Sold on 89 Octane

[roaniecowpony]

Don't confuse compression ratio with cylinder pressure. Compression ratio is a simple mathematical calculation of the swept volume of the cylinder and combustion chamber when the piston is at the bottom, vs the volume of the chamber with the piston at the top. It's a design characteristic, not a performance characteristic. It does not include/consider leakage or the volumetric efficiency of the engine.

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[Bikemobile]

Don't confuse compression ratio with cylinder pressure. Compression ratio is a simple mathematical calculation of the swept volume of the cylinder and combustion chamber when the piston is at the bottom, vs the volume of the chamber with the piston at the top. It's a design characteristic, not a performance characteristic. It does not include/consider leakage or the volumetric efficiency of the engine.

Yeah actual cylinder pressure vs the compression ratio the engine was designed for. my big point is there are too many variables to consider to definitively say that 89 octane gives you better MPG or running characteristics.

 

[roaniecowpony]

In ww2, Jimmy Stewart... I mean Charles Lindberg went to Europe to teach the fighter escort pilots how to get better fuel economy from their planes so they could cover the bombers on more of the flights to targets. He did this by increasing BMEP by running lower rpm at higher throttlesettings. Modern automatic transmissions are programmed to do this and play a large part in fuel economy.

 

[jmr]

The problem is that the 3.6L circulates a decent amount oil back into the intake manifold. The oil is then burned and by doing so lowers the octane level of the fuel resulting in pinging. A catch can will help alleviate that issue by capturing the oil that would have gone into the intake manifold.

 

[roaniecowpony]

The problem is that the 3.6L circulates a decent amount oil back into the intake manifold. The oil is then burned and by doing so lowers the octane level of the fuel resulting in pinging. A catch can will help alleviate that issue by capturing the oil that would have gone into the intake manifold.

The latest design oil separator/PCV valve will also reduce oil ingestion.

 

[Cire]

The problem is that the 3.6L circulates a decent amount oil back into the intake manifold. The oil is then burned and by doing so lowers the octane level of the fuel resulting in pinging. A catch can will help alleviate that issue by capturing the oil that would have gone into the intake manifold.

Should I put a catch can on a 2021 rubicon with 12,000 miles? If so, what is recommended? I am not concerned with spending money if it will make the 3.6 last.

 

[azjl#3]

oh boy..

 

[jmr]

Should I put a catch can on a 2021 rubicon with 12,000 miles? If so, what is recommended? I am not concerned with spending money if it will make the 3.6 last.

I put a J&L catch can on my 2024 Gladiator and was surprised how much oil it caught.

 

[Old Dogger]

Why not just use, what your Owners manual suggests that the engine is designed to use?

 

[Odyssey USA]

The latest design oil separator/PCV valve will also reduce oil ingestion.

Have that part number handy? Got a ‘21 3.6 eTorque.

 

[LDSSILLS]

Heres a little thing I did with my 2021 3.6 Torque Rubi with 14,000 miles. I tried different grades one tank at a time.
So you know, I am aware that the EPM needs to settle in with octane changes so I let the EPM adjust until the tank was about 1/2 full before I paid attention.

Driving was on a highway with rolling hills. There was no passing. Lane changes were nominal. Elevation 700-850 miles. Climate Control was on auto, heat seaters on, I have a bad back. Wind was 10-15mph on all trips from the passenger side.

Temp ranged from 50F to 71F.

-I tried 87 octane with 10% ethanol. Onboard average MPG gauge at 70mph for 16 miles revealed 17.5 MPG. Could hear the terrible Chrysler Engine ticking in driveway when returned home.
-I tried 87 octane with NO ethanol. Onboard average MPG gauge at 70mph for 16 miles revealed 18.3 MPG. Could NOT hear the terrible Chrysler Engine ticking in driveway when returned home.
-I tried 91 octane with NO ethanol. Onboard average MPG gauge at 70mph for 16 miles revealed 21.2 MPG. Could NOT hear the terrible Chrysler Engine ticking in driveway when returned.

Ill pay more for 91 Octane. MPG increases alone show power

 

[TheRaven]

Why not just use, what your Owners manual suggests that the engine is designed to use?

Because of the 0w-20 fuel mileage conspiracy. They're all in on it!

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