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Jet Chip and Gas - What octane?

5118 Views 5 Replies 4 Participants Last post by  xxkazp3rxx
Lets not get into the talk about "you should get a tuner instead, this is better than a chip, etc..", it's all opinion and like and dislike on whether to get a chip or tuner and i'm full aware of all that. My question is.....

If your going to put a jet chip in your mustang GT, as well as a cool air intake etc.. can you still use regular gasoline (octane 87) or do you have to use a higher octane, like 91 or so??

I know using a higher octane is better and more efficient, but I just wanted to make sure that if I accidently put 87 in numerous times that I wasn't hurting my engine.

Can I run 87 in my tank, or is it a must to not but run a certain octane otherwise I will hurt/damage my engine/car. Anyone know?
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Good question and I for one am looking forward to the answers.

I'm 99% sure that you need to use the octane rating your "tune" is designed for to avoid engine damage. Thus, if you have an 87 octane tune, 87/89/91/93 octane are all OK. But, if you have a 91 octane tune and you run 87 octane gas, you will probably get some pinging/knocking, especially if you accelerate hard. Detonation (ping/knock) can be *REALLY* bad for the life of your car.

You *may* be able to get by with a couple octane less than whatever your tune was designed for (eg. 89 octane w/ a 91 octane tune) if you drive very easy on the gas. However, I don't recommend ever using a lower grade than the tune is designed for. Better to reflash the computer to a lower (ie: stock) tune if you have to fill up with a lower rating, then re-load the higher tune when you can get the proper fuel.

P.S. using a higher octane than the car and tune are designed for is simply a waste of money. You will NOT get any additional power or mpg by using a higher octane than the car is tuned for.

P.P.S. A CAI by itself shouldn't change your octane requirements. Just the programming.
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Thanks, yeah I called them up and that is what they said. I have to run at least 89, 91 for the best, if I run 87 i'll hear some pinging etc.. in the engine. How does that improve economy like it says, and help on mpg, when I'll be paying more for a higher grade of gas???

Oh well, looks like i'll be paying more at the pump. Does any other tuners, like the predator or SCT XCalibrator 2 require to use a higher grade of gas as well?

So the magical question then is this: If I'm basically wanting to tune my car, using which ever way someone is going to do it, JET CHIP or SCT XCalibrator 2 etc... do you definitely have to use a higher grade of gas????

If you want an increase in HP/tq from your "retune", you will have to utilize one of the higher octane settings (typically 89, 91 or 93) and then fill with the corresponding gas grade. Generally, the higher the octane requirements of the tune, the more additional HP it generates.

However, there are some advantages to using an 87 octane tune (at least w/ the Xcal2) with the S197 (2005) Mustang, especially if you have an automatic trans. While you won't get any additional HP from the tune, you can/will get the following...

1) elimination of the WOT delay (which is really annoying)
2) elimination of rpm or top speed limiters.
3) recalibration of the tach/speedometer to compensate for wheel/tire/gearing changes
4) improved shift points & characteristics for auto transmissions.

Plus, you can always fill up w/ premium, load the 91 tune and go lead-footin it. Just be sure to reload the 87 when you go back to regular...
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Xcal2 you can choose the tune setting. On my xcal2 I have a program from 87 Octane and one for 93 Octane.
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