110 vs 118 octane

[ChavoLC2]

VP Racing Fuel

C-12
* green
*specific gravity .710@60 degree F.
*motor octane: 105
*aromatic hydrocarbon content 12%
*recommended for compression ratios up to 13.5:1
*will satisfy 75- 80% of todays racing engines
USED IN
* endurance & oval track racing
*NHRA superstock cars
*NHRA competition eliminators
* off-road vehicles
*2- stroke
* outboard boats

C-14
*yellow
*specific gravity: .690 @ 60 degrees F.
*motor octane 114
*High Compression
*High RPMs
*aromatic hydrocarbons 0%
USED IN
*NHRA prostock
*4-stroke motorcycle racing
*high speed Comp eliminator cars
* any NA engine above 8500 rpm

C-16
*blue
*specific gravity .740 @ 60 degrees F.
*motor octane 117
*aromatic hydrocarbons 20%
*recommended for Turbocharged or Blown applications
USED IN
*turbochargers or blowers
*Airplane racing - pylon aircraft racing
*Nitrous Oxide application

Octane- ability of a fuel to resist preignition and detonation, however the ability to resist PI and D is more then just a function of octane...

Burning Speed is the speed at which a fuel releases it's energy. In a high speed combustion engine there is very little time for the fuel to release it's energy(real time not crank rotation) Peak cylinder pressure should occur around 17 degrees ATDC. If fuel is still burning after this, it is not contributing to peak cylinder pres., which is what the rear wheels see...

Energy Value is an expression of the potential energy in a fuel. The value is measured in BTUs per pound not per gallon. This difference is important as the air fuel ratio is in weight not volume. Remember, this potential energy value of the fuel will show up at any compression ratio or engine speed...

Cooling Effect of the fuel is related to the heat of vaporization. The higher the heat evaporation the better it's effect on cooling the intake mixture. This is of some benefit on 4 strokes but can be a big gain on 2 stroke engines...

This is off a VP racing fuel pamphlet/ premade chart, short and sweet, it makes sense to me I got lost at specific gravity

 

[Boost231]

damnit i just want to run race gas and alky to cool my intake now i have all these factors. humm im lost

 

[VadersV6]

Ok smart guy (turbo6smacktalk)....in case you didnt notice, the car I was referring to is also a "hotair" motor...and the fact its a ford has no bearing on anything. And the reference to a hotter plug creating a hotter spark? Did you go to bubba's backyard nascar school and hot dog cart?
You want to run as little octane as you need. Too much octane not only leads to power loss, but fouling plugs, misfires that cant always be detected until your ET is going to hell and you dont know why, nasty carbon infested chambers and fouled o2 sensors (yes, they foul as well), and chasing tuning "problems" that cant be fixed for some reason. The TR combustion chambers arent fast burn chambers which adds to the trouble. For one, energy value (BTU) in a given fuel is useless if its not being completely burned, or burning so slowly that the maximum energy isnt being extracted until the piston is way too far down the hole to be of any value. Slow it down drastically by spraying it with alky and basically extinguishing the flame, add an IC ontop of that and you're in trouble. The entire point is to barely keep detonation or pre-ignition at bay. Barely. If you go overboard, you're beating a dead horse. Say you add a really good IC and now you can run 20psi with 20 degrees timing on 91 pump. You want more timing, but cant add it because the a/f is igniting prematurely from HEAT....coming in many forms. Add alky and now you can run 23psi with 25 degrees timing. The alky had the same effect as running straight 98 octane fuel (roughly). 7 points of octane had a huge effect. Try running 100 octane instead of alky, and you'll probably achieve the same results. Add another 18 points of octane...ok now the flame is burning so slowly that the motor is running like crap, plugs are fouling and the turbo cant spool for ****. Only way to take care of this is to get the flame started sooner. Add boost (more cylinder pressure equals more heat), and add timing. Now we can run almost 30 degrees timing and 30psi. Ok. Now we want to spray alky which is like adding another 7 points of octane. Now we're in the turbo sport compact 4 cylinder scene with cars making 50psi. That kind of cylinder pressure is the only way to make use of all that octane.
Running both I think is a waste of time. A good IC, alky and 110 octane will be plenty to run 30psi and healthy timing on its own. Going to 118 and alky has no point unless you're way up there in power. Of course polished chambers, piston design, proper quench, spark plugs, air charge temperature, turbulence and other things, all have an effect on tendency to pre-ignite. You properly address those things in your engine buildup, you could run much less octane. Like I said, you should run the minimum level of octane/alky you need to achieve your results.
As far as aviation fuel goes, those fuels are engineered with poorly oxygenated air in mind. At those altitudes you need to find other ways to catalyze the burn. It works ok for many people, but the people who make race gas have plenty to say about running av gas in motor vehicles.

 

[Turbo1dr]

PS - before anyone says it....I already have alky,

Ha ha ha....that's' funny. You knew all the alky guys would've bombarded you had you not had it didn't you? Funny how that always happens......sooo predictable!

 

[SloGN]

i'm quoting so infor from the above post....Energy Value is an expression of the potential energy in a fuel. The value is measured in BTUs per pound not per gallon. This difference is important as the air fuel ratio is in weight not volume. Remember, this potential energy value of the fuel will show up at any compression ratio or engine speed...



From the info here it's seems to be the benefit of the alky injection is only for the cooling effect. because the alky don't produce near as much heat when it burns. heat energy is what makes it all happen.

 

[SloGN]

Ok smart guy (turbo6smacktalk)....in case you didnt notice, the car I was referring to is also a "hotair" motor...and the fact its a ford has no bearing on anything. And the reference to a hotter plug creating a hotter spark? Did you go to bubba's backyard nascar school and hot dog cart?
You want to run as little octane as you need. Too much octane not only leads to power loss, but fouling plugs, misfires that cant always be detected until your ET is going to hell and you dont know why, nasty carbon infested chambers and fouled o2 sensors (yes, they foul as well), and chasing tuning "problems" that cant be fixed for some reason. The TR combustion chambers arent fast burn chambers which adds to the trouble. For one, energy value (BTU) in a given fuel is useless if its not being completely burned, or burning so slowly that the maximum energy isnt being extracted until the piston is way too far down the hole to be of any value. Slow it down drastically by spraying it with alky and basically extinguishing the flame, add an IC ontop of that and you're in trouble. The entire point is to barely keep detonation or pre-ignition at bay. Barely. If you go overboard, you're beating a dead horse. Say you add a really good IC and now you can run 20psi with 20 degrees timing on 91 pump. You want more timing, but cant add it because the a/f is igniting prematurely from HEAT....coming in many forms. Add alky and now you can run 23psi with 25 degrees timing. The alky had the same effect as running straight 98 octane fuel (roughly). 7 points of octane had a huge effect. Try running 100 octane instead of alky, and you'll probably achieve the same results. Add another 18 points of octane...ok now the flame is burning so slowly that the motor is running like crap, plugs are fouling and the turbo cant spool for ****. Only way to take care of this is to get the flame started sooner. Add boost (more cylinder pressure equals more heat), and add timing. Now we can run almost 30 degrees timing and 30psi. Ok. Now we want to spray alky which is like adding another 7 points of octane. Now we're in the turbo sport compact 4 cylinder scene with cars making 50psi. That kind of cylinder pressure is the only way to make use of all that octane.
Running both I think is a waste of time. A good IC, alky and 110 octane will be plenty to run 30psi and healthy timing on its own. Going to 118 and alky has no point unless you're way up there in power. Of course polished chambers, piston design, proper quench, spark plugs, air charge temperature, turbulence and other things, all have an effect on tendency to pre-ignite. You properly address those things in your engine buildup, you could run much less octane. Like I said, you should run the minimum level of octane/alky you need to achieve your results.
As far as aviation fuel goes, those fuels are engineered with poorly oxygenated air in mind. At those altitudes you need to find other ways to catalyze the burn. It works ok for many people, but the people who make race gas have plenty to say about running av gas in motor vehicles.

Also aince you talk about the buick not having a fast burn chambers. what about the issues witht he cam opening the exhaust valve a little early to help the cylinder to exhaust a litlle better. but thats for another topic. small exhaust ports and valve timing.

 

[ChavoLC2]

Octane

In line with what Vader said this is off VP Racing Fuel Pamphlet.

How much octane do I need?

Only enough to stop preignition and detonation. Remember there are other important factors in power output than just octane. Octane is not the measure of the fuels power output, it is only a measure of it's resistance to preignition.

example: In a oval track motor with 9:1 compression the engine will make more power with C12 then the higher octane C16. You can usually see an improvement of up to a 3% increase in torque. The fuel will burn faster and have a higher BTU value then a higher octane fuel.

High octane fuels have a high amount of hydrocarbons. VP fuels have a relatively lower amount n comparrison to other high octane brands. So plugs look cleaner not as fouled looking. Hydrocarbons produce soot forming properties,i.e. the more HC the more soot produced. That's what Fouls up plugs and 02 sensors.

 

[VadersV6]

Also aince you talk about the buick not having a fast burn chambers. what about the issues with the cam opening the exhaust valve a little early to help the cylinder to exhaust a litlle better. but thats for another topic. small exhaust ports and valve timing.

Im not quite sure what this topic is about...typically with a turbo cam, you want to delay the exhaust event a little bit to trap exhaust gases, which helps to spool the turbo quicker. You also want to keep overlap to a minimum, as during the overlap phase, the pressure in the intake tract is much lower than the the exhaust tract....so during the point where both valves are open, you'll find burnt exhaust pushing its way into the intake and grossly contaminating it. You can offset this a bit by porting the exhaust side of the cylinder heads to achieve a higher intake to exhaust flow ratio...its not uncommon to see exhaust ports flow 75-80% of the intake, on forced induction race motors. But its best to do it right from the get go. Its much easier to change a cam than add metal back to the exhaust ports. Most people will use a cam favoring the exhaust side on a forced induction engine. But the needs of a belt driven system and a turbo are different. And the split duration specs between exhaust and intake should have the flow ratio of the heads in mind when choosing a cam. I'll have to do a search and figure out what the stock flow ratio is on these heads. I know that the edelbrock cam has something like 204/214...a good number for a turbo motor, but if the flow ratio doesnt justify it, then a straight even number may be better, like a 204/204...which seems to be what alot of TR guys go with...exhaust specs that match the intake. Plus Im not sure if that edelbrock cam was designed with a turbo in mind...delayed exhaust event, wide lobe separation, etc.

 

[Turbo6Smackdown]

Ok smart guy (turbo6smacktalk)....in case you didnt notice, the car I was referring to is also a "hotair" motor...and the fact its a ford has no bearing on anything. And the reference to a hotter plug creating a hotter spark? Did you go to bubba's backyard nascar school and hot dog cart?
You want to run as little octane as you need. Too much octane not only leads to power loss, but fouling plugs, misfires that cant always be detected until your ET is going to hell and you dont know why, nasty carbon infested chambers and fouled o2 sensors (yes, they foul as well), and chasing tuning "problems" that cant be fixed for some reason. The TR combustion chambers arent fast burn chambers which adds to the trouble. For one, energy value (BTU) in a given fuel is useless if its not being completely burned, or burning so slowly that the maximum energy isnt being extracted until the piston is way too far down the hole to be of any value. Slow it down drastically by spraying it with alky and basically extinguishing the flame, add an IC ontop of that and you're in trouble. The entire point is to barely keep detonation or pre-ignition at bay. Barely. If you go overboard, you're beating a dead horse. Say you add a really good IC and now you can run 20psi with 20 degrees timing on 91 pump. You want more timing, but cant add it because the a/f is igniting prematurely from HEAT....coming in many forms. Add alky and now you can run 23psi with 25 degrees timing. The alky had the same effect as running straight 98 octane fuel (roughly). 7 points of octane had a huge effect. Try running 100 octane instead of alky, and you'll probably achieve the same results. Add another 18 points of octane...ok now the flame is burning so slowly that the motor is running like crap, plugs are fouling and the turbo cant spool for ****. Only way to take care of this is to get the flame started sooner. Add boost (more cylinder pressure equals more heat), and add timing. Now we can run almost 30 degrees timing and 30psi. Ok. Now we want to spray alky which is like adding another 7 points of octane. Now we're in the turbo sport compact 4 cylinder scene with cars making 50psi. That kind of cylinder pressure is the only way to make use of all that octane.
Running both I think is a waste of time. A good IC, alky and 110 octane will be plenty to run 30psi and healthy timing on its own. Going to 118 and alky has no point unless you're way up there in power. Of course polished chambers, piston design, proper quench, spark plugs, air charge temperature, turbulence and other things, all have an effect on tendency to pre-ignite. You properly address those things in your engine buildup, you could run much less octane. Like I said, you should run the minimum level of octane/alky you need to achieve your results.
As far as aviation fuel goes, those fuels are engineered with poorly oxygenated air in mind. At those altitudes you need to find other ways to catalyze the burn. It works ok for many people, but the people who make race gas have plenty to say about running av gas in motor vehicles.

What the F**K are you talking about vaders?? Are you talking to me?? Why did you call me a 'smart guy' and 'smack talk' ? Where did I talk s hit at? Where did I lie. Where did I say that something I had was better than someone elses. Nowhere, so noone here was 'talking smack'. I think you're a bit bi-polar, and are mixing several situations together there Sybil... Snap out of it.
And the the fact that it is a ford has no bearing on anything?? Uhh YEA, no $hit sherlock. When did I say it being a ford meant anything? Can you find something like that in my response? No? OH ok then, the shut the f**k up. And all I asked was, was if anyone out there had a premade chart, for certain setups, so that we can more closely match our fuel selection to our individual cars.
The last I heard, a more fuller, hotter spark always helps out. Why? I dont really know, but I sort of assumed it could help a 'too cool' condition like this. Is that such a bad question? Was it that far off?? Sorry I dont spend my every single spare second studying the theory of internal combustion engines there hotrod. I work. This is just a hobby to me, when I have time. So you can eat my a$$. How 'bout that.

 

[SloGN]

DAMN.................................

 

[Boost231]

wow. im just trying to figure out if i should run 100 octane and alky 110 octane and alky or c16 and alky but cant figure it out. let keep on track guys

 

[VadersV6]

Oh... I see said the blind man. So youre telling me that my plans of super cooling my buick should hold off for a while? lol. DAMMIT! Just when I learn one thing... I learn another. And that makes the first thing I learned change lol. VERY good to know.

Well if that didnt sound like a smartass comment in response to my post, then I dont know what would be a smartass comment.
Its also a hobby of mine. I machined and built every type of engine for many years, but then I had to make money, so got out of it. I'm an automation integrator, not a mechanic. My back is too bad to be one. The Ford comment was a pre-emptive remark to anyone who was about to say "Its a Ford, it's different"....Cant count the number of times Ive heard **** like that on this board.
As for spark, a hotter plug or colder plus has absolutely nothing to do with the "hotness" or "coldness" of a spark. That's all electrical energy. The heat range of a plug only describes a particular plug's ability to transfer heat into the cylinder head. A plug can run too hot if it cant transfer it's heat out and away into the cylinder head.
If you werent being a smartass, then I apologize....Im so used to hostility around here that its hard to see it any other way.

 

[Turbo6Smackdown]

"Originally Posted by Turbo6Smackdown
Oh... I see said the blind man. So youre telling me that my plans of super cooling my buick should hold off for a while? lol. DAMMIT! Just when I learn one thing... I learn another. And that makes the first thing I learned change lol. VERY good to know."

So what part of "just when I learn one thing, I learn another, and that makes the first thing I learn change." is hostile??? Especially followed by an lol??
THEN I go on to say 'VERY good to know.' How in any way could THAT be viewed as sarcastic or hostile??? I'm not sure what kinda world you live in, but maybe you should move to a nicer neighborhood, and get on Zoloft. I have PTSD from Iraq, and I'M not even that preemptive.. Holy christ. Other than that, very good information there. I will copy it for further reference. I want the best for my buick. Period.

 

[Boost231]

vader you posted. "A good IC, alky and 110 octane will be plenty to run 30psi and healthy timing on its own"

What if you dont have an intercooler. will 110 and alky still be sufficient?