Unleaded or Super?

[UlrichFennec]

My dad believes I should run my 325i on Super, rather than unleaded. What would the advantages be compared to mid-grade and regular? I want my car to be in tip top shape from now on.

[ELVA164]

No advantages at all unless you have an M42 motor. The other motors were made to run on 87 octane.

[JordsProject]

When I bought my car, the old guy before me always used premium (98 octane) but I found no difference in switching to 91. But I think I might go back to 98, for peace of mind.

[UlrichFennec]

Looks like I have the M20 motor, since it's a 91 cabrio. Still a pretty stellar engine, either way. Appreciate the insight!

[BruceJ]

Be best off running branded gas. These typically have just a little more detergent in them. Just enough to keep stuff clean in the cylinder if the engine is running right. More critical in DI type engines(not 325i) but still effective for long term.

[estoguy]

Even the owner's manual says that regular is OK. I'd say running anything else would be a waste. I've had my Eta two years, and she's only seen regular fuel. The only time my fuel economy goes down is if I do a lot of city driving, drive fast or it's winter time. But overall, the fuel economy has been consistent.

I do run Seafoam through the gas at every oil change, and twice a year (usually spring and fall) I run it in the crankcase and suck it in through the intake.

[JordsProject]

Does it really matter if you change gases? Like say if you had used 91 for the last 2 years of I were on next fill up put 98 in, would it hurt the engine?

[dnguyen1963]

Does it really matter if you change gases? Like say if you had used 91 for the last 2 years of I were on next fill up put 98 in, would it hurt the engine?

No.

[ST1G]

Does it really matter if you change gases? Like say if you had used 91 for the last 2 years of I were on next fill up put 98 in, would it hurt the engine?

All Octane rating is the amount of compression needed to have the fuel combust. An M20 will not pre ignite lower octane fuel, so there is no reason for higher grades. New Zealand doesn't show the average of the RON and MON like the US and Canada does, just the RON grade so I'm assuming 91 is your lower level fuel grade.

[itsonlygeorge]

91 is usually Premium here, although some gas stations have 93. My eta is chipped so I have to run 91 with the MarkD chip.


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[slammin.e28]

Stock M20 need not run any more than 87.

OPs question looks like he wants to run unleaded, or super....leaded?

GL finding leaded gas.....

[dnguyen1963]

Stock M20 need not run any more than 87.

OPs question looks like he wants to run unleaded, or super....leaded?

GL finding leaded gas.....

A bit safer than lead...

http://www.amazon.com/Radiator-Specialty-M5012-12OZ-Additive/dp/B004CX71I0

[ST1G]

Stock M20 need not run any more than 87.

OPs question looks like he wants to run unleaded, or super....leaded?

GL finding leaded gas.....

I put lead shot in my gas tank. I've noticed an 80% gain in mileage with 30 KG of bbs' in there.

[dnguyen1963]

Only 30 kg?

[3vilE30]

Anybody want to run 100LL and report back :)