104 Octane too much?

[Smitty Smithsonite]

I watched 2 back-to-back dyno runs using a Kawasaki Ninja ZX-9 back in the early '00's lose 3 RWHP going from 93 octane, to leaded 109 octane Sunoco Cam-2 race fuel.

If it doesn't detonate or ping on 93, you definitely don't need anything higher than that.

 

[bwalker]

Higher octane fuels only control the flash point of the fuel. The lower the octane the lower the flash point . It’s all for detonation purposes. Higher octane allows higher compression and more advanced timing . The “heat” is controlled by additives . So in theory any gas can be made to burn hotter or cooler regardless of octane

That's also not even remotely true.
Propane has a octane rating of around 105 yet has a very low flash point for instance.

 

[bwalker]

I watched 2 back-to-back dyno runs using a Kawasaki Ninja ZX-9 back in the early '00's lose 3 RWHP going from 93 octane, to leaded 109 octane Sunoco Cam-2 race fuel.

If it doesn't detonate or ping on 93, you definitely don't need anything higher than that.

You can lose that much power just from being heat soaked on back to back runs..

 

[rocco611]

95 octane is ok, you will likely lose performance running 104 octane. I use 100LL avgas in my old cars and lawn equipment. the only other ethanol free fuel pump gas is over 100 miles away for me here in California. Race gas in 5 gallon cans $18 a gallon. avgas at the pump is $8 a gallon. ethanol free gas in 1 gallon cans $25 a gallon. Small engines like string trimmers and chainsaws (engines that are easy to dump the fuel) I sometimes run 10% ethanol fuel in them with no problem, I just dump the fuel and store them dry.

New California law 2024 bans sale of new small gas engines rated at or below 25 hp (19 kW) , will be interesting to see how that works out.

 

[rogue60]

Octane has absolutely nothing to do with how fast or slow a fuel burns

 

[retiredfarmer]

That is just new engines I'd it not? My understanding is that if you had a gas powered lawnmower you could continue to use it and when you went to buy a new one you would not be able to do so. Did I understand that correctly?

 

[rocco611]

That is just new engines I'd it not? My understanding is that if you had a gas powered lawnmower you could continue to use it and when you went to buy a new one you would not be able to do so. Did I understand that correctly?

correct, the ban is on the sale of new engines and equipment.

 

[retiredfarmer]

Up here in Canada some privinces are talking about banning all small engines new and old. And as usual at no compensation for your old one.

 

[greenvillemowerguy]

Why would he have higher engine temps?

The higher the octane the higher the temp. Is that not so?

 

[greenvillemowerguy]

That's also not even remotely true.
Propane has a octane rating of around 105 yet has a very low flash point for instance.

Different chemicals, apples & oranges.

 

[SS396driver]

That's also not even remotely true.
Propane has an octane rating of around 105 yet has a very low flash point for instance.

The lower the octane the easier it will ignite under heat and pressure . Pinging or pre ignition is just that ,the gas is ignited by pressure in a high compression environment this is prior to the spark . I shouldn’t have said flashpoint which is where the liquid turns to vapor . The higher the octane the higher the resistance to pre ignition.

 

[bwalker]

The higher the octane the higher the temp. Is that not so?

No, not at all.

Different chemicals, apples & oranges.

Gasoline is a soup of dozens of different chemicals. Propane would be one of them... How about you just admit you have no clue what your talking about?

 

[bwalker]

The lower the octane the easier it will ignite under heat and pressure . Pinging or pre ignition is just that ,the gas is ignited by pressure in a high compression environment this is prior to the spark . I shouldn’t have said flashpoint which is where the liquid turns to vapor . The higher the octane the higher the resistance to pre ignition.

Again no. Detonation happens after the plug fires, so it has nothing to do with ignition, ease of ignition, etc
And flash pint isn't where liquid turns to vapor. That's boiling point.
And octane is a measure of a fuels resistance to detonation. Preignition is a whole other thing that's not same is detonation.

 

[SS396driver]

Again no. Detonation happens after the plug fires, so it has nothing to do with ignition, ease of ignition, etc
And flash pint isn't where liquid turns to vapor. That's boiling point.
And octane is a measure of a fuels resistance to detonation. Preignition is a whole other thing that's not same is detonation.

Really ? Where did I even mention detonation ? So tell me why an engine will ping on 87 but run fine on 91 . The fuel ignites before the plug fires .

 

[bwalker]

Really ? Where did I even mention detonation ?

You didn't, but should have.. Octane is a measure of a fuels resistance to detonation. Nothing more, nothing else.
You know the terms, you don't understand what they mean.
One other thing. Pre ignition is not "ignited by compression". In pre ignition a hot spot, which on a two stroke is usually the spark plug ground strap, becomes incandescent and that's what sets of the fuel air mixture. Of course this has the effect of massively increasing timing. This dumps a bunch of heat into the piston which inturn starts to ventilate itself.

 

[bwalker]

Octane has absolutely nothing to do with how fast or slow a fuel burns

You can lead a horse to water, but you can't make them drink...
And part of the problem is there is so much bad info out there that's its difficult to sift the wheat from the chaff.

 

[Hos]

Sometimes we’re just hooked on the smell! Run my motorcross bike mix for convenience and it smells good!

 

[Hermio]

95 octane is ok, you will likely lose performance running 104 octane. I use 100LL avgas in my old cars and lawn equipment. the only other ethanol free fuel pump gas is over 100 miles away for me here in California. Race gas in 5 gallon cans $18 a gallon. avgas at the pump is $8 a gallon. ethanol free gas in 1 gallon cans $25 a gallon. Small engines like string trimmers and chainsaws (engines that are easy to dump the fuel) I sometimes run 10% ethanol fuel in them with no problem, I just dump the fuel and store them dry.

New California law 2024 bans sale of new small gas engines rated at or below 25 hp (19 kW) , will be interesting to see how that works out.

If I lived in CA, I would travel to a nearby state to buy my small equipment.

 

[thompsoncustom]

If I lived in CA, I would travel to a nearby state to buy my small equipment.

If I lived in CA I would move elsewhere.

 

[JRM]

If I lived in CA, I would travel to a nearby state to buy my small equipment.

CA residents could always start buying diesel powered small equipment.....no restrictions there, for obvious reasons....