Im this has been asked 100 times but.....

I just got my new TSX last night. Had all of 10.7 miles on it. I absolutely love it. I am wondering if anyone does not use premimum fuel? And if so what are the results?

 

You can certainly use lower octane fuel. What you will see is lower MPG and less power. The engine will self compensate for the lower octane gas so it will not hurt the engine at all.

I have tried running both mid grade (in Boise, ID) 89 octane and 87 octane gas. It works fine but the MPG hit you take actually makes it more expensive to use it - go figure. Also you take quite a performance hit.

Recently, however, I found a gasoline additive that allows me to run 87 octane gas without losing any MPG. It does not give back the performance, but with the additive it is cheaper to run 87 octane + additive then 91 octane. On top of that, the additive keeps everything in the fuel system nice and clean.

If anyone is interested in the additive look at: http://theoildrop.server101.com/ubb/ultimatebb.php and go to the additive forum section. The additive is called "Fuel Power" or "FP". It works really well.
For those that don't know this website is like the Holy Grail of everything related to oil, filters, additives, and grease...... have fun.

 

The search feature on this site is really handy for questions that have been asked 100 times. I searched on "octane" and found this one for you as a start:

http://www.acura-tsx.com/forums/showthread.php?t=10744

Welcome to the board.

 

Thanks for the info. I will stick with the premium and see how it goes. Im in Texas so gas prices arent too bad compared to the national avg.

 

Have you tried running the additive AND premium fuel?
Maybe you can make it super-fuel-efficient.

Anyone noticed a difference between 94 octane and 92? Over here in the North only Sunoco carries 94 octane I think, just wondering if it's worth it being picky. My friend has a Golf 1.8T and he says it makes a big difference.

 

Not yet but it is on my list of things to try. I was really hoping to use lower octane gas with additive and get back the MPG and performance. This was in an effort to save some gasoline money. I certainly got back the MPG, but not the performance. Man the TSX is boring to drive with 87 octane gas (even with 6MT).

My next tank will be 91 octane and additive. I will let you know how it does.

 

Oh, that's just beggin' for negative rep points!

 

In case you guys are wondering why you don't find many 91 octane stations near the coast line... it has to do with the amount of atmosphere available to your car's engine. octane serves really one purpose and it ain't to give you a more powerful explosion as a lot of people think. it is to retard detonation in the combustion chamber. that's it.

So if you live near sea level you have the optimum if not more than optimum air mixture entering into your engine. A higer octane gas (93) compensates for the extra air. The reason you don't need 93 in Denver is that you are much higher in altitude to begin with, so no need to further hinder detonation. So 91 is perfectly acceptable.

 

In the end the difference between using premium and regular will be about $200 to $250 dollars a year. Hardly worth the worries of damaging your vehicle.

 

Belzebutt- I always use 94, given it is usually only .9 - 1.1 cents more expensive than the 92. So that's like $0.40 more per fill up, or approximately $41.60 more per year....

 

The Sunoco where I buy my gas sells 92 and 94 for the same price on weekends. My car requires 91, so for when the 92 and 94 cost the same, I put in the 94. I cannot tell that it makes a difference. Everything I've ever read from what I consider knowledgeable sources says that using anything higher than the recommended octane is a waste.

Where I live, pretty much every gas station I see goes straight from 89 to 92 or 93. I couldn't tell you one station in this city (or about anywhere I've been in the midwest) that actually sells 91, even though most cars that require something above regular I think specify 91.

 

Just a bit of educated speculation based on the information in this post and my background with cars. The reference to reduced mileage at lower octane, my guess is that the car's ECU is richening up the mixture and or pulling ignition timing to eliminate knock (the reason for the high octane spec in the first place). It's a common cure for ping/knock/pre-ignition. The problem w/knock is that the chemical reaction in the engine has gone from a smooth burn with a single flame front to abnormal combustion with multiple flame fronts (see this article from the z car library and museum for more information). This results in increased cylinder pressures and temperatures that will damage an engine.

Now, the rub here w/the TSX is that the ECU does not know the octane of the gas. It is richening the mixture because I imagine its knock sensor is detecting knock. This knock is probably not even audible to you as a driver, but occurring non the less. The $5K question is: is the knock severe enough to damage the engine. Over one tank, probably not, over 50K miles, 100K miles, it's a gamble. Also, if you do experience failure of engine components under warranty, what will the dealer think when he sees that the ECU has been operating at the ragged edge of it's tolerances due to knock.

Bottom line is that it is your car and your money, but it seems silly to invest so much $$$ into a car (the TSX is no Bentley but it is far, far, far removed from basic transportation) and then get miserly over an extra $200 a year...

 

If you can't afford premium gas, you shouldn't own a TSX.

 

I was also worried about having to put in premium fuel when I was contemplating buying the TSX, but those worries went away quickly after I did a little math.

My old car averaged around 18 MPG in the city (that's where I do most of my driving). And let's say the TSX will average 22 MPG. And let's say I'll drive about 10,000 miles per year.

I used 87 Octane in my old car and the going price of it here is about $1.85/gallon. So in 1 year with my old car I would use 555.56 gallons, or spend $1027.79.

In the TSX, I'll be using 93 Octane (no 91 here) which costs about $2.05/gallon. So in 1 year with my new car I would use 454.55 gallons, or spend $931.82.

So in fact, I'll be saving almost $100 per year using premium gas in the TSX. Of course, my car insurance is coincidentally about $100 more year, so it all evens out in the end.

 

I didnt say I couldnt afford it I was just asking a question. Thanks for your thoughtful input you jackass.

 

I didnt say I couldnt afford it I was just asking a question. Thanks for your thoughtful input you jackass. :sqntfawk:

 

Listen noob. You are lucky this thread is still open - this is a of a .

#1 - Use the search button next time. You'll be surprised at how much info has already been discussed ad nasuem on here (this subject included).

#2 - It says to use premium fuel only.

#3 - Since gas prices "aren't too bad", pay for the premium fuel and you don't have to worry about any potential problems.

 

Always use the HIGHEST Grade SHELL or BP gas you can find..........those are my 2 options.......and BOTH give me the same/BEST MPG....anything less in the OCT department lowers MPG and performance.........DO NOT USE ADDITIVES.......just use GOOD GAS!!!!!

 

I would stay away from Shell gas. Just recently they admitted to using high sulfur content gas that messed up fuel gauge sensors. They are reimbursing those that it happened to.

 

Ohhhh all bow down to meteorman with his all inpressive 775 posts in almost a year. Isnt he just the end all be all of the TSX board. I see a moderator title coming up for you!

We are soooo lucky.

 

why don't we just all relax? it's a Sunday, the day of rest. this thread is, in fact, a repost, but it was kept open because it looked like there was some additional information at the beginning.

continue this petty argument and it gets locked, with the useful posts merged into another fuel related thread.

 

Somehow people don't get it.... lower octane gas DOES NOT mean BAD gas! higher octane gas DOES NOT mean GOOD gas.

Use what your car needs. Period.

 

I always put premium, but recently one of my friends drove my car and filled up with regular

I would like to bitch slap him for doing so, but seriously, what can I do..

iamhomin, who rarely let's his friends drive his TSX.

 

You should all try one gallon of racing fuel (106 octane) to 15 gallon of high octane premium for a speed experience. Make sure to use a fuel system cleaner the next tank to remove the lead. Have a nice flight.

 

Eh? All of our stations "on the coastline" here are 91. I'm not sure if you made a typo and meant 93 or not. Most stations in higher altitude areas were 89 or 90 if I recall.

 

In Kansas, which is about 1500 ft above sea level, the highest octane I have seen is 92 with ethanol. Do not use ethanol type fuel. It makes your engine f**k up. That being said, there is a station that carries racing fuel (106 octane). It is very expensive, and contains lead. It makes a significant power/acceleration difference by just adding a little to your premium drinking TSX. Check it out, but use a fuel system cleaning additive on the next full tank afterwards. Make sure it is about 1 gallon 106 to 15 or so gallons of premium.

 

Anyone ever try 106 octane racing fuel mixed in with normal gas?

 

It's just a 10.5:1 compression ratio engine with slight cam retard: No point in using racing fuel.

The placebo effect pwns you.

 

No but I'm wondering if I should. Last night I was merging onto the highway and floored and I swear I hear slight knocking in the engine. I only put Prem. fuel - 93 octane here and always name brand.

 

So you tell me you feel no difference in the use of a higher octane? Have you tried it? It is racing fuel for a reason.

 

I've never used it but heard that higher octane won't make a difference in our car, only lower octane will affect performance. There is a thread on this topic elsewhere if you search for "octane" or similar.

 

BTW anyone else experience any knocking in the engine while using premium fuel?

 

Your car will develop a need for it. Mine even coughs as I pass the filling station that carries it. Feed me the good stuff!

 

The problem with using leaded gasoline is not that it contaminates the fuel system, but that lead will clog up the catalytic converter. It doesn't take much lead to ruin a converter, and there is no effective way to clean it. Replacement is the only option. I would recommend that you refrain from using any leaded fuel in your TSX, unless your want to ruin your converter and substantially increase your emissions.

 

Racing engines use much higher compression ratios where detonation could become a problem with lower octane fuel. Thus "racing fuel".

Our engine is tuned for 91 octane. It will not advance the timing any further to accomodate higher octance fuels, nor is the compression ratio high enough to warrant it.

 

I have already been there, tested at the tracks, and with higher than normal octane, I actually experienced a decrease in performance.

Racing gas exists... for racing cars! The TSX doesn't have a race engine. Racing cars have a much higher CR and usually run with lots of advance as well as a much poorer A/F ratio, so racing fuel is good for these engines to prevent detonation from happening.

We don't have that sort of problem with the TSX, Octane 91 will do just fine.

Lung Fu just beat me to it.

 

Why do many people use 93 octane in their TSX? I have seen it many times on various threads.

 

Just because.

But it's of no particular use.

 

Exactly right. This just proves you should be very cautious about taking advice on a public forum.

 

Usually, on a fair-sized forum like here, for every mis-informed person posting, you'll have some well informed member who'll correct the issue with the right arguments.