[GritsNGravy]

I am hoping to pick up a 2007 mustang gt this week. It has uber low miles (>30K). Well taken care of and no issues. has CAI and exhaust. sct tuned for premium fuel. Since this car has been running like this for most of its life.

What are the cons if I lower the tune from 93 to 91 or 89? One of the reasons for buying the stang was not having to use premium fuel but this one car is to nice to pass up. Just looking for thoughts or possible personal stories on similar situations. Thanks in advance.

Also, was looking at the push button start from american muscle. Anyone had bad experiences with them? I know its an extra step to start the car but the cool factor out weighs that. At least for me.

 

[PonyX]

I believe for my sct tune 2014 gt mustang from 89 to 93 octane is like 10 hp more but its the throttle response that I felt the most difference. If you take the tune out you more than likely will have to install the original air filter box. Personally I would leave the tune in unless you can get the original owner to install the oem filter and take the tune off with his programmer. I would be hesitant with a used mustang with aftermarket parts since you dont know what else the previous owner had on the car and replaced back to oem before selling. Beside that go for it!

 

[boink]

I've only run 87 and it's enough for me. Bama's 87 performance v2 tune is great. What cai do you have? It may not require a tune so you could go back to the stock tune.


Sent from my microwave.

 

[richy04]

The first mod should be a synthetic oil change and motorcraft filter. Then a new set of plugs with anti seize on the threads to set you up on a bright future with your new stang.. Good luck with the new car!!

You will see a difference going from 93 to 89, I had to dump the tune on my marauder to use 89 when gas hit $3.75+, it was livable and remember to get the handheld tuner from the guy so you can juggle tunes and have the original handy.

 

[Krieg]

Custom tune, big difference. Canned tune, meh.

Just don't cheat it. If you're tuned for 93, don't put anything lower in...ever.

What's your reason for wanting to switch? 93 is cheap right now (and still cheap if you live near a gas wholesale station, like Costco). If it's your daily driver I can understand, but otherwise stick with 93.

 

[jlee910]

You're only going to see a small hp difference with the miniscule mods, but throttle response will vary.

I've ran 87 and 93 quite a bit. 93 gets better fuel economy on the highway in my GT, so I justify it, while 87 gets better than 93 in the city, but that just may be because of how much more I stay in the gas with the little power and response bump... choice is yours. I say let the ponies free!

 

[fchavez73]

I am hoping to pick up a 2007 mustang gt this week. It has uber low miles (>30K). Well taken care of and no issues. has CAI and exhaust. sct tuned for premium fuel. Since this car has been running like this for most of its life.

What are the cons if I lower the tune from 93 to 91 or 89? One of the reasons for buying the stang was not having to use premium fuel but this one car is to nice to pass up. Just looking for thoughts or possible personal stories on similar situations. Thanks in advance.

Also, was looking at the push button start from american muscle. Anyone had bad experiences with them? I know its an extra step to start the car but the cool factor out weighs that. At least for me.

I looked at that starter too. It does have a cool factor for sure. I just can't seem to get over still needing to put keys in ignition to make it work. I think I may hold out for one you don't need to insert key, key has to only be nearby. I know it will probably be expensive, but I rather just have my key in my pocket, sit in car and push the button. There are also remote starts as well, like what Viper sells. I've considered that, but it's still on the back-burner after some engine and suspension and exhaust mods I want to do first. Good luck, and congrats on the car!

 

[GritsNGravy]

I will probably keep the car the way it is. He had a custom sct tune with all three gas grades on it, he just has used premium all its life. I was wondering about the cons of using one of the lower grade tunes. So ready for some V8 muscle!

 

[Herb07GT]

The '07 Mustang GT has about 9.7 or 9.8 compressions ratio.
93 octane actually requires a higher compression ratio to function better.
As far as getting better mileage, I think it is more in your mind.

 

[jchopper62]

I'm mot going to bet my car on it, but I'm pretty sure octane does nothing when it comes to horsepower. I put 87 octane in my '06 GT, and if I were to put 93 or 94, I would still get the same HP as 87. The only difference is, the higher octane takes longer to combust, so you might get better mileage. In my opinion the only 'cons' you have GritsNGravy with a lower octane, is maybe an extra stop at the pump.

GO for the 07 GT, and enjoy it.

 

[GritsNGravy]

The car is in my driveway!!!!! Super happy with it once I can get it to pass an emissions/inspection so I can get a license plate. Had an off-road xpipe on it and had to revert back to original exhaust. Keep getting 02 codes (P2196 & P2198). Had American Muscle send me new tunes and it made the car run like ****. Check engine light came on immediately with the 02 codes. Exhaust smelled terrible and the drive just was not right. Figure it running rich at the moment. Gonna call tomorrow to see if they can revise the tune. Really hoping to get this right this week so I can get a plate for it. Want to put the xpipe back on!

Thanks for all the advice. Really been enjoying the forums.