck, now I only run 89. I think it's a mental thing, but it feels like it runs better but I am probably imagining things. I don't think I'd put 91 in it; don't see a need for it.