Jeff, how do you figure I got it to 90.1? I can understand and follow directions and have a background in chemistry, so I added the proper amount to get to 91. No where have I read that the product I used does not achieve the octane increase when you use it properly. If it's a lie then that's news to me. Regardless, I don't care because I'm not going to use it anymore.

 

Because a full point as noted on the 8os can is .1

Knowing chemistry, what in 8oz or so can raise the octane of a 20gal tank 10 points from 90 to 91?

AKI is a average of RON and MON..so it's all a mess.

A gallon of Toulene in a tank of gas can help a little too.

 

Porsche state that fuels with 10% ethanol can only be used for model year 96 onwards. The S4/GT/GTS need a 98 RON [93 PON in the US] fuel to run correctly. They will run OK with 95 RON [91 PON] fuel but the EZK will likely be pulling some timing in some cells of the ignition map.

Ethanol is a useful tool for boosting octane with a RON of 110 but the calorific value per kg of fuel burnt is only about 2/3rds that of gasoline. Stoich for gasoline is 14.7 whereas Stoich for alcohol is about 9 which is why a motor tuned for alcohol can make so much power but given it swallows about 50% more fuel weight wise compared to gasoline it is not so practical for street use.

One of the best components for "home brewers" is toluene with a RON of around 117 and a heat of combustion about 20% less than gasoline but again the fuel maps really need to be compensated- no problem with ST2. I have no idea regarding the properties of xylene or its commercial availability but I suspect it is similar stuff to toluene.

To be clear, there is no direct relationship between octane rating and heat of combustion for fuels but as a general statement fuels that have better octane rating than gasoline invariably have to burn more fuel to make the same power. Refiners do not like blending high octane gasoline since TEL [lead] was banned because it reduces the size of the gasoline blending pool. If the refiners had their way we would all be be running around with "witch ****" in our fuel tanks.

 

Define "older".

The fuel lines changed in the late 60s/early 70s. I've run E10 in mid seventies cars without any issues.
I run E10 in my 83 944 and have for 14 years. No issues. It gets a fresh full tank and SeaFoam before I put it away for the winter, every year. Again, no issues.
My understanding is that really old fuel lines will be damaged by the ethanol. But anything made since the mid-seventies is fine.

Ethanol will absorb water. Mix with it actually. There's a point called "Phase separation", where there's enough water in the alcohol that they won't mix with the gas anymore and separate out.
However, until that point is reached, the alcohol will take any water out of the tank & burn it with the gas (yes, I know the water doesn't actually burn). There's very little market for fuel line deicers like Heet anymore for that reason.
And I used to drive my Blazer very little during the summer. One tank would last from May until mid August. I'd fill it back up at about half. So it was sitting, partially full, with the normal day/night temp swings, getting condensation into the tank. I never experienced any issues.

I wouldn't run E10 in a boat. Older (really old) fuel lines are common and lots of water/moisture.

But I don't think it's a problem in cars. At least it hasn't been for me.

 

Yes, we can read that too in the link provided. Speedtoys and myself are saying it's hogwash and not something to get too excited about.

I'm not paying significantly more money for E10 free fuel for my stock early cars since in most areas around the US, only the highest octane is ethanol free and some areas even the highest octane has 10% in it.

I strongly disagree with the practice of forced 10% (some want to see 15%) ethanol in our fuels which is a BS political move to appease the corn growing states. But it is what it is.

 

Joe, I feel no need to define anything. I only stated "might" be a problem. The only hose I actually suspect of being really problematic here is the intank pump hose. But I don't know if the OP's model even has an intank pump or not. Further, for me, as I have replaced all lines with GB lines and have the "blue" hose in the intank pump, I feel quite safe.

However, I have worked on cars that set a lot and had lots of rusty fuel system components. I believe this is due to ethanol absorbing water from condensation. But, hey, if you drive so much that the car never sits long winters with condensation etc, you are safe on that point too.

NOTE: The wording in my previous post pretty much demonstrates my strong opinions and makes no claim to absolute authority here. If you need other proof or not, that's fine and I'd like to hear what every you find out. Thanks.

 

The point I was trying to make is that octane rating is what it is and how a given fuel makes it octane rating is more or less irrelevant. The fact is a fuel with 10% ethanol will not make the same power as conventional gasoline without enriching the fuel appropriately so the logic behind Porsche's position has to be one of material degradation by such exposure- if your experience suggests this is not the case all well and good.

 

I dont think the bare-faced liability statement is about making less power, over 30yr old product chemistry reacting in the presence of ethanol.

 

Exactly the point I was making irrespective of whether it is fact or fiction. We do not have any ethanol component in the fuel over here so I am no position to comment on whether it is an issue or not. What I can say with confidence is that the in-tank pump stock rubber connector perishes after about 10 years immersion in gasoline but we have no other fuel issues that I can tell. I have to run 95 RON [91 PON] and that has some small amount of knock retard but in my case the true situation is not readily apparent as I also have a faster exhaust that needs less advance.

By sticking ethanol into the gasoline you use it will cause a small increment of power loss but that can be corrected in the likes of ST2. If you pay a proportionate decrease in gasoline premiums fair enough I suppose.

As for these octane "enhancers" you are spot on with your assessment. Add 10 bottles at $5 per bottle and you will get one full octane unit increase but then the additive will cost you the same of the gasoline itself in the States. In all probability the stuff in those bottles is toluene. Now mix two gallons of the stuff with gasoline to make a tank full of fuel and you will get an octane improvement worth having!.

 

P-Xylene is the best single component octane enhancer.

146 RON & 127 MON

 

Would you add it with a shovel by any chance?

Melting point of p-xylene is 57F.

 

Fred, do you every get that low a temperature where you're at? :-)

 

Well my point about 'defining older' is that it is true that 'older' cars have fuel lines that aren't safe to use with ethanol. However, no 928 is 'old enough' for that to be an issue.

And I have quite a bit of experience using E10, in a variety of cars of various ages.
Some of that experience includes cars that sit over winter (Novemeber to sometime in March is typical here). Tank is always full, usually fairly fresh. I try to run it low before I store it so that it has gas that is as fresh as practical.
Some of that experience includes cars that sat a lot during the summer, driven weekly but not everyday, without topping off the tank for a couple of months. While I did have a fuel line rust out on that, it was from the outside, not the inside. I had a brake line fail on it too. One failed, the other 3 were close behind. Wisconsin winters and salty roads are brutal.

I have yet to see any significant problems develop from using E10. That doesn't mean they don't occur. Just that I haven't seen them. I know a few people with very strong opinions on running 'corn squeezins' in their cars. Very few can cite actual bad experiences.

Also, to Fred's point, while the actual energy content of ethanol is about 2/3 that of gas and 'stoich' is different, the 10% that is in typical gas doesn't make enough difference to really require tune adjustments. Power and economy are a couple percent lower.
E85 is a different animal. I know a few folks that have performance engines tuned to run on E85 for knock resistance. They can't run regular gas.
Flex fuel cars usually have sensors that determine how much ethanol is in what ever gas is going through the lines and adjust tune accordingly.

 

About once in the last 30 years!

I happened to be riding my BMW motorcycle that night and it nearly froze the nuts off me! It can get down to freezing point in the interior far away from the coast. It has even snowed on the mountains that border Oman and the Emirates on a few occasions.

Gasoline blending pools in refineries are very fickle things and if the industry does not use such components to boost octane then invariably there are good reasons why. TEL got kicked out for toxicity as did MTBE and others. Gasoline blends vary according to climate and even the season. Refiners like winter time in cold climates because they can throw in more butane and thus get more bucks for their efforts. The last thing gasoline needs is any component that might freeze- that basically means in European climates that the components need to be liquid to at least minus 10C. This is not usually a problem with gasoline and is more an issue with diesel that has heavier components.

 

To use E85 properly you should have that flex fuel sensor, unless you are buying ethanol in barrels and ensuring the mixture never changes.

E85 is just "maximum" of 85%, and in reality it can be much lower, like in the low 70's. Twin Turbo Todd has a gauge which tells him what percentage of ethanol is going into the system. He's currently working on the next development of his car tuning it for 100% gasoline through 85% ethanol.

Most started out using the off the shelf GM sensor, now the aftermarket tuners are supplying their own:
https://www.aemelectronics.com/produ...ontent-sensors