ZL1 fuel question part 2

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91 octane is the best I can get here in western Colorado at 4500 feet elevation. Shell has 91 octane pure gas
Would that be better than regular Shell 91 octane??
Thanks in advance.
 
Not really. Certainly not better performance. I've even heard some claims that E10 might have better performance because you're throwing in oxygen right in the fuel. I mean - there's all these convoluted things done to try and increase the amount of oxygen in the charge, including forced induction, multi valves, polished intakes, etc.

I certainly wouldn't pay a huge premium for it.
 
I assume you're at high elevation - iirc, at higher elevation octane requirements drop.

It has never been compelling to me to pay a premium for pure gas, as the mpg improvements don't make up the cost.

Ethanol does have higher octane rating, which is why e85 is favorable to some.
 
If Shell 91 is all you can get then I'm sure it will be ok, is this a stock Zl1? or is it heavily modded like the car in your sig?

Ethanol (E10) fuel is oxygenated to some degree so I'd think it would work better in your performance car than plain gas.
 
It has a axel back dual stage exhaust. Will add a good CAI this spring but that's it. Want to keep it under warranty for the next 6 years
 
Last edited:
Originally Posted by dbvettez061
Owners manual says NO E10.


How is that possible?

Many markets have only E10
 
Originally Posted by Linctex
Originally Posted by dbvettez061
Owners manual says NO E10.


How is that possible?

Many markets have only E10

I don't believe that's the case with the Camaro ZL1. I found a copy of the Camaro High Performance Owners' Manual Supplement. It's on page 33 and it looks like anything up to E15 is approved. It is different in that the base model Camaros recommend at least 87, the higher performance models recommend at least 91 with 87 acceptable if 91 isn't available. That one recommends 93 but says 91 is the minimum acceptable AKI rating. I had to reassemble the order. It's really weird how it seemed out of order with a cut and paste.

Quote
https://my.chevrolet.com/content/da...performance-owners-manual-supplement.pdf
Fuel
GM recommends the use of TOP TIER detergent gasoline to keep the engine cleaner and reduce engine deposits. See www.toptiergas.com for a list of TOP TIER detergent gasoline marketers and applicable countries.

Do not use any fuel labeled E85 or FlexFuel. Do not use gasoline with
ethanol levels greater than 15% by volume.

Use premium unleaded gasoline meeting ASTM specification D4814
with a posted octane rating of 93.

If unavailable, unleaded gasoline with a posted octane rating of 91 may be used, but with reduced performance and fuel economy.
If the octane is less than 91, the engine could be damaged and the repairs would not be covered by the vehicle warranty. If heavy knocking is heard when using gasoline rated at 93 octane, the engine needs service.

Prohibited Fuels
Caution
Do not use fuels with any of the following conditions; doing so may damage the vehicle and void its warranty:
. For vehicles which are not FlexFuel, fuel labeled greater than 15% ethanol by volume, such as mid-level ethanol blends (16 - 50% ethanol), E85, or FlexFuel.
 
Originally Posted by Linctex
Originally Posted by dbvettez061
Owners manual says NO E10.


How is that possible?

Many markets have only E10


That just made 99% of the US ineligible for one.
 
Originally Posted by Pew
Originally Posted by Linctex
Originally Posted by dbvettez061
Owners manual says NO E10.


How is that possible?

Many markets have only E10


That just made 99% of the US ineligible for one.

The vast majority of the fuel sold in the US does use ethanol, but I'm not sure that the maximum is always the case. Using oxygenates is almost a no brainer given that it's both cheaper than non-oxygenated gasoline and it's the easiest octane booster to use.

I know there are some regions where the demand for premium is low, and even where E0 93 AKI premium is the norm. However, there's no way that would be likely in a place like California where there's a huge demand for premium. They would need to waste fuel to get the numbers to work even if 87 and 89 were E10 but 93 was E0.
 
Originally Posted by JHZR2
I assume you're at high elevation - iirc, at higher elevation octane requirements drop.



Only if your engine is NA. Boosted engines retain the same octane requirements...
 
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