vwong

I use 91 since that is what we have as Premium in Calif.

kaliraver69

I use 91 Premium Chevron with Techron

ABP-CL9-TSX

I use 87-89 octane for my TSX.

joerockt

And you dont have any problems? Be honest!

Nd4Spd

I use midgrade (89) and no I don't ever hear any popping. Like i said before the only thing I think I notice is more power with the 91.

NeoChaser

lol even dealers put 87? how cheap can they be lol

dom

Those that put in 87 to 89 must have the TSX's on lease. If not then I hope you enjoy that roughly $250 a year your saving at the expense of your car's engine.

CGTSX2004

iTrader: (1)

That's pretty lame though if they're selling cars that require premium. I know that the dealer I bought my car from actually had a contract with the local gas station and they filled up the tank with premium from the gas station.

Nd4Spd

Check this out http Octane Levels

Although it says to look at your owners manual, it also says that if there aren't any knocks then there aren't any problems.

I've never heard any knocking from my engine with 89

dom

I hope you are very in tune and familar with what knocking sounds like. You eventually get used to noises and think its entirely normal. Not a chance I'm willing to take.

Now if I was leasing then sure......

joerockt

Its just not worth it...

Nd4Spd

Knocking in an engine is a pretty distinctive sound. My friend used to get it in his A4 and had to switch to higher octane. I'm no car expert, but even I could notice knocking...

Viking

If your car does not specify premium then yeah don't waste your money but the TSX owner's manual says use premium.

Acura would not recommend it's customers to put premium in their car if they didn't have a reason for it. If it wasn't necessary they wouldn't put that in the owner's manual because it would be looked at negatively by consumers as increasing their annual fuel costs.

By the time you realize you need to use the higher octane, the damage will already be done...... It's just not worth it.

dantsx

If they can get more horsepower out of the engine with higher octane (200 instead of 196), then they would say that premium is what is suggested.
I was thinking that they did all the performance testing with premium to get just barely to 200 hp, but it could really take 87 or 89. After all, 200 hp sounds ALOT better than 196, or even 199 hp.

ABP-CL9-TSX

When I use 87 I notice reduced performance, especially when accelerating and merging. 89 doesn't have problems, plus I average about 23.5MPG in my TSX using these grades of gas, 87 octane my MPG is slightly higher by 1.5MPG. Other than that no big problems.

Nd4Spd

CGTSX2004

iTrader: (1)

See, but this is a matter of efficient use. Your engine produces maximum power with premium fuel. If you use regular in it, the ECU is designed to retard the timing and do whatever is necessary to reduce knock. This means that you're short-changing yourself by not allowing the engine to produce at peak efficiency.

VTECLuvaLuva

I don't think that I've ever even seen 91 Octane gas where I live. I've used 93 on occasion when I can find it.

Nd4Spd

That's why i notice better performance on the premium fills... Since the ECU is present lower octane does not ruin the engine as others have implied

Viking

The engine was designed to run on premium.

Here is an excerpt from a SEARCH on google, regarding required high-octane.

Link to entire article Demystifying Octane Ratings

iamhomin

Doesn't matter what people use, as long as you use what you like and feel safe from.

TSX 'R' US

that's funny....I rarely see octane 91...

VeniceBeachTSX

On my old (V6) A4, 87 octane worked fine even though 91 was specified. Not true on my turbo TT, where the one time I was forced to use 87 I did notice that the engine performed erratically (I didn't notice knocking, but the behavior I noted would have been typical of what occurs when the knock sensor cuts in, retards timing and thus causes a sudden loss of top-end power.

I haven't had the TSX for long, and so far have been using 91, which is standard premium in California. However, for my typical driving (which realistically rarely involves going above 4000RPM or anywhere even close to peak power) I would not hesitate to use a lower octane.

Keep in mind that the higher octane is there to do only one thing and that is to prevent detonation and pre-ignition (colloquially "knocking"). Both of these phenomena occur only at high pressure/high temperature power settings. At more moderate settings (where internal cylinder pressures are limited by the throttle), knocking is virtualy impossible to achieve unless you're grossly negligent about what you put in your car (I'm talking about doing somthing dumb like putting naptha -- ~70 octane -- in there).

We've done some fun tests with aircraft engines at my friend George's company (http://www.gami.com). Aircraft engines are high-pressure, high-temperature air cooled beasts that use old style magneto-based fixed timing systems with no knock sensors or other "protection" devices. You can ruin one in 30 seconds if you don't know what you're doing and allow severe detonation to occur. Yet, he's demonstrated that most of these 100 octane beasts can be safely run with normal premium unleaded simply by avoiding the upper edges of the power curve -- the only place it really matters. Read the SAE literature and you'll find the same is true of most motor vehicle engines as well.

I suspect that most people here drive far more aggressively than I do. If I drove that way, I'd probably be more concerned about this than I am.

VeniceBeachTSX

Octane levels vary regionally. West coast (Alaska, California) crude tends to be a bit heavier so refines to lower octanes. Gulf crude refines more easily to higher octanes. Also, things tend to be adjusted to account for regional differences in altidudes, temperature and humidity, which impact air density. Places with colder climates tend -- in general -- to get higher octanes. I remember a decade or so ago you couldn't get anything higher than 90 in the Rocky Mountain states. With the high altitude, you can never get anything close to the max sea-level pressures and power, so there's no need for all that octane. At the time, gas stations in Salt Lake were 85-87-89, or in some cases 85-87-90. These days some of them have moved up to 85-88-91, mostly reflecting the need for higher octanes in newer high-pressure turbo cars, even at altitude but you still see lots of chains selling 90 as premium.

VeniceBeachTSX

Yup, as my other posts point out, the higher octane only comes into play when you're close to WOT. At lower power settings (lower induction pressure, hence lower peak cylinder pressure), there isn't enouh pressure in the cylinder for it to matter much.

This is true of all conventional gasoline engines. I'd be very careful with a high-pressure turbo though.

vifferman

I use 92 octane, as I rarely see 91 in west-central Ohio.

sauceman

You don't hear it because the ECU detects it and retards a lot earlier than you can come to hear it.

It's not because you don't hear it that it doesn't occur, and it's not because you don't hear it that there aren't any long term problems w/r/t using 87.

slo007

I used 89 while in school... for 18,000 miles. Never had a problem. My dad put 87 in a couple of occasions and the car didn't make any noises (though I felt a drop in performance).

I've been using 91 since I got a job. Reached 23,000 miles this week.

JTso

iTrader: (2)

If you actually hear the knocks, that means the knocking condition is beyond the ECU's ability to further retard the timing.

Tsx536

Any idea what the people in Europe use?
They are the ones that have been driving the TSX the longest, so it would be interesting to get some information on the European Accord and also what type of fuel is recommended and used.

knthornt

from what I have read, using anything under 91 octane reduces performance. It seems that many people here equate performace to horsepower. I would think that performace is also gas milage. Using a lower grade fuel because it is 10 cents cheaper doesn't really makes sense when you are getting less gas milage. in the end, if you use a lower octane, you will still fill up just as often, but will also have reduced performace. Might as well get the better performace for essentially the same price.

VeniceBeachTSX

All other things being equal, you shouldn't see much difference in mileage between 91 and 87. Octane has nothing to do with the amount of energy the fuel can produce. In fact, low octane diesel and kerosene have more energy per pound (or gallon) than regular gasoline, and regular gasoline has more energy per pound or gallon than higher octane alcohol.

Unless the gas companies are using radically different formulations for their regular and premium products, there shouldn't be much difference in mileage. The way refineries are set up, that's very unlikely. In my own driving I have not noticed much of a difference, though it's been a while since I've kept detailed mileage logs.

Not using premium fuel should only impact top-end power and torque, nothing else. (Of course, using a fuel that causes detonation would have rather severe impact on fuel economy, and I suspect that might be a problem for some of the folks here who are more frequently up around WOT than I...)

VeniceBeachTSX

Europe uses a different octane scale than motor vehicles in the US do. They specify 95 (RON) while we use 91 (R+M/2)

The engine is also not identical.

A direct compare is not possible.

elduderino

I use 91... occasionally I use 89 but only in cooler weather.

hata_teru

I use 94 Sunoco

TSX 3Pedal

I would put 93 octane in my TSX, but I don't think it's available in California, or at least I havn't seen it.
I regularly put 91 octane, I have never gone below.

PixelHarmony

I put 93 since 91 isn't available. You want to put in the right octane value that is recommended, exceeding 91 really doesn't help at all unless you're running higher compression, and since no one here is running a FI TSX I can safely tell everyone to just stick with whatever is closest but not below 91.

Here's a follow up from "howstuffworks.com" I think before posing a question people should go there and ask them first. I bet 90% of non TSX specific car questions can be answered there.

Octance Value
--------------------------------
The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.

The compression ratio of your engine determines the octane rating of the gas you must use in the car. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance." The disadvantage is that the gasoline for your engine costs more.

The name "octane" comes from the following fact: When you take crude oil and "crack" it in a refinery, you end up getting hydrocarbon chains of different lengths. These different chain lengths can then be separated from each other and blended to form different fuels. For example, you may have heard of methane, propane and butane. All three of them are hydrocarbons. Methane has just a single carbon atom. Propane has three carbon atoms chained together. Butane has four carbon atoms chained together. Pentane has five, hexane has six, heptane has seven and octane has eight carbons chained together.

It turns out that heptane handles compression very poorly. Compress it just a little and it ignites spontaneously. Octane handles compression very well -- you can compress it a lot and nothing happens. Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio.

bob shiftright

Sunoco offers unleaded up to 104 octane and leaded up to 116-117 octane (117 w. NO2).

It sure ain't cheap.

http://www.racegas.com/fuelspecs/default.asp

iamhomin

I'm guessing, $4.50/gallon for 104 and 4.75 for 116 and 4.85 for 117?

(In NJ, 93 Octane is currently 2.11)

PixelHarmony

I'm assuming it's not your nextdoor Sunoco. Probablly a gas station at the tracks.