Fuel enigma

In my opinion, the best thing you can do for your car with regard to fuel is keep ethanol out of your car's diet.  In 5 years of tracking every drop of fuel I put in my car, I can say with absolute certainty that pure gas is better for every reason you can think of.

Also, I am not ready to believe that with all the lies our governments foist upon us, that they are telling us the truth about what goes into these "blends" of gasoline.

Posted by: @petrus

Over here in Europe we have a bewildering offering. I will not expand on that beyond the observation that aprt from the RON number the cocumer is by and large not informed about the contents of the fuel. 

I looked into the ethanol contents and properties to find out a confusing and wildly differeng offering at the pumps.

Decided to go for the 0% ethanol BP 98 for a few tankfulls just to clean up the fuel system.

Now, that should not have been noticeable. The difference in caloric value of 5% gasoline versus that of ethanol is too small to notice. The 98 octane rating should have nó effect either as even with the MAF mod, the 95 RON is well beyond the need.

Yet..., now halfway the secon tank and... there ís a difference. I live in the mountains and going uphill, the car pulls smoother, better from low revs to 3,5k.  I am baffled. Why would it? 

The explanation is that your engine is knock limited on 95 RON fuel.  Knock tendency is a function of compression ratio, air temp, coolant temp, engine speed and load, combustion chamber carbon deposits, valve timing, spark timing calibration, and inversely proportional to humidity

@dblotii

´knock limited´???

My point is that a higher octane rating than needed should have no effect. Also is was designed for California lówer octane rating. Only because of potential !!! added heat soak with the MAF mod Cap Weir suggested using 93 US which is 95 EU. 

That said, the European user manual says RON 95 so I also think that the EU has a slightly different ecu programming. The JDM has it´s own specific too. Máybe the MAF mod. means that 98 is better suited but I have read nothing about that form the UK. 

On a side note, TTE states 98 as requirement for the TTE turbo.

Anyway, I suspect the ethanol that has been added since our cars have been designed doés have effects despite what gvt and gas peddlers say.

I agree @pwnzor but that is easier said than done. It was a h.... of a job to unearthe which gas from whom had how much. The premiums from Repsol had 10%!!! and over here only the 98 BP has none. 

Extracting ethanol is relatively easy as chemical process but a VERY challenging thing to do on tank load scale simply because you do not have the installation to manage 50 liters of gas safely. Also it means throwing away 5 -10% of what you paid for dearly at the pump.

For the moment though I will drive ethanol free and enjoy the difference.

Remains; why does the, my? 1ZZ-FE run notably better at low revs on ethanol free 98 compared to 5-10% ethanol 95?

To me, the answer is simple:

Because it's all gas and no bullshit.

Posted by: @pwnzor

To me, the answer is simple:

 

Because it's all gas and no bullshit.

Fingers crossed that ethanol free will be availeble for some time yet then.

@petrus Since the engine has a knock detection system, you should never know if your engine knocks or if you are running at the knock limited load of the engine.  The system can detect incipient knock (which should be inaudible) and retards the ignition timing in response.  Retarding the ignition gets you out of knock, but decreases the engine efficiency very significantly.  The net effect is that you end up running less efficiently at high loads, even though you never actually hear knock.  The effect on fuel economy of 10% Ethanol in your gas should only be 3%, since that is the difference in energy content.  If you are seeing more than a 3% effect from the 98 RON fuel, it is because you are running on the knock limit (at high load) with the other fuel.  You know the MAF mod does increase the Octane requirement of the engine.

@dblotii

Thanks.

Now thát is an answer which totally support/explains my line of thinking.

The 3% is not thát much, although not to be discarded; not what I notice. It is ineed very much like the ignition is not retarded now. And yes it is under the ´ideal´ knock inducing conditions that it is now responding better.

Petrus, Dave is a smart guy! He is very knowledgeable, and his answers are intelligent and understandable. He "speaks to" us, not "at" us.