Should I tune for 91 and just run 93 for an extra margin of safety?

[SwissLime]

Now that all my new parts are here (S280, Xtreme-DI HPFP, and bigger Bosch Injectors). I'm worried I might be getting cold feet on the amount of power, as this is my daily driver I'd hate to blow up the motor. Is it crazy talk to think about getting tuned for 91 Octane then running 93 after the tuning process just to give myself more headroom and knock protection. I'm sure any quality tuner represented here on the forum would provide a safe tune at 93 and I would have nothing to worry about, but I do like the thought of operating safety margins.

 

[TyphoonFiST]

If it was me.... Id get tuned for 93 and then get a low boost option so you could run 91 if you cant find 93 when you need to fill up.

 

[TemecFist]

Tune on 91. The amount of extra power from tuning on 93 is not worth the trade off you would get instead of tuning on 91 and having a nice safety margin.

 

[powermatt]

Tune on 91. The amount of extra power from tuning on 93 is not worth the trade off you would get instead of tuning on 91 and having a nice safety margin.

I've run both 91 (while I was in California) and 93 (here in Virginia) versions of the same tune (Cobb stage 1 and 2 OTS) on stock Fiesta STs. The difference is noticeable. The 93 octane versions feel much more aggressive with their power delivery. Peak numbers may not be very different, but the space under the graph feels very different. This is of course a butt dyno result with a year of separation between the vehicles tested, so take that with some sodium chloride.

I say go with what your tuner recommends. If you're in an area with quality 93 octane, there's no reason to stay away from it. Like TyphoonFiST said, just ask your tuner for a second "low boost" map in the eventuality that you need to run a lower octane. Any reputable tuner is going to build in plenty of anti-knock protection in case you get some bad gas by accident.

 

[MagnetiseST]

with a good tuner you will be fine on 93, and there is plenty of protection built in to those maps. Tuning for 91 and running 93 might result in a sluggish feeling in a pro-tune.

 

[apex1]

To answer your specific question-yes. It's crazy.

 

[TemecFist]

Oh boy. Lol. I have OTS tunes and Pro tunes from Stratified, JST, Cobb, and Dizzy. Anyone that says they can feel the difference between a 91 vs 93 tune, or a stage 1 vs stage 2 OTS tune, are the same guys that can feel a difference with an intake, or drop in filter. Lol.
It's not the fuel, it's the way the tune is set up. I can have my tuner make a stage 1 tune "feel" faster than a Pro tune. The numbers dont lie tho.

Do what your comfortable with.

 

[Se7eN]

just go with 93oct tune and do that @TyphoonFiST said

 

[gtx3076]

93 is not pushing any limits on this car. I've been running E30 daily for the past year.

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[Spork1569]

93 is not pushing any limits on this car. I've been running E30 daily for the past year.

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Same I ran e30 for a year and a half with no issues on my daily driver. As long as you keep up with maintenance the car can usually handle what you throw at it.

 

[TemecFist]

Yeah, I run e40 with wmi or 110 with meth

 

[gtx3076]

Really, if you think about it, a poorly made 87 tune could just as well grenade your motor as a poorly made 93 tune. A quality tune will be safe for whatever octane you're using.

My 93 tune is my lowest octane tune. If I were ever stuck somewhere and only could access 91, I'd just take it easy until I found a higher octane.

 

[TemecFist]

Really, if you think about it, a poorly made 87 tune could just as well grenade your motor as a poorly made 93 tune. A quality tune will be safe for whatever octane you're using.

My 93 tune is my lowest octane tune. If I were ever stuck somewhere and only could access 91, I'd just take it easy until I found a higher octane.

Gotta remember, the OP is already a little hesitant. So let's put this in perspective. Line a car up with a 91 tune against the exact same car with a 93 tune. You will never see a noticeable difference (if any at all)....GUARANTEED. Now, isnt it better for HIM to tune on 91, then run 93 for his own peace of mind? He isnt giving up anything at all performance wise, but gaining safety and peace of mind. He also doesnt have to worry about getting crappy gas. Let's be honest.......what's the best decision for HIM.......?

 

[TemecFist]

Btw....the difference between a 91 tune and a 93 tune....is +1* of global timing. I would like to see the guy who's butt dyno can feel that. Lol

 

[powermatt]

And here's the joy of asking for tuning advice. Ten people will give you fifteen answers.

 

[TemecFist]

And here's the joy of asking for tuning advice. Ten people will give you fifteen answers.

Truth!

 

[Erick_V]

As far as I know most tuners won't push the motor that last 10%-20% unless you ask them to, they aren't looking to blow your motor either. I say go 93 and be forward with your tuner about your concerns and I'm sure you'll be happy. E85 will be your friend if you're looking to keep things safe. I've been running E85 for 2 years and I haven't looked back.

 

[Muldoon]

You’re upgrading the fueling system and not using Ethanol?

 

[TyphoonFiST]

As far as I know most tuners won't push the motor that last 10%-20% unless you ask them to, they aren't looking to blow your motor either. I say go 93 and be forward with your tuner about your concerns and I'm sure you'll be happy. E85 will be your friend if you're looking to keep things safe. I've been running E85 for 2 years and I haven't looked back.

Which fuel pump setup did you go with running full E85?

 

[Erick_V]

Didn't mean to imply I was running Full E85. I'm Dizzy E30! Was Stratified E30 before that