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View Full Version : Running 91 octane on the 93 tune?



TechTitan08
01-21-2010, 09:51 PM
Quick question, but a little more complex than a simple yea or neh answer. Living up in Lubbock, (elevation ~3200ft) the highest octane gas they sell is 91. On the otherhand in DFW with an avg elevation of ~500ft, I can find 93 octane fuel almost anywhere. I did some internet research and apparently the reason being for this is that due to the lower oxygen levels as elevation rises, the engines have to work a little harder to combust the fuel they are running. So my question to y'all is...

A) If the goal for higher octane gas is to reduce possibility of engine knock, will 91 achieve the same result as 93 at this elevation?
B) Is it just coincidence that they don't sell 93 here, and I am really going to fuck the engine up pushing it with the 93 tune?

Thanks again guys, I freakin love the 93 tune, but I'd rather be safe than sorry!

Chris

O-Fivecc
01-21-2010, 10:04 PM
Why not get a 91 octane tune? Some even suspect that their is really only need for a good 89 tune on our trucks. I'm not sure about the elevation thing, I know where I live, I would not run a 93 tune on 91 gas just for safety although you may be ok.

tat2titan
01-21-2010, 11:14 PM
Don't do it! Just get yourself a 91oct. tune. I know in my tune my 93map has more timing advance then my 91 map. If you run too low an octain you risk a chance of getting some detination.

Sleepertrk
01-21-2010, 11:24 PM
I have the Superchips Cortex and i find the best performance is with my 87oct tune. I might be wrong but that tune with the WOT disabled and my exhaust and CAI puts out damn good power. I just can't justify paying the extra money for the 91 or 93 octane fuel for the little performance difference i've noticed over the 87 tune.

O-Fivecc
01-21-2010, 11:32 PM
93 also helps keep the motor cleaner..but it is a bitch to have to pay that much every time I get gas...I think Suddenurge also ran better times with his Bullydog in the 87 tune map. But thats probably just because you may need a little custom tuning to get a good 91 or 93 tune. But still, I hate paying for 93 Octane, but it is all i will run now

tat2titan
01-21-2010, 11:33 PM
That's fine w/ a handheld tuner, but when you start doing timing advance, header's, cam's, other custom stuff it's going to make a lot of difference.

Warp09
01-21-2010, 11:35 PM
It depends on how much timing you are running. If I can see how much timing your truck is pushing out, it gives a better ballpark at which octane you could/should run. I can run 34 degrees of timing on 89 octane and I am OK. Don't quote me on that because it works for my truck, and it may not work for yours or anyone else for that matter.

Layer1
01-22-2010, 09:55 AM
You are only going to see maybe 2-5hp increase between 91 and 93 octane. The biggest results will be better mpg. I have the following tunes:
91 perf.
89 per
89 ecom
89 tow
89 stock tune (with anti theft, 1mph, 1500rpm limits)

TechTitan08
01-22-2010, 02:17 PM
Honestly when I first got my Superchips Flashpaq, I threw the 87 tune on and disabled my WOT restriction, and wasn't incredibly impressed. Don't know if I was expecting too much or if the ECU just needed to learn a little more. A little disappointed I found a 93 octane tune and ran it for a few runs and the power was incredible. I spun straight up to 40 from takeoff, something I couldn't do with the 87. That said I just updated it with datalogging capabilities last night so I may poke around and see what I can find.

Also, I'm thinking on rigging up a way to keep my tuner on the console, you think it will burn up if I leave it plugged in while I drive for a while?

Sleepertrk
01-22-2010, 02:27 PM
LOL----No it won't burn up.. I'm sorry for laughing it just caught me as hilarious. I've actually ran my Cortex on Data Logging and drove around town just mess'n with it to check some numbers. I'd say the biggest worry is the cable thats running down your right leg and plugging in under the dash. Make sure you don't get all tangled up with your accelerator and run over some old lady on the sidewalk. I'd also be aware that depending on what state your in and what the laws are, a cop may look at it as driving and texting if your holding the thing while driving. They just made texting and driving illegal here in Illinois. I would think a cop would see it as the same thing. Mounting it like you said would get around that, maybe. Let us know what results you get. I wasn't checking anything specific when i did it. I was just curious like you.

TechTitan08
01-22-2010, 02:31 PM
[QUOTEAlso, I'm thinking on rigging up a way to keep my tuner on the console, you think it will burn up if I leave it plugged in while I drive for a while?

LOL----No it won't burn up.. I'm sorry for laughing it just caught me as hilarious. I've actually ran my Cortex on Data Logging and drove around town just mess'n with it to check some numbers. I'd say the biggest worry is the cable thats running down your right leg and plugging in under the dash. Make sure you don't get all tangled up with your accelerator and run over some old lady on the sidewalk. I'd also be aware that depending on what state your in and what the laws are, a cop may look at it as driving and texting if your holding the thing while driving. They just made texting and driving illegal here in Illinois. I would think a cop would see it as the same thing. Mounting it like you said would get around that, maybe. Let us know what results you get. I wasn't checking anything specific when i did it. I was just curious like you.

Haha good just checking, it just amazes me how this thing that's so small light, and seemingly empty can rewrite all the shit in the ECU. I just wanted to make doubly sure $300 bucks didn't fry from overuse!