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gonefishin776 10-24-2012 06:57 AM

Switching from 87 octane to 91
(Sorry if this isn't the best sub-forum, please move if necessary)

So I bought the superchips tuner recently and have been running the mileage tune, which is great for highway driving. Still sucks city driving on MPG. Anyways, I want to try the 91 octane tune.

Do I need to get every last drop of 87 out before I fill up with 91? or just run it till the light comes on? Because there is still what...~5 gallons left once the light comes on?

I guess I could siphon it into a gas can (hate to waste it) then put the 91 in? SUGGESTIONS PLEASE!

Grubrunner 10-24-2012 07:37 AM

On every past vehicle that I've had a Superchips tuner on, when I've switched to and run the 91 performance tune, I've run the old fuel until about 20DTE then filled up with 91 octane.....without an issue.

You'll be fine.

gonefishin776 10-24-2012 07:39 AM

Thanks grubrunner!

snrusnak 10-24-2012 08:41 AM

You'll be fine, just as long as you have nearly a full tank of it. The engine has knock sensors for protection against detonation anyway.

I've run my truck with the 93 tune on 91 before, just was easier on the throttle(less load on the engine). Other times I run 92 octane. Not all stations have 93 octane unfortunately...

gonefishin776 10-24-2012 08:49 AM

See around me, it's rare to find 91...only 93 is here. But i'm pretty sure my tuner only has the 91 octane tune. Could I install that tune and run 93?

snrusnak 10-24-2012 08:53 AM

You're tuner should have the 93 tune, is it a 3865?

No you need to run 93 with the 93 tune. I'm just saying if you get caught and only have 91 available and don't want to re tune it will not damage the engine, just drive easier for that tank, don't do WOT runs. Same concept as you can't tow/haul much with the performance tunes, it puts too much load on the engine with that much ignition timing advance. I mean really it doesn't matter because there are knock sensors that retard timing but try to stick with the right octane level. Just when I get caught travelling out of my area and there's no 93, I don't spend 15 minutes at the pump re tuning, I just fill up with the highest grade. Now I probably wouldn't ever put 89 or 87 in the tank with 93 tune, that's a bit of a stretch...

gonefishin776 10-24-2012 08:59 AM

yeah it is the 3865...I swear I remember it only having 91...but i'll look again. But okay, thanks for info! Makes sense.

snrusnak 10-24-2012 09:03 AM

Mine has a 93 tune, maybe when they started the 93 tunes they didn't add them for previous model years, not sure.... I know my buddy's 01 camaro only had a 91 tune, then he updated it later on and it now has a 93 tune...

gonefishin776 10-24-2012 09:16 AM

Ok, well I figured when I registered it and updated it a month ago when I first used it, it would install the most recent updates. I will check again when I get home, and if it doesn't have it I will update it. And if for some reason I still only end up with the 91 tune I will just put that on and I think the Sunoco (sp?) station up the road from me sells 91.

gonefishin776 10-27-2012 11:31 AM

so I updated my tuner and still only have a 91-performance tune. (On the SC site it says the 93-performance tunes vary depending on vehicle. That bad thing is....I can't find a gas station that sells 91 around me. And filling up half 89/93 seems like a pain. But I might have to do it if I want to test out this tune.

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