dgracer

I cheaped out and switched to regular unleaded since it is cold and damp here (less risk of pinging) and my mileage went from 29 to 33! No change in driving conditions. 448 miles on 13.6 gallons. I'm doing it again this week to see if I can back it up. I'm losing it and am now addicted to getting higher mileage! Next thing you know, I'll be fabricating ugly cardboard sideskirts and airdams. Somebody stop me!

RaptorCLS

IMHO...87 octance...:thumbsdn: :shakehd:

But hey, whatever works

blackmagiCL_S

My understanding is that in order to get some extra hp we need to us >91 octane, right? Maybe dgracer is right, we will get better mileage but we won't have the power? We'll see after he tries this for a week or two.

Jon Bon Bonachinballs

Does it have something to do with the temp or weather? On a full tank of 93 octane, Im getting an average of 320-340 miles per tank. And this is all highway miles. I commute 60 miles a day of only highway...... Does anyone else get this kind of crappy milage. During the summer I was getting just over 400 miles a tank and I know that winter gas is worse, but it shouldnt be this bad.

SiGGy

I bet your engine is knocking or very close to it. The ECU will try and correct for the BAD gas by adjusting the timing. But it can only adjust so far. Gasoline serves as more than just a fuel, it also cools your pistons/valves. If you are burning all of the fuel in the cylinder you will cause damage to your engine from the excess heat. Might want to read this...

http://howstuffworks.lycoszone.com/question90.htm

We have 10.5:1 pistons. Not 8:1 or 9:1 which can handle 87 octane. Someone with knowledge of the ECU and what it's spec is for +/- timing could proably give you a better idea if your doing any harm. I haven't a clue. I would assume its +/-5 degrees at least But I honestly don't know.

http://216.239.33.100/search?q=cache...n&ie=UTF-8</a>

1killercls

Siggy is right on the money on this...you are risking damaging your motor to save a few bucks...Don't jump over that Dollar to get to that Dime!!!!

AK_MOBBER

You will be fine running 87 octane you just wont have near as much power as running 91 or 93 octane. Some gas stations have additives in the 91+ octane to clean your engine out and they don't always have those additives in the 87 octane gas. Use good gas such as chevron that has the techron additive in all their gas. If you get any pinging bump the octane up to 89 or switch back to 91.

Gas prices are getting pretty expensive I have even found myself pumping 87 into my car... I usually use 87 for a couple weeks then put 91 in every third week or so. If you like to floor your car a lot you should be running 91+ ocatne though.

1killercls

You'll be sorry...mark my words...read the links...scroll up...you are gonna burn a valve...:shakehd:

And if you have to be that cheap on gas... and risk fukking up a 30k car...BUy a METRO...they will run on ANYTHING.

Tom2

Hahahaha....burn a valve....that's funny.

Automotive engineers have long realized that some people will ALWAYS put the cheaper 87 octane stuff in their tanks, regardless of the octane that they recommend. Knowing this, the system is designed to be able to reliably run on the lower octane stuff.

The knock sensors will retard the timing at the very first hint of detonation/ping, so the worse thing that could happen is a slight loss of HP.

My Mother has about 70,000 miles on her TL, and it has had nothing but 87 octane from day one.

And guess what? Never a problem. Never even burned a valve

Tom2

A lot of people seem to think that octane rating and burn rate are directly related. But in reality, they are not.

Burn rate is not affected octane rating.

tuleman

Your mom's TL a Type-S? If not then she doesn't have the same comp. ratio. Which is achieved by the Type-S having domed pistons. Comp. ratio is what matters in relation to octane levels.
At 10.5- 1 I am suprised we are running on pump gas as it is.
I would NOT use anything less that 91 oct.

topdaytrader

I always use 87 on my CL. I can get 350 miles on 87, but only 320 miles on 91.

Allout

If it's cold and damp, 87 should be fine. It's definitely within what the engine can adjust to. Once weather warms up, it may be a different story.

You're right on the money on the ECU retarding the timing as needed.

I run lower octane in winter and go back to premium when the weather gets back above 85-90.

NJ_CLS_driver

i have never gotten over 300 miles on a full tank.

EdgarFanCLS

My car gets 40 rods to the hog's head, and that's the way I likes it.

SilverBullet_RENAMED

Oh please. Burn a valve? lol The car is recommended to run 91+ but you can run 87 if needed. The dealer says its fine.

I bet you 70% of the people out there who bought TL-S/CL-S use 87.

JRock

You might have a problem then. I get 330 with at least 2-3 ticks left on the guage if I let it get that low before fill-up, and several people here have reported over 400miles on a tank.

I guess you might be doing all city driving which could understandably be lower.

SilverBullet_RENAMED

I noticed when my CL-S was new it got 320-340 a tank. It decreased as time went by. The last few fill ups before I got rid of the car it would only get 275-280 a tank before the light came on. It was getting 18mpg.

On a trip to Houston I was able to get 400 a tank with 26-27 mpg driving 90. So it did well there. I dunno.

Samer007

juniorbean

iTrader: (5)

If I drive "normal" (60-70mph) I can get over 25mpg easily.... however, I tend to drive a little fast (75-85mph).. so it's killing my MPG and I'm only getting around 22-23mpg.... I should slow down a little . Sport-shifting all of the time can't be helping either.....

sidemarker

mix driving and mix traffic(higway/city)

i still get about 300-315 before the light turns on!

sidemarker

dgracer

The point of my thread was to see if anyone could explain why the lower octane fuel increased mileage by 10+%. It normally only varies +/- 1MPG each tank max. I did see another response that indicated similar experience. I dont intend on running 87 permanently, it was just my little personal protest at the gouging going on at the pump and to see if there was noticeable difference. I was just surprised to see the increase in MPG. I do also use FI cleaner at each oil change and that always gives another 2mpg and improved throttle response.

ZodiakTL

I would guess that due to the reduced performance, the car probably drives less aggressively, and so the drivers would tend to drive calmer.. dunno... i know that when i've tried driving at 60mph on a long trip, my mileage sky-rocketed, but who the hell can go 60 in this car... if i stop paying attention to the speed for even a second i'm up to 80mph right away

torqueaholic

87 octane on your 30K luxury car= CHEAP BASTARD!

topdaytrader

Thinking CL is a luxury car = POOR BASTARD !!!!

GS Dave

I agree with most of whats been posted. The only input I can give(not being too familiar with you cars). Is that for a knock sensor to work and adjust the timing, it must first detect knock. Any amount of knock is bad. Will a little kill an engine, probably not, but it is still not a good thing. I know for my car, 91 is the required minimum due to the blower. I filled up this morning and at my secret little gas station it was $2.02(Mobil). And that is a good 7-10 cents cheaper than the rest of town.

tuleman

The dealer says it's fine? These are the same dealers that promised several of us two free Nav upgrades when we bought our cars that was a lie.
This is the same company that denied a tranny problem until it made news headlines. This is the same company that tells me to pound sand when I complain my brakes are warped. You just keep believing the dealer.

87 oct will force the ecu to tweak the timing. 87 will eventually screw with the plugs. A burnt vavle is not the problem. A vavle hitting the top of the piston is the POTENTIAL problem.

Pappy

Don't do it. If you have an S which I see you do, you have a high compression engine. You could get away with it on the Premium, but not the S.

dfreder371

A few things here guys (and gals). First off, winter gas is not crappy gas. It is actually better then the summer blends. Secondly, gasoline in its raw form WILL NOT BURN! In fact, there are very few liquids in the world that will burn, unless they contain oxygen, and even then, it has to be in the proper, stochiometric ratio.

But the vapors of gasoline will burn. Fuel has something called "reid vapor pressure", and here in Chicago it must be adjusted seasonally, whereas in say, Key West, it does not.

Fuel that will ignite readily at 80 f has a hard time igniting at 0 f. Hence, they adjust the vapor pressure in winter with costly additives to fool the engine into thinking it is summer out. Another reason why gasoline prices go higher in winter in cold climates.

A parallel analogy can be drawn with charcole starting fluid. We in the lower 48 get basically either kerosene or naphtha. In barrow, alaska, the label on the can is the same (lighter fluid), they get gasoline. It is really, really cold, in barrow.

Before I think about saving a few bucks a week on 87 octane, I think I would call my service advisor and ask him what the cost is to remove an original short block, buy a new one, and replace it. I am just guessing here, but I would bet $5,000 to $10,000 would be in the zone. If I divide that by a cost savings of 20 cents per gallon, I can buy a lot of 91 octane and still sleep at night.

Acura advises we use the high octane stuff, but says in a pinch, any gasoline will do, as long as no methanol is involved. Methanol is EXTREMELY CORROSIVE TO METAL, do not use it!

And this whole thread may be moot, and here is why. Gasoline mileage measurements are only valid if the car is filled up at a particular pump, at a particular gas station, with the nozzel set at the same fill setting, with the car pointed the same way, with no change in the load of the car. Don't tell me you got 35 mph when you filled up in chicago, and filled again in toledo. it is meaningless.

I fly airplanes (Certified Flight Instructor). At full throttle, if we experience detonation, simply retard the throttle until it stops, and you are ok. Please realize our airplane engines usually cost more than our entire car.

And, DO NOT go to your local airport and fill up with our 130 octane "low lead" gasoline, which now coats about twice as much as car fuel. "low lead" refers to "as considered as to other airplane engines. Using this stuff, which contains about five times as much lead as before lead was banned for car use, will GUARANTEE you a valve job, or a new engine. Our air cooled engines expand and contract alot, as compared to our water colled engines, hence, the airplanes need more lubrication. Replys to this should be interesting...

dfreder371

Another thing: ever wonder why our gas guages on the 2003 S do NOT say "Premium Fuel Required?"

Tom2

Nope, it's not a Type-S. The compression ratio alone is not the reason for Acura's recommendation of high octane fuel. If it was the only reason, then the non-Type S TL and CL would have 87 octane as recommended fuel. In my Mom's owners manual, it says to use the premium stuff.

Tom2

Knock sensors can detect knock and retard timing much faster than you might realize. If a knock sensor is working properly, it should be able to detect even the slightest amount of knock- MUCH less than you'd be able to even hear.

A little knock won't hurt anything either. I've read time and time again in many auto manuals (of various makes/models) that a small amount of knock is okay, and to use higher octane fuel only if the knock gets worse, which can easily happen with age.

Just simple carbon desposits in the combustion chamber can raise the compression ratio (because it makes the combustion chamber slightly smaller), and neccessitate higher octane gas, especially in a car without knock sensors.

1killercls

WITH ALL THOSE NICE RIDES YOU HAVE...WHY ARE YOU EVEN IN
HERE?

I have an idea...get the fuck out...

Tom2

87 octane will do nothing to the plugs.

And please tell me you were kidding when you said that a valve hitting the piston is the potential problem.

Octane has nothing at all to do with valves hitting pistions. If your valve hits a piston, it's most likely because your timing belt is broken. Or your piston rod/wrist pin is broken.

It's impossible for a valve to hit a piston without something major broken. And don't even mention valve train float.........

The only real danger of using low octane gas is that detonation can actually blow a hole in the piston. But that will only happen on a car that requires high octane fuel and that doesn't have knock sensors and that has a person behind the wheel that is deaf enough to NOT hear severe knocking.

In other words, it doens't happen often, even if your car doesn't have a knock sensor.

SilverBullet_RENAMED

Let me tell you something. I have yet to see a dealer tell the customer what kind of gas the car requires. They never ask, the dealer never tells. The user goes and puts 87 octane for the life of the car. People drive them all day and do not care. Cars don't have problems. The car can run off 87 and live its whole life without a problem.

tuleman

Ford owners
Impossible to tap the top of a domed piston you say.
Is that possibly why we have such a low redline?????
Hindsight is 20/20.
You go on and save your .20 cents a gallon.

Tom2

Don't give me this "Ford owners" bullshit. I've had all kinds of cars, including a CL-S.

Now back to the subject at hand--

If you had any clue of the inner workings of an engine, you'd realize that it is mechanically impossible for a valve to hit a piston (domed or not) on an engine unless something is broken, such as a timing belt or wrist pin/rod.

The only other possible way for it to happen would be valve train float, which would require exceeding the redline of the engine by quite a bit. And even then, it's not likely, especially in a car like YOURS with a rev limiter.

Octane doens't have a fucking thing to do with valves hitting pistons. I can't believe you're that ignorant, yet you talk shit about me being a Ford owner. That's funny.....

Tom2

I can't believe how stupid some of the people here are...... It never ceases to amaze me.

SilverBullet_RENAMED

I have to agree with Tom. He is right on this part.

mattg

bwahahahaha