GAS- Premium or Regular?
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I think anyone who is considering this has never experienced engine knock.
I bought my first bimmer (318is E36) about 10 years ago.
The first few months, I filled it with premium. A few months later, I tried to "save" money by putting cheap gas.
After driving for a while, I would hear my engine knocking at low speed. I thought my engine is going to die or something. So, I immidiate went for an oil change. No go, still hear it. So I went back again to put on Mobil 1. Still hear the knock. I replaced almost every fluid in the car, bought expensive additives, etc....still knocking.
Then, one day, gas price went down a bit so I filled with premium gas. Whoaaaaa....the difference in power is noticeable.
The knocking sound was history and the engine ran quieter and smoother....
Since then - I always put the recommended fuel on my cars.
I bought my first bimmer (318is E36) about 10 years ago.
The first few months, I filled it with premium. A few months later, I tried to "save" money by putting cheap gas.
After driving for a while, I would hear my engine knocking at low speed. I thought my engine is going to die or something. So, I immidiate went for an oil change. No go, still hear it. So I went back again to put on Mobil 1. Still hear the knock. I replaced almost every fluid in the car, bought expensive additives, etc....still knocking.
Then, one day, gas price went down a bit so I filled with premium gas. Whoaaaaa....the difference in power is noticeable.
The knocking sound was history and the engine ran quieter and smoother....
Since then - I always put the recommended fuel on my cars.
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Originally Posted by fastkevin' post='596708' date='Jun 5 2008, 11:55 PM
Unfortunately the knocking you speak if is actually detonation, and detonation can burn a piston. If you burn a piston, you kill the motor, and I doubt BMW will cover it. Burnt pistons don't happen on accident, and you could do serious damage instantaneously depending on how severe the detonation is. Even if you don't kill it right off, you could get an area of the piston hot enough to weaken it, which could be a ticking time bomb that could surface at any time.
Speaking of knocking... The computer alters a few things to keep the "knock count" within it's acceptable limits as it is. I would think at the very least, it would sense a much larger knock count, and start dropping ign timing, fuel mapping, turbo boost etc.. to try to control it. Obviously this would lessen your motor's hp output. Having written this second paragraph, I must tell you I'm a bike guy, not a car guy. I'm speculating on what the computer might do. The mechanical repercussions would be the same on any gasoline engine, but with the complex software a car computer possesses compared to a bike's computer, I can only guess about that.
I like bikes
Speaking of knocking... The computer alters a few things to keep the "knock count" within it's acceptable limits as it is. I would think at the very least, it would sense a much larger knock count, and start dropping ign timing, fuel mapping, turbo boost etc.. to try to control it. Obviously this would lessen your motor's hp output. Having written this second paragraph, I must tell you I'm a bike guy, not a car guy. I'm speculating on what the computer might do. The mechanical repercussions would be the same on any gasoline engine, but with the complex software a car computer possesses compared to a bike's computer, I can only guess about that.
I like bikes
Engine knock is actually UNCONTROLLED detonation in a cylinder. Please educate me because I've never heard of a "burnt" piston on a car.
The engine does compensate by adjusting the things you mentioned. The engine would most likely shut itself off if the knock becomes too bad to avoid dieseling.
I know plenty of people who use regular octane vice premium even though its recommended and none have had engine problems that could be traced to lower quality gas.
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Originally Posted by skylolow' post='596638' date='Jun 5 2008, 08:55 PM
Where I live premium fuel is only about 10 cents to 15 cents higher then reg. So if you pump in 15 gallons your only looking at about $2.00 or so difference in each tank. Say you fill up once a week, in a whole year you'd only save about $100 or so. I'm sure most of us will spend a $100 on something worthless in the next few weeks so to me it isn't even worth putting in regular gas.
been saying it for years.
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From: York, UK
My Ride: Nov 07 530i M Sport - Sports Auto - Carbon Black - black dakota - 172's - Media - Visibility - Heated front seats - Auto dim / fold mirrors
I am curious to know if UK and US petrol are measured on the same scale
Our standard unledaed petrol is 95 RON and Super Unleadeds (which have various brands like BP Ultimate or Shell V Power for instance) are 98 RON
The 95 stuff is about 116 pence per litre and the 98 is about 123 pence per litre
Our standard unledaed petrol is 95 RON and Super Unleadeds (which have various brands like BP Ultimate or Shell V Power for instance) are 98 RON
The 95 stuff is about 116 pence per litre and the 98 is about 123 pence per litre
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Originally Posted by JPJP' post='598524' date='Jun 8 2008, 02:51 PM
I am curious to know if UK and US petrol are measured on the same scale
Our standard unledaed petrol is 95 RON and Super Unleadeds (which have various brands like BP Ultimate or Shell V Power for instance) are 98 RON
The 95 stuff is about 116 pence per litre and the 98 is about 123 pence per litre
Our standard unledaed petrol is 95 RON and Super Unleadeds (which have various brands like BP Ultimate or Shell V Power for instance) are 98 RON
The 95 stuff is about 116 pence per litre and the 98 is about 123 pence per litre