Hi everyone,

Quick question, has anyone tried high octane trick fuel in their trucks? I saw a sign the other day listing 101, 111 and 119 octane fuel. I could do a 50/50 mix of 101 in my 390 to see if there's any difference. Waste of money and/or hard on engine?

Thanks everyone.

 

Not going to be any harder on the engine, this is an old wives tail. Higher octane fuel does not burn any hotter (although slight BTU output can be argued, but not enough to make this an incorrect statement) and does not cause any additional stress on the engine.
because you have a reasonably mild engine, I can only assume that your engine does not "ping" like a higher compression / higher output engine would. This means you will never see any benifit od a higher octane fuel. The higher rated fuel will only be an advantage if your vehicle struggles for performance due to an increased amount of compression. If your ride does not "ping" now, you will be wasting your money.
Sure does smell nice as it burns, but you need to look at the price tag on the pump. You should expect to pay at least $7.00 per gallon. Probably more if it is being dispensed at a pump.
I buy VP C-14 by the drum, and it comes out to be more than $8.00 per gallon. The big engine (521 CI BBF) really needs the stuff (especially on the nitrous) but the smaller lower compression engines never notice a difference. STick with the lowest octane rating possible that will allow full ignition advance without detonation.

 

Yeah, what he said. Don't waste your $$ unless you have a performace built engine.

 

As mentioned, it does not burn any "Hotter"...However a higher octane fuel does need a slightly "Hotter" combustion chamber temp to ignite. Sounds silly?

Pre-ignition or "Spark Knock" can be extremely hard on an engine. (also known as "Pinging"). This is caused by the air/fuel mixture igniting before the spark plug tells it to!. Sometimes caused by low octane gas or "Cheapo" gas that is not well monitored..It's flash point is lower....so that can result in the heat from the combustion chamber on the compression stroke igniting it before it's supposed to happen. The "Ping" part is actually quite interesting. The piston is still being pressed "UP" by the force of the rest of the cylinders doing their thing...but that piston now has extreme downwards pressure on it. Then you get the spark plug firing. The "Ping" sound is actually the result of the ignition starting in a different area of the combustion chamber...and the plug firing a millisecond afterwards. The two flame fronts meet---and you get "spark knock".

At least that is the text book answer when I was back in school. It makes a bit more sense that when the pre-ignition takes place...it's trying to force the piston "downwards" while it's still trying to finish the compression stroke. All that extra energy created makes a lot of noise and stress due to it still trying to burn/expand...while it's trying to finish the compression stroke.

The higher octane gas is made using a higher flash point of ignition. It will take more physical "Heat" for the mixture to ignite on it's own...so if you have an engine that "pings", and it's in decent shape for timing and ignition parts? Sometimes using a higher octane fuel can help reduce that problem.

It's highly recommended for performance engines that use a much higher compression ratio, as cheap fuel can ignite before the plug fires it. The higher the compression ratio? The hotter the air/fuel mixture will become during that compression stroke.

Unless you have problems with spark knock, pre-ignition, detonation knock? Gas is expensive enough....and if you do not need it? Why waste the money?

S-

 

I used to treat my truck to a tank full of a 50-50 mixture of 91* and av-gas 110* on it's yearly birth anniversary.

My 10.5:1 comp 429 just loves it.

In BC one can still buy 95* Octane.

Zoom Zoom Zoom !

 

Best we have in this area is 93. Our former Probe GT loved the stuff. That's good stuff when you work on and drive a turbo charged engine. (now that's compression LOL)

S-