What grade of gas do you run?
Monte Of The Month -- March 2011
Joined: Sep 2009
Posts: 1,835
From: Shelby, MI
Using a higher rated octane fuel then recommended will more then likely make things dirtier due to the unburnt fuel. You may make your cat fail prematurely by using octane that's rated higher then recommended and you will probably get less mileage too. Gasoline is a dirty fuel and will not clean your engine. The only fuel that will clean your engine is ethanol.
My Monte though has a 3800 with a little higher compression, a centrifugal supercharger, and a tune for 93 octane. No KR at all.
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Monte Of The Month -- November 2012
Monte Of The Month -- August 2015
Monte Of The Month -- August 2015
Joined: Aug 2011
Posts: 4,793
From: Ann Arbor, Michigan
2007 manual info:
If your vehicle has the 5.3L V8 engine (VIN
Code C), use premium unleaded gasoline with a
posted octane rating of 91 or higher. You may
also use regular unleaded gasoline rated at
87 octane or higher, but your vehicle’s acceleration
may be slightly reduced, and you may notice a
slight audible knocking noise, commonly referred
to as spark knock. If the octane is less than
87, you may notice a heavy knocking noise when
you drive. If this occurs, use a gasoline rated
at 87 octane or higher as soon as possible.
Otherwise, you might damage your engine.
If you are using gasoline rated at 87 octane or
higher and you hear heavy knocking, your engine
needs service.
If your vehicle has the 5.3L V8 engine (VIN
Code C), use premium unleaded gasoline with a
posted octane rating of 91 or higher. You may
also use regular unleaded gasoline rated at
87 octane or higher, but your vehicle’s acceleration
may be slightly reduced, and you may notice a
slight audible knocking noise, commonly referred
to as spark knock. If the octane is less than
87, you may notice a heavy knocking noise when
you drive. If this occurs, use a gasoline rated
at 87 octane or higher as soon as possible.
Otherwise, you might damage your engine.
If you are using gasoline rated at 87 octane or
higher and you hear heavy knocking, your engine
needs service.
Mary Jane (the Monte) gets 93 with a 350 not stock
the durango with a 5.2v8 get 87 but runs best an gets a little better mpg on 89
the Mule (98 dakota)with a 3.9v6 gets 93 runs better an gets about 5-6 mpg's better than 87 don't really know why she's just picky like that.
Jess's cavi gets 93 with a turbo 2.2 ecotec.when it was stock we put iridunm plus an switch for 87 to 93 an got 2-3mpg better an dropped .3 in the 1/4 mile.
Every car is different an reacts differently to changes fuel/mods
the durango with a 5.2v8 get 87 but runs best an gets a little better mpg on 89
the Mule (98 dakota)with a 3.9v6 gets 93 runs better an gets about 5-6 mpg's better than 87 don't really know why she's just picky like that.
Jess's cavi gets 93 with a turbo 2.2 ecotec.when it was stock we put iridunm plus an switch for 87 to 93 an got 2-3mpg better an dropped .3 in the 1/4 mile.
Every car is different an reacts differently to changes fuel/mods
Monte Of The Month -- February 2014
Joined: Oct 2010
Posts: 1,715
From: British Columbia, Canada
Monte Of The Month -- August 2014
Joined: Sep 2008
Posts: 25,145
From: Southeast PA
Which is why I said that :p
But here, it's all the same haha.
Personally for the LS4, I think running the higher octane is worth it. Your car is pulling timing to compensate for the lower octane, but you should run it for what it is ideally tuned for. Let the gas burn at the right time
But here, it's all the same haha.
Personally for the LS4, I think running the higher octane is worth it. Your car is pulling timing to compensate for the lower octane, but you should run it for what it is ideally tuned for. Let the gas burn at the right time
