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Discussion Starter #1
Since the 5.0 can run on regular or premium gas, what are you all using? Let me guess - 9 out of 10 use premium.
 

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94 octane at the one place but when its closed i run the 93 oct
 

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I will use premium, but if Wannapony (who started this thread) does not mind, could I also ask what folks think about octane additives?
 

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as far as the additives they dont actually raise your octane 1 point or 5 points they only add .1 or .5 points just depending on which octane booster you run. I dont have a new 2011 mustang but i have a 93 gt and i only run 91 octane in it but soon ill have to look around for places with 93 octane around here
 

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I "hope" to use 91 someday! Probably try some lower just to see how it performs (SOTP & MPG) for comparison.
 

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Best stick with premium

You could try some 87 octane but with the automatic (that's what I have), I noticed a slight hesitation and power loss at low rpm. Like right off idle and at around 30-35 mph when it is lugging along at 1000 rpm. The intake drone inducer would cackle a bit as the throttle is pressed- slight hesitation and then it would accelerate. The outside temps were pretty high around 95-100 degrees.
Premium 93 cured these symptoms in less than 25 miles. My car was filled with 87 from the dealer new. I have only run premium since.
Guess maybe the timing and cams retard under these conditions with the 87. Car runs great with 93!!
 

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93. because sunoco no longer offers 94
 

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I had a 2010, and I noticed no difference on the butt dyno when going from 87 to 93 octane.

However, with the 2011, I noticed a significant difference -- well worth the price to put 93 octane in there.
 

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Well I just filled up for the 2nd time at 87. I am going to test this again for the second week. Gas mileage is still up in the air since I have been hot roddin it a little and then taking it to shows and everywhere i go and then driving to work. i am doing my last 87 round this week. then i am switching to the premium grade. we will see if there ia a difference that i notice.
 

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It is much better to run 93 because it keeps your engine much cleaner inside and also it makes my 5/0 run like a swiss watch.
Higher octane does not keep an engine cleaner... it just burns at a higher temperature.

Let's be careful throwing this stuff out there/:laughlitt
 

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In Arizona Premium is 91 at all stations I wonder what people do in that situation?
 

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I had a 2010, and I noticed no difference on the butt dyno when going from 87 to 93 octane.

However, with the 2011, I noticed a significant difference -- well worth the price to put 93 octane in there.
On the 10 the 91 octane gives you an extra bit of tq to 335ft/lbs and no official horsepower rating (although one can assume if it bumps the tq up by 10 pts then the HP should be around 325 on 91). There is no performance increase going to 93oct.

On the 11 you only get 377ft/lbs tq and 402hp on 87 so its a SIGNIFICANT loss of performance from the 390ft'lbs and 412hp they rate it for 91 (again i dont think they rate for 93 as its not even legal in california??).

Both models have dual knock sensors and will adjust for cheaper gas to prevent knocking. Both run better on premium but the 11 runs MUCH better on premium.

Temperature has nothing to do with it. Neither does clieanliness. Its more complicated than that. Basically though...it has to do with the more aggressive engine timings and the higher octanes ability to not mis-fire knock at the more aggressive timings/compression speeds. Burns "faster" might be a more appropriate analogy.

According the super tuner Chris.....a 93 octane tune on a 10 would push the hp closer to 340 and a 93 only octane on an 11 would be good for something like 430+ But if you get the tune and run 87 your kinda screwed as your engine will be knocking like crazy which can be damaging.
 

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Does anyone run 87 consistently? I will eventually run 91 but with my current drive 87 is sometimes a better choice.

Even though Ford claims you can run 87, does anyone believe it may cause engine damage?

By the way I'm purchasing a 2011 5.0 MT with 3.73
 

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Does anyone run 87 consistently? I will eventually run 91 but with my current drive 87 is sometimes a better choice.

Even though Ford claims you can run 87, does anyone believe it may cause engine damage?

By the way I'm purchasing a 2011 5.0 MT with 3.73
It wont cause any engine damage if you are running the stock tune. The stock tune is designed to run 87octaine, its just that you are not getting the "advertised" tq and HP numbers if you run the 87.

Some say the improved gas mileadge offsets the cost of the premium but thats anectedotal and i havent seen scientific proof. Its possible if you are just cruisin down the freeway and dont plan on putting your foot in it that you can save a few bucks and run 87 but come one....its a 5.0, you are going to be getting on it...so to my thinking...you WANT the premium. I run premium in my 10 just for the extra 10 ft/lb tq.
 

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I think 87 is making my Cats and Exhaust smell like rotten eggs....I just started to notice it. Do you think that is what its from? Or is there somthing else on the horizon. Also, when I picked it up from the dealer it had a top end ticking noise. I think they hot rodded it to hard or something. I am taking it to the dealer on Wed to see if its a lifter or a noisy injector. What do you guys think?
 

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I think 87 is making my Cats and Exhaust smell like rotten eggs....I just started to notice it. Do you think that is what its from? Or is there somthing else on the horizon. Also, when I picked it up from the dealer it had a top end ticking noise. I think they hot rodded it to hard or something. I am taking it to the dealer on Wed to see if its a lifter or a noisy injector. What do you guys think?
You'll get all kinds of funny smells until it's broken in. Mine has 700 miles on it, and it still smells funny, especially after running it hard. I get the rotten eggs now and again, and I always run 93 octane.

As for the tick, if you hear it only when the hood is open, you're hearing injectors. With the hood closed, if you're hearing it through the wheel wells at idle, you're hearing the typical Ford engine tick that apparently was not fixed even in this new iteration. Look at these threads:

http://www.allfordmustangs.com/forums/2011-mustang/242856-3-issues-one-question-2-hour-old-2011-gt.html

Loud Valvetrain? - MustangForums.com

http://www.allfordmustangs.com/forums/2011-mustang/240734-2011-mustang-gt-5-0-ford-service-question.html
 

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Lots of cars have that ticking sound. My 2008 4cy nissan has it.

Although i will say that my 2010 Gt does not have it.
 

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You could try some 87 octane but with the automatic (that's what I have), I noticed a slight hesitation and power loss at low rpm. Like right off idle and at around 30-35 mph when it is lugging along at 1000 rpm. The intake drone inducer would cackle a bit as the throttle is pressed- slight hesitation and then it would accelerate. The outside temps were pretty high around 95-100 degrees.
Ditto here. The hesitation only happens every now and then at low RPN's. I'm going to try 91 octane next time I fuel up to see if it makes a difference.
 
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