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9/22/2017 12:11:25 AM
Posted: 8/18/2005 3:23:05 AM EDT
My car has "Premium Unleaded Only" written on the gas gauge and in the manual it says to put atleast 91 octane in the tank. Now 92 is like $3 a gallon here so I have been putting 89 and sometimes even 87. I have been doing half of 92 and then half 89 but today with the increase in price I just put all 87 and it still vost $41. I dont not a difference except maybe a slight decrease in acceleration. Does all this really matter ?
Link Posted: 8/18/2005 3:31:39 AM EDT
You need to be concerned about detonation not seat of the pants performance.
Higher octane has slower burn rates that is crucial for high compression heads.
If your ride is knocking with the 87-89 you best put the 91-92 fuel in pronto!
As they say pay me now or pay me later. If there is a price gap of about 20 cents per gallon
your only talking 3-5 bucks per tankful. I can blow that out my ass for lunch everyday.
Link Posted: 8/18/2005 3:33:37 AM EDT
Best I can tell you is read the book! (that came with the car)
BTW, what kind of car?
Most cars like this since they're "high-end" or high performance engines have sensors
that can detect "knock" from octane that is lower than recomended and they retard the spark
or otherwise adjust the electronic ignition for less h.p.
Link Posted: 8/18/2005 3:42:33 AM EDT
if you can't afford to put premium in the tank you shouldn't have bought a car that requires premium fuel

Link Posted: 8/18/2005 3:43:53 AM EDT

Originally Posted By livefreeordieNH:
if you can't afford to put premium in the tank you shouldn't have bought a car that requires premium fuel




+1
Link Posted: 8/18/2005 3:47:48 AM EDT

"Hey! That thing got a HEMI???"



Link Posted: 8/18/2005 3:50:58 AM EDT

Originally Posted By BayEagle:
"Hey! That thing got a HEMI???"

www.jonreep.com/albums/3rd-Commercial-%28Hemi-to-go%29/tshirtpicsc_011.sized.jpg




Link Posted: 8/18/2005 3:54:10 AM EDT
I noticed something with my town car. It is the cartier which states to use premium fuel. I tried to cheat and ran arco regular and got pinging. I went back to super. The other day I was running low, make that on fumes.... anyhow I pulled into the chevron station and filled with regular which is against my better judgement but what the hell. Anyhow a nice suprise, no ping. I'm wondering if one of their additives is suppressing the knock or if arco just has really crappy fuel.
Link Posted: 8/18/2005 3:58:56 AM EDT
[Last Edit: 8/18/2005 4:00:44 AM EDT by TacticalStrat]
Most new cars have knock-sensors and will auto-adjust for the octane of gas that you're using if you put a lower than recommended octane gas in the car. By using a lower than recommend octane, you'll definitely be lowering the power output (and possibly the fuel economy) of your engine by 10-15%.

If your car doesn't have a knock sensor capable of auto-adjusting for lower octane gas, then you'll risk damaging your engine.

A Porsche I owned recommended 91 or better octane, but it said in the manual that under emergency conditions, it's OK to use lower octane, but that you shouldn't depress the gas pedal more than halfway. My current BMW says in the manual that you should only use 91 octane or better and that the use of lower octane fuels may result in engine damage or more frequent service intervals (service is controlled by on-board computer).
Link Posted: 8/18/2005 4:02:58 AM EDT

Originally Posted By TacticalStrat:


A Porsche I owned recommended 91 or better octane, but it said in the manual that under emergency conditions, it's OK to use lower octane, but that you shouldn't depress the gas pedal more than halfway. My current BMW says in the manual that you should only use 91 octane or better and that the use of lower octane fuels may result in engine damage or more frequent service intervals (service is controlled by on-board computer).



My Porsche actually has 2 wires under the floormat you need to connect if you use
low octane fuel in an emergency. When connected, another program takes over in the
ignition computer.

I see a lot of these cars at car shows etc, and I've had a few people complain about the
performance, they were disappointed. I have surprised more than one owner by
showing them those 2 wires were connected, and simply unhooking them. Almost
doubles the performance of the car.
Link Posted: 8/18/2005 4:04:40 AM EDT

Originally Posted By adair_usmc:

Originally Posted By livefreeordieNH:
if you can't afford to put premium in the tank you shouldn't have bought a car that requires premium fuel




+1



And everyone with a credit card is stupid. I love you holier than all of you types when it comes to this kind of stuff. Guy asks a question, and you all go off on him for it.



Link Posted: 8/18/2005 4:17:38 AM EDT
Typically the pinging/knocking will only occur under heavy load. (i.e. pulling a trailer up a hill, accelerating hard) If you aren't doing these things typically the engine will not knock with regular fuel and therefore the timing will not be retarded. 99% of the time you drive the car with premium fuel you do not need the the added octane (resistance to detonation).

Fill it up with regular, drive like an old man and don't worry about it.

Kent
Link Posted: 8/18/2005 4:23:17 AM EDT

Originally Posted By TacticalStrat:
Most new cars have knock-sensors and will auto-adjust for the octane of gas that you're using if you put a lower than recommended octane gas in the car. By using a lower than recommend octane, you'll definitely be lowering the power output (and possibly the fuel economy) of your engine by 10-15%. If your car doesn't have a knock sensor capable of auto-adjusting for lower octane gas, then you'll risk damaging your engine.

Yep. The higher octane keeps the engine smooth at higher rpm's and higher compression ratios. If you're not stressing the engine, it won't matter and the computer will adjust the timing. Just remember NOT to punch the gas!
Link Posted: 8/18/2005 4:29:17 AM EDT
[Last Edit: 8/18/2005 4:30:28 AM EDT by jimtash9]

Originally Posted By livefreeordieNH:
if you can't afford to put premium in the tank you shouldn't have bought a car that requires premium fuel




Oh great one with all your forsight and wisdom, tell me which numbers to choose so I can hit the lottery too. I should of thought about that when I purchased my '89 Yamaha engined SHO 3 YEARS AGO when I could fill it up for $20.00 and again when I got my '98 SHO almost a YEAR AGO.
Link Posted: 8/18/2005 4:35:09 AM EDT

Originally Posted By MTUSA:
You need to be concerned about detonation...



+1
Link Posted: 8/18/2005 4:42:12 AM EDT
[Last Edit: 8/18/2005 4:46:03 AM EDT by BigB1129]

Originally Posted By Lloyd-Jr:
Best I can tell you is read the book! (that came with the car)
BTW, what kind of car?
Most cars like this since they're "high-end" or high performance engines have sensors
that can detect "knock" from octane that is lower than recomended and they retard the spark
or otherwise adjust the electronic ignition for less h.p.



Infiniti q45, I never said I couldnt afford it, but wouldnt mind saving a few bucks if I can. I was just wondering if it really makes a difference. I feel like im getting ripped off with such a high gas price? It was 20 cents cheaper yesterday, what the hell happend in 1 night that gas is worth 20 cents more to me? Ill probably go back to mixing 92 with 89 which is what the manual said.
Link Posted: 8/18/2005 4:48:36 AM EDT

Originally Posted By BayEagle:
"Hey! That thing got a HEMI???"

www.jonreep.com/albums/3rd-Commercial-%28Hemi-to-go%29/tshirtpicsc_011.sized.jpg




And now you're going to get a real hemi from being stuck up the ass for premium fuel, dude.
Link Posted: 8/18/2005 4:56:16 AM EDT

Originally Posted By billclo:

Originally Posted By BayEagle:
"Hey! That thing got a HEMI???"

www.jonreep.com/albums/3rd-Commercial-%28Hemi-to-go%29/tshirtpicsc_011.sized.jpg




And now you're going to get a real hemi from being stuck up the ass for premium fuel, dude.



Yeah, we just bought a Durango and passed on the Hemi, cool as it may be. It requires Premium gas and lots of it. The gas for the regular 4.7l is bad enough.
Link Posted: 8/18/2005 5:07:28 AM EDT
The manufacturer didn't put that information in there for fun,if you run lower octane than recommended it may do nothing,but then again almost all the internals on that particular car are made of aluminum and you will be taking a risk of detonation.
Link Posted: 8/18/2005 5:09:15 AM EDT
Link Posted: 8/18/2005 5:11:51 AM EDT
My Ford Lightning would barely run on 87.
Link Posted: 8/18/2005 5:20:35 AM EDT

Originally Posted By TomJefferson:

The quality of gas is also a factor and if you burn the cheapest brand you can then this limits your options. I always laugh when I see an expensive car filling up with off brand no additive gas. It's like buying an M16 and shooting only commericial offbrand reloads.

Tj



I don't know how it is where you live but anytime I see a tanker truck at a gas station, it's an off brand distributor and not a company branded tanker. And since all gas stations here are independently owned, they probably buy whatever is cheapest to get. And BTW, the last time I actually saw a big oil company branded tanker truck was at a BP station in Greensboro, NC about 3 years ago and I assume that station was actually owned by BP.
Link Posted: 8/18/2005 5:22:24 AM EDT
I wonder what a melted piston in a MB , BMW or Porsche costs to repair?
Link Posted: 8/18/2005 5:45:16 AM EDT
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