Horsepower increase in 2005 and Gas Requirements

[R90]

In 2005 BMW made a large increase in horespower and torque. How did they do it? Did the 2004 and earlier models use regular gas? Do the post 2005 models need premium gas or Plus to run properly?

[DavidTaylor]

A variety of changes to the valvetrain, head, exhaust, compression ratio and ECU. I believe mid grade (89 octane or better) has been the spec for all LTs since the beginning.

[jrlakin]

I am sure my manual states to use Premium gas for my 2000. Having said that, I mostly run mid grade in mine, and notice no bad effects. In colder weather, many times I run regular. I also have a friend who has an 06 LT, and he almost always runs regular.

[cfell]

In my '05 I run anything... sometimes no choice.. especially on "single hose" pump dispensers.

So, I carry a few ounces of the "additive" made by Lucas.. smooths out the performance on Misty.

[hwread]

A variety of changes to the valvetrain, head, exhaust, compression ratio and ECU. I believe mid grade (89 octane or better) has been the spec for all LTs since the beginning.
The manual in my '99 and now my 2000 calls for 90 octane. I ran my '99 on 89 octane and pretty much destroyed the engine with SILENT detonation! I'm running my 2000 on premium and it's holding up at least somewhat better, but I admit there was never any real diagnosis of the exact cause of the detonation that ruined my '99. I'm also aware that some have run regular for extended periods. I believe that the detonation damage on the '99 may have been at least partly related to the "hot ambient hesitation recall". So, my 2000 has not and will not receive these mods.