Is premium gas worth it?

tomtucson

tomtucson

New member
Is there a benefit to using high octane in small engines? Theoretical benefit? Actual experienced benefit?
 
Yes their is, check your engines minimum required spec for fuel, some engines require higher octane fuel as their engines compression ratio is higher, A dragster with a high compression engine. 11:1 would benefit from the higher combustion pressure point of say 93o vs 87o. Meaning the fuel can be squeezed tighter building more potential stored energy before it ignites by too much pressure or from a spark. So if you threw in 87o to that dragster the fuel being squeezed in the piston would self ignite before the piston traveled up the cylinder to its maximum point and highest energy producing point. This is called detonation, it can destroy an engine instantaneously in extreme situations. Most common engines are able to use regular fuel no problems.. My 13horse Subaru engine asks for 91o. When im running it at full throttle and I let off the wand, the engine might backfire or hiccup until it normalizes usally a split second, but when I do that with proper fuel in, no hiccup, no backfire no nothing by smooth running. I think you'll be fine with normal fuel.

No difference in quality as far as unwanted stuff in lower octane fuels vs higher ones, just the fuels ability to resist ignition when being squeezed tighter by a higher compression engine.
 
About three years ago I kept having problems with my rigs. Cutting off, then hard to start etc. Ron told to me use the high octane gas. Have used it since and never a problem since.
 
Higher octanes burn cleaner - less carbon build up = longer oil life & longer periods between servicing engine internals due to normal wear = longer engine life. Not to mention a little more umph in HP.
 
I use middle grade because high grade explodes faster and hotter. Hotter on a small engine without a coolant system = wear and tear. Then again, the low grade is kind of opposite. Less explosive and can leave unburnt gas pushing out the valves causing harder running and pinging. So middle grade for me!


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My brand new Pressure Pro unit has a Honda GX690 on it that was designed with a compression ratio of 9.3:1. This is so that it may be compatible with the industry minimum standard octane rating of 86. The engine will not put more force on the fuel in any situation during normal operation so technically I should have zero need for anything higher as far as pressure and ignition of the fuel is concerned. Now to say that this machine will only get 91/93 is true.. the math supports the use of basic fuel, but I prefer the higher rating as you can tell a difference when parts/machines are forced to run at peak performance as stated earlier. What engine do you have... ?

In my motorcycle its engine was rated at 12.8:1. I never gave it anything less than 93o or 80% of the time it was running 114o. There was a major difference between the two, but then again the compression was there to support the fuels characteristics. If I put 86 in that bike, it would blow up.. likely blow a hole in the valves or shatter the cylinder or break a connecting rod due to pre-ignition of the fuel forcing the piston downwards before its stroke has completed, essentially working backwords.
 
Honda gx 690 and a generac gth 990 here. I would like to see actual myth-buster type tests I guess. I understand the concept but, if it's not knocking, is there then nothing to be gained by increasing the octane? Running at constant speed and load, does that matter? I'm inclined to take the testimony of long time users.
 
tomtucson said:
Honda gx 690 and a generac gth 990 here. I would like to see actual myth-buster type tests I guess. I understand the concept but, if it's not knocking, is there then nothing to be gained by increasing the octane? Running at constant speed and load, does that matter? I'm inclined to take the testimony of long time users.
Click to expand...

what about trying ethanol free marine gas?
 
More learning,

[h=2]Read Your Owner’s Manual[/h]Unless your engine is knocking, buying higher octane gasoline is a waste of money. Premium gas costs 15 to 20 cents per gallon more than regular. That can add up to $100 or more a year in extra costs. Studies indicate that altogether, drivers may be spending hundreds of millions of dollars each year for higher octane gas than they need.
It may seem like buying higher octane “premium” gas is like giving your car a treat, or boosting its performance. But take note: the recommended gasoline for most cars is regular octane. In fact, in most cases, using a higher octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage, or run cleaner. Your best bet: listen to your owner's manual.
The only time you might need to switch to a higher octane level is if your car engine knocks when you use the recommended fuel. This happens to a small percentage of cars.

From the FTC.

http://www.consumer.ftc.gov/articles/0210-paying-premium-high-octane-gasoline

Knocking is generally caused by engine tolerances going out of spec, either on rods, bearings, valves, etc. Not by fuel type unless drastically different, 86o vs 114o You put 114 in a small engine it will likely run very hot, melting parts, would knock as soon as springs for the valves heated up and stretch out.
 
valley pressure wash said:
More learning,

[h=2]Read Your Owner’s Manual[/h]Unless your engine is knocking, buying higher octane gasoline is a waste of money. Premium gas costs 15 to 20 cents per gallon more than regular. That can add up to $100 or more a year in extra costs. Studies indicate that altogether, drivers may be spending hundreds of millions of dollars each year for higher octane gas than they need.
It may seem like buying higher octane “premium” gas is like giving your car a treat, or boosting its performance. But take note: the recommended gasoline for most cars is regular octane. In fact, in most cases, using a higher octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage, or run cleaner. Your best bet: listen to your owner's manual.
The only time you might need to switch to a higher octane level is if your car engine knocks when you use the recommended fuel. This happens to a small percentage of cars.

From the FTC.

http://www.consumer.ftc.gov/articles/0210-paying-premium-high-octane-gasoline

Knocking is generally caused by engine tolerances going out of spec, either on rods, bearings, valves, etc. Not by fuel type unless drastically different, 86o vs 114o You put 114 in a small engine it will likely run very hot, melting parts, would knock as soon as springs for the valves heated up and stretch out.
Click to expand...

I think we are talking small engines not vehicles. I know switching to the premium gas in my rigs eliminated problems I was having. But that's just my experience.


Doug Rucker
Clean and Green Solutions
Pressure Washing Roof Cleaning School
Call or Text 281.883.8470
 
Tom, you need to read your spark plug. I'm sure there is info on U Tube and the net. Start there, then worry about octane, hotter plugs, and more that relates to a performance engine than a small engine. Oh ya the engine in my dragster is basically a 511, it runs on race fuel, for mine I run 120 octane, she get in the 7s at 170 mph. I used to run down at SIR down in you area, nice track. Hope this helps or gets you a start.
 
Solopressure washer said:
Tom, you need to read your spark plug. I'm sure there is info on U Tube and the net. Start there, then worry about octane, hotter plugs, and more that relates to a performance engine than a small engine. Oh ya the engine in my dragster is basically a 511, it runs on race fuel, for mine I run 120 octane, she get in the 7s at 170 mph. I used to run down at SIR down in you area, nice track. Hope this helps or gets you a start.
Click to expand...

My Honda runs like a champ, I was just wondering about the gas. As far as reading spark plugs, I never knew about it till I found this - really thorough and interesting.
http://forums.bimmerforums.com/forum/showthread.php?1282968-Ultimate-Spark-Plug-Reading-Thread
 
You ever heard of color tune spark plugs? It's a clear spark plug that you look through and compare the color in the combustion chamber with a chart.
 
Oh ya forgot, wake up this am and go out on the back porch to see what kind a day it's going to be and I hear a humming noise, go out to the trailer and my starter motor is just turning try to turn the key on and back off and nothing starter still turning, run to the tool box get a set of dikes and cut the cable to the battery, guess I will be taking back it back for a new one. Just proves that electricity is FM f...ing magic. Have a great weekend to all.
 
Solopressure washer said:
Never heard of it, sounds like snake oil........ If it runs like a champ and I'm sure there a few hours on it then leave it alone and go make more money with the Honda.
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I think that thing is for real - you actually observe the flame directly - and this tells you the mixture that is burning. But that is for another project I've been interested in. The honda v-twin blows doors on everything else as far as I can tell, still new though. Is that a Phoenix house in your pic?
 
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