Gasoline Grade

[Unregistered]

I use regular 87 in my 92 525i,

Is it bad to use this fuel?
What would it effect?

Jonathan

[Bill R.]

have knock sensors.. which is why they specify premium for your year
excessive preignition can take place on yours damaging the motor if its severe enough. I would say that yes its bad to use this fuel.
Now if you had a newer m50 with vanos then you could get away with regular since it has knock sensors and will retard the timing if knock is detected.

I use regular 87 in my 92 525i,

Is it bad to use this fuel?
What would it effect?

Jonathan

[Russell]

I have heard conflicting info about the benfits of higher octane on the newer m50 engines. Some say performace/gas mileage is better with 89 than 91-93 octane. I have tried both in my car. It seems as if performace/gas mileage was better in the summer with 91 chevron (for example) and no difference/worse in the colder winter months here in KY.

Just an observation.

have knock sensors.. which is why they specify premium for your year
excessive preignition can take place on yours damaging the motor if its severe enough. I would say that yes its bad to use this fuel.
Now if you had a newer m50 with vanos then you could get away with regular since it has knock sensors and will retard the timing if knock is detected.

[shragon]

my 95 says to use midgrade (89) or higher.

but since my car is chipped, i have to use 91 (yea, cali sucks, it's the highest we have).

[Bill R.]

motor has an even higher compression ration 10.5 to 1 than the m50, in order to get the maximum power and efficiency out of it, you should run that octane or higher. Probably higher to keep from retarding the timing any.. although i can't verify that. It will run on the lower octane 89 but I suspect that maximum power will be produced with 91 or higher.

I have heard conflicting info about the benfits of higher octane on the newer m50 engines. Some say performace/gas mileage is better with 89 than 91-93 octane. I have tried both in my car. It seems as if performace/gas mileage was better in the summer with 91 chevron (for example) and no difference/worse in the colder winter months here in KY.

Just an observation.

[Russell]

motor has an even higher compression ration 10.5 to 1 than the m50, in order to get the maximum power and efficiency out of it, you should run that octane or higher. Probably higher to keep from retarding the timing any.. although i can't verify that. It will run on the lower octane 89 but I suspect that maximum power will be produced with 91 or higher.