Jump to content

Recommended Posts

Posted

I use 89 octane at the advice of Blackbear tuning. They recommend at minimum using 89 octane even on STOCK tuning (for the 5.3 and 4.3). 6.2 motors should be using a minimum of 91.

Posted

I use regular 87 for daily driving and I use premium 91 for towing my 6000lbs camper... sometimes the boat too at 3500lbs, but not always... depends on how full tank already was... but only premium 91 in the boat or else it pings.

Unless you are tuned for the higher octane or have the 6.2L engine, you are wasting your money filling up with 91 octane. Putting higher octane in your truck because you are towing something will not help with anything but making your wallet lighter.

 

 

Sent from my crappy iPhone 6

using Tapatalk

Posted

I use 89 octane at the advice of Blackbear tuning. They recommend at minimum using 89 octane even on STOCK tuning (for the 5.3 and 4.3). 6.2 motors should be using a minimum of 91.

That must have been you that I heard that from. Why did he recommend 89? Was it due to what he was seeing via engine knock sensors? My thoughts are that perhaps it was with 87 he saw some knock retarding happening while 89 was just enough to avoid it and 92+ wasn't necessary?

  • Like 1
Posted (edited)

89. These engines have to high of a compression ration to run the cheap stuff.

Edited by haider320
  • Like 3
Posted

I ran several tanks over two months with 93 and saw absolutely no difference from 87. Now I stick with 87 and save ~$10 a tank.

  • Like 2
Posted

I use 87 exclusively and only fill up at Shell, BP, Chevron, or Mobil. My lifetime average fuel economy is 18.1 mpg for 8,000 miles. My typical highway economy is 21 mpg. I cannot run e85 because my 2015 engine is not compatible.

Posted

E85 or mid grade gas. E85 locally mid grade on trips.

 

 

Sent from my iPhone using Tapatalk

Posted

The 5.3 can get by with 87 but I bet it will show better numbers with 89 over the long run, the 6.2 with approximately 11.5:1 compression needs the good stuff, 93 octane is all my truck sees.

Posted

Unless you are tuned for the higher octane or have the 6.2L engine, you are wasting your money filling up with 91 octane. Putting higher octane in your truck because you are towing something will not help with anything but making your wallet lighter.

 

 

Sent from my crappy iPhone 6

using Tapatalk

It won't get me any better fuel economy and certainly costs me more, all true... but has better additives and runs cooler. It's worth the extra $$$ to run cooler when towing to me.

Posted (edited)

I have the 6.2 so I run 92 or 93 depending on where I gas up.

Edited by Last C5
Posted (edited)

E85 or mid grade gas. E85 locally mid grade on trips.

 

 

Sent from my iPhone using Tapatalk

This.

 

I average around 18-18.5 with e85 and 20.5-21 with 89. Financially it doesn't make any since to run regular gas as long as I can find e85.

Edited by Stars_Fan
Posted

E85 or mid grade gas. E85 locally mid grade on trips.

 

 

Sent from my iPhone using Tapatalk

 

Same thing here! Except I only use e85 when home and use gas when I go up north. I wonder if the motor will ever have long term effects with using roughly 95% of my fuel being e85. Thats what a warranty is for.

Posted

This.

 

I average around 18-18.5 with e85 and 20.5-21 with 89. Financially it doesn't make any since to run regular gas as long as I can find e85.

I pay between 1.35-1.65 for E 85, even if was the same price as mid grade gas Id buy it for the extra HP. I only use gas when I can't get E85 traveling.

 

 

Sent from my iPhone using Tapatalk

Posted

It won't get me any better fuel economy and certainly costs me more, all true... but has better additives and runs cooler. It's worth the extra $$$ to run cooler when towing to me.

This has me confused, can you explain why it would run cooler?

Posted

Ethanol burns cooler than gas, but your engine has to burn more e85 which makes it run hotter than burning gas.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Latest Articles

  • Posts

    • That is a good correction. I think “severity” was probably the wrong word for what I meant. What I really mean is closer to event priority, relevance, and actionability — not “this code is severe” or “replace this part.” I agree that a truck can have a lot of trivial or historical communication codes, and if the product starts pushing alerts for every stored or low-value event, people will ignore it very quickly. So the alert logic would need to be filtered. For example, I would not want a random old communication code to generate a push notification by itself. A useful alert would probably need to be based on things like: - new vs historical - active vs stored - repeated vs one-time - duration of the event - whether it happened near the driver-marked symptom - whether it happened together with voltage drop, reset, bus-off, misfire, oil-pressure change, etc. - whether the same pattern repeats under similar conditions So instead of saying “severity,” maybe the product should organize events by affected system and priority. For example: Misfire event: Show misfire counts / roughness first, then fuel trims, RPM/load, DFM/AFM state if available, coolant/oil temp, voltage, and related DTCs. Oil-pressure event: Show oil pressure first, but only in context — RPM, load, oil temperature, coolant temperature, DFM/AFM state if available, voltage, and baseline comparison. Communication event: Show which module/network/message dropped, whether voltage dropped, whether the recorder reset, whether it was active or historical, and whether it repeated. Voltage/reset event: Show battery voltage, crank/wake/sleep state, module reset, communication dropouts, and what came back online first. That also solves the display-order problem you mentioned. The main report should not always show the same fixed list first. It should show the system that appears abnormal first, and then the supporting values for that system. I also agree that the truck already has an oil pressure gauge and MIL. The point would not be to duplicate those. The value would be in showing what else was happening before and after the warning or symptom. For example, if the MIL comes on for a misfire, the truck already told the driver there is a problem. The useful part would be: - which cylinder or bank looked abnormal first - whether it happened after an AFM/DFM transition - whether fuel trims were already moving - whether oil pressure or voltage changed at the same time - whether the same pattern happened previously without a MIL On the OBD port point, I think you may be right for a consumer-facing version. OBD is much easier for the average owner: - easier install - easier removal - inside the cabin - easier phone connection - easier data download - easier to include a pass-through port for another scanner OBD is also the right place for DTCs, freeze frame, VIN, calibration information, Mode 6, and normal scan-tool parameters. The reason I was looking at ECM-side recording is that some events may be gone by the time someone plugs in a scanner, and some powertrain-side network evidence may not be available the same way through the DLC. But I agree that if an OBD-based version can capture enough useful evidence for most owners, that is probably the cleaner consumer product. Maybe the split is: - OBD/DLC version for most consumers - ECM-side version only if it proves it adds evidence that the OBD version cannot get - shop/pro version if deeper powertrain-side event evidence is actually useful So I would not want to force the inline approach if the OBD workflow solves most of the real-world problem. Your last point is probably the key product requirement: the report should be specific to the system showing the abnormality. Not “here are 50 parameters.” More like: “Misfire-related event detected. Here are the misfire/fuel/DFM/context values.” or “Oil-pressure-related event detected. Here is oil pressure compared with RPM/load/temp/baseline.” or “Communication event detected. Here is what dropped, when, and whether voltage/reset happened first.” That is a much better way to think about the report.
    • It was all part of the tiny bit of fuel savings it goes towards what was mandated by the government. Much like cylinder deactivation. That was relaxed by the recent administration. All that doesn’t help the individual buyer. But as a whole helps the manufacturer to try to reach the previous ridiculous past mileage per gallon mandate. So yes it was mandated and added cost to the vehicle. 
    • You do realize that auto stop/start...was never mandated by the fed...right?     EPA Says It's 'Killing' Stop-Start, and Here's What Automakers Have to Say   "Start‑stop technology has never been federally mandated, and the EPA’s recent action removes regulatory incentives associated with it rather than prohibiting its use."
    • Anytime the government mandates something, you can bet on it being absolutely senseless.
    • just logged my best MPG for one leg this am - drove home from the Denver Airport, 45 min drive - all freeway, lots of traffic so speeds were limited and some stop and go, got 17.7 for the ~30 mile trip.
  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...