new to bmw forums

hello, im sure there is a community of beemer fanatics, but i have a couple questions.

for starters background about me, 1 im not car savvy, yeah i know what a car is, and how the engine "work", ie the physics of it, but i dont know all the part, functions of parts minus drive train, fuel pump, water pump, radiator, and other simple shit.

im curious to what dammage is done to the 325i 1995 engine if a previous owner used regular 85 octaine gas opposed to premium gas (which i believe is 89).

i hear from my girlfriends father which is a beemer nut, that it becomes a foamy sludge. then causes the engine to run awefully when its cold, but when its warm it runs well.

are there any fixes, and if there are. how would one go about doing that, in layman's terms, then the techinal jargon. just so i can come to par with using the techinal jargon

ps. im thinking about buying the car, for 3,500. is it worth it. it has winter and summer tires, new brakes, oil change every 3 months, and 120k miles.

I'm no beamer buff, but that sounds pretty good.

Man, you get low grade stuff where you are...I don't let anything sub 90 octane go into my tank.

I wouldn't worry to much about it, just get the fuel lines and what not cleaned out, and run higher octane gas from now on. For the most part, the computers in the cars can tell your runing a low octane that could be nasty for the motor, so it adjusts fuel flow and what not in order to protect the motor.

If you are worried about it, take it for a test drive before you buy it, and set up to meet with a mechanic who know's BMWs to have them take a quick look at it. They can tell you if anything is wrong, and for the most part, its only about a hundred bucks. If there is anything wrong, and it isn't major, then you can use that as a barganing tool with the price.

That sounds like a good deal on a car if its all good, I know I would go with it.

Oh, and its not Beamer. Its Bimmer

low octane fuel does not turn to a sludge any quicker than fuel a couple octane higher. It has to get very cold for gas to freeze. (Actually what generally causes the problem is moisture in the gas which can be remedied by adding gas line antifreeze to your tank during extreme cold temps). There is not much difference between 91 and 89 octane fuel. The octane refers to the quickness of the fuel to burn and the heat produced. A lot of people run high or middle octane fuel in vehicles that don't need it and waste their money.
The bmw computer should adjust the timing if necessary when running a fuel that is to low of an octane. The computer will pick up the "pinging" through the knock sensors and make adjustments so 87 octane should not hurt the engine. However, for it to run at the proper timing and performance levels you should probably run 89 or 91 octane because this car probably runs around 10:1 compression or higher but this depends somewhat on the combustion chamber design. My chevelle runs about 10.25:1 - 10.5:1 compression ration and I can get by just fine with 89 octane because of the fast burn techknowledgy designed into my heads.
bottom line, drive the car. If you like it and it runs good buy it and run the high grade fuel in it if you like and be happy!!

I get better miliage, and hardly noticable but still there performance when I run 93 octane. Survival wise, running high 80 low 90 is just fine.