I own a 2007 TSX. I know the owners manual says Premium fuel only, and it does not say recomended. I just saw an artical and here is how it read.
Give regular fuel a try.

Even if your car says premium fuel recommended—or even required—few really need it. Most late-model cars can adjust to regular fuel because engines are now equipped with knock sensors, which adjust the engine's timing automatically when they detect uncontrolled burning—the tell-tale 'pinging'—and forestall any engine damage. You may experience a slight decrease in power and fuel economy, but even the mileage loss won't come anywhere near the difference between regular and premium.


A key exception: If your car is turbo- or supercharged and specifies super, follow the manual. And for Pete's sake, you're doing neither your car nor your wallet any favors by putting higher-grade gas in a car that calls for regular.

So what do you think??

 

Hey I read articles like this too. With gas prices deciding to go sky high I too thought about the ~lesser grades~ :P.

My thoughts are if you do it once and a while, say use 87 instead of 93, it is ok. But do not V-Tek the engine.

So basically commuter is ok for short durations, but you need to give it 91 for a week or so to allow the engine to run normaly.

I myself will never do a full fil-up using anything less than 91, but I have added Mid-Grade to a half tank before without issues.

 

I think the manufacturer designed the engine to run on fuel with an octane of 91+ so that's what should be used when available.

There's always the chance that manufacturers are 'in' on a plan to earn more money from making owners buy premium gas, but I don't think that's practical.

 

I've only put 87 in my car a few times, I usually fill up with 89 or 93. I noticed my car feels very sluggish when I'm running 87, my friend says its a placebo but I drive my car enough to know when it's not running the same. I don't see a clear difference between 89 or 93 but with gas prices I recently put 87 in and am not planning on doing that again for a while.

 

I maybe one of the few that does use regular gas and feels I have more than enough power and getting very good gas mileage (over 30MPG) I did use premium gas when I first owned the car (about 2-3 months or about 7,000 miles) I then switched to regular and never went back. I am rather a conservative driver. My car has 120,000+problem free miles.

 

put what is suppose to go in your car

 

according to the owner's manual 91 octane is recommended and it also states not to use a gas with lower than 87 octane.

 

I dont know how the TSX is but on the fuel door of the TL it says Premium fuel only

 

I stopped reading there. how many cars that have a 4 cylinder engine, besides the tsx, have 200hp?

 

i dont know of any commercial gas station that even offers a grade below 87. ive seen kerosine or diesel but those are different kinds of fuel

 

Keyword is "adjust." It was designed to work at X levels, but now it's forced to adjust and work at (X-Y) levels. The engineers could have designed an engine to run on regular fuel, but then they wouldn't be able to extract as much power. If a TSX engine on premium fuel has 205 hp, then a TSX engine on regular will have less horsepower than that.

Of course if you don't need the power (you always stay in low RPMs and never hit VTEC), you can get away with regular fuel. The car will just retard itself to protect itself from your choice. Don't expect all of the power though when you decide to drive spiritedly or need to floor the gas pedal.

People have done their own tests to compare the two fuels. While the tests will vary due to region (available fuels, elevation, temperature, etc), most of the tests showed that using regular gas lowered fuel economy to the point that they had to go to a gas station much sooner than when they used premium. I think I've only seen 1 or 2 people who had different results, but they were extreme cases (I think they only did highway miles and hardly any city miles).

Premium is 20 cents more than regular. I usually fill up 13 gallons of gas per trip to the gas station. Thus, premium is $2.60 more for a full tank. By spending that $2.60, I can push the car to its maximum power and fuel economy, and I can visit the gas station less often.

The $2.60 is also insurance and peace of mind for me. I spent $30k on something, and I want it to last as long as possible. The fuel cleaners and additives help to keep the engine cleaner.

By the way, the engine calls for premium because it is a high compression engine. Octane levels basically indicate how easily the fuel ignites. Compression of a fluid, including gas, causes it to heat up. Fuels with lower octane levels are easier to ignite, and may ignite on itself without a spark from the spark plug (compressed to a certain point, heat from the cylinder walls, etc). This is called pre-ignition, and you'll hear the engine knock or ping. By using premium fuel (higher octane levels), the fuel can be compressed and ignited at the proper time (when the spark plug sparks).

As mentioned before, the car is smart enough to make adjustments when regular fuel is used. The manufacturer, in order to not steer customers away, now says that regular fuel can be used (when premium used to be required). However, they don't say that the car will have sub-par performance if you don't follow their recommendations. If you want to use regular fuel and have sub-par performance, it might be a better financial decision to switch to a car that was designed for regular fuel so that you can use that car's engine to its maximum potential.

$2.60. That's half of a combo meal at McDonald's (or two items off their dollar menu). It's a third of the cost to park in Downtown LA for a single day. It's cheaper than most of the things I can imagine, yet it's the approximate cost to keep your engine clean and performing at its best.

 

I have an 06 TSX mid grade gets me 24-25 mpg Premium gets me 28 mpg

 

I read the article (copied and pasted by the O.P. above), in today's Wall Street Journal -- and oddly enough, thought of the discussions about this subject that we've had on this board.

The author, Jonathan Welsh, has discussed the 1G TSX in his column before, and mentioned it as one of his favorite cars, saying its high revving engine reminds him of something from a sports car. Given that it has a Vtec engine that benefits from higher octane, I think the TSX falls into the category closer to the group he lists as an exception.

It has been proven that regular gas can be used without damage, (by folks like nj2pa2nc)...but I agree with SoCaltrojan and Brandon; it has also been proven that power and gas mileage in our high compression engines are affected. I've tried regular gas a few times, and noticed a difference in both.

Speaking of such things, I was thinking that right now, with gas prices high, premium gas is actually a better buy than usual. When gas was at or below $2 a gallon, premium was 30 cents a gallon more. Now at over $3 a gallon, (over 50% more expensive), premium is still only 30 cents per gallon more. In terms of a percentage of total cost, premium is a good deal.

 

Seen it in Lubbock, TX...all the fuel was 1 to 2 points lower in octane rating.

 

in our travels in the some of the states-Arizona, Colorado, Wyoming I saw 85 octane gas.

 

I've only seen 87 89 and 91 in my area

 

The higher elevation states (Colorado etc.) will have 85 octane fuel.

 

I've seen Sunoco stations in Ohio sell 86 before. I'm not sure they do it anymore since it's been a while since I've been back, but still an interesting little tidbit.

And as for the regular v. premium debate, the jump between the two grades is usually 30 cents a gallon nowadays (though there are still 1-2 stations here in Athens, GA that will sell for 20 cents over, one of which is a Shell down the street from me- win!) and over 15 gallons or so, that averages out to about $4.50 per tank.

While I don't have a ton of money right now, I'd rather reduce the number of miles I drive (almost all of which are for "fun" trips) than downgrade back to regular in the TSX. I used to buy anywhere from 3-4 tanks a month to go places, but I've bought a little bit less now that prices are relatively high.

 

my first fill up or two was premium. then i went to regular gas at sam's club. my car still runs great. it probably would be a little faster with premium though..

 

life and death decisions should not be made at the pump haha

 

I've put 87 in a couple of times. I made sure I did not rev the engine over 3500 that entire tank.
No ill effects noted. Gas mileage was the same as with 91 or 93.

 

we have 87 89 92/93

I normally use 93 in the tsx and rl since it's required. Sometimes when i have about a half tank, i'll put in 89 to fill the rest of the tank. It saves a little money and the combo of 89 and 93 should keep it colse to the 91 that is required.

 

I only pump 93. If I'm gonna spend $14,500 on something, I'm gonna make damn sure I treat it right. SoCaliTrojan pretty much summed up everything better than I could. Mainly keeping the engine as clean as possible is the reason I pump 93.

 

My question for the people running 87 all the time is "Why did you buy this car"? It was a dumb move if you can't afford the extra money for 93 octane which is a difference of 2-3 bucks on a full tank, I'd call you a cheapskate. Its that simple. If you are trying to same the price of a burger by doing the crappy gas when your car strictly says premium ONLY then you should have bought an accord. You're not ready to own a luxury car. When your spark plugs are F'd up or you need a tune-up earlier than you car should. You should know why. Right? When i bought my TL I knew than it needs 93 octane before i bought it so I was up for that in my budget. So that is all i EVER put in my car. It'll thank me in the long run with less maintenance costs. You saving 3.00 an tank by using 87 octane you better put in a jar for the added costs to maintain the car because you didn't use what was asked of you. City mpg will suffer more than highway. Just think for a second. The ecu retards timing when using 87 which means less power available so at a light it'll take more gas to get it up to speed than it would with 91/93. It makes no sense guys and ladies.

 

The higher gas prices go, the harder it is for some people to keep up with the cost of living. some people buy their $20k car and live right to their limits and no longer have the ability to spend any extra money, that would be my guess about why they are skimping. Also if your going to pussy foot your car around anyways why pay the extra? If your going to the drag strip thats one thing, but sitting it traffic for hours not getting above 20mph dosn't seem like the engine would be affected by the octane difference. Also some of us that live up at 6500ft+ can survive on 85 and 87 without any issues. I've seen this issue with my ATV as well, it requires higher octane but it's made to run at sealevel with 91+ octane, as you go up and there's less oxygen in the air the octane can be lower and not affect the performance or can acctually improve performance. sorry for the long post just my .02

 

Again the difference on a full tank is 3-5 bux compared to 87. If things are that bad that you cant handle 5.00 extra for gas, sell the car and buy a Honda FIT. If they just wanted to "look" upper class because of the car the own or house they live in, I feel sorry for them. Again i read up on the cars im interested in. My car takes Premium. Not 87 from GoGas...lol. Wanna use 87, buy a Honda.

 

Besides owning the tsx (traded my p.o.s. honda civic for it) I am the proud owner of hyundai's. When I was looking to get rid of the honda I also did my research. I was looking for a vehicle with 4-doors and 6MT. At that time the choice was limited. I could own a lexus or bmw but I do not like them and my friends do not judge me on what I own. I am very pleased with our '11 sonata-just wish it had more options (sunroof, power seats, etc) with the 6MT. Use what works for you-

 

If your TSX lasts you 150K miles (most will last longer), and you get an average of 24 MPG(then again, if you drive right, you'll get better efficiency), you'll have burned 6,250 gallons of gas. Since regular gas is about $0.20 cheaper, you'd save $1,250 over the long run.

However, that's not why I get regular gas... I get it 'cuz I'm cheap :-). (and no, there's nothing wrong with that)

 

I don't think there's anything wrong with being cheap, but personally, I just prefer to stick by the manual and sticker.

I actually did forget the TSX takes premium gas when I bought the car; I knew I had known before, but I was in such a Volvo state of mind that I forgot about double checking before I signed (all the Volvos I looked at, even the turbos, only asked for 87 octane) and bought the car. Not a huge deal, though.

I still try to be cheap by researching which places have the lowest prices for premium fuel.

 

Everyone has their own views for what gas should be put in. Personally I usually switch between 89 and 93 near me. Usually shell but sometimes mobil. I'm pretty sure consumer reports did an overall study on recommended octane and showed anything above the suggested octane is a waste, (TSX being 91 which isn't available near me).

 

If premium gets 24 MPG in your example, and regular is only slightly lower, say 22 MPG, then in the same distance you will have burned 6,818 gallons of gas. That's a difference of 568 gallons. If regular gas costs $3 per gallon (just a low number...gas in Cali is nearing $4), that's $1,704 more money you spent than you would have if you stuck with premium. Don't forget that with lower MPG means that you had to visit a gas station more often, so that's more waste of your time.

In any example, it doesn't matter how many miles you drive or how much each gallon costs. What matters is MPG, or how much gas is used.

 

The engine was designed to run on 91+ Octance. On a high compression motor why take the chance? Sure, the ECU makes adjustments to compensate for knock and detonation but sometimes it takes 2-3 counts of knock before it pulls timing.

If you can't afford to put in the recommended fuel then YOU CAN'T AFFORD THE CAR, plain and simple.

 

Theres really no damage in cycling 89 and 93 though..

 

Oh, yawn. This discussion again. Perennial favorite.

If you're in the reading mood, read articles on why high compression engines are made to use higher octane fuel. Sure, the TSX' engine has an anti-knock sensor, sure it will "run ok" on 89, sure you will save $1 at the pump, but your engine will not work as efficiently or powerfully (ref: prior discussions). Do you ever take it WOT to the redline? Want to do it with low oil, old dirty tranny fluid, or ... lower grade gas?

I've filled up with 89 once or twice at a station that's trying to gouge me (e.g. stations right outside airports ) , but adding 6 gals of 89 to a tank 1/2 full of 93 ... you can do the math. I also tried alternating fuel types 89/93, 89/93, noticed my mileage dropped 5% or so. Rather a PITA to remember what I used last, and ... then did the math on how much I was saving PER YEAR (with reduced mileage). LOL. Not enough $ to worry about my engine long term, that's certain.

I have Hondata. I use it from time to time. I want the engine running optimally. That means I put in 91 octane or better. ... It's your car, treat it nice or treat it cheap, your choice.

End of line.

 

^ + 1.

For me it's this simple. You buy a relatively expensive car that was designed with a specific gas in mind. The car will work with less, but it was not designed for prolonged use. Will you be OK? Maybe, maybe not. You take a chance. I trust the fact that a bunch of smart engine design engineers know what they are doing and journalists do not. The people making the claim that regular is OK have NO documented long term tests proving there are no consequences.

If you are that cost sensitve, buy an Accord. Or buy one less latee per week and put the right gas in your car. If you want to drive a luxury sports sedan, sit at the adult table own it like one. That's just how I feel - I paid a lot of money for it, and I want to take care of it. To each his own.....

 

:ROFL: I don't think I would even save enough for a couple of lattes for per week using the cheaper (inappropriate) petrol. LOL

 

MPG is what really matters, especially if you plan on keeping the car for any period of time

SO TRUE, i see people with there cars all the time, with just the maintenance/repair costs, let alone fuel costs (recommended shocks [bags were cut open on the rears, and fronts where leaking fluid excessively] on a Cadillac Escalade, and the quote came to like $3000, YES $3k; can't really do much about it when the only place to get shocks is through the dealer, because they are electronic shocks, and are priced at something like $650 a piece ; labor was only like 2-3 hours or something minimal, compared to part costs)

should average out to ROUGHLY 91 over the LONG run, but not per tank though, so personally i would still just put in the 93 and call it good

 

You two said it perfect. Also let's not forget Honda/Acura's have a black box of sorts so when you car breaks on you. They'll look to see what kind of gas you've been using per what the knock sensors have been doing and deny a warranty repair. Then you'll be yelling on here asking what to do. Does a human being live healthy when they eat nothing but cheaper fast food? NO!!! Will an engine? NO!!! Get a performance sedan don't you want it to perform like one? YES!!! Think a car on 87 octane revs to a 7300RPM rev limiter (the Accord does but only making 190hp/162tq vs. TSX's 201hp/172tq)?

 

I've been using regular for 3 years now without a hiccup. The only difference is a drop in mpg, like by 1 or 2 mpg difference. The car still takes off like it was on the first day when I drove off the lot. Maybe it was the Hondata reflash that I got installed.

 

well said. But again it's all about the wallet size in your pocket. I've seen people bought expensive homes but too afraid to turn on their lights at night because it would cost them too much in electricity.