Premium in a 5.3?

[Silverado-Hareek]

Despite the facts people continue to believe premium fuel is better, its not. If your engine does not require it, its doing nothing to improve performance.

 

Blackbear Performance disagrees. Read their FAQ's on their website.

[pcruis1]

 

Blackbear Performance disagrees. Read their FAQ's on their website.

Similarly, and for whatever it is worth, the guy that did my tune told me to avoid low octane fuel. After the tune and other modifications, I've run nothing but 93.

[diyer2]

IMO

If you're after top performance at all times I can see premium and/or a tune. I want reliability. My method works for me.

[sdeeter19555]

Despite the facts people continue to believe premium fuel is better, its not. If your engine does not require it, its doing nothing to improve performance.

I can tell when pulling a hill loaded whether it's got 91+ or 87 in mine...it will maintain speed better with 91+ (i.e., pull the hill faster) with 91+ and less downshifts, that's no placebo affect...that's the same truck and trailer and same stretch of highway and multiple trips on that same stretch of highway.

 

I also hand calculate my fuel mileage, and I get slightly better mileage with 91+ versus 87 in both unloaded and towing. It's not much, but it's consistent.

 

You can argue placebo affect all day long, but the performance difference and mileage numbers don't lie?

 

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[diyer2]

Agree ^^^^ lots of hills, mountains in Colorado.

[Z45]

 

There is no sense paying a premium for premium gasoline if your car is designed to run on regular, according to research by the automobile club AAA.

Some drivers occasionally like to treat their cars to higher-octane fuel in the belief it boosts performance. But premium blends can cost around 50 cents a gallon more than regular.

AAA says it's just money out the tailpipe — lots of it. In a national survey on gasoline use, AAA said 16.5 million U.S. drivers spent $2.1 billion they didn't need to in the past year on premium gasoline.

Many think premium means quality. But AAA researchers found that while it has more octane, it didn't increase horsepower or fuel economy, decrease emissions or clean engines any better than regular gas in cars that are designed by the manufacturer to run on 87-octane regular.

"Drivers see the 'premium' name at the pump and may assume the fuel is better for their vehicle," said John Nielsen, AAA's managing director of automotive engineering.

[Colossus]

Despite the facts people continue to believe premium fuel is better, its not. If your engine does not require it, its doing nothing to improve performance

High test? What is this, the 60s again? It's called Premium. You don't see a "high test" sticker somewhere on pumps now do you. No offense meant, I just find it humorous when I hear people use that term. Last time I saw premium referred to as something other than premium was a "Super Unleaded" thing by Phillips 66 back in the mid 80s.

[camcamaro1991]

http://blackbearperformance.com/faqs.asp

Quote = "All 2014+ direct injected vehicles. Compression ratio is simply too high to efficiently burn 87 octane." <- I would agree with that.

How noticeable is the diff in a '87 oct tune' and a '89 oct tune'?

Quote= "It really depends on the vehicle. Some can run just as well on 87, whereas others need 93 to make good power. There are quite a few factors that go into this, including environmental and mechanical." <- I would agree with that as well.

On a thread similar to this I got ripped about saying a loaner vehicle with a 5.3L engine pings on 87 octane under full throttle. I know for a fact, the dealer use's 87 octane and it pinged like marbles for me first time out and punched it on the highway for a short bit, I was told I was full of it.... then asked if I could prove it! It just so happens I didn't have my HP Tuners to provide an actual scan of HP Tuners KR (*) table. As a former Mercedes Benz master tech... I am damn sure the new GM 2014+ 5.3L will ping at times using 87 octane with a 11.0 -1 compression ratio under full throttle, even with understanding GDI engines are fairly octane tolerant, esp… a brand new dealer loaner truck with low miles on it.

GM's stock software is fairly good, it will cut timing to reduce any knock, so in many instances a loud radio running it hard, they may never notice in fact many don't. There some factors overlooked other than octane and knock or even AAA fuel's, in some engines exhaust temps are greatly reduced with running higher octane or e85, some engines see no change.

I don't know of any well documented fuel grade testing on GM's 2014+ GDI engines, it’s a typical hot topic on all the automotive forums, tuners stay away from this unless they have actual evidence including margin of error % with final test results. In this case, black bear doesn't actually show us this data, but they do tune a heck lot more engines than I do so they get to see actual data when using different fuel octane hence their "FAQ page", I would say its save to bet mid grade or higher will run at an optimum level in varying conditions given GM's GDI's truck engines are 11.0+ to 1.

example Blackbears CAI review that’s coming up shortly.

[sdeeter19555]

One thing following on the above post, if it senses knock, it will reduce timing, and hence performance suffers...correct?

 

I know running 87 on my hard pulls causes the truck to simply castrate the throttle...basically it reduces power to the point I lose speed up a grade even at lower gears, it even limits RPM. I know it had more, but the computer wasn't giving it to me. Same hill I pulled many times in higher gears with plenty left in reserve running higher octane.

 

My truck might also be a bad example...I've had a low rpm surge for the entire 95k miles I've owned it and higher octane fuels reduces that surging. I've tried finding a compromise (89, blend of 87 and 89, blend of 89 and 91+, etc.) but 91+ seems to work the best. That's the main reason I run 91+.

 

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[TJay74]

I don't notice anything with performance. No change in mileage either. Never said that. Just said I personally think it might burn cleaner and not gum up things in the process. I find it amusing how guys will spend $50k on a truck, then add another $15k of stuff to it, then cheap out at the pump. Worried about saving a few bucks now?

My other vehicle runs pretty rough on 87, but runs fine on 92/93. That's what I run. While I may not notice a difference, I feel that it's probably better to run a higher test in my expensive truck as well. Sure, it will run fine on the cheaper gas, but it's not that much more. Granted, I don't tack on miles like some do, so the added expense isn't as much, but even if I did, I feel it's worth it in the long run.

Again, I do not care about added power or mpg, I run 92/93 because I think it will help keep things cleaner inside the engine over time. Maybe I'm wrong. Just my opinion.

 

Sadly on the new trucks the better detergents wont due a thing for gumming issues related to the valves since it is a dry fuel system. Fuel is sprayed directly into the combustion chamber on the 2014+ trucks.

 

Here in Colorado we have 85,87, and 91 octane fuel. In this 2012 5.3 truck and my 93 5.7 TBI I run 85 unless towing, then 91. Always Top Tier gas. A tank with fuel system cleaner every 6k miles. Currently using Chevron Techron.

 

There is absolutely no way I would run 85 in anything, mush less a 2014+ GM truck. As said, Blackbear, several other members and even myself included have all done scans to watch for knock events being recorded by the ECM. The 5.3 knocks under normal driving on 87, no way in heck I would run 85 octane in the truck. More so since the system uses a fuel sensor to know what the octane in the fuel is. Octane wont force the ECM into the low octane timing tables (which kills power by the way) but if 87 already causes knock I sure wouldn't want to put 85 octane in it to cause it to knock even more or harder.

 

Main reason why BB and most of the members that have done the research all say 91 is the minimum you should run in these trucks.

 

IMO

If you're after top performance at all times I can see premium and/or a tune. I want reliability. My method works for me.

 

Once again, see the above post. If you could see the knock events that are being recorded by the ECM you would change your mind, but in the end I don't care as I don't pay your truck payment. If you want to submit your truck and engine to multiple daily events of detonation that will do damage to the piston tops, ring lands and valves then by all means go for it.

Moot point for me, 6.2 and I have to run 91 or higher. The truck pings so bad on 87 you can hear the sound reflecting off of the concrete barriers when I drive down the road.

 

[Cowpie]

I can tell when pulling a hill loaded whether it's got 91+ or 87 in mine...it will maintain speed better with 91+ (i.e., pull the hill faster) with 91+ and less downshifts, that's no placebo affect...that's the same truck and trailer and same stretch of highway and multiple trips on that same stretch of highway.

 

I also hand calculate my fuel mileage, and I get slightly better mileage with 91+ versus 87 in both unloaded and towing. It's not much, but it's consistent.

 

You can argue placebo affect all day long, but the performance difference and mileage numbers don't lie?

 

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What kind of mpg improvement? You said it is not much, then is it really worth it?

 

Let's say I were averaging 18 mpg on regular 87. At the prices in my area for it, about $2.09, that would come out at about 11.6 cents a mile.

 

Now, for Premium... in my area that is about $2.57. So just to break even on the cost per mile, I would have to be getting at least 22 mpg doing the exact same thing with the pickup just to break even on the cost per mile. That would be almost a 20% improvement in mpg using premium. Considerably more than "not much" I would guess.

 

Call me a skeptic, but I have not ever seen premium deliver that big of spread on mpg compared to regular. In that scenario, if one is not getting at least 4 mpg better, they are actually losing money compared to using regular. Of course, each area has different price spreads so this could change a little. But it is safe to say, that "not much" improvement in mpg by using premium compared to regular is not a good deal.

 

If it was all about preventing a knock, to hell with premium, I would use E85. 100 octane. The cost for that is around $1.49 in my area. Sure it delivers less mpg, but may still be a good value. My 2500 will average about 14 mpg on regular. I typically can average 11-12 mpg on E85. So using regular, my cost per mile is just shy of 15 cents a mile. With E85, the cost per mile is about 13.5 cents a mile. Yeah, I can live with a lower mpg when it is actually costing me less per mile. And premium hardly comes close to the octane rating of E85.

[sdeeter19555]

I never said I was running it for mileage, only that it does make a measurable improvement.

 

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[Crazy_Josh]

Since I bought my '16 Silverado, I've been filling up with premium. I can't really say I notice a difference, since I've only used 93 octane. However, I think there is a difference in brand and octane rating. Some do leave more deposits than others and it also depends on if you use top tier or not.

In my own experience the best average MPG recorded is 25. That was probably when I was driving long distance on highway. My normal average that I'm getting is 19. That's about 80% city driving and 20% highway.

Hope that helps.

 

 

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[diyer2]

TJay74 and all others.

Are you saying my engine is pinging constantly on 85 octane?

I don't hear it.

The computer adjusts timing so it doesn't ping but at the cost of loosing power?

 

Really?

Once again, see the above post. If you could see the knock events that are being recorded by the ECM you would change your mind, but in the end I don't care as I don't pay your truck payment. If you want to submit your truck and engine to multiple daily events of detonation that will do damage to the piston tops, ring lands and valves then by all means go for it.

 

I'm skeptical but maybe wrong.

[KARNUT]

When I had my 14 GMC I ran E-85 in town my truck performed the best. When I went on my numerous trips to the same place on the same roads and the same speeds there was no difference between 87-93. I would spend more on for E-85 if I could get it on my trips the performance was noticeable, otherwise not so much.

 

 

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