Octane rating when mixing Regular gas (93octane) with Racing fuel (110) octane.

[mrhemi]

I did start my response by saying "I am reluctant get into this fray". (again)

 

[RemCharger]

I guess I could understand wanting the race gas smell...

 

[Jeff Peterson]

 

[66 Sat]

Not sure I want to get involved in this fray, but the OP did not specify whether the racing fuel was leaded or not.
Back in the day, when I actually worked for Suncor (Canadian Sunoco), we did all of the different blends with pump unleaded, av gas and race gas. All were verified in the Waukeshaw knock engines in the lab. If the race fuel in question is unleaded, the straight ratio math formula can be used. If it is leaded race fuel, it is not that simple.

So @pnora was correct back on page 1.

 

[33 IMP]

Imo, bottom line.....
The actual "number" means nothing. You need to run whatever it takes to not detonate. If that's best available local pump gas, or something to increase detonation resistance, that what you need to do. An octane booster, (if you can find one that actually works!), some avgas, some race gas, whatever.
Experiment! 20 gal tank? Put in 15 gals of the best pump, add two gallons of 110.(or avgas). If that doesnt get it done, toss in another one or two. When I doesnt detonate any more, you're done!
You don't need a degree, or a calculator. You need good hearing, and the ability to read plugs!

 

[33 IMP]

Beware of "octane boosters" that say they'll raise octane by (whatever number) of points. Say five points for discussion.
What that REALLY means is it raises by five DECIMAL points. From 91..... to 91.5!

 

[dadsbee]

 

[j-c-c-62]

So @pnora was correct back on page 1.

I support your right to believe anything for or without any reason.
I also believe ignorance is bliss still remains true.

 

[j-c-c-62]

It's been well known that adding lead increases octane. It was a popular trick in the 1970s, with published tests showing the improvements, to mix unleaded and leaded gas. A 50/50 mix of regular leaded and regular unleaded resulted in higher octane than either on their own, due to the 'kick' of the lead being added to the unleaded. It was not logarithmic; the unleaded gained more octane than the leaded would than either on their own would

Published you say? Got a link?

 

[j-c-c-62]

All this discussion (crap), is worthless to me. I'm just doing what works for my cars. You have beat this horse to death.

So just go away then, if you have nothing of worth to share.

kelly's heros clips - Search Videos

 

[j-c-c-62]

This is the most definitive answer on the topic IMO so far with my highlights added:

"The latest question was about blending octane number. For example, if you blend a 100/130 (commonly referred to as 100LL) fuel with a 90 octane mogas, will a 50/50 mix give you a 95 octane fuel? The answer is possibly, but probably not.

I know that this is kind of a trick question, but the answer can be useful.

The most important thing to remember is that the octane of a fuel is not a physical property of the fuel, but rather a performance property.

A physical property of a fuel or oil is like the viscosity of oil. If you mix grade 80 oil 50/50 with 120 grade oil, you will have grade 100 oil.

As a performance property, a given octane fuel can perform differently than another fuel when compared in different applications.

When comparing octane, you must consider that there are four different octane rating procedures."
Ben Visser is an aviation fuels and lubricants expert who spent 33 years with Shell Oil. He has been a private pilot since 1985.
The trick to blending fuels — General Aviation News


Ben Visser is an aviation fuels and lubricants expert who spent 33 years with Shell Oil. He has been a private pilot since 1985

In the spirit of FBBO camaraderie, consider this reply my mea culpa.

 

[Jerry Hall]

So just go away then, if you have nothing of worth to share.

kelly's heros clips - Search Videos

I added my thoughts 2 different times on this subject, but you choose to ignore it, therfore I could care less. Do what you will. There are people on this forum that like good advice and then there's you. Buzz off.

 

[j-c-c-62]

I added my thoughts 2 different times on this subject, but you choose to ignore it, therfore I could care less. Do what you will. There are people on this forum that like good advice and then there's you. Buzz off.

Now I need to justify no response on my part because your feelings are hurt because I chose to not reply to your first response of stating the obvious, that did not address the OP's initial question directly of determining blended octanes?
Your second reply doesn't deserve a further comment.

Tough crowd.

I'm not going anywhere.

You could take your own advice BTW.

 

[66 Sat]

I support your right to believe anything for or without any reason.
I also believe ignorance is bliss still remains true.

It wasn't "without any reason", it was based on what mrhemi said "back in the day, when I actually worked for Suncor (Canadian Sunoco), we did all of the different blends with pump unleaded, av gas and race gas. All were verified in the Waukeshaw knock engines in the lab. If the race fuel in question is unleaded, the straight ratio math formula can be used. If it is leaded race fuel, it is not that simple.

Which is what pnora said on page 1.

You're an argumentative ******* prick, which I believe you get off on, stirring people up on the internet.

 

[j-c-c-62]

It wasn't "without any reason", it was based on what mrhemi said "back in the day, when I actually worked for Suncor (Canadian Sunoco), we did all of the different blends with pump unleaded, av gas and race gas. All were verified in the Waukeshaw knock engines in the lab. If the race fuel in question is unleaded, the straight ratio math formula can be used. If it is leaded race fuel, it is not that simple.

Which is what pnora said on page 1.

You're an argumentative ******* prick, which I believe you get off on, stirring people up on the internet.

Noted

 

[kiwigtx]

That looks like how many guys Stormy Daniels had sex with.

 

[Photon440]

Published you say? Got a link?

No, I didn't see it online. I had it in a magazine article but no idea where it is now.

 

[kiwigtx]

As others have posted, just find a station (better yet, a network of stations in your area) that offer ethanol-free gas.
Preferably 93 alky-free.
Adjust timing so it just barely doesn't detonate (knock) on it and you're golden - but that "alcohol-free" part matters
more than you'd think.
Here locally, the difference between the 93 ethanol blend and 93 no alky is readily apparent in Fred; he runs noticeably
better on the no-alky stuff and gets further on a gallon, too.
(Hint: Check with the closest Co-op; they sometimes offer alcohol-free).

BTW, this is "Fred" on the good stuff:
View attachment 1821985

Fred looks surprised.

I used to put about 25% AV-Gas to premium in my GTX, and the best it did was clean up the tail pipe and make it go a lighter colour. It did seem to add extra go, but really that was 'seat-of-the-pants' measuring.

 

[ROYSTOLL2]

When I was racing my 383 4-speed '68 Road Runner in the '70's at the drag strip, I experimented with 140 octane avgas that I bought at the local airport as my roomate at the time had an A & P license and worked in one of the hangers. My 383 had second hand stock heads and I ported and polished them out myself. The problem was that they had been milled a touch too far and the car had over a 13 to one compression. When I shut it off, it would diesel for 30 to 45 seconds. I tried the 140 octane avgas at the strip, and it ADDED almost a second to my time. What you have to remember is that regular gas with no added octane is actually purer than the premiums with added chemicals that do not burn but that actual retard the burning. You can measure the octane in the fuel with a hydrometer. Back then, I was kinda in the stone age so that mas my understanding so maybe I was wrong. My son races a 67 Nova with dual turbo chargers and he runs it on E-85. #1. On this go around with my '70 Road Runner, 440, I am going to be more conservative on the heads as to compression.

 

[jdsgtx]

Was talking with a friend on this, he says the Regular Gas (93 Octane) will Degrade the Racing gas (110 octane). I always thought it was the opposite. If you have and 20 gallon fuel tank and have 10 gallons of Regular 93 Octane gas and add 10 gallons of Racing Fuel at 110 Octane; what would be the Octane rating of the mixed fuel in the 20 gallon tank ? I'd say it would be somewhere around 101 octane. What say you on this ? I know you could run all 20 gallons of Racing fuel but at $12.00 per gallon that would be a $240.00 fill-up, can't afford this. Also, the 10% Ethanol in the 93 octane gas comes into the picture.... Also, what about mixing with Aviation gasoline.... I've heard good and bad on this, something like AvGas has additives to keep airplane carbs from icing up in higher altitudes. Any views on this ? This mixed gas is for my 69 Charger with a 383 Magnum engine, stock rebuild.
Tks
Bob32268

Was talking with a friend on this, he says the Regular Gas (93 Octane) will Degrade the Racing gas (110 octane). I always thought it was the opposite. If you have and 20 gallon fuel tank and have 10 gallons of Regular 93 Octane gas and add 10 gallons of Racing Fuel at 110 Octane; what would be the Octane rating of the mixed fuel in the 20 gallon tank ? I'd say it would be somewhere around 101 octane. What say you on this ? I know you could run all 20 gallons of Racing fuel but at $12.00 per gallon that would be a $240.00 fill-up, can't afford this. Also, the 10% Ethanol in the 93 octane gas comes into the picture.... Also, what about mixing with Aviation gasoline.... I've heard good and bad on this, something like AvGas has additives to keep airplane carbs from icing up in higher altitudes. Any views on this ? This mixed gas is for my 69 Charger with a 383 Magnum engine, stock rebuild.
Tks
Bob32268

Not understanding why you need to run anything past the 93 octane in a a stock build 383??