908 replies to this topic

[ski3pin]

Thanks Ted.

Do you know if your winter blend is the same as the rest of the countries?

My understanding (above my pay grade) is that various areas - basins mostly including the Reno NV area - have "oxygenated" winter blends to help them burn more completely.

[Casa Escarlata Robles Too]

My understanding (above my pay grade) is that various areas - basins mostly including the Reno NV area - have "oxygenated" winter blends to help them burn more completely.

Yea Ski it's all above our pay grade.Just keep the gas flowing and I'll use it wisely.
Frank

[pods8]

I'm glad I'm not going anywhere near CA gas stations in a couple weeks on the drive to CO. Gonna have my rig sucking down gasoline and a 26' penskee also pulling a car trailer drink'n the diesel in the caravan.

[ski3pin]

I'm glad I'm not going anywhere near CA gas stations in a couple weeks on the drive to CO. Gonna have my rig sucking down gasoline and a 26' penskee also pulling a car trailer drink'n the diesel in the caravan.

Pods, some of the lowest gas prices I find on the websites are in Colorado. Enjoy and have a safe trip!

[pods8]

Midwest tends to be lower in general I've seen, but also I wonder on the CO front if the pricing is for 85 octane rather that 87 which would be regular elsewhere?

[Overland Hadley]

Midwest tends to be lower in general I've seen, but also I wonder on the CO front if the pricing is for 85 octane rather that 87 which would be regular elsewhere?

Yes, I have found that the price listed on GassBuddy etc is for the 85. What runs on 85 anyway?

[Casa Escarlata Robles Too]

Yes, I have found that the price listed on GassBuddy etc is for the 85. What runs on 85 anyway?

I ran on the 85 for several tanks full.Didn't notice any difference.Still got 15.5 MPG.
Frank

[pods8]

Yes, I have found that the price listed on GassBuddy etc is for the 85. What runs on 85 anyway?

Anything that runs on 87 at sea level can run 85 around Denver type altitudes. The thinner air means less air mass in the cylinder stroke thus the compression ratio is reduced. The need for higher octane is strictly to deter engine knock and that is typically a function of the compression ratio of the engine. Higher compression is typically higher performance and requires higher octane for the ratio not the "performance". Thus less air means the grade of performance for each octane level at the pump is typically reduced. IE "regular" is 85 instead of 87.

In turn the reduced air mass means lower power out of the engine but that is regardless of the gas used.

[Casa Escarlata Robles Too]

Anything that runs on 87 at sea level can run 85 around Denver type altitudes. The thinner air means less air mass in the cylinder stroke thus the compression ratio is reduced. The need for higher octane is strictly to deter engine knock and that is typically a function of the compression ratio of the engine. Higher compression is typically higher performance and requires higher octane for the ratio not the "performance". Thus less air means the grade of performance for each octane level at the pump is typically reduced. IE "regular" is 85 instead of 87.

In turn the reduced air mass means lower power out of the engine but that is regardless of the gas used.

Pods the compression ratio doesn't change with the air mass.The compression ratio is set according to the capacity of the cylinder volume to the combustion chamber capacity in the head.It's the file/air ratio that changes from sea level to higher altitude.That's why carburetor-ed engines don't run 'as well as fuel injected ones at high altitudes.
I wouldn't want to use 85 down at sea level most likely hear a lot of knocking under power up hills.I even saw high mixes of Ethanol on the trip some as much as 85% ,which came from a different nozzle of the pump.The normal mix that was used was 10/15%.
Frank

[pods8]

Sorry typed that while drink'n. The final developed pressure verse being at sea level is reduced thus if you compared that against your sea level pressure the compression ratio in terms of pressure would appear to be reduced when it comes to fuel mixture even though the engine is still compressing the local atmospheric pressure the same amount, there is just a lower starting pressure to compress. So in the world of octane which higher levels are needed for retarding knocking of higher compression engines you inherently would need less octane if your ultimate pressure is reduced by atmospheric changes.

Assuming 0' of elevation is 14.7psi on a 10:1 engine would develop 147psi at sea level but at 5000' with a pressure of 12.2psi the engine would only have 122psi at the top of the stroke. Less octane is needed. Less power is also made. Less fuel is also used relatively but more throttle may be need to make up for the less power. Etc. I'll be feeling the whole situation out soon.