Premium in 2F (1 Viewer)

[Tylerh84]

On the way home I decided to put some premium in her to try to help flush some old gunk out and boy did she not like that! I just got it tuned and all of a sudden the idle jumped up to 1200 and she sputters like crazy under acceleration.

Anybody else have the same thing?
I know they aren't designed to run a higher octane and I didn't think of that at the time . But luckily I only put 10 gal in her and filled the other 25 up with regular. So I'm letting it idle now to try to get to the mixed gas.

 

[FJ40Jim]

The only way the idle jumped from 650 to 1200 is if there is twice as much air getting into the engine.

 

[micruz60]

I run pure gas, sans ethanol in winter, 87-93 octane... Better running. ymmv.
In rest of world (row) 2F runs on pisswater, or so I've read.
It's the ethanol here that makes 2F unhappy.

 

[Rustic76]

I’ve been running premium for the last month after my desmog and it runs great. The octane of the fuel isn’t the source of your problem, gotta be something else.

 

[HemiAlex]

I’ve not seen anything raise the idle except for a vacuum leak from a misfire kicking off a hose in a random circumstance.

 

[OSS]

Premium fuel (that isn't contaminated) runs great in a 2F.

 

[Rustic76]

Could it be that your choke is stuck or something is hanging up carb linkage somewhere?

 

[Tylerh84]

Could it be that your choke is stuck or something is hanging up carb linkage somewhere?

Possibly. I'm gonna check it after work. It was fine but I revved it once to see how the idle dropped but it just stayed up and ran rough .

 

[Seth S]

High octane fuel won't make a low compression engine run better....it might help you if you have carbon buildup inside and reduce pre-ignition but if anything you will run worse. The ethanol will mostly effect old gaskets and lines. If you are running high compression pistons or a turbo you will see a benefit from the higher octane.

 

[LAMBCRUSHER]

Lower octane makes more energy.

 

[HemiAlex]

In honor of this post i filed up with 93 at Costco. I still get passed by every Prius I see.

 

[Jaric00n]

Might get passed by Prius on Dry roads....
let's see dem priuses on some trails
<.<

 

[OSS]

Here's a little story...
There are two grades of gasolina in Mexico: Magna Sin (regular) & Premium. Stated octane rating of the two fuels is 87 & 92 but the 87 feels more like octane 85 or 86. El crapo.

Premium fuel has been available down there at stations in larger towns for the last 20 years. But before then... It was only Magna Sin regular and leaded Nova (which had an even lower octane rating).

Trips to Mexico in the past always meant low power and pinging/knocking when pushing the engine. The timing could be retarded a few degrees to prevent pinging, but the power & fuel economy would take a hit.

There are a few mountain grades that always required a downshift into 2nd gear to finally clear the top (with a loaded cruiser) when running on Magna Sin regular. I would always have to downshift to 2nd almost at the exact same location every time... Slowly cresting the hill.

Then in the late 90s Pemex introduced Premium fuel down there- Octane 92. The stuff was like rocket fuel in my cruiser's 2F. It was as if a NOS injection system had been hooked up or my pokey 2F suddenly became a V8.


The difference in power, torque and improved fuel economy was striking. Engine ran cooler too. The 2F running on premium down there was a completely different engine. It ran better down there on Pemex premium than any fuel I could buy in the states.

With their premium, I could now crest those mountain passes in 3rd gear easily which used to drop me down into 2nd every time.

It was probably because it wasn't diluted with alcohol or something that gives it a "fake" octane rating like we have here in the states with blended RFG.
The bottom line is...when the 2F gets the right fuel of the right octane - it's a plenty powerful engine.

 

[HemiAlex]

I was really impressed how my truck handled all the hills in big bend NP and even the SP.

I only had one second gear hill and it was just a tight and windy road that I couldn’t hit with any speed.

Picture taken in BBSP.

 

[bwesty]

92+ octane name brand fuel with zero ethanol makes for a very happy 2f especially with advanced timing. Hard to find ethanol free fuel in AZ but as mentioned in Mexico or other places it's common.

 

[HemiAlex]

I really like the 87 NEG but it’s hard to find in Texas. All over Louisiana and Mississippi.

I wonder how leaded 93 on a desmogged and decatted truck would run.