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I just filled up a tank of premium after running a bottle of Techron. Haven't noticed a difference in mileage. It does sound a big better, less pingey/clickey under load. Does my butt feel a power diffference? Too biased to give a straight answer

 

 

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Truck would run faster due to weight loss on a lighter wallet.

 

If you are not tuned for it, it is a waste.

 

 

People really need to start reading thread on the forums before they just spout the typical "If GM wanted you to run premium" answer.

 

In short yes, I would run at least 89 or higher in the 5.3. Multiple people have recorded and seen that the 5.3l engines will knock on 87 octane fuel, the compression ratio is not far off from the 6.2l trucks, and even the 6.2 trucks knock on 91 and really need to be on 93 if you have it availiable. The less knock the engine sees the more consistent power it will make and smoother it will run.

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People really need to start reading thread on the forums before they just spout the typical "If GM wanted you to run premium" answer.

 

In short yes, I would run at least 89 or higher in the 5.3. Multiple people have recorded and seen that the 5.3l engines will knock on 87 octane fuel, the compression ratio is not far off from the 6.2l trucks, and even the 6.2 trucks knock on 91 and really need to be on 93 if you have it availiable. The less knock the engine sees the more consistent power it will make and smoother it will run.

Thanks guys that's exactly what I was getting at. I've only had my truck about a month so and I ran premium fuel the last two fill ups and felt the truck a little better responsive and less pingy. I just wanted to get a feel of what other people were experiencing.

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I get better millage but that is because there is no ethanol formula mixed into the 91/93 in Canada and only at particular fuel stations.

 

Power wise it is all running under the same tune so you feel no difference.

 

I just run the 87 and dump injector cleaner regularly and use the CRC intake valve cleaner and the engine is happy.

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Power wise it is all running under the same tune so you feel no difference.

 

 

 

I disagree.....when the valves start clattering or should I say when detonation is detected by the knock sensors, timing is pulled by the ECM. Retarding the timing reduces power.

On the other side of the argument, the factory tune has a limit of how far the timing will advance. So if lets say 90 octane fuel allows the timing to advance to the factory limit then it would not matter if you ran 91 or 93 octane there would be no benefit performance wise.

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I found this information interesting from Lingenfelter when they did some dyno runs with the new 5.3 engine: "Also, two of four gasoline runs showed knock during the acceleration test (including the fastest run). Neither of the E85 runs showed knock during the acceleration tests (only did 2 runs with E85 since they were so similar). Interesting to note that when not at high throttle angles the ECM shows a lot of knock with either fuel."

 

Source: http://www.lingenfelter.com/forum_lingenfelter/forum/lingenfelter-forum/general-motors-suv-trucks/1245-2014-1500-silverado-with-5-3l-l83-engine-work-begins

 

I have a 5.3 and with my ScanGauge I can monitor KR (knock retard) and timing advance. I notice the most KR when running 87. It usually shows up at low RPM's with increased engine loads (example: going up a hill/incline with cruise set). V4 mode is particularly sensitive to KR. E85 all but eliminates any KR and timing advance is noticeably higher when cruising (especially in V4 mode)

 

I try to run 89 as much as I can. Usually it's only 10-15 cents more a gallon then 87. Some stations eve have it priced the same. I will occasionally run 91 if it's on that much more then 89. Where I live 91 octane is usually ethanol free which makes it more expensive (around 50 cents a gallon over 87 octane).

 

From what I have gathered (at least with my vehicle) is that the engine is sensitive to octane levels. Can it run on 87? Absolutely but it's right on the edge of developing KR and pulling timing back. Running 89 doesn't cost that much more in the long run and provides a little cushion to KR. Every engine is different so results will vary but from what I have seen I'll stick with 89 minimum.

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Truck would run faster due to weight loss on a lighter wallet.

 

If you are not tuned for it, it is a waste.

Geez.... You couldn't be more wrong. Tuners all over have said the running at least 89 is a real benifit for this high compression engine.

 

RT

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Reference for mine is with a Hypertech Tune. Have tuned it for both the Premium Fuel Tune and the Regular Fuel Tune. First did the premium fuel (91 octane) tune, on 91 octane I could hear a slight bit of pinging at WOT in the upper rpms. Ran it like this taking it easy for few tanks of 91 fuel, last fill up was 93 octane, did not notice any pinging on the 93. Reprogrammed it to the regular fuel (87 octane) tune which is where it has been for about a year now. Have tried fuel from several different stations, bottom line, it doesn't like 87 octane, so I either run 89 octane if I can get it. Been buying most of my gas at the Costco near me (around here anymore you have few choices, there's a Sunoco few miles away that's in the other direction I travel, WAWA convenience stores or the Costco) they only have 87 or 93 octane. Motor will get by on 87 octane just fine for normal driving even with the tune installed as long as you drive with a light foot, but it does run better with premium fuel in the tank if you want to go WOT.

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