Premium in a 5.3?

[SierraHD17]

They knock stock on regular... I have logged it.  Adding a couple degrees of ignition timing, removing some limiters and retarding the cam a bit makes a world of difference on premium gas.  Stock it won't knock on premium but won't feel any stronger really either.

[DTOMKIDD]

I agree. 89 and up is the way to go with these trucks. I started running premium at the beginning of the year with everything stock and loved the way it ran, then I spent some coin about 5 months ago on a Diablo trinity tuner and Diablew tune with premium and I'm blown away at the difference in the truck. It's a night and day difference.

Sent from my SM-G950U using Tapatalk

[willeh_ca]

On 07/11/2017 at 10:42 AM, SierraHD17 said:

They knock stock on regular... I have logged it.  Adding a couple degrees of ignition timing, removing some limiters and retarding the cam a bit makes a world of difference on premium gas.  Stock it won't knock on premium but won't feel any stronger really either.

What did you use to log it? I'm trying to see the difference between 87 and 91 using an Elm327 Bluetooth and torque pro but I don't think I'm getting real numbers. Knock counter is randomly going off on both so I'm having difficulty quantifying the difference between the two. 

[SierraHD17]

HP tuners 

[willeh_ca]

8 hours ago, SierraHD17 said:

HP tuners 

Thank you, I thought maybe it'd be something more advanced than I was trying.

[ata3001]

I have a 14 with 5.3 L and tow  6k lb camper. I ran 87 for a year including towing then ran another year running 89. Never noticed any pinging with either and 89 ran no better than 87. Back to running 87.

[swathdiver]

7 hours ago, ata3001 said:

I have a 14 with 5.3 L and tow  6k lb camper. I ran 87 for a year including towing then ran another year running 89. Never noticed any pinging with either and 89 ran no better than 87. Back to running 87.

You're right, they're not much different.  Next time run 93 and note the difference in mpgs after your 3rd tank and notice how much better the engine idles and runs on the higher octane fuel.  If you have a FlexFuel capability, run some tanks of that in the spring.  While the mpgs will go down, the engine will make more power and love it!  If the price is low enough, it will actually cost less to burn that instead of 93 or maybe even one of the lower quality fuels.

[RDKILL]

I run 50/50 93/E85.

I had BBP tune my truck to run this mixture, (and a few other ECM adjustments) since my truck is not a Flex truck...love it!

I also pour Techron (every other fill) and Sta-Bil 360 performance (every fill) since I use Costco fuel and E85.

After adding in the cost of the Techron and Sta-Bil it's about average or maybe a slight bit higher...I haven't really crunched the numbers.

 

However, with that said, Costco's premium is much cheaper than other places, and E85 is even cheaper than Costco...this helps to keep the overall cost down for those looking to keep cost down.

The return is a kick in the pants!

[swathdiver]

It doesn't run too lean with that mixture?

[Cowpie]

Well, I am back in the high octane camp.  Prices have fluctuated enough so that E85 is the most cost effective fuel in my area right now.  Filled up Saturday at $1.49 a gallon.  Regular E10 is going for $2.41 a gallon.  Even with the mpg loss of E85, it is still cheaper to use on a cost per mile basis.  And 100 octane is a nice plus.

 

Went thru this several years ago when fuel cost was trying to reach the stratosphere.  Regular gas was dancing around $4 a gallon and I could get E85 for roughly $1.50 a gallon less.  The 2013 1500 I had at the time lived on E85 for almost 2 years.  Now my 2015 2500 is living on the stuff.  Wish my wife's Cadillac was flex fuel.

[Goinovr]

I run mainly on 91 and the truck runs great. Unfortunately 91 is as high octane I can get here in CA without additives. The lowest I've gone is Mid grade and it ran ok.