do any of you use 91 octane in your f wun fiddy? do you see any difference in gas milage or hp or tq or any bs? Don't say yes if your truck isnt all stock.

 

As far as i know if you dont have a tune it makes your truck run sucky and can cause pinging

 

What he said. If you don't have a tune optimized for premium fuel, you're just throwing money out the window.

 

I can't say.....I'm not stock

 

well I cant run on anything less than 93... so I like it

 

No, it can't cause pinging. It will ping on too LOW an octane. It also won't run bad, it's just not worth the extra expense.

 

The army is paying for my gas.So i figured if there was a time to experiment it was now. I just didnt want to harm my truck. So as far as $$$ is concerned nopers.

 

get a tune that requires 91 octane, then you can take advantage of a lot more timing.

 

Sorry, mine too runs a chip requiring at least 91 octane, but from others, they say it makes a difference in how clean the engine runs. No hp gains that anyone notices, but when it comes time to change the plugs, they are showing a better burn which could only do good for the rest of the system, EGR for example. I don't think running it always is worth it, unchipped, but a few tanks here and there wouldn't hurt.

 

I just run normal 87 octane. There's really no reason to use anything more than regular if you have a stock truck, and it isn't pinging.

 

I run 87 in mine.....

Unless you add a blower or in some way increase your compression you won't need 91. (flame suit one)

I know many of you have been told by tuner manufacturers and belive that you need to remove the 4% of heptane do to a tune. You didnt increase the compression, you just changed the timing, so why would you suddenly ignite from compression sooner if you ran more heptane?

Dont belive me?

http://auto.howstuffworks.com/question90.htm

 

i ran 93 in my truck for a couple of tanks and got a little better gas mileage, but the extra .5 mpg didnt out weigh the extra cost

 

What you quoted doesn't say anything about increased timing, only compression. Since back in the 70's, I have always managed a lot more timing without knocking by running higher octane. That is fact. Higher octane changes the flashpoint and burn rate of the gas.

With a programmer, you can set it to run on higher octane (advanced timing). If you run low octane on the high octane setting, the computer retards the spark to stock levels. Mileage and performance suffer. I've tested my Superchips in all settings. FOr best mileage (well over the amount that justifies premium) I run the "tow" setting - the high performance setting gives me more performance, but lower mileage.

Around here, the cost of Premium is less than 5% over regular. I get over 20% better mileage. If you run Premium, use a programmer to optimize it's use. The computer will back down the timing for low octane, but doesn't take advantage of higher octane.

 

This is true. Everything else said is moot point cause this guys truck is stock, therefore the change in burn rate will have no noticable effect on the efficiency of his engine mechanics.

stick with a *quality* 89. There is no point in putting in higher octane if you have stock.


Ordinance- Is that b/c you are doing a DITY move? I'm doing my first one coming up here, and still trying to iron out the details...

 

That's why I said if you run Premium, get a programmer to optimize it. the computer will decrease the timing, but not increase it enough for Premium.