100 Octane Pump Gas in So Cal

[daepp]

I was very surprised to see a new VP Racing station about 8 miles from my home offering 100 Octane gasoline. Yes, it is a bit spendy I know, but how often do you really fill up your 911? Has anyone heard of these guys?

http://www.vpracingfuels.com/index2.html

For my first try, I filled my tank to a mixture of approx 60/40 of 100 and 91 (as the tank was just below half full of 91 Octane).

Of course, the car seems to run much better (and even looks better ) - I guess what I'm wondering is how much of an improvement can this truly be, or is it just psychological?

BTW, I run a single plug 9.5:1.

(I also live near a general aviation airport - I wonder what a gallon of av gas goes for - and would leaded hurt my engine???)

[beepbeep]

No knock sensor = no improvement.

W/o higher C/R or more advanced ignition, you are only throwing money away.

[crustychief]

What airport? If you are in East county San Diego there is a gas station in Alpine that sells high octane fuel as well. As far as I know avgas 100LL will not hurt the engine but may clog a cat if you have one. I would wait for more advice here though. In my own experience I get a little cooler/smoother running on higher octane in a stock 3.0 but don't really notice a power difference unless I am really pushing it hard.

[EarlyPorsche]

Unless you had a knock you are actually losing power. The key to making power is to use the least amount of octane while avoiding all knock.

[daepp]

My 72T was rebuilt w/ higher compression pistons and "S" cylinders. Since it is single plug only, I am judicious in avoiding knock. I almost never hear any, but I also am very careful never to lug the engine.

[wastintime]

Originally Posted by EarlyPorsche

Unless you had a knock you are actually losing power. The key to making power is to use the least amount of octane while avoiding all knock.

says who?, that is about the silliest, most unfounded, uneducated statement I've ever heard on the subject of tuning cars.

They're not talking about 130 octane avgas that most motors wouldn't even run on. Especially in what is essentially an aircraft engine like the 911 has. The key to making power is using the highest octane available and using the most optimum AFRs, while trying to stay on the lean side to improve exhaust flow and engine response, and the most advanced timing possible which will make knock more likely (the risk decreases with HIGHER OCTANE GAS), but also makes more power and lowers internal temps, all while balancing internal engine temperatures and how much power and torque your combination is making... gets even more complicated when you throw a turbo in the mix. Why do you think different chips are available for cars running different octane ratings and the higher the octane always results in more power?

That's damn expensive though, it's only about $6.50/gallon for all Sonoco Race Gases, 100, 110, and 114, in Savannah, GA the last time I was at Roebling. That's about as bad as the prices you pay for the convenience of the pumps at VIR.

I also disagree entirely, if 93 isn't even available in your area, I'd certianly try to make a mixture that would give you those few extra octane points. So, pure 100 octane probably isn't doing much for the car, unless that's what the owner's manual called for. I know my '67 912 wanted 96 leaded... 100 unleaded doesn't sound like a terrible alternative. Now one thing you could probably do is to safely advance your ignition timing and you WILL see a gain in power if you're running 100 octane gas. It's easier with DIS cars where you can specifically go in and modify the timing maps to only advance it under certain loads or RPMs, and you could retain more safety for normal driving, but still... Splashing a gallon or two of 100 in your tank when you fill it is NOT a bad idea, it's probably a GOOD idea if you only have 91 available where you are.

[Flieger]

Octane is needed to cope with the high compression ratios which can be more efficient or make more power.

Higher octane ratings means the fuel needs more activation energy to ignite. That comes from heat due to compression, spark, or just a hot engine. Fuels with higher activation energy usulally have more ultimate energy value (Btus) but the catch is that they are harder to get going. It is easy to light a fuse on a firework with a match's energy but the fuse doesn't do anything too spectacular. When the powder in the firework gets lit by the fuse, though, watch out.

Theoretically, if you run too high an octane number (say 1000), you may not be able to light off the mixture. In practice, spark plugs will light almost any fuel.

[Formerly Steve Wilkinson]

subscribed.

[Zeke]

VP has been around for a long time. Go to any motocross or track event and you will see some cans of VP.

[911 Dog]

I have been running low lead AV gas in my 2-Stroke bikes for years in extreme heat and conditions like Glamis (sand dunes). Works GREAT!!.........Now for my 75 911 I haven't tried it.

[wastintime]

since lead keeps getting brought up, lead is a lubricant and an anti-knock additive, it's actually good for the motor... it will kill cats and 02 sensors though.

[Capt. Crunch]

I remember a small service station on 7th between Santa Monica and Pacific Palisades selling 100 octane. Not sure If the station still exists..

[safe]

Quote:
Originally Posted by EarlyPorsche
Unless you had a knock you are actually losing power. The key to making power is to use the least amount of octane while avoiding all knock.

Originally Posted by wastintime

says who?, that is about the silliest, most unfounded, uneducated statement I've ever heard on the subject of tuning cars.

Thats true lower octane rated fuel burns easier and faster.
Not sure if you could feel or meassure it in a car, but in Karting it pretty well documented.

[EarlyPorsche]

I thought what I said was spot on correct and its what I have been taught my entire life because the higher the octane the more power you need to make it give off its highest potential and until then you are not getting a complete combustion. Seems like there are competing theories so you will need to do independent research.

[wastintime]

Originally Posted by safe

Quote:
Originally Posted by EarlyPorsche
Unless you had a knock you are actually losing power. The key to making power is to use the least amount of octane while avoiding all knock.



Thats true lower octane rated fuel burns easier and faster.
Not sure if you could feel or meassure it in a car, but in Karting it pretty well documented.

To start, you're talking about two wildly different motors, and by that logic nothing will ever make more hp than a diesel motor since it runs on the lowest octane gas available, however, diesel has never been accused of burning completely and more effiiently. They also in effect don't even use spark plugs.

the simple fact is if you took two motors designed for 87 octane gas, and ran one on 87, and one on 93 with more advanced timing, and a modified fuel map, you'd have no detrimental side affects apart from slightly worse gas mileage, and you'd make significantly more HP with the 93 octane setup. No matter how you tuned the 87 the motor would knock itself to pieces before it would ever make the HP of the 93 setup.

[Porsche-O-Phile]

So where are these stations? There's no useful information on the web site about where to get their gas, just what appears to be wholesale distributors.

Is it the one in Corona? Is that even a station?

[safe]

Originally Posted by wastintime

To start, you're talking about two wildly different motors, and by that logic nothing will ever make more hp than a diesel motor since it runs on the lowest octane gas available, however, diesel has never been accused of burning completely and more effiiently. They also in effect don't even use spark plugs.

the simple fact is if you took two motors designed for 87 octane gas, and ran one on 87, and one on 93 with more advanced timing, and a modified fuel map, you'd have no detrimental side affects apart from slightly worse gas mileage, and you'd make significantly more HP with the 93 octane setup. No matter how you tuned the 87 the motor would knock itself to pieces before it would ever make the HP of the 93 setup.

If you have any (gasoline) engine it will make the most power on the lowest octane gas that won't make the engine knock. Everything else the same. That's the point that EarlyPorsche was making.
Now you introduced advancing the timing and changing the fuel map, that wasn't on the table....

Edit:
Basically if you have a stock pre -89 911, you will not get any more power choosing a higher octane fuel (than what is the minimum requirement) at the gas station. Not without tinkering with the engine.

[richde]

Originally Posted by safe

Quote:
Originally Posted by EarlyPorsche
Unless you had a knock you are actually losing power. The key to making power is to use the least amount of octane while avoiding all knock.



Thats true lower octane rated fuel burns easier and faster.
Not sure if you could feel or meassure it in a car, but in Karting it pretty well documented.

With no other changes, the only thing lost by using higher octane fuel is money.

No gasoline can resist ignition from a spark plug.

[daepp]

The station I found was in a very unlikely place - South Ontario, no where near a race track, etc. I was surprised, to say the least, when I saw the sign.

[wastintime]

No, I put advanced fueling and timing on the table from the get go, and let's face it, a Porsche is not a honda civic. Even without a knock sensor you will not lose power in a 911 motor by raising the octane unless you possibly were running something nuts like 130 octane avgas where you were having issues with incomplete burns, etc... You are going to lose power if you lower the octane and it knocks it'self to pieces at high RPMs

The only motors where lower octane could possibly help, and it wouldn't be much would be motors where you're lowering the octane to essentially advance the timing and allow an earlier combustion, however, you're not gaining anything from fueling, and it's more wear on the motor, so I don't really see how you're claiming it to be better.

My best argument is the true secret weapon that won the battle of brittain was 100 octane avgas shipped to England from the U.S. it increased the performance of their interceptors so much they were able to climb and meet the luftwaffe planes farther from their shores.

I'm sorry, diesels have their place, but not in a non-diesel motor. I'm not saying Audi doesn't build some amazing 1000hp Diesel monsters that are making tons of power on "low octane gas", but Porsche still ends up beating them at times, so... plus you're getting into turbo territory with that too and that's a whole other complication.