mau108

So was wondering, for the Canadian RDX owners which brand of gas do you get the best mileage with the RDX?

On my 99 Honda Prelude which requires premium fuel, I found Shell 91 to give awesome mileage (about 9.8l / 100km) compared to Sunoco and Petro.

On the RDX since I've purchased it, I've been putting in Sunoco Ultra 94 and have been averaging 14l / 100km. (90% City driving)

loulinjai

what kinda mileage does your prelude get with non-shell gas. have you tried using V-Power on your rdx? I would expect that although Ultra 94 has a octane rating of 94, it is ethanol blended, where as V-Power contains zero ethanol in Ontario. (I'm assuming you live in ON since you mentioned Sunoco and Sunoco is only available in ON). Although V-Power is 91 rated, I think the RDX will operate with minimum gains between 91 vs 94.

I noticed on my tsx, it pulls harder on V-Power, and there is a familar highway on-ramp on the 401 i take quite often. At the same speed accelerating, it doesn't downshift on V-Power, but downshifts on gas such as Esso 91 in identical driving habits. I noticed better gas mileage on V-Power as well vs. Esso (usually I fill up at Shell or Esso), but I heard recently Esso has crap gas.

mau108

Ya Shell, Petro and Sunoco are top tier

With Petro or Sunoco on the prelude I was getting about 10.5L / 100KM, this time on Shell I got 8.8L / 100 KM

Pumped with Petro 91 again as I get 4 cents off per a litre (407 etr rewards card and citibank petro card). will get an exact figure of how the petro performs.

loulinjai

wow thats almost 20% difference, maybe your driving habits and/or condition changed for this tank with shell (more hwy cruising). that definitely is a impressive figure. post how your petro tank goes when you know.

FEPTS

I am in toronto and using petro 91, I am averaging around 14l/100km as well, I never use other company yet, but may try shell in future and see what happen

mau108

Let me know how Shell works out on the RDX, I am currently putting in sunoco 94 until end of this year as my insurance company is CAA and I earn CAA dollars towards my insurance and membership by filling up with sunoco (plus their new program, so I get double the points plus my creditcard rewards :P)

mav238

I currently run my RDX on Shell 91 V-Power, with the very rare occasional tank of Chevron Techron 92. I do not find any real significant difference in fuel economy between Shell V-power or Chevron.

IMHO, if both gasoline qualities are similar and rated as top-tier, you would be very hard pressed to find any real detectable difference in fuel economy. This is especially true if the car is new (less than year old) and only driven in regular day-day driving. The fuel economy is more dependent on how you drive the car, the traffic conditions and if you maintain the car well.

On the other hand, for my other car, the TSX, I initially had it running on ESSO supreme, but found that the car does not run as smoothly consistently, as compared to when I switched to Shell V-power. The effect was detected after a sustained period of using ESSO. Maybe ESSO does not have as concentrated a detergent package as shell or Chevron. So now I don't run my cars on ESSO at all.

So, IMHO, you probably won't find real-time difference in fuel economy when you compare different gasoline brands. But over a long period of sustained usage, you will find out if the quality of the gas is good or bad for your car.

On the other hand, on the F1 circuit, gasoline chemistry makes a huge impact on engine perfomance and sustaining power to stay in the race with long intervals to re-fueling.

mau108

The kicker is I do find a big difference on my prelude. Shell advertises they use no ethanol alcohol in their v-power (but have a concentration in their other two). Where as sunoco and petro they say the fuel may contain up to 10% ethanol (and the ultra 94 according to sunoco's site does contain ethanol alcohol in it as suncor manufacturers their own ethanol)

Ethanol burns cleaner = Better for the Environment but crappier MPG
Non Ethanol doesn't burn as clean = Crappy for environment but better MPG

mav238

I don't want to seem like I am doubting your claim to your prelude having great mileage with V-power, but how much "greater" did you see in the difference in comparison to say Sunoco, Petro, Chevron? You claim ~10L/100km with V-power, what was it with Sunoco? Was it like 10.5L/100km? Like I said before, the fuel economy is very dependent on traffic conditions, weather conditions (summer vs winter) and how one drives.

If you say, with sunoco, you were consistently running at 11.5L/100km (over like 5-6 tanks of gas), while with v-power, you see a consistent 10L/100km, okay, I would say that there is a real significant difference.
I do not disagree that gasoline chemistry will have "some" impact on "instantaneous" fuel economy, but my feeling is that it is not significant (<10%). The more important thing would be how well the gasoline keeps the engine from fouling up over long term usage, which IMHO is more important in everyday stop-go driving.
And that is why I keep my RDX and TSX running either on Shell V-power or Chevron 92 Techron.

mav238

BTW, ever since the barnet hwy in burnaby, BC, was closed due to a terrible oil spill, I have had to reroute to use a more congested route to get to work everyday. I use to be able to run the RDX @ 11.8L/100km, but now, I am consistently @ 12.8L/100km. All the time on Shell V-power, car runs as smooth as from day one, but fuel economy definitely hit by the more heavy traffic congestion route.

mau108

If you note above, I was getting about 10.5 (or higher) with sunoco or petro, with shell I got 8.8 / 100km (I filled up last night so I calculated it from how much I filled and the mileage on my odo)

mau108

ya our rdx goes downtown and back uptown (30km trip one way but takes an hour and a half to get to in the morning lol)

russianDude

Do you have to use premium gas? I think manual recommends it, but its not required?

mau108

yes do put it in, especially if you drive the rdx hard. If one can't afford to put in premium fuel (when required) then I don't see how one can afford an RDX

russianDude

I don't think manual requires it, it recommends, and thats a big difference.
For my acura CLS 01, premium fuel is pretty much required as per manual.

Sometimes manual will say something like "for optimizal performance, use preimum fuel. However, regular fuel can still be used wityh reduced performance".
Thats why I am asking exactly what manual says.

chipt911

Here's the exact wording from my 07 manual. I don't think it changed for the 08:

Fuel Recommendation
Your vehicle is designed to operate
on premium unleaded gasoline with a
pump octane of 91 or higher. If this
octane grade is unavailable, regular
unleaded gasoline with a pump
octane of 87 or higher may be used
temporarily. The use of regular
unleaded gasoline can cause metallic
knocking noises in the engine and
will result in decreased engine
performance. The long-term use of
regular-grade gasoline can lead to
engine damage.

mav238

Wow, that is pretty impressive difference...

Now if that was true for all cars, for all driving habits, for all weather conditions, and granting that that difference was not due to an overfill with the Shell, I am wondering why Shell is not seriously marketing that fact, that it will give you a "night and day" difference the moment you switch over to Shell V-power. That kind of difference is big, and you will find everyone flocking over to Shell V-power, especially those SUV drivers. Soon, Sonoco and Petro will be out of business.

My old 2001 BMW 330i was running on ESSO for the longest time (like 3 years), and the fuel economy was like 13.0L per 100km (originally was about 10.5L per 100km)... When I ran Chevron Techron 92 through it, after 2 full tanks, and in the next tank of gas, I immediately felt a big difference in performance and fuel economy, went up to 11L/100 km. I attributed it to the chevron techron cleaning out the engine deposits, and making the engine more efficient in combusting the fuel. The effect was not immediate, like just by filling the gas tank, and start the engine, and immediately my gas consumption went down.

Sorry, don't mean to doubt, but I am still leaning towards < 10% difference in fuel efficiency between gasoline brands. The calculation is getting those fuel economy numbers will also have a 1-5% error built in.

Try running Sonoco/Petro through your RDX (which I assume is pretty new, less than 1 year old) for 2 tanks, run it relatively low, calculate the gas consumption, then go fill it up with Shell V-power, run again for 1 tank, and calculate the fuel consumption again. And then see if you really see that kind of immediate difference like you saw with your Prelude.

If it is really gasoline chemistry that generated the difference, the difference should have been observed immediately, by changing the tank over from one gasoline to another.

Otherwise, long term fuel economy (e.g. 6 months of use) should be a better gauge of a gasoline quality and efficiency.

there is really only so much you can squeeze out of a litre of fuel in an engine. Law of thermodynamic physics in an internal combustion engine. So if the car when brand new was delivering 10L per 100 km on a good brand gas like Sunoco, running it on Shell will not give you 8L per 100km improvement in fuel economy.

Boon

My 2 cents....

I switch it up between Shell and Sunoco depending on which is most convenient. Even go up to 94-supreme at the Sunoco's once every few months. Haven't really noticed any differences in terms of performance from the RDX...but I've been stuck at work 24/7 lately and haven't driven in almost a month.

When I was driving the X3 though, filling up with 94 definitely made a difference. Not sure if I got better mileage, but it seemed to accelerate a bit smoother and had a little extra spring in its step.

k23a1

Forced Induction = highest octane available by pump. Even NA vehicles with HC will require highest octane levels. But almost automatically, for FI, highest octane.

A $40k vehicle (which requires 91 octane) does not justfy for not spending the extra $2.00 (overall) at the pump.

mav238

And to add to my point above, I have tried many brands of gasoline in the bimmer, some with 10% ethanol, and never saw any real significant difference in fuel consumption at all.

Honestly, If a car is sold brand new, as giving 10L per 100km, I really sincerely find it hard to believe that in two consecutive tanks, one with Sunoco, and one with Shell V-power, that the gas consumption is any different. When the car is brand new, all internal engine components are brand new, so we should not expect much engine deposits in just two tanks of gas. so we can most likely rule out any difference due to a "dirtier" engine.

But if you take an older car (like 3-5 years old), which never really had a complete engine deposit clean-up done professionally, there will definitely be some substantial deposit build-up. So you run your typical gasoline for the past 3-5 years, and then now you switch over to a gasoline with a detergent chemistry package that is really advanced and superior to anything you have ever used, I would not be surprised if you find that suddenly, after only one tank, you are getting a significant improvement in fuel economy, BUT it is never ever going to be better than what you had when the car was brand spanking new. JMHO

mau108

I understand what your saying, but Shells Vpower has 0 ethanol, where as other brands have some % of concentration in their premium fuel.

The ethanol is the one thats making the difference.

In BC at the shell stations do you see the stickers where it tells you the concentration of ethanol in the fuel ?

mau108

On FI engines yes its recommended to go with atleast the recommended octane or higher, but on a NA high compression engine (like my ludes) 91 is sufficient. I see nor feel any gains using 94 octane, in fact its the crappiest when it comes to fuel economy numbers in that engine lol.

Honestly I think the RDX will work perfectly at 91 octane as well as thats how honda has tuned and set the timings, so 94 octane really is not necessary (but I put it in for the heck of it)

ShadowGirl

Hey mau...to answer your original post, I've got around 2700 kms on my RDX and have consistently used premium gas (assuming 91 octane?) from Superstore gas station. I didn't really expect there to be much difference between brands. I seem to be maintaining around 11L/100km in mostly city driving.

mau108

wow thats friggen good. I have noticed after the last fill up (last night) the Range milage seems to be getting larger each time I fill up.

First time I filled up with Ultra 94 I got 437 range, then next time I fill up 450ish and this time 485 :S

The engine isn't even breaking in, its got 7200km on it.

ShadowGirl

A-Ha! so the range has something to do with mileage? I've been wondering what that reading is supposed to mean. With all the gadgets in the RDX I haven't gotten around to figuring everything out yet!

drtdvl

I have used Shell V-Power (91 Octane) and Husky (92 and 94 octane). For the last two months, I have switched to Husky as the location is more convenient and used both 92 and 94 octane fuel intermittently. The Husky fuel has ethanol but I do not know the percentage (probably 10%).

With highway driving, I tend to get about 10% more range from a tank of gas as compared to V-Power and that is filling with 94 Octane. The cost difference right now is a penny per litre between 92 and 94 Octane.

In the city, I have not noticed any mileage differences between Shell and Husky. My city mileage varies between 12l/100km to 12.5l /100km.

mau108

Range tells you how many clicks you can drive before the tanks is empty, the range can change anytime as if your crusing at 100 your obviosly using less gas then stop and go.

I look at both the l/100km (it resets every time you reset your trip a which I do at every fill up) and range.

Some good features, goto the Tire Pressure Monitor check screen and hit the select/reset button on the steering, it will give you the tire pressure for each individual tire.

Also some hidden menus (look in the manual for it :P)

Enjoy!

mau108

I'm thinking shell on the east coast here is providing a different formulation then out west ?

k23a1

Our pumps, in the past, use to offer 93 Octane, but was revised a few years back, which is now 91 octane. The RDX will get the highest available by pump, and will never get anything less than the highest.

I was knocking on a summer day, while I had mid grade gas in my civic (b16a2 motor).

Saving 2 bucks on the overall cost, for a vehicle that costs 40K+, does not seem to make any sense; I just don't understand why people assume that they are pumping their money away, and they can save a bundle, especially when it is required.