xplane

I found something odd about my car. I was having a hard time getting it to go back to the same Power and mileage it had before i Fixed the exhaust(crappy as the gas mileage was it was Way better that what i started having). well after going through all I had learned about this car I was at work today and remembered I changed the timing on my car to get it to run right with all the exhaust leaks so i go get the timing light and get to work.
At first i forgot to unplug the EST wire so when i shot it I got a reading of 30* I was like Holy S**T so i turned the car off and disconnected the wire and i got a reading of 20* again Holy Crap. I also noticed i had a quiet but still noticeable Knock. so i set the timing back to 12* and i noticed that the knock went to where i had to concentrate to hear it. so i shut the car off again and reconnected the EST wire and checked the timing the computer was putting the timing and startup at like 25 and then it would back down to 23-20*, again the knock returned not as bad but back. So I disconnected the EST and set the timing back to 10* and i could not hear the knock. I reconnected the EST and the timing on startup poped up to 23* and then settled to 18*-22* still seams way high but i just left it there even tho i was still hearing the knock.
I dont hear the knock under load only at idle and it usually gets worse as when the car is hot but is not there when the car is started cold.
The Reason for the main question was I put 2 gallons of 91oct in the tank with 3 or so of 87 and the knock has gotten a lot quieter. I was thinking that this knock was in the valvetrain as it seemed to come from the top of the engine only that dont seem to be the case seeing as it changes intensity based on how far in advance the timing is set and what oct of gas the car is running.

Sorry for the Long winded post.

Oh and setting the timing back to 10* restored a LOT of my cars power and mileage tho i am still only getting about 150miles to a tank.

Leo_padakin

150 to the tank??????? omg, my crappy reliant kills that. but back to what you asked, i use 92 octane.

2_point8_boy

Good ol' California 87 BABY!!!

firstfirebird

iTrader: (3)

Nothing but 93, I drive about 30,000mi a year (even though it's in my pick-up) and I fill twice a week. I have found that dollar per mile doesn't change across the grades, seems like I get better milage on the good stuff. Also you can run some acetone through your tank and it will help with mileage, cleaning, octane, etc.
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Before I get some flack for saying that, I've been doing it for the last 4 mos. in my truck and got a 12% increase in mileage.
You put 3oz. of acetone for every 10 gallons of gas - MAKE SURE IT'S PURE!
My mileage went from between 270 and 300 now get between 290 and 340. This was done in my 1998 F150 (wanted to try it in the Ford before the 'Bird, lol), my other 2004 F150, my 2002 Navigator, my 2000 Excursion, my co-workers 2000 Sierra 1500, 2000 Suburban, 1976 Vette, the list goes on. Everyone I know who tried it says nothing but good things. The last 3 fill-ups I haven't put any in and the mileage went back to normal by the end of the third tank.

Project: 85 2.8 bird

I was using 89 in all teh swaps, and w/the mero, I was told by previous owner that it throw codes out for anything but 87.

Derickab

I was running 87 when I had the 2.8 it ran smoother for some unknown reason. Since the swap I have been running 89 with the 3.4 along with a bottle of treatment every 3rd tank. I get about 260 to 285 a tank I would guess. No real major mods tough just a gutted dual snorkel intake and 2.5 catback w/ dynomax super turbo muffler.

firstfirebird

iTrader: (3)

I also have a dynomax cat-back, run only 93octane and get about 280 miles/tank in the city.

daves12secV6

iTrader: (3)

93/94 most of the time,but when the gas station has 100 i get that that instead

Stealthy-One

Dave, You dont count. Your car just aint like the rest of ours.

I run 87 in mine, seems to like it best. I have NO idea what my timing is set at though... Might try to find my light and check it.

as to magik ingredients to add to gas... look for Zylene in a paint store. it is around 114 octane. In my Turbo Eclipse I would run one gal of that in a tank of 93. allowed me to run higher boost numbers and definately made a differance on the Rump Dyno.

zoddri

I use 95, mostly because it´s the cheapest stuff you get here. The car seems to like it

Gas stations here only sell 95, 98 and diesel. Some stations also have Shells V-Power that is 99+.

daves12secV6

iTrader: (3)

hey i can still run the cheap stuff,lol but id have to bring the boost level back down tyo like 3 psi lmao

firstfirebird

iTrader: (3)

Gallileo60

I use the highest stuff, I can get at the pump...92, or 93...I DO get better mileage with higher octane, but I have my timing bumped up..My car runs SO much better with the added timing......Who has the highest octane gas around your area???? And what is the octane rating??? I live in the Houston, Texas area......Damn Zoddri, you are so lucky....95 octane wow, I havent seen anything over 93 in a long time....

firstfirebird

iTrader: (3)

I know!!!
Wish we had that good gas in the States! (He's from Sweden)

Gallileo60

I saw that, man im jelious..........I remember back in the day you could get 98, and evenn 100 sometimes....Where is the highest octane gas in the states???? I mena like gas stations, not race gas...

zoddri

Yep, it´s good stuff but.. The price.
Are you sitting down while reading this? Good.

It´s 1,49$/litre (10,54 Swedish kronor) wich makes 5,63$ a gallon.

(using todays prices from shell.se and 1 US Gallon = 3,78 litre)

firstfirebird

iTrader: (3)

Here in South Florida, I've paid as much as $3.43 a Gal.
Right now it's down to around $2.50.
The prices here are some of the highest, but that's OK because right now it is 78*F outside

Gallileo60

70 degree's here right now..............Fixxing to get cold tho..

firstfirebird

iTrader: (3)

Yeah, but Texas is like Florida - 60* is cold to me! Once in a while it will get in th 50's brrr.

Rocketerz

Gas is 1.98 here in VA.

1989karr

LOL

you guys have never seen Hawaii gas prices have you???.....we can only DREAM of gas being $2.50!.....in fact at the moment regular 87 octane is about $2.80 - $2.90 or so I believe *sighs*

anyway, I used 92 octane (the highest stuff we can get) back when the bird was running

syko

How does timing affet mileage? I don't know anything about that --can someone fill me in? I use 91/92 and I have no idea what my timing is set at... Should I use lower octane?

shdwghst457

sure is, was a 1.98 when i left VA for texas, and it just dropped the other day from 2.16 to 2.06 (i always put in $25 and today i had to go inside for my $1.30 change)

bobdole369

Uggh.

Why... Why.... WHY!!!!!

Why is it that people STILL think using 92 octane gives better gas mileage? Or is better for their car? Or is a "treat" for their car. Or does anything at all besides cost you more money?

Octane is anti-knock. If your car has advanced timing (such as the first gentleman in this thread), or regularly knocks on 87 octane, then you need to go up.

High octane gas does nothing for gas mileage, its ALL in your head people.

High octane gas does not make your car run better (unless its knocking of course).

Granted some stock engines may need high octane at this point to run reliably, but thats due to knock more than anything else....
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Crackpots... I don't believe this at all.

noahTHEpurdy

iTrader: (1)

My car knocks a bit when I first start it up, but it goes away, should I run higher than 87 octane?

Greg Shorty

agree with bobdole369- octane is nothing more than a way to slow down the rate of burn in the combustion chamber. "knock" caused by increased timing or bad fuel is actually preignition- a condition in which the fuel mixture begins to burn before the engine is 'ready' for it. Octane is often a 'band-aid' fix for less than optimal tuning.

Automotive manufacturers generally must trade a small amount of total performance in the quest for long term reliability. If you push the envelope of total ignition timing to the point of preignition you exponantially increase the combustion chamber temps and greatly reduce the lifespan of the parts therein.

My experience has shown that many-a-street car will actually run faster (and longer) on 87-89 pump gas- until you increase compression beyond the limits of the cheap(er) stuff.

Get the intake and exhaust free of restrictions, build the motor you want, then use an exhaust gas analizer to get the mixture right (lean= TOO HOT),
then play with timing to match what the combo wants.
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oops forgot to answer the last question-- if it's knocking upon start-up but quieting down, I'd look at the oiling or bottom end first. It could be too much advance and the ESC is immediately retarding your timing, but it would run more like a turtle with a walker if it was that far off.

noahTHEpurdy

iTrader: (1)

My dad said it was lifter clicking, not a knock, would higher octane do something for that?

Greg Shorty

doubtful- lifter/valvetrain noise would indicate excessive clearance- due to wear or lack of oil between moving parts. If it's only on start-up, I would guess a lifter is bleeding off internal pressure- but "pumping up" again when the oil reaches it again- try a comercially available oil detergent like CD2 or STP and you may flush out the debris causing it to allow the oil to drain. If not---- it's time for surgery.

ttypecamaro

iTrader: (2)

My brother ran 87 in his 88 bird... Now that the turbo is almost done, he'll be running 93.

I had a textbook freshmen year that listed the specific energy of different fossil fuels. 93 was very slightly lower than 89, which was slighly lower than 87, which was a lot lower than diesel. Those numbers supported the statment that 93 octane does not improve fuel economy. It actually supports the statment that it decreases your fuel economy.

any gains seen by increasing octane are masking/fixing other problems.

Firebat

iTrader: (7)

I run 89 octane with E10 and its usually cheaper than 87. I don't think the bone stock 3.1 V6 has high enough compression to require anything higher so there is no point in getting higher octane.

I've been reading up on the "acetone" thing on fuelsaver forums, and it seems that its no myth that it increases fuel mileage. It causes more fuel to burn, thus causing an increase in gas mileage. By the way, hydrogen injection does the same thing (in a sense) but thats kind of a different story...

firstfirebird

iTrader: (3)

Thank you very much!
Have you tested your theory?
I'm speaking from experience, I must be doing something right - the truck has 178,xxx miles on it right now and shows NO signs of having any problems in the near future (with a stop or wide open driving habit). I even still get 15+MPG AVERAGE, and that's good considering living in metro Ft.Lauderdale area with frequent traffic jams.
.
Before The acetone was started I would get a slight knock at hywy speeds with acceleration, now it's gone (was worse with the 89 of course).

Gallileo60

Well on my car with the timing advanced, and running high octane, I DO GET BETTER MILAGE...Now with the timing retarded (0) and low octane gas, I get less milage, but since it is cheaper, it comes out the same.....Now I can not speak for anyone else, but I have had my car for a good number of years, and have had it in several different states of tune...For me I run 92, because, I can advance the timing, and it is so much more enjoyable to drive that way....Tom

BTW, I do not argue with you about the slower burn rate of high octane, nor do I argue about all things being equal high octane does not increase milage, but a timing advance will in alot of cases increase milage, and throttle response....It is only because of the timing advance that I run high octane....just to clarify....

matt_p

lol guys. Europe uses a different method of calculating octane than here in the North America

95 octane there is like 91 here

firstfirebird

iTrader: (3)

Hey, bobdole369 - I'm in Coral Springs (NW Broward for those of you who don't know), where are you?
.
EDIT : You can catch me on CH34 in my moble...

bobdole369

Tamarac, Margate, Coral Springs. I live in margate (down winfield now), but I used to live at pine island between southgate and mcnab (just south of taravella). You may have seen my wreck, its the only red firebird badly in need of a paint job that has a grey passenger door that I've seen around! Also note my F**K Work sticker, and my "Yoda loves me" one.

I work down by all the marinas on SR84, and wife works on sample/pine island so you might have seen me around there too.

firstfirebird

iTrader: (3)

I'm off University and Royal Palm, are your lights stuck up? Seen a couple of red 'Birds around. One of mine sticks down now and again.

zoddri

Really? Did'nt know that.
Why can't you guys try to be like the rest of the world sometimes?

bobdole369

Yup. stuck up for years now. The red paints getting pretty bad too, but you can definitely tell its me by the grey door. I'm always around university/royal palm.

tnt_viper

I use 94 octane over her in canada, but my daily driver piece of crap dodge neon has the cheapest stuff, 87 octane

matt_p

We have stubborn neighbours

firstfirebird

iTrader: (3)

There's some other S.Florida guys here, come on in!...
Click here