Cars that are supposed to only be filled up with "Premium only fuel"

[ARCHIVED THREAD] - Cars that are supposed to only be filled up with "Premium only fuel"

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 ?

Posted: 8/18/2005 3:31:39 AM EDT

[#1]

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.

Posted: 8/18/2005 3:33:37 AM EDT

[#2]

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.

Posted: 8/18/2005 3:42:33 AM EDT

[#3]

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

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

[#4]

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

+1

Posted: 8/18/2005 3:47:48 AM EDT

[#5]

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

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

[#6]

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

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

Posted: 8/18/2005 3:54:10 AM EDT

[#7]

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.

Posted: 8/18/2005 3:58:56 AM EDT

[#8]

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).

Posted: 8/18/2005 4:02:58 AM EDT

[#9]

Quoted:

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.

Posted: 8/18/2005 4:04:40 AM EDT

[#10]

Quoted:
Quoted:
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.

Posted: 8/18/2005 4:17:38 AM EDT

[#11]

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

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

[#12]

Quoted:
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!

Posted: 8/18/2005 4:29:17 AM EDT

[#13]

Quoted:
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.

Posted: 8/18/2005 4:35:09 AM EDT

[#14]

Quoted:
You need to be concerned about detonation...

+1

Posted: 8/18/2005 4:42:12 AM EDT

[#15]

Quoted:
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.

Posted: 8/18/2005 4:48:36 AM EDT

[#16]

Quoted:
"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.

Posted: 8/18/2005 4:56:16 AM EDT

[#17]

Quoted:
Quoted:
"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.

Posted: 8/18/2005 5:07:28 AM EDT

[#18]

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.

Posted: 8/18/2005 5:09:15 AM EDT

[#19]

If you car doesn't knock or diesel after turning it off, I suggest you look at the economics. You may find that saving $4 at the pump is costing you $6 in milage per tank full. The octane rating is based on the timing gap for your engine.

As a rule of thumb most cars that recommend high octane only not only do so for Hp rating but for maximum fuel economy.

Another little trick is to mix. If your car is rated for 91 octane then fill up with 93 and then at say a little over half a tank top off with 87.

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

Posted: 8/18/2005 5:11:51 AM EDT

[#20]

My Ford Lightning would barely run on 87.

Posted: 8/18/2005 5:20:35 AM EDT

[#21]

Quoted:

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.

Posted: 8/18/2005 5:22:24 AM EDT

[#22]

I wonder what a melted piston in a MB , BMW or Porsche costs to repair?

Posted: 8/18/2005 5:45:16 AM EDT

[#23]

Quoted:
Quoted:

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.

Thankyou I will answer that for you. Most brands of gas come from common tank farms and carried by common carriers however they are blended with additives at the tank farm for specific brands.

I use to design and sell the equipment that does the blending. If you think your local convient store carries the same additives as Mobil, you're mistaken.

Tj

[ARCHIVED THREAD] - Cars that are supposed to only be filled up with "Premium only fuel"

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