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Sorry to hear you have to use 93 octane in your truck, my 17 does just fine on 87..
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It does matter. 2019 5.0. Runs smoother with either E85 (which is ~100 octane), or 91. Running 87 is fine, but you can hear/feel it more under acceleration (when port injection opens up).

So, I compute actual cents per mile (divide $/gallon by actual miles per gallon) and switch between E85 and 91 depending on how the fuel prices fluctuate.

 

I've run 87 in my 18 since I got it; never had it ping once, runs like the 60's muscle cars.

 

I only run 93 in my 2018 5.0. The exception is when I had to run 91 on a couple trips out West.

 

I wish I could get 93 we are stuck for the most part on 91 unless I drive considerably further. I think some people don't quite get the concept of a knock sensor and the car re-tuning on the fly to compensate for lower octane gas (reducing performance). It really isn't that difficult to understand. It reminds me of people that stop 3 car lengths back from a light and make everyone wait a full cycle because they live under a rock and don't realize most lights have car sensors that effect the light cycle.

 

I was driving 34 miles to another state to get E85. I like it a lot and just filled up for the fifth time. I will get regular gas locally now because the price last time was $4.09/gal 93 was $4.19. thanks brandon.

 

I just watched last night an episode of 'Engine Masters' where they took an LS3 engine and ran it on 87, 91, 106, 116, and E85 fuel. Did several dyno pulls and the results were stunning...essentially the timing stayed at 29 degrees and the hp and torque results were within like 1 or 2 hp and lb/ft of torque on ALL the gasolines...it simply made NO DIFFERENCE AT ALL. E85 saw about a 10 hp and torque gain, which makes sense as it has more oxygen in it. I encourage everyone to find that episode and watch it...it really opened up my eyes.

 

It's the fuel injection (direct injection) timing that matters.

 

The point was...there was simply no difference in power between all the gasolines.

 

That's b/c its an LS3, timing, and lower compression, go dyno the 6.2 (L9H) which is higher compression at 11:5 in the trucks on 87 vs 93, big difference, even moreso on 18+ Coyotes which gains huge on 93 stock and even more E85. On the 2nd Gen Coyote, that would be like the LS3 block, essentially 0 difference (untuned). LS3s pretty much gain nothing even tuned over 93 w/ E85, without further mods it can't take full advantage. Vs 18+ Coyote which is an animal tuned on E85 for a n/a block. Beastmode, except mileage sucks ballz on E85 even stock, same for flex fuel GMs..... Oh if we could only get 93 mileage with E85 performance lol

I've been well involved on both platforms, cars or trucks. 18+ Coyotes are in another league from any other n/a block made today, not even my Viper gained tuned like the 18+ Coyote does Stang or F150.
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