I noticed there is a warning in the brochure that says using lower than 91 octane can cause engine damage. In other cars, such as the Passat, it just lowers your performance, but can't kill the engine.

Anyone use anything less than 91? If I buy this car and use 87, is my warranty void?

Thanks

 

Ok the scientific reason you need to use 91 or higher is because of the compression ratio of the engine. Normal engines have a lower compression ratio when means they can use lower octane gas. The TSX and other sport/lux cars have higher compression ratios in the higher performing engines. I dont know how knowledgeable about enginesyou are so I will leave it at that. But trust me this engine needs 91 or higher.

Plus...you just bought a $30000 car....why would you worry about 20 cents a gallon difference.......it really doesnt add up to that much more in the long run

 

What others have posted before and have done some dedicated studies on is that the TSX gets better gas mileage with 91 octane gas and the money that you think that you are saving in getting a lower octane gas is lost in poorer gas mileage.

I don't think if you use one gas tank of lower octane gas that your engine will get ruined, but it is designed to operate best at 91 octane gas.



Excited

 

https://acurazine.com/forums/showthr...commended+fuel

https://acurazine.com/forums/showthr...commended+fuel

not from the tsx sub-forum, but, the ideas/concepts/theories can be applied to the tsx...

 

Its not about the money. It does limit choices. Here in south Florida, when a hurricane is approaching or has just gone by, the gas stations run out quickly. When the trucks finally get in with more fuel, it is usually the low octane stuff first. This can go on for several weeks with no high octane fuel locally. So I just want to be sure I won't kill the car in this emergency situation. I hate being limited, but I agree, in normal circumstances, it won't be a problem.

 

x 1000

*Before starting a new thread, search first to check that the thread you are about to start hasn't already been written.

 

Where I live, we pump our own gas, but where I work in NJ, there are gas station attendents. One day I filled up in NJ and asked the guy to fill it with Super... when I paid and got my receipt, I thought...hmmm it was a little cheaper than usual. When I looked up at the pump, the kid had pressed the regular unleaded button and filled the tank.

I drove it for a half tank then refilled the rest with super.

It ran fine, but I am not going to make a habit of it. Now I make sure that super is going in the car when I fill up in NJ.

 

Compression ratio is only one factor and definitely not THE reason. Take a look at the following cars:
Honda Accord Coupe V6: 10.0:1 ratio, regular
Mazda6 V6: 10.0:1 ratio, regular
Mazdaspeed6: 9.5:1 ratio, premium
TSX: 10.5:1, premium
Mitsu Lancer Evo: 8.8:1, premium
VW Golf: 10.0:1, regular
Honda Civic: 10.5:1, regular

I'm sorry, but please don't put "the scientific reason" if you don't have data to back it up properly.

 

the evo and mazdaspd6 runs turbo, thats why it has a lower compression ratio. trust me if a mazdaspd or a evo run regular, your going to have major problems. you do not want the gas to burn before you want it to, 87 can only withstand certain pressures. and as for the civic, the bore and stroke is 81 by 87.5, i think the shape of the cylinder explains itself.

 

Anything less than 91 and your motor is toast!!

 

I didnt say that it was the almighty one reason but it is a factor and you should use 91 or higher if possible....

and i'll put "scientific data" when i feel like it because I do know what i am talking about, i just didnt want to get too detailed with a guy that I wasnt sure how much knowledge he had about engines and how they work.......no need for a smart asscome back at me for trying to help

 

thank you for your support of my statement...

 

91 not REQUIRED, but ROFL don't keep running it. Im thinking you can put 87 in as long as you don't run the engine hard *pussy foot LOL*. If you push your engine like a normal vtec should be pushed, and you keep putting in 87 your engine probably wont last till 100k. When a TSX turbocharger comes out *pray pray pray pray althoughprobablynotgonnahappen still pray pray pray!* your engine will literally sputter and die with 87 in fact, it probably even might blow up.

 

- hehe.

 

According to my Thermodynamics professor in college, compression ratio is the ONLY reason to use higher octane fuel. In fact, (assuming he wasn't teaching me bullshit), in order to get the best fuel economy, you are supposed to run the lowest octane before your engine starts to knock (incomplete combustion). That is supposed to maximize performance.
With that said, I still follow the manufacturer's recommended fuel octane because I don't trust Air Force officers. (I went to West Point, but had a "zoomie" for my Thermo prof.)

 

Some info on octane level for your car. What was new to me was that a car's requirement for octane level can rise as the engine ages or as the load increases:

What is octane?

A gasoline's octane number is a measure of its ability to resist knocking as it burns in the combustion chamber of an engine. A spark from the spark plug starts normal combustion. The flame travels across the combustion chamber rapidly and smoothly until all the fuel is consumed. Abnormal combustion occurs when part of the fuel/air mixture ignites spontaneously and burns very rapidly, causing the pressure to rise suddenly. This results in a metallic knocking or pinging sound. A gasoline's ability to resist knocking is called its anti-knock quality. The octane number of a gasoline indicates the anti-knock quality of the fuel. A gasoline's octane number is determined by comparing its resistance to knocking to the performance of reference fuels in a test engine.


What octane does my vehicle need?
To determine your vehicle's octane requirement, look at the manufacturer's recommendation in your owner's manual. Most auto manufacturers recommend 87 octane gasoline, as measured by the (R + M) / 2 method on a test engine under defined operating conditions. If the vehicle knocks on the recommended grade, a higher octane grade should be selected. Some foreign vehicle manuals recommend a Research Octane Number (RON) instead of the more common octane rating that appears on most gasoline pumps. As a rule of thumb, the recommended octane rating can be determined by subtracting four (4) from the recommended RON number. A vehicle that calls for "91 RON" should use 87 octane gasoline (as measured by the (R + M) / 2 method). Using a higher grade than is required will not usually increase performance. However, if the vehicle is equipped with knock sensors, as many late model vehicles are, a higher octane grade may enhance performance.


Why does my vehicle require a higher octane gasoline than is recommended in my owner's manual?
There are two reasons. First, the engine may be at the upper end of the octane requirement range for the particular model. It may, therefore, knock during periods of heavy engine load. The octane requirement for each engine in vehicles of the same make is different because of variations in manufacturing tolerances. Industry testing has shown that this difference can range between two and five octane numbers. While you will not hear knock, the spark timing will be retarded, resulting in loss of power and performance.

The second reason for using a higher-octane gasoline than recommended is because the equilibrium level of combustion chamber deposits is higher than average resulting in a higher than average octane requirement for the engine. Industry testing shows that the octane requirement increase (over the initial 20-50,000 kilometres) can be as much as nine octane numbers. This means that a vehicle that was originally designed for 82 octane fuel may eventually require 91 octane fuel to perform satisfactorily.



Excited

 

BTW - I use a 92 octane gas with an ethanol blend.



Excited

 

Yes, you can fill up with regular fuel in case of an emergency when premium is not available. If plus is available fill up with the highest octane possible but dont exceed premium. The principle behind it is that it doesn't burn as quickly and thus prevents preignition/pinging. Putting a lower octane fuel in the tank will only cause the ECU to retard the timing and you will loose some HP and torque. That's pretty much it. The engine wasn't designed to run with the retarded timing either but it can for short periods.

So as long as you go easy on it, you can run regular when premium is not available.

 

pretty funny how everyone is agreeing with me swirlie....

 

i suggest purchasing some extra gas and keeping it in tanks. at least i would.

as for your question....the TSX can run on lower octane, as it is RECOMMENDED to run higher octane, not required. running lower octane will cause the ECU to adjust the timing, which in turn gives you less performance. your engine won't blow out by 100k miles, but you shouldn't be pushing the car hard with lower octane, it's not gonna respond with power.

again, not gonna blow the engine. a turbo is a different story.

finally, a voice of reason. but the engine will be fine, just less responsive. many threads on this already.

 

Boy, we sure seem to cover this topic a lot, and the same disinformation seems to swirl around (no pun intended). The TSX is 10.5:1 compression and likely also has enough spark advance to combine to require 91 octane for peak performance. Lower octane gas will cause the ECU to retard the timing to eliminate detonation, and that retarded timing will lower engine performance but won't damage the engine or make your hair fall out or anything.

If you drive your car like a grandma and absolutely must put 87 in it because you're just a knucklehead (or you're in a pinch), have at it. It won't hurt it. If you drive the TSX in a spirited manner and want all the performance for which you paid $28k, put the friggin' 91 in it and bring your lunch to work a couple days a week if you're that badly in need of a few bucks.

Geez.

 

Sure, I can admit I was wrong in this case.

But as far as your comment about "smart asscome back"s, that above post was rather unnecessary.

 

But as far as your comment about "smart asscome back"s, that above post was rather unnecessary.[/QUOTE]


NO it wasnt because you were trying to be smart and punk me out.....but in reality I clearly knew what I was talking about and you just got served...

 

Well said

 

My car runs on grain alcohol. :wink:

 

Seriously...151 proof with 93 Shell V-Power boosted my HP up to 345hp and my 0-60 time was .4 seconds...

 

awwwww yeah. foshizzle.

 

Yup, you guessed it, Dyno please

 

if ur not willing to pay the extra 20-30 cents for premium gas, then you shouldn't be driving a TSX (or any other performance/luxury brand) in the first place.

it sux but you gotta live with it. better safe than sorry to fill up with 91

 

Read the rest of the posts. Its not a cost issue to him, but an availability issue...

 

if that's the case, my bad. too lazy to read up. just seems with all these new 06 owners, im starting to see a lot of reposted questions/ threads pop up

 

 

Hmmmm....what do you guys think about buying a bottle of octane booster and keeping it in your car in case the gas attendent fills up your car with the wrong grade of fuel or the gas station runs out of regular?

 

I think thats a bit anal.

 

In case you haven't noticed, there are alot of people that are really anal about their cars here. For those who are, it should set their minds at ease.

 

Yea, like me...

Its just anal for that situation, just not necessary...

 

Nothing is going to happen if you run on 87 octane. You will just see a slight decrease in performance. Your engine will not have ANY PERMANENT DAMAGE!

I owned a 1996 Acura Integra GS-R that requires "preminum fuel only" and I have put in 87, 89, and 91 octane it in. Nothing happend. I ran 87 octane for like a year nothing happend. The engine has 150k miles and runs like new. Does not burn any oil nothing, runs like BRAND NEW. I have had the car for 5 plus years now.

Dont have these poeple on here scare you that running 87 octane will damage your engine. IT WILL NOT!!

 

If availability is a problem, move! If it's money, sell the car and buy a Ford Focus!

 

yes he is right....science has nothing to do with anything and people who design engines know nothing about combustion rates of gasoline therefore just go ahead and put corn oil in your car and you will get 200k miles and get a little worse mpg....

in all seriousness....it says to put in premium for a reason....so please....just do it....its a $30000 car remember....

 

jesus, can we all please READ the original poster's dilemna. If the world runs out of 91 octane, and he wants to drive to see the hurricane that made the world run out of 91, can he safely run 87 in his car. and the answer is YES. because the people who design engines do know....that they can program the ECU to adjust the timing, thus reducing performance, but preventing the engine from knocking.

this car requires 91 octane to utilize it's full performance capabilities, but the way i understand it, 87 can be put in the car, and not cause harm to the engine, but just reduce performance. that's coming from multiple people in the MULTIPLE reposts of this thread. just do a search on octane, or 91, or gas, and see what you come up with. read all your hearts desire.

but the cliff notes of most threads are:

a bunch of people calling other people cheap for asking the question after purchasing a $30,000 (forgetting that most people who bought the car purchased it because the VALUE of the car, therefore, i assume are very smart shoppers, who do not want to get ripped off on something that isn't necessary, which 91 is necessary for full performance).

yes, 91 is required to fully utilize the performance of the car, but no, 87 will not damage your engine due to those bright engineers (computer programmers too!) who helped tell betsy to calm down a little if she didn't get her full portion of baked beans today. betsy will be fine if you give her less gassy beans, she'll still fart, just a little less potency in those farts.

enjoy your car man, keep an extra few gallons in reserve if you're that worried about it and store em in your garage. put some 93 in your lawnmower just for shits and giggles and watch that baby go (just kidding).