Mid-Grade Gas in a LS?

[atlang3lo]

Will putting Mid-Grade gas in my LS mess up my car? I heard it will mess up my car.

[SlingShot]

Nope, it's kool ... I run 89-91 in wife's car and no problems ...

[atlang3lo]

Oh Okay

[KarFan]

Putting in a higher octane gasoline than is required is just wasting your money.

[Berean]

I run premium in my Iron Duke, but it's not a daily driver.

[CamaroScotty]

Originally Posted by KarFan

Putting in a higher octane gasoline than is required is just wasting your money.

unless you achieve better MPG

[formare]

Folks at conoco tell me to buy the mid grade. Reason being if something (gunk) is in the supply pipes that needs to be blended off they only blend it with the low octane gas.

[axis]

Originally Posted by CamaroScotty

unless you achieve better MPG

In that case, there's something wrong with the unleaded you're getting. If your car is tuned for regular unleaded, and you aren't knocking, there should be no difference in mileage.

Originally Posted by formare

Folks at conoco tell me to buy the mid grade. Reason being if something (gunk) is in the supply pipes that needs to be blended off they only blend it with the low octane gas.

And you bought that reasoning?

[formare]

Originally Posted by axis

In that case, there's something wrong with the unleaded you're getting. If your car is tuned for regular unleaded, and you aren't knocking, there should be no difference in mileage.



And you bought that reasoning?

Yep - was working on industrial automation project and these folks are the ones who understand the entire process to ready the product for the pump...

[KarFan]

Originally Posted by CamaroScotty

unless you achieve better MPG

You’re not supposed to. As axis stated if higher octane gasoline is yielding consistently better MPG then it's more than likely the brand of gas your buying.
Actually using higher octane gasoline can slightly degrade performance for vehicles made to run on regular unleaded. 89, 91, 93 octane burn slower and are more resistant to heat and combustion the higher the octane number. That's why higher compression engines sometimes require 91 octane to prevent detonation. It also works the other way where the fuel is burning too late for optimum performance. The PCM will have to change timing to compensate and some performance is lost.

[SlingShot]

Originally Posted by KarFan

You’re not supposed to. As axis stated if higher octane gasoline is yielding consistently better MPG then it's more than likely the brand of gas your buying.
Actually using higher octane gasoline can slightly degrade performance for vehicles made to run on regular unleaded. 89, 91, 93 octane burn slower and are more resistant to heat and combustion the higher the octane number. That's why higher compression engines sometimes require 91 octane to prevent detonation. It also works the other way where the fuel is burning too late for optimum performance. The PCM will have to change timing to compensate and some performance is lost.

It's already been proven that running mid grade in the LLT puts less of a load on the ping sensors, thus pulling less timing and increasing performance ...

[formare]

Originally Posted by SlingShot

It's already been proven that running mid grade in the LLT puts less of a load on the ping sensors, thus pulling less timing and increasing performance ...

What he said.... All dyno research indicates increase in performance with increase octane.