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Stock 350 and gas options, couple questions

FuzzyGuy

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New here, new to me GT350 but have questions pertaining to the best gas option as well as the best gas conditioner/octane booster. I recently had a conversation with a pretty knowledgeable guy on some things about my stock 350 and some options. He recommended I post up the questions here. So here we are.

I live in an area where I have fortunately numerous gasoline options. Everything from E85 to real gas 93 octane and everything in-between. Because of the high compression of the voodoo and some of its volatility with inconsistent gasoline I wanna be able to consistently add a better gasoline treatment or octane booster. However, my knowledge is not the best when it comes to this so I'm reaching out for a little help and advice. What is the best gasoline to put in a stock voodoo? Also, what are some of the best gasoline treatment and or octane boosters out there that would keep things consistent so I don't unintentionally detonate the voodoo?
Thanks in advance for you time to reply. I appreciate it.

*Because I have significant warranty left I don't want to take the risk of switching over to E85.
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460Fred

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As far as I can tell, 91+ will get you exactly what you need with the stock set up. Just use top-tier gas in you’ll be fine.
 

Bluelightning

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Gas from a top tier station such as Shell, Valero, Chevron, etc. 93 is preferable, but 91 will work. Naturally aspirated there really isn't a need for an octane booster. If you decide that you just want to run one, Boostane professional is great.
 

GT4EVR

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It's wise to not do or use anything that would jeopardize your warranty. Since 93 octane is available to you, I would simply use that, from a well-established brand, such as Shell, Gulf, Mobil, etc. as noted previously. It's what I use and do, and never had a problem after nearly 8,100 miles.

I would caution about the use of gasoline additives/treatments. If I remember correctly, I believe the owner's manual recommends against using them. Check to be certain and preclude any warranty concerns you rightly have.

Welcome to the forum; much good info contained herein, especially in the "sticky" thread section. Congratulations on your purchase, and hoping many good times are ahead for you in your Shelby.
 
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FuzzyGuy

FuzzyGuy

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I appreciate the advice so far. I should clarify that I'm not necessarily interested in an octane boost as I am making should the gas is consistent in quality.
 

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AZRobert

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Check your owners manual - It says what was stated above. Just use top tier 91+ octane fuel.
It also states to stay away from certain additives and honestly, if you use "good quality" fuel additives are not necessary.
 

glockholiday

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You only need 91 so use 93 and you'll always be in the green. When you say you want the gas "consistent in quality" do you mean octane? If so even if a stations 93 is 92 or 91 you're still fine. If by quality you mean additive package or top tier rated, if a station is not, there is no bottle to add that will fix it.

I think you're overthinking it. Use 93, top tier brands preferably and you're done.

Just because, you can also run 87 and be fine as long as you don't drive it hard.
 

TommyBoyDIY

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I was told that the GT350 computer will adjust to the octane accordingly. I have 93 and even 100 octane at my local gas station. So lately I've been running a 50/50 mix of the two and letting the car enjoy the higher octane.
 

Postal Bob

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I was told that the GT350 computer will adjust to the octane accordingly. I have 93 and even 100 octane at my local gas station. So lately I've been running a 50/50 mix of the two and letting the car enjoy the higher octane.
Do you notice a significant power boost with 100 octane?
 

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460Fred

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Do you notice a significant power boost with 96.5 octane?
Fixed that for you.

I’m thinking you won’t find much of a difference. These cars are tuned to run on 91-93 from the factory.
Unless I missed something….
 

tdstuart

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Run 93 and call it a day. If you start modifying the car then you can worry about using ethanol or higher octane gas to squeeze out more power.

Your car has knock sensors that will adjust if the gas is lower octane for some reason. Ford designed the car for use with 91 as well so running 93 should even give you a little room for error.

When the car is stock, no reason to stress. When you start tuning the car you have less room for error and you need to make sure you have good-quality gas.

I have a 2015 mustang gt with a gen3 short block and modified gen 2 heads so I am running slightly higher compression than your car. No direct injection, just port injection like you. Car is making more power than you on 91 and no knock. I wouldn't stress about it personally, especially with access to 93.
 

loco_GT350

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I have run my 2017 GT350 with 91, 94(my own blend) and 100 octane and I can tell you the car definitely feels stronger as the octane increases. It has been awhile since I did a full tank of just 100 octane but I typically run a blend of 91 and 100 that works out to 94 octane and the car definitely feels more responsive, quicker, angrier, not really sure how to explain it on 94 then on 91. Maybe I can say it this way, it feels down on power when I run straight 91 over my 94 blend. Also the car does not seem to pop and burble as much when Im running 91 as when I run 94.

It is my understanding that the car will continue to advance the timing until the knock sensor says to stop so increasing the octane will help up to a point and I can say this appears to be true with my experience of using different octane levels.
 

Racinjason65

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15B55783-2DE9-4ED9-85A2-550AC5D3F480.png

I had a tank of poor guality fuel and the car was pulling a ton of timing, added enough VP octanium to not get any knock and you can see the difference. Stock car, no changes other than fuel octane and at 435 with no retard this is by no means a generous dyno.
 

Damonfl

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This is what I do. Top tier brands only. I run the same brand for a few thousands miles then switch to another brand for a few thousand miles. Repeat. There’s a fellow on the Internet who came up with that system. The logic is that each brand has its own formula. By consistently running the same formula less build up. The next brand will eventually reduce any buildup from the previous brand. I did that with a jetta 1.8T. Never needed a tuneup to 90k miles.
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