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DTOMKIDD

By DTOMKIDD
in Engines & Drivetrain

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TJay74 Senior Enthusiast

TJay74

Posted
Posted

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. :happysad:

 

I wouldn't run 85 octane at all, 89 would the minimum for me during cooler weather. once summer hits 91 no matter what, the hotter it is outside the more prone to detonation it becomes. While the truck does have 2 main tables for regular mode and DOD mode (high and Low) I don't want to be in the low octane table, it is about 15° less timing all the way across that table.

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diyer2 Senior Enthusiast

diyer2

Posted
Posted

Does your info apply to a 2012 non DI engine.

I have put 11k + miles on this engine since buying it used. Yes the manual says 87 octane but I have never heard a knock or ping.

Could the altitude in Colorado have an influence?

You have gotten me curious about this fuel thing. I do have Scan Tool software on my lap top but haven't hooked it up to my truck. I think it will work for the truck. :happysad:

Aaron1085 Senior Enthusiast

Aaron1085

Posted
Posted

Any input on running a can of sea foam thru your tank every once in a while ??

 

 

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mjoekingz28 Enthusiast

mjoekingz28

Posted
Posted

Any input on running a can of sea foam thru your tank every once in a while ??

Sent from my iPhone using Tapatalk

 

 

Read the manual. I do not think Chevrolet wants us pouring alien substances into our tanks.

TJay74 Senior Enthusiast

TJay74

Posted
Posted

Read the manual. I do not think Chevrolet wants us pouring alien substances into our tanks.

 

 

Actually you can run Seafoam thru the tank just fine.

Cowpie Senior Enthusiast

Cowpie

Posted
Posted

 

Could the altitude in Colorado have an influence?

 

 

 

Yes, indeed. At higher elevations on naturally aspirated engines, less octane is required to prevent knock. Hence, why you see 85 octane around the front range and the hill country of Colorado.

 

But knock is caused by a number of things. Carbon buildup on pistons can cause it, by elevating the compression a little. A stock engine that is in good shape and designed for 87 should do just fine on 87. If there is a need to use higher octane to overcome knock, that is the sign of another problem, not the fuel.

 

I am not in the Seafoam camp, but I do like Techron, Amsoil P.I., or Schaeffer Neutra added to the fuel every couple thousand miles to reduce carbon and other buildup.

diyer2 Senior Enthusiast

diyer2

Posted
Posted

Thanks Cowpie.

I'm no engineer but I bet a lot of vehicles require 87 octane. If that is true why would 85 octane be offered at all here in Colorado. It is the number 1 selling gas so a lot of motors requiring 87 octane are being run on 85 octane.

I know for sure my 93 5.7 specked 87, my lawn equipment does, my outboard, 2 cycle, 4 carbs and jetted,(premium only in it), my leaf blower and lawn mower speck 87. Every one of the wife's cars specked 87.

I put over 200k miles on my 93 primarily run on 85 octane except when towing the boat during fishing season, then premium, 91 octane here.

 

I also buy the majority of my gas at Costco, Top Tier with 5 times the amount of detergent additives than the gov. standard.

 

If I lived some where else it would get 87 octane.

 

I may try 87 for a while but Costco doesn't have it so I would have to switch brands.

 

To sum it up why give money away. :happysad:

KARNUT Senior Enthusiast

KARNUT

Posted
Posted

I never heard of 85, just E-85. Must have something to do with high elevation. So do you have 85,87,89,91,93?

sdeeter19555 Senior Enthusiast

sdeeter19555

Posted
Posted

They have 85, 87, and 91 typically. The other thing I noticed when I was out there is that 85 is often touted as "alcohol free", while 87 and 91 are e10.

 

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Jon A Senior Enthusiast

Jon A

Posted
Posted

Does your info apply to a 2012 non DI engine.

 

No. They are different engines. You do realize you're in the 2014+ section where the conversation is regarding the new engines, right?

sdeeter19555 Senior Enthusiast

sdeeter19555

Posted
Posted

E85 isn't 85 octane. It's 85% ethanol where regular gas rather it's 87 octane or 91 octane has about 10% ethanol. Some stations offer non-ethanol.

There is 85 octane gasoline as well...not e85.

 

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