Premium Fuel

[Sturdevant]

We know that Chrysler recommends premium fuel. Apparently the anti-knock sensor will retard timing or reduce boost, thereby reducing performance.

Has anyone actually documented these reductions? I know it seems slower, but can we show it by the numbers?

[Dalite]

I know I will be corrected if wrong, but isn't the octane rating only an indication of the anti-knock quality of the fuel?

In other words, the higher the octane (in the range of 87 to 93) the less chance of knock. In our case, that would equate to a higher probability of optimal performance with 93 than produced while using a lower octane.

If we could ever get some kind of data logger that is compatible with our systems, we would be able to measure and find out for sure...

[PVO PT]

I always put the highest availible in. I think you are right tho, Dalite. I could see no reason why it would not.

[COP TZER]

i got screwed once on a road trip at a gas station that RAN OUT OF PREMIUM!!?? I had to settle for the mid range crap, and boy did I feel a difference. It felt like I was driving around with the A/C on full blast and a garbage bag rapped around my intake cone

[PVO PT]

That sucks!! I hope I am never in that situation!

[rice_killing_GT]

I was in Vegas over the weekend, a couple 76 stations where I was getting gas, had competition fuel available, 100 octane. I didn't have my GT with me but it was like $3.95/gal. How would that help/hurt the engine. I figured you would need high perf spark plugs, wires. What else?

[bobs turbo pt]

i use 92 oct all the time,( thats when my car is running right) that 100 oct im not sure what it would have done

[Steve03GT]

quote:Originally posted by rice_killing_GT

I was in Vegas over the weekend, a couple 76 stations where I was getting gas, had competition fuel available, 100 octane. I didn't have my GT with me but it was like $3.95/gal. How would that help/hurt the engine. I figured you would need high perf spark plugs, wires. What else?

As Dalite noted, octane (or octane number) is defined as a number that measures the ability of a liquid motor fuel such as gasoline to prevent preignition or knocking. Fuels with higher numbers are less likely to cause knocking; conversely, the lower the octane number, the more energy (btu)per unit, which is why using a higher-than-necessary octane number (less energy/unit) results in decreased performance.
To answer your question concerning what effect 100 octane would have with your GT Cruiser, if you haven't done anything to increase cylinder pressure, e.g., more boost, timing-advance, or static compression, I suspect the 100 octane would hurt performance; this is assuming Chrysler has designed the engine and the PCM to perform optimally using 93 octane. Others feel free to chime in here.

[DTs_PTGT]

According to the owner's manual, the PT is tuned to perform optimally using 91 octane.

[PK Cruiser]

quote:Originally posted by DTs_PTGT

According to the owner's manual, the PT is tuned to perform optimally using 91 octane.

To bad I can't find any 91 octane here...closest is 89...I use 92 or 93 depending on when I need gas, which station I'm closest to...