With gas prices the highest they've been in months ( at least here in Canada, eh! ) What kind of fuel does the TSX REQUIRE? Regular or Premium?

 

It's rated for premium. While knock sensors that mean you won't damage the motor if you run regular, you'll be running the engine in a less efficient way, which will probably negate a good portion of the savings.

I don't know about you, but the biggest factor in my gas mileage is how I drive. I could add 4 mpg by just not revving up to 7k a lot and shifting at 3.5-4k all the time and driving more gently without feeling the need to pass everyone.

But then driving wouldn't be any fun! Perhaps you already drive efficiently.

Short answer: I think it's a false economy to use regular in a car that wants premium. (It's also pointless to put premium in a car that only needs regular.)

C.

 

Premium. It needs at least 91 octane, though 93 is all I can get around here.

 

If you don't mind giving up the increased power you get with premium, my understanding is it will run just fine with 87. Chrisalberts makes an interesting point. I'd be curious to see just how much worse the mileage is with 87 compared to 91, and whether it's enough of a difference to justify the extra cost of 91.

I was told by both my mechanic and the dealership that the engine control system in my 528i (actually, the mechanic said "modern cars," but he was working on the BMW at the time) would let it run fine on any octane grade, but with some degradation in performance for 89 or 87. I tried them all. The difference in performance between 91 and 87 was significant enough that I could feel it, but I never checked mileage.

 

The only mention that Acura makes in their specifications listing is that you'll get decreased performance. That would be curious of gas mileage suffered too.

There have been other discussions about this, and there have been two general opinions offered by members:

- Acknowledging the knock sensor that adjusts the engine to accomodate different Octane ratings of gasoline, and thus averting engine damage.

- No acknowledgment of a knock sensor along with the opinion that engine damage will certainly occur if you use lower Octane gasoline.

I would like to believe the "knock sensor" opinion. Acura's specifications make no mention of knock sensors, however. What authoritative sources are there that a knock sensor adjusts the engine and averts engine damage?

 

To me "decreased performance" means either:

ultimate maximum speed and acceleration will be reduced, or if you maintain the same speed as you did with higher octane fuel (likely) then you'll be working the engine harder to get that speed. Working the engine harder implies worse fuel consumption.

That's my logic anyway. I could well be wrong, though.

C.

 

The "adjustment of the engine" would be that the timing would be retarded. In view of the fact that the i-VTEC motor in the Acura modifies it's timing anyway in a dynamic fashion, even without checking I am willing to guarantee you that it has knock sensors and can retard its timing to accomodate lower quality gas. This feature first started appearing in cars (Saab were the first to make a big deal of it in their ads) in the mid 80s and with fuel injection, emissions controls and OBD2 now, I doubt there are any performance oriented cars currently produced without this feature.

I'll go check though, and report back if I find anything interesting.

C.

 

Does anyone really know how much more gas the TSX takes when the AC is on? What would the decrease in MPG be?

 

Just got my TSX yesterday and was looking at the manual last night(in the car of course) and it did state that lower octane gas could cause damage to the engine. I was wondering the same thing based on earlier discussions on the site. I'm going with what the manual said and sticking with the correct octane.

 

THe AC doesnt make that much of a difference. If fact its been reported that driving with the windows open will hurt your mpg more than having the AC on.

 

Seems to me this is mentioned in another thread. My guess is that the Acura has such a low drag coeffecient that it does just as well or better with the AC on and the windows up as with the AC off and the windows down. I believe open windows creates significant drag.

 

Thanks. That's the first time I recall anyone referencing the Fine Manual.

 

Well,

if it's going to DAMAGE the engine, this is a nick in buying a TSX then.

Talking about driving habits, I drive like a regular joe, but when some dick is tailgating, trying to pig in from the right, or a semi that will be merging soon, I want the poop to get out of those situations.

 

An article that someone posted talked about what kind of fuel is needed in the cars to run well. Car company executives said themselves that under 91 is ok but it will decrease the car performance. However on supercharged engines one needs to use 91. Turbo charged are okay under it. Most cars do come with sensors that can detect the different quality anyways.

IMO i think that if you bought an entry luxury sedan you should go with 91. its about 2.26 a gallon at the moment when i went to fuel up my maxima here in LA. Personally i can tell the difference between 91 and 87 easily. Just stick with the 91.

 

Octane and fuel economy are interesting subjects. Octane requirement was something I compared when deciding on my vehicle purchase. There are many fine cars that run on 87 octane, but very few truly desirable cars that get very good gas mileage on 87 octane. The 03 Honda Accord is one that gets great mileage on 87 octane, but it's not nearly as fun to drive as the TSX.

With that being said, I benchmarked the Mazda6 V6 (27mpg hwy, 87 octane) and the TSX (32mpg hwy, 91 octane) and here's what I found:

Ex: 15,000 miles per year
Est Gallons used (using hwy mpg only):
M6: 555.55
TSX: 468.75

Est cost per gallon: 1.90 (87), 2.10 (91)
M6 annual fuel cost: 555.55 x 1.90 = $1055
TSX annual fuel cost: 468.75 x 2.10 = $984

Ironically, the TSX using 91 octane is cheaper to operate than the M6 using 87!

Naturally, this is a very simplistic way to determine whether a less fuel-efficient vehicle that runs on 87 is more cost-efficient than a more fuel-efficient vehicle that runs on 91, but it's interesting food for thought.

 

This may be a stupid question, but since it has been reported that the Accord V6 gets an extra 10hp boost with premium gas, does that mean that the knock sensors are constantly retarding the timing with regular gas (which, from my understanding, does not damage the engine at all)? Therefore the EX-V6 really has a 250hp, premium-requiring V6 that "retards" down to 240hp w/ regular fuel.

If the above is true, then there should be no physical damage caused by driving the TSX w/ regular fuel, despite the reduction in the engine's performance...

 

I don't qualify as an authoritative source, but I will tell you what I know.

Electrically, a knock sensor is the same as a piezoelectric microphone. There are multiple knock sensors mounted to different points on the engine block to determine whether the engine is experiencing unwanted detonation (pinging). When the sensors detect this, the ECU will change the timing of the spark and fuel delivery to ensure that the pinging or knocking goes away.

What this doesn't do is guarantee that you won't get any long term engine damage from using fuels that cause your ECU to run rich (or lean, I can't remember which it is) all the time. However, I can say that the amount of damage done with short term usage of low octane gas is negligable.

The only places I can see there being any real potential for damage is with the increase of deposits in the cylinders and on the emissions control componentry (O2 sensor, HEGO sensor at the catalyst), which can cause them to prematurely fail over time.

 

OK. We gotta be VERY careful now. We're starting to enter a very weird area here. I'm not sure we want to allow actual calculations. That starts to get in the way of "I think" or "It's obvious" or "You're an idiot if you don't see it."

Nice try XPLORx4. I'm afraid we're gonna have to ban you.

Well, just this one time we'll give you a pass. But from now on......... no math, no science. Conjecture only. And argued with passion and even threats. No more "this is a very simplistic......" From now on, begin all your arguments with "what an asshole!", and you'll do just fine.


Seriously, anybody with a nav willing to try a (full) tank of 87 and see what the highway mileage readout is to compare it to 91? I'll do it.........if I ever get my car.

 

Hahah. lshenretty- you're an idiot! (happy? )

I think the test you're proposing is interesting, but I wonder how many people would submit their brand-new baby to "substandard" fuel. Not me! I haven'ty even used my second tank of gas all the way yet! Maybe when you get your car you can be the guinea pig! :P

 

Great post

 

ish you asshole! who the heck on this board is going to use substandard fuel, why dont you get your tsx first then tell us how to user our tsxs as guinea pigs!!!

 

Well, I'm not yet willing to put 87 octane in my new TSX, but despite what the owner's manual says (I have read it all, BTW), both the Acura website and the TSX brochure state: "** Gasoline with an octane number lower than 91 may be used, with reduced performance."

So I don't really think it is substandard. Honda uses many of the same engines in Honda models and Acura models and in all cases the Honda version runs on 87 octane, but the Acura version (probably tuned for better performance) recommends 91 Octane.

My other car is a 2000 Odyssey Van, with an engine very similar to that in the Acura MDX. The Odyssey runs on runs on either 91 Octane or 87 Octane (with a 5 hp decrease, per Honda). The Acura recommends 91 Octane. I have used 87 Octane in the Odyssey for 4 years with no problems. (I have tried 93 octane a few tanks, with no noticeable difference.)


I am considering trying 87 or 89 octane in the TSX after it is broken in. If I do, I will be glad to report back...

CG/Quartz, AT, Navi, purchased 8/9/2003

 

What are the differences between the odyssey and the mdx engines? My guess one difference will be compression. High compression is one of the main factors that lead to the need for higher octane. If your Odysseys compression is low enough that it wont knock under 87 octane then you would never notice any difference using higher octane gas...because there would be no difference.

 

I wonder how much of the 91 vs 87 fuel issue plays towards our perceptions. Just look at the names for the fuel - 91=premium, 87=regular. Acura takes premium, Honda takes regular. If the TSX recommended 87 octane, what would Audi/BMW/MB drivers think??? I don't doubt there's a small difference, but I wonder if it's more image than anything - like 0-to-60 in 7.2 instead of 7.1 seconds.

That being said, I still use "premium" - I don't know if I would if I was in Phoenix right now.

 

That's the spirit, dabuda! That's even better than the "What an asshole!" start that I suggested to XPLORx4. More direct. Good job.

 

Yay!!!

91 octane just hit 97 cents a liter today!!! Vancouver is now the highest in Canada!! WooWooooo!!
Can we just pillage Iraq of all its oil already?

Actually, I'm not one to observe gas prices and hunt around for the 2 cent savings. The shit is still relatively cheap, as our diesel driving euro friends would attest.

 

Good point, Keyser.

 

97 cents a litre is fucking ridiculous.

 

I just filled up a few minutes ago! Gas was $1.77 a gallon, up $.10/gallon from last week. What the hell happened? This is Austin F'ing Texas, already... Oil state!

 

I think continued instability in our newest 'oil state' is contributing, particularly after the sabotage of that pipeline.

 

2.31 per gallon here in LA, CA. God $30... sucks putting gas in here in LA...