Just wondering what type of fuel everyone uses in their TSX Sportwagon. I know a few people with different Acura's and most just use regular gas and say they have no issues. Is it really that important to use premium fuel in a naturally aspirated 4 cylinder engine.

 

It's all about the compression ratio, not the number of cylinders.

You'd be insane to run regular in an S2000 for example...

As for the wagon, we always use premium. You get the full power it was designed to deliver and excellent gas mileage. Sure it can run regular but with reduced performance and fuel economy.

Why pay more dollars per mile to get a slightly slower vehicle and more carbon build-up?

 

^^^^^^^^^^ i also use the premium in my wagon. and at 6K above sea level its actually helpful/ IMO

 

You'll no doubt get some pinging (esp under loads) when running octane lower than 91 (as stated in the owner's manual.) You won't notice it since the ECU knock sensors should step in and retard the timing to prevent the pinging. But then you will notice decreased performance as the timing is pulled.

 

I use premium, Sunoco 93. I drive in in the city mostly. Lots of stop signs and heavy traffic. I'm averaging between 19 and 20 mpg. No complaints.

 

Sigh...

 

What's the price difference between 87 and 91 octane gas? Often it's less than 5%. In my case the difference is about $2 per about 500 miles. This is just not worth compromising optimal engine performance.

 

About .30 cent a gallon more where I'm at. About $5.50 per 18.5 gallon tank.

About $22 a month - $266 a year in my case.

Not the end of the world but it just seems like a lot for a non turbo 4 cyc engine.

Volvo's turbo 5 250hp in the s60 uses regular - thinking Acura could come up with a way to use regular in their engines.

As gas goes to $5 a gal every little bit helps...

 

dont you guys have 89 in the states? use that its a nice compromise. 87 is fine with these cars so long as you dont venture into vtec range. even if you do the ecu will retard timing.

 

Honda squeezes out quite a bit of power out of a 2.4 that isn't a turbo.

It would be rated around 190 hp if it ran on regular. In other words, it would be an Accord motor.

By the way, the fuel economy in the wagon is fantastic. On long trips we've gotten 34 mpg with a loaded vehicle including some furniture.

 

We do. Sometimes we even have four octane choices.

The problem with the ECU timing being retarded is that it listens for pinging, in other words, the car is waiting for small amounts of damage being done. Why risk it?

 

One-hundredth of a dollar wise and 16 ounces something else.

 

Didn't say I'd use regular just wondering why they couldn't have come up with a way to avoid it. For me the 10hp is not that big a deal. What attracted me the this car was not the 0-60.

Now if I was getting the performance of a TL w/S-AWD wouldn't be an issue at all...

 

Acuras have always used premium with only a couple minor exceptions. In Japan for many many years they've had taxes on engines based upon their displacement. So the Japanese motors are tuned for high compression and therefore, premium fuel.

 

Remember, premium fuel is recommended with the TSX IL4 motor. It is required with the TSX V6. Read here (direct from Honda) for the specifics about your motor: http://www.honda.com/newsandviews/ar...spx?id=6212-en

To put it into perspective, the IL4 has a compression ratio of 11:0:1. The V6 has a compression ratio of 11:2:1. The V6 also has bigger displacement than the IL4 (3.5l versus 2.4l.) Combine high compression with displacement and you get the balance of performance and fuel efficiency.

But with high compression motors there is an issue of knocking when residual fuel is not burned in the combustion chamber and detonates under temperature and pressure (after TDC and the flame front of the combustion chamber explosion.) The octane rating of gasoline is solely an indicator of how resistant the fuel is to knock. It used to be that they used lead to prevent knocking. Today, lead is banned from fuel (expect for certain applications) and so the higher octane and additives (manganese) help reduce knocking. High octane reduces the fuel's combustion temperature and reduces the tendency to detonate.

The TSX's motor has sensors that recognize any abnormal detonation and will retard the timing (the ignition advance) to help prevent the knocking. But that will also mean less efficient fuel consumption and power. Lower octane may not cause damage (due to the preventive sensors) but it can decrease mpg and performance overall. But these are sensors and not 'anti-knocking' devices, so you can still run the risk of knocking (if you do use regular be sure to keep an ear out for pinging sounds.)

So with high compression motors it's all about a balancing act of moderate displacement (for various regulations and for taxation purposes in certain countries, like in Japan as Ken already mentioned), performance, and fuel efficiency (which is also highly regulated.) But high compression means issues with fuel burning and detonation based on commercial gasoline and its octane rating.

Mazda has designed a super high compression engine with a ratio of 14.0:1, a world's first (the SKYACTIV-G series.) 91 octane fuel is required for the SKYACTIV-G motors. But they've had to do a lot of engineering tricks to prevent detonation issues even with 91 octane. The combustion duration is shortened by intensifying air flow, increasing injection pressure, and using multi-hole injectors and a piston cavity. This will help reduce knocking issues. But designing such a high compression motor like this allows for good performance from a small displacement and with very good mpg.

Nonetheless, they are building a lower compression version for the US to run on regular fuel. To run on regular gas, it will have a lower compression ratio of 13:1. And that means means fuel economy and torque will be reduced by about 5% (according to Mazda themselves.)

So, you can see the issues of octane, compression, mpg, efficiency, displacement, fuel detonation and knocking (knocking can destroy pistons, so it's not an issue taken lightly.) Add to the mix a myriad of regulations and motor designers have their work cut out for them.

In the meantime all you can do is what the mfgs suggests in order to keep a properly maintained car running for a long time.

 

I think Acura guessed right for the most part when they assumed that people buying a $30,000 car aren't concerned about $5 a week at the pump.

 

Thanks all - a lot of good the info here.

Not a big deal using premium fuel just wondering why it was required. Now I know.

As far as what I could afford and what Acura thinks about that I'd say that many people buy cars that they can't afford these days as so many people live beyond their means.

I'm lucky at this point in my life that I can buy the car I want. One of the things I like about this car is the fact that it's such a great value. I could spend a lot more but choose not to.

I am concerned about seeming insignificant things like the price I pay for fuel and it's got nothing to do with what I can or cannot afford.

If that means I'm not one of Acura's "target" customers I couldn’t really care less...

 

You actually are one of Acura's target customers.

fwiw, I came from a $96,000 Mercedes AMG E63. A lot of people I know have always 'downsized' in ways that make sense, such as with a depreciating 'asset' like automobiles. Money is better spent in other things these days (and in things that can give you a monetary return.) Cars are only good for their use value (unless you buy collectables on speculation.) My E63 gave me pleasure but it wasn't sensible economically even though I could afford it and its high maintenance. (And its depreciation was very high which meant all that money was just going into immediate gratification.)

Wealthy people stay wealthy because they do pay attention to little things like fuel costs. It's also how one makes a profit in business and investments: you look at every penny.

Here's classic book that's been around for a long time: http://www.thomasjstanley.com/pub-bo...Next_Door.html

"Focusing on those with a net worth of at least $1 million, their surprising results reveal fundamental qualities of this group that are diametrically opposed to today's earn-and-consume culture, including living below their means, allocating funds efficiently in ways that build wealth, ignoring conspicuous consumption, being proficient in targeting marketing opportunities, and choosing the "right" occupation."

Don't let somebody tell you it's lame to be frugal and sensible. You don't need to prove anything to anybody and especially not with the kind of car you drive or the clothes you wear. The proof is in your bank account.

 

Cudfoo, fyi: in another thread here about octane ratings I mentioned that it was really just a waste of money to use anything over the 91 octane (that Acura themselves recommend in order to keep the car well maintained and properly running, and to last.)

Another poster said the cost difference between 93 octane and 91 octane was only $2.77 per fill up. I replied that if one commutes a lot (e.g., uses 2x a tank per week) that it will add up over a year. And even if you don't commute a lot, it still will add up.

Their response was if "I'm that cheap than I should be taking public transit."

When somebody says "it's only $200 a year" and then spends that $200 on something they don't need at all, I tell them this: imagine having $200 cash in your pocket everyday for 365 days to have for emergencies. It gives you a nice feeling of security, right? But it gets even better. After another 365 days, you'll have $400 cash in your pocket to carry around. Visualizing the actual cash being in your pocket can sometimes make people think twice about needless spending.

http://www.ftc.gov/bcp/edu/pubs/cons...tos/aut12.shtm

 

Thanks for all the valuable information TJ.

No one wants to be told how to spend their money - especially by those who do nothing but waste it.

91 sounds good to me.