Hello everyone and welcome! In this video
we're gonna be talking about a new AAA study, which was just published looking at six different vehicles that recommend
but do not require premium fuel so none of them require it
but all of them recommend it. So why might a car recommend using premium fuel or higher octane fuel?
Well you know there's three major reasons you can think of for performance so more horsepower for better fuel economy and to prevent engine knock or
to prevent damage to that engine so that it can use advanced timing so we're gonna work through first of all how this works
then get into the actual results the study and kind of compare some of these different vehicles, which were used in the test now
It's important to understand that the octane rating of a fuel as it increases
that fuel is more
resistant to knock it's less likely to have knock occur and that allows it have more power because you can advance the timing more so
if we look at two engines, how does an engine with premium fuel make more horsepower than an engine using
regular octane fuel? If we look at the exact same engine in two different scenarios
this one using premium fuel this one using regular fuel this one will be able to
ignite that air fuel mixture as the piston is coming up so you have intake, compression, power, and on that
compression stroke
the spark plug will fire earlier with premium fuel than with regular fuel because it won't have to worry about knock and by firing
earlier it makes more power now if this doesn't make total sense
i've got a separate video where I dive deep into detail of how that works
but the most important thing to know is if you advance timing you can make more power, okay?
so now we understand how you can make more power with premium fuel
but how can you get better fuel economy?
so if you look at the same two engines and you look at the amount of air and fuel that's going into them
they'll have the exact same amount of air and fuel going in but because this one has advanced timing
it's actually going to make more power, so we've got air here in blue
the green is going to be our fuel and then red is power and as you can see you're gonna make more power
using premium fuel because of that advanced timing with the exact same amount of air and fuel
so logically if you were to use less air and fuel here
you could still make the same amount of power as if you had that retarded timing though the later sparkplug firing
and so that's how you're able to have better fuel economy
it's by using less air and fuel
but advancing the timing so you're getting more power from a smaller amount of air and fuel and thus getting better miles per gallon
okay, so the first test AAA
did here simulating fuel economy what they did is they took four different grades to a 0%, 2%, 4%, and 6%
grade. They had the car traveling at
65 mph for the 0%, 2%, and 4% grades and at 55 mph for the 6% grade,
and they measured the fuel economy at each of those grades. Now the six cars were comparing are a:
2017 Ford F-150, a 2016 Cadillac Escalade, 2015 Mazda Miata, 2016 Audi A3, 2017 Ford Mustang, and a 2016 Jeep Renegade.
And there's a bit of variance between all of these as far as half of them are naturally aspirated half of them are
turbocharged half of them are four cylinders
there's two V8s, a V6. A half of them have direct injection half of them have port injection
so there's a wide variance here, which you know AAA
put in place to see the different effects on these different styles of engines. Okay, so here
we're looking at a summary of that data, so the 0% grade, the 2% grade, the 4%, and the 6% grade.
Here we've got our average improvement
on the left each vehicle which was tested and then you can see the actual fuel economy numbers in miles per gallon here for each
vehicle so interesting to see you know when the Ford F-150 isn't very loaded up not too big of a difference between
premium which is this number right here and regular octane fuel right here,
but as you start to get a steeper hill the improvement starts to show so you know 10 mpg
versus 9.29 there
in the Cadillac Escalade very interesting to see this huge improvement at a
0% grade and the reason for this is it was actually shut down
into a four cylinder mode and in the four cylinder mode
it was able to advance the timing quite a bit in the Escalade and get much better fuel economy
these were all in the V8 mode the computers choose the driver does not choose
so it was just in the four cylinder mode for the 0% grade
but the computer decided for each of these it would be in the V8 mode running all 8 cylinders
so interesting to see you know some decent improvements for the F-150 in certain scenarios for the Escalade in certain scenarios
not much of a difference for the Miata, the Audi actually doing worse in low grade scenarios and
very small improvements in higher grade scenarios 0.1%, 0.3% percent. The Ford Mustang kind of similar to the F-150
where you know with those higher loads, it was actually able to take advantage of the premium fuel at lower loads
it wasn't quite as needed and then finally looking at the Jeep Renegade a small improvement across the board there.
Now what's fascinating to look at it and which proves the point that premium fuel can give you better fuel economy is to look at the
ignition timing so here
we're looking at the Cadillac Escalade and remember in that first scenario, so it's at a 0% grade
and this is at 65 mph
so premium versus regular, premium here in red and here we're looking at the ignition timing advance
And so you can see that the timing advance is far more using the premium fuel
than using the regular fuel and as a result you're able to use less air and fuel so here
we've got the mass airflow sensor, and it's measuring significantly less air you can see that gap right there coming in the engine
and it's able to do that because it's making the same amount of power with far more ignition timing so
significantly more advanced ignition timing, and then you see in the other scenario
phase 3 so the 4% grade where the Cadillac also had a big gap in fuel economy almost 10%
there, also a huge gap in the ignition timing and a corresponding gap in the amount of air needed
so less air needed with premium fuel and so as a result better fuel economy
with that scenario
looking at a different example the Ford Mustang
you know using very similar timing for those low loads
and then you can see as you get into the higher load it actually advances the timing
significantly more versus the regular fuel and as a result
there's a gap in the amount of air required and it gets better fuel economy
so really cool to see the actual data behind it
proving that you know advancing the ignition timing can result in less air used and as a result less fuel used
it's also interesting to look at the Jeep Renegade's ignition timing
so this is a super small 1.4L engine so high boost and as a result you can see that as that load
increases as you build into the boost you have to significantly retard that ignition timing, so you don't run into engine problems
so you can see a huge dip in the ignition timing and that's as a result of using a small engine with high boost
so you can see that you know,
significant drop now
honestly between the two not a big difference so you're not noticing a huge difference in fuel economy as a result of
the advanced ignition timing and it's only slightly advanced in a couple scenarios
now something else interesting to see it seems like the larger engines
benefited more from the premium fuel rather than the smaller engines
which didn't improve as much,
seeing peak improvements as high as 7.8, 13.5, and 8.0 in
the V6s and V8s versus 2.9, was the highest seen in an individual test with the Jeep Renegade.
Now this certainly doesn't imply that the reason why they did better is because they have larger engines, but it's interesting to see that
that's how it played out.
So the next tests were to look at how much horsepower does this vehicle make, so there were three tests done
two of them holding the engine at a constant RPM, so 2,000 and
4,000 RPM and then the break for the dyno adjusts its braking force
to allow that engine to stay at a specific
RPM 2,000 or 4,000 as you apply throttle so you apply full throttle the engine is held at a specific RPM
and then you measure the
power at each of those so at 2,000 and at 4,000 RPM. Then a more traditional dyno plot
where you're simply you know just doing the traditional dyno revving it up from a low RPM to a higher RPM to redline and
seeing its torque and horsepower curves, okay, so looking at the horsepower data 2,000 RPM so low engine RPM
however a high engine load
you are flooring at doing this seeing what the effects are and then a
mid-engine RPM, 4000 RPM with a high engine load as you can see a small improvement for most of them the Jeep renegade
losing a little bit of power and then at 4000 RPM the Mazda Miata actually losing a little bit of power
but you know the Ford F-150 actually doing pretty well 1.1% improvement there 3.9% improvement
at the 4000 RPM test you know 11 horsepower. That's a significant difference there same with the Ford Mustang,
4 horsepower gain 4.3%, 9 horsepower gain 3.6%. So interesting to see the differences
but these different engines here now more exciting is looking at the actual dyno graphs for each of these vehicles
so you can see premium is the dotted line,
so we've got torque here in black and then horsepower here in red dotted
represents premium fuel and the solid line is the regular fuel so you can see in the mid to high rpm range,
that this Ford F-150 is producing more power and more torque
moving on to the Cadillac Escalade very little difference in power and torque between premium and regular fuel
looking at the Mazda Miata actually a significant difference in the torque curve, so you can see you know 2.9%
boost across almost the entire curve
there's a benefit there, and so consequently you also have 2.8%
improvement in horsepower so pretty cool to see you know a pretty sizeable difference
in using premium fuel versus regular with the Mazda Miata remember, this is the previous generation
this is the 2015 so the NC not the ND.
Looking here at the Audi A3 on a decent you know from this point onward making more torque more power
smoothening out that torque and power curve
so looking pretty good for the Audi as well you know 2%, improvement in torque 2.1% improvement in horsepower and
looking at the Mustang GT
you know at the beginning and at the end not a huge difference, but a significant boost in the mid range
using premium fuel 1.8%, 1.6% horsepower,
adds a little bit of grunt in the mid-range for the Mustang and finally moving on to the Jeep Renegade
sadly the loser here of the group with 1.4L making less horsepower and less torque
fairly consistently not a huge number. You know just 1% torque and horsepower
but sad to see that you know an engine that small
isn't actually seeing a benefit from using this premium fuel you would think would be able to advance a bit more
but perhaps that high boost just kind of prevents that from happening and you can see here in the data
that using regular fuel or premium fuel you're not going to get a huge difference so looking at the average power numbers all of them
did on average improve with the exception of the Jeep Renegade,
which actually did a bit worse power wise with premium fuel and then looking at the peak numbers for
individual tests the highest one for each some as high as 4.3 for the Ford Mustang 4.3%
you know power increase simply from using premium fuel in a specific scenario, that's pretty impressive
I mean just a fuel swap and the car is able to adjust timing enough to you know to actually show an improvement in performance
4.3% for horsepower and what about knock well
it looks like the only car they had an issue with knock was the Audi A3 and so for that one
you know obviously you should be using
premium fuel because you don't want to run into knock and have engine problems. So ultimately what's the
recommendation here? If your car says it requires premium, fuel then obviously you should use premium fuel. If it says you should use regular fuel
then you should use regular fuel now if it says it recommends premium fuel you may get a power
benefit from it in towing scenarios it may be useful
but from a cost perspective
you know there's not really a justification for it because the percentage improvement you get in fuel economy 2.7% percent
is not equal to the price gap in premium fuel,
which is you know 20 to 25% which is increased quite a bit in the past several years the gap between regular fuel and
premium fuel is increasing even though fuel
itself is actually fairly cheap still so it's interesting
that you know that price has been kind of
inflated there, It seems, but regardless you know and and of course if if you hear knock if your car recommends to use
premium fuel and use regular fuel and you hear knock like AAA
did with the Audi A3 then obviously you should be using premium fuel to keep your engine in good condition.
So if you have any questions or comments feel free to leave those below, thank you all for watching
and I'll include some relevant videos for you to check out help you understand these topics if not all of this made total sense.