:facepalm:

1.11 here in Calgary. Daamm
Posted via RS Mobile

So ethanol causes engine knocking is a myth?
Posted via RS Mobile

so would Shell gold be the way to go then? As I have only ever used Chevron 94

My car feels like it runs better, and it for sure gets better milage on shell 91 over chevron 94. In my old gti and my m3.

From my understanding, especially in older cars, carbon buildup and deposits in the combustion chamber can lead to the engine running like it has an effectively higher compression ratio than original spec. So those in this situation may find and feel that they get better mileage on higher octane than required may not be wasting their money. I could be just spewing garbage info though

E85 cars can make more power, but they are specifically tuned to run on E85 and that is also widely available in the US. The Canadian ethanol content in gas 'may contain up to 10% ethanol' blended in, not exactly a reliable or consistent number that manufacturer can tune stock ECU's to maximize. I doubt the up to 10% ethanol will do ANY damage to stock internals with stock tunes, but doesn't mean its optimized

I recall guys who had EGT gauges saying that ethanol blends resulted in higher temps than same octane fuel with no ethanol. So if your car is finely tuned to squeeze out every last HP on straight gas, than an ethanol blend can likely cause detonation under similar load conditions.

Gawd damn, i can only imagine how good it must feel to say that! :ahwow:

haha technically I own the shittiest M3 ever made, but its like being the dumbest brain surgeon. I cant see myself ever not owning some incarnation of it.

Thats why i've been running shell 91 since ive had cars, something is up with chev.

what car do you drive? some V8s don't require premium...

Mustang GT for example...

_____Copy_______
Choosing the right fuel
Use only UNLEADED fuel or UNLEADED fuel blended with a maximum
of 10% ethanol. Do not use fuel ethanol (E85), diesel, methanol, leaded
fuel or any other fuel. The use of leaded fuel is prohibited by law and
could damage your vehicle.
Your vehicle was not designed to use fuel or fuel additives with metallic
compounds, including manganese-based additives.
Note: Use of any fuel other than those recommended may cause
powertrain damage, a loss of vehicle performance, and repairs may not
be covered under warranty.
Octane recommendations
Your vehicle is designed to use
“Regular” unleaded gasoline with a
pump (R+M)/2 octane rating of 87.
Some stations offer fuels posted as
“Regular” with an octane rating
below 87, particularly in high altitude areas. Fuels with octane levels
below 87 are not recommended.

Octane recommendations (5.0L V8 engine)
Your vehicle will run normally on 87 octane regular fuel without
damaging the engine, but premium fuel with an octane rating of 91
(R+M)/2 or higher is recommended for best overall performance.
___end Copy_____

That is very very interesting for sure. as a fellow "m" owner, I think I will try some shell gold for my next couple tanks.

I can't see how ethanol would increase the chances of engine knock...it artificially increases the knock resistance of the gas....if anything it should diminish the likelihood of knocking

I agree, "up to 10% ethanol" will not damage internals. Likewise, any noticeable increase in performance is unlikely but rather dependent on how well that vehicle's ECU can self adjust. You can fill your car with rocket fuel and it wouldn't make a difference until you tell the ecu to lean out the mixture and advance timing.

I don't think it's black and white like that. It all depends on how your ecu controls fuel and timing. I can't speak for other vehicles...only my own because I've datalogged Chevron 94 and Shell 91 enough to testify that the car runs better in both closed and open loop mode with the latter. Chevron 94 should have better knock resistance but I haven't found this to be the case. I get just as much knock if not more on Chevron 94 in my logs as Shell 91...BUT the difference is the Shell is consistent.

If I get a knock count of say 3@7000rpm and 5500rpm and retard timing a degree then it goes away with the Shell and never comes back. The Chevron is all over the place...it will knock at one spot and disappear and then show up in another. Sometimes the knock counts are higher than the Shell. You pull timing and sometimes it goes away, sometimes it doesn't...it's really iffy that way.

Tune for it one day and it's all good. Next fill up the car will knock again. I would especially see knock at higher rpm like 7k with the Chevron where that wouldn't happen with the Shell.

If your ecu is self adjusting in open loop (when going wide open throttle) then you should be fine with ethanol blended gas as the ecu will account for the variation and increase/decrease timing accordinly. The evo's ecu runs off high and low octane fuel and ignition maps during open loop. For every 3 counts the knock sensor registers the ECU pulls 1 degree of timing...and will look to interpolate between the high and low octane maps. So if the car is running knock free it will stay happy and use the AFRs and timing from the high octane map and my face looks like :fullofwin:

But from the time it starts knocking the ECU dumps fuel to richen up the mixture and pulls timing...:okay:


you can immediately feel the difference in performance. Outside of upping boost...timing is where you really make power and that's why it's crucial that my car like the gas I'm running...and so far Shell has proven to be the lesser of the two evils. STI's run in a similar way...except they have a number called the IAM: Ignition Advance Multiplier. A confluence of factors account for this number...but the long and short of it is the higher the IAM the more timing the ECU will throw at the mix...but if the car doesn't like the gas it lowers the IAM and the car feels like poop.