I've just been given two conflicting suggestions:

Run non-ethanol 89 octane gas and use a lead substitute (instead o' lead)

or

just use modern 91/93 octane gas that contains ethanol.

I had been using non-ethanol gas in my 72 Beetle and then switched to modern 91/93 gas with ethanol and it seemed to develop a hesitation on acceleration.

I just got a 71 914 and am interested to know what you all are using so I can decide which gas to use in it.

check this site.

https://marcnelsonoil.com/the-pros-and-cons...on-ethanol-gas/

If you want Ethanol free gas check out this site. Click maps and enter your state.

https://www.pure-gas.org/

Had a long talk with Richard Parr, the maker of PMO carbs, on this issue recently. My choices are 93 octane with ethanol or 90 octane with no ethanol. He suggests the latter with a supplement. I use Turbo 108 Octane Boost. All seems well with a 2.7 six with 10.8 compression twin spark.

My limited understanding is that higher octane fuel does not burn as easily as lower octane. So putting high octane in a low compression motor is basically useless. Don't know how common low octane ethanol free gas is though.

I've been using 87 octane ethanol free in my '75 2.0 for 5 years. No additives. Continues to run great. As an aside, I use 93 octane ethanol free in my '61 Ford big block. Again, no additives. Running great for years.

only Stewart's 91 ethanol-free

same 87 octane ethanol free in my 73 1.7 FI, no additives. Been using it in my 69 Bug many years as well.

Chevron Supreme

I've used same for years...my early 1.7 wants high octane to avoid pre-ignition and vapor lock... problems solved with this fuel.

If I'm road tripping and can't find it, then Texaco or Shell.



*(my Mazda RX7 Race Car ran best on the shittiest gas you could find. Some guys would go down to TJ and fill up 55 gal. drums of Pemex.)

Comes down to what's available. Some states don't allow non-ethanol fuels to be put in cars. others have no issue with it.

These cars were built to run on leaded regular (which of course did not have ethanol). Good luck finding that

Most cars get buy with any 87-93 octane fuel, ethanol or not. If you've advanced your timing trying to squeek out the last few hp, running 91 or higher could help with some predetonation.

If you are using an ethanol fuel in a car that sits awhile, run some kind of Stabil/Heet/Water evaporator to help keep lines and injectors/carbs cleaner.. not spotless, but cleaner.

Feel free to add a lead additive if you are worried about valvetrain wear.

Asking what fuel to use is like asking what oil to use. Everyone will tell you something to conflict with the last opinion!

except I'm not sure what would be gained with a lead additive since our cars have hardened valve seats.

There is no advantage to running higher octane than needed unless you are trying to lose weight in your wallet. All stock 914 engines should run fine on regular octane unless you've tweaked them from stock specs.

I haven't driven my 914 since the days of leaded but hopefully she'll be mobile by this spring. I'll fill with ethanol free gas most of the time but won't hesitate to fill with ethanol blend on long trips when I know the tank will be used before storing the car for any length of time. If I do have to park the car for any length of time with ethanol blend in the tank, I'll use a stabilizer additive.

One other thought not mentioned. The lower the octane you use, the COOLER the engine will run. You should run the lowest octane possible as long as your engine doesn't knock. This means that primarily only higher compression altered engines will require above 87 octane.
I've been running California's 15% ethanol blend 87 octane gas for 20 years in my stock smogged 76 2.0 and it hasn't missed a beat.

Oh boy. I've seen this subject come up over and over again through the years.






I have an Original Customs 2056, carb'd. I run whatever regular I find at the pump, occasionally I'll try a mid-grade. Doesn't make any difference. Never had any problems. No need for lead additive in my opinion. Runs great. If I know it's going to sit for a while (like at the height of the pandemic and quarantine etc...), I definitely put Stabil in the tank. Cheap peace of mind.

Nice article but it understates the ecological train wreck ethanol fuels have caused in the Midwest.

My mechanics know their stuff, and both recommend running 91 from Chevron or 76. Ethanol is tough to avoid here in CA.

I can get higher octane—and even leaded race gas—by driving over to Sears Point, but I very rarely do so. I tend to forget which octane I should go for, and whether it would be helpful or harmful with an engine built and tuned to run on our crappy 91-octane gas. Will say it made 169.9 rwhp (so, 190-200 hp at the flywheel?) from 2.2 liters on CA 91 and runs beautifully throughout the rev range.

I'd be very curious to hear what someone like Jake Raby or others here have to say about the occasional tank of leaded race gas, and if there are any benefits. I suspect any octane bump would be wasted?

I use regular (87) from any gas station with ethanol. 15,000 miles in 2 years with good performance and no problems. I’m much pickier about my oil.

2056 with 8.6 comp I usually run the mid-grade, 89 10% ethanol.

Occasionally I will put in the 93 from Sam's Club because it is cheaper than the 89 elsewhere.

Runs just fine.

i usually run the NO ethanol 87or89 on my stock 2.0/4 motor. i only get the 10% if i know i am burning thru a whole tank, and since the car may sit for a few weeks with out driving i will put stabil in a full tank. we have no problem getting non-ethanol gas but it does cost about the same as 93 octane premium.
remember for the low compression cars 1.7,1.8, 2.0 stock motors 87 is what factory tuned the car for. i set my timing with this in the tank, if you run 93 instead of 87, it will effect you even if you think i’m your seat of the pants experience and feeling it’s running “just fine” . and for sure if you just got the car change out all your fuel lines for the ethanol rated ones. ethanol even just 10% will attract moisture if it’s sitting in that tank and we live in a high humidity region, so i try not to use it. same reason you should never run it in you 2stroke or 4 stroke lawn equipment!

For what it's worth, I've access to 87 ethanol free and that's what I run in my Civic... mpg went up 6 miles per gallon
I also have access to 110 ethanol free but it's over $8 per gallon

Some of this is folklore.
All VW and porsche heads are fine on unleaded, they have steel seats which are not effected by the lack of lead. The folklore is from old cast iron heads where the seat is cast as part of the head and needed lead to act as a lube so the seat would not degrade. There were cases back in the day of low budget VW builders who used cheap cast iron seats and guides, but factory seats were steel. I think you can only get steel seats now days.
Don't run leaded if you have an O2 sensor, the lead will deposit on the sensor and ruin it.

AV gas uses a completely different octane rating procedure and is a waste of money. The same can be said running race gas if your CR is set for pump gas.
Octane boosters and top end lubes to me are all snake oil designed solely to pick your pocket. I've tried but some of the products, but except for occasional FI cleaner I don't use them. I only use busy stations that I know is filling the premium tank weekly.
Don't blame the gas for a mechanically poor engine.

If you drive your FI teen regularly and you have new E10 certified fuel hose you should have no problem with E10. For carbs the new gasket kits have diaphragms that are more ethanol resistant. If your car sits for long periods just with my nose I can tell that E10 starts to go skunky within a month. Not sure how to store a car with E10, I'd likely run the system dry for storage.
One plus of E10 is it actually cools the head better than pure gas.

I run 91 pure gas pretty well all the time, although I did run a few tanks of 93 E10 through my /6 with webers with no issues this year. The winter (or 6 month storage) all I do is run in with some sta-bil and fill the tank with 91 pure gas.
Longer storage I run it dry, but it's in a heated shop, my '67 bug is in unheated storage so I drain and fill my tank 2X year.





Do I have pure gas or E10? Quick down and dirty.

-Find a small but tall glass container. (large test tube)
-Fill 1/10 with water, mark with sharpie.
-Fill with gas.
-Shake and let it sit a couple minutes.

The gas and water will separate with water on the bottom, if it looks like the same 1/10 of water then it's pure gas. If it looks like the water has doubled in volume (2/10 ths) then it's E10.

YMMV

Mark- I was told that Porsche knew unleaded was coming so they also started using sodium filled valves early?

I thought this was just to improve heat transfer from the exhaust valves rather than anything to do with lead. Also, per your earlier comment about better mileage with ethanol free gas. Yes. Pure ethanol has about 30% less energy per gallon than gasoline so the reduction in fuel economy depends on the strength of the blend.

Another small thing about octane. You may still run into lower octane fuels traveling in high elevation areas. You don't need as much octane in the thinner air. Until just a few years ago, our regular gas was all 85 octane but then it switched to 87. I think that happened when they started blending more ethanol in our fuel as ethanol has higher base octane than gasoline. I wish we could go back to the 85 octane because it usually had little or no ethanol.

I was also told that lead also helped with valve lubrication and no lead in the gas = hotter valves, hence sodium filled. Also, the regular leaded gas from back in the day was 89 octane which is why we have "plus" today.

That makes sense. My understanding is that lead was originally added as an octane booster and had a side benefit of coating valves and seats to create a cushion that helped protect against pounding which led some manufacturers to go with cheaper cast iron seats. Makes sense it could help lubricate and reduce friction too.

I should clarify that I was saying ethanol has higher octane than unleaded gas.