E0 90 vs. E10 93, help me understand the dif...

sasilverbullet

sasilverbullet

Joined
Aug 22, 2004
Messages
1,675
Location
San Antonio, Texas
Car: 03 Porsche 911, C2, all stock
Been filling up almost exclusively with Chevron E10 93 octane (premium).
Found a station nearby that sells E0 90 octane and filled up this morning.
Seems to be running fine.

Many questions - not sure I'm asking them correctly, please help a newbie out.
1. Which would you use, the E0 90, or the E10 93?
2. Please explain the pros/cons to either.

Thanks eveyone! (y)


Here's what my manual says on fuel:

PXL_20210809_121656414_2.jpg
 
What is the station selling E0 90 Octane?
I would personally use 93 E10 because its coming from a Chevron - known Top Tier.
You probably wont get a straight answer from the gas station about whether the E0 90 is top tier or contains top tier additives so I would pass.

For engine performance the higher Octane/oxygenated fuel will be better.
If your storing for a long period of time then the E0 might be better to avoid water absorption.
 
well the 90 octane is below the recommended so I'd keep going with 93. so you dont lose performance.

There is nothing awful with upto 10% e10 fuel.. in a vehicle designed for it and not stored for years at a time.
 
Last edited:
the last sentence under Fuel Quality gives you the answer. the engine gives best performance with higher octane. The electronics can cope with lower octane at cost of some performance.

Alcohol content is a completely separate question. At equal octane ratings alcohol content may add additional performance by its cooling effect to incoming air charge. Turbo cars gain even more from this effect. Downside of alcohol is it is hard on fuel system and absorbs water. not so good for storage.
 
For me, the benefits of the E0 fuel come into play in a few cases...

-old engines that aren't designed for ethanol (cars more than a couple decades old - likely not too common)
-outdoor power equipment - mowers, snowblowers, boat engines, trimmers, blowers, etc. (that may or may not be designed for ethanol, but which aren't necessarily used frequently)
-storage (if I had a summer car that I didn't drive during the winter, I'd try to run the fuel low and put in a half tank or so of E0 before storage)

I run 91 E0 in our mower, trimmer, blower, snowblower, tiller, and our 1970s Evinrude outboard. Despite good availability of the fuel, I've never run it in any of our cars. Your Porsche recommends higher octane fuel for performance, so I'd use the premium E10 93 octane (this is likely recommended because of preignition/knocking concerns, and would be the best fuel in this case).
 
TmanP said:
For me, the benefits of the E0 fuel come into play in a few cases...

-old engines that aren't designed for ethanol (cars more than a couple decades old - likely not too common)
-outdoor power equipment - mowers, snowblowers, boat engines, trimmers, blowers, etc. (that may or may not be designed for ethanol, but which aren't necessarily used frequently)
-storage (if I had a summer car that I didn't drive during the winter, I'd try to run the fuel low and put in a half tank or so of E0 before storage)

I run 91 E0 in our mower, trimmer, blower, snowblower, tiller, and our 1970s Evinrude outboard. Despite good availability of the fuel, I've never run it in any of our cars. Your Porsche recommends higher octane fuel for performance, so I'd use the premium E10 93 octane (this is likely recommended because of preignition/knocking concerns, and would be the best fuel in this case).
Click to expand...

The main issue with most power equipment and storage is that the tanks aren't like modern emissions-controlled cars. A modern car's tank is pretty well sealed.
 
Kawiguy454 said:
the last sentence under Fuel Quality gives you the answer. the engine gives best performance with higher octane. The electronics can cope with lower octane at cost of some performance.

Alcohol content is a completely separate question. At equal octane ratings alcohol content may add additional performance by its cooling effect to incoming air charge. Turbo cars gain even more from this effect. Downside of alcohol is it is hard on fuel system and absorbs water. not so good for storage.
Click to expand...

Not just the cooling effect, but that oxygen is already in the fuel.
 
Kawiguy454 said:
At equal octane ratings alcohol content may add additional performance by its cooling effect to incoming air charge. Turbo cars gain even more from this effect. Downside of alcohol is it is hard on fuel system and absorbs water. not so good for storage.
Click to expand...
Davejam said:
What is the station selling E0 90 Octane?
I would personally use 93 E10 because its coming from a Chevron - known Top Tier.
You probably wont get a straight answer from the gas station about whether the E0 90 is top tier or contains top tier additives so I would pass.

For engine performance the higher Octane/oxygenated fuel will be better.
If your storing for a long period of time then the E0 might be better to avoid water absorption.
Click to expand...
QuickTrip
 
Thanks for the inputs so far!
It's my daily driver, so storage is not a problem for the E10.
I'll have this tank of E0 out by the end of the week and I'll go back to using Chevron E10 93 octane.

I still would like to know a little more about the chemistry involved.
 
chemistry? 90% gasoline + 10% alcohol = E10. The alcohol does have higher octane by itself but it doesent matter once it is mixed just lppk at the pump sticker. Stick with top tier gas stations.
 
I'm pretty sure 90 Octane E0 is usually recreational fuel for off-highway (ie. OPE) use only, I'm not sure if it necessarily contains the EPA required detergents for passenger cars or it may still be allowed to be higher sulfur, I'd stick with top tier fuel in the highest octane you can find.
 
E10 93 is pretty much just E0 90 with 10% ethanol. Ethanol is an octane booster and a cleaner. If you ever change over from long time E0 use to E10 you need to be ready to replace the fuel filter. It was very bad in carbed engines because the ethanol would wash the built up varnish off tank wall, bowl and lines and clog the jets.
Many stations have a sign that the E0 is not a product of that brand similar to what they do with off road diesel so I was never able to find out if the E0 had the same additive package as their branded fuel.
Stick with the 93.
 
sasilverbullet said:
I still would like to know a little more about the chemistry involved.
Click to expand...

There's really no chemistry involved. At least nothing where you'd really need to worry about it. As others h8nted, it’s really just the equivalent of a lower octane rated base gasoline, where a mixture with fuel ethanol raises the AKI rating a little over 2.

But it’s not just a fuel meant for use on its own. Most fuel these days is specifically meant for blending with 10% fuel ethanol. The fuel ethanol itself contains a certain amount (up to 5%) of gasoline so that people won’t be tempted to drink it. Commodity base fuel is sold in a number of different ratings with the intent to reach a specified octane rating when blended with a specified oxygenate level.
 
You must log in or register to reply here.

Similar threads

J
  • Locked
E0 vs Premium E10, same price, choice?
2
Replies
37
Views
12K
SOHCman
JHZR2
  • Locked
no knock sensor: car requires 93, runs better on 89?
Replies
3
Views
1K
GT Mike
Back
Top