I'm trying to find information where the rev limiter on the z3 1.9L is at. My z3 cuts off at around the 6,700 limit. The AI tools give a vague limit. Anyone has about this limit or different limit?
1.9L M44 Engine RPM Rev Limit
- Thread starter FLZ_Boy
- Start date
It varies slightly visually as not all gauges read exactly the same. Hard cut is set in the ecu to 6500.
Several things about the m44:
Peak hp is 6000, going beyond that you’ll go slower, not faster.
The crank dampers have a reputation now for coming apart beyond 6500. They’re not available new and decent s/h are getting scarce. I can’t find anyone selling alloy dampers commercially anymore, so it’s Custom only.
BMW engine internals are not balanced from the factory, pistons vary +/-3.5g, rods 3-5g, doesn’t sound much but the forces acting on them are proportional to the square of the revs. If you wish to continually rev above 6K, balancing is an absolute MUST, otherwise the engine WILL go Bang.
Several things about the m44:
Peak hp is 6000, going beyond that you’ll go slower, not faster.
The crank dampers have a reputation now for coming apart beyond 6500. They’re not available new and decent s/h are getting scarce. I can’t find anyone selling alloy dampers commercially anymore, so it’s Custom only.
BMW engine internals are not balanced from the factory, pistons vary +/-3.5g, rods 3-5g, doesn’t sound much but the forces acting on them are proportional to the square of the revs. If you wish to continually rev above 6K, balancing is an absolute MUST, otherwise the engine WILL go Bang.
Actually, I was trying to determine if prior owners did a Dinan or similar issue flash to the ECU. I have a suspicion when my cluster is showing my cut off around 6700 or 6800 rpm before I get a hard cut. In addition, I believe it may be the cause of my fuel pump noise when I left off throttle beyound 6000 rpms.
Is this a road car?
I would suspect your pump noise is simply the return dumping into the tank when the throttle closes. I’m wearing a helmet when the shift light comes on so I can’t say I’ve been listening to pump noises.
Those ecu flashes are pretty pointless at the top end, raising the rev limit does absolutely nothing at all but make it more likely the poor motor will grenade itself spectacularly. They can give very slightly more power mid range through advancing the ignition, but chasing a higher rev limit is pointless.
I would suspect your pump noise is simply the return dumping into the tank when the throttle closes. I’m wearing a helmet when the shift light comes on so I can’t say I’ve been listening to pump noises.
Those ecu flashes are pretty pointless at the top end, raising the rev limit does absolutely nothing at all but make it more likely the poor motor will grenade itself spectacularly. They can give very slightly more power mid range through advancing the ignition, but chasing a higher rev limit is pointless.
This is a road car, upon my inspection and maintaining the Z3 it had it's original stock components when I purchased it. I believe that it's most likely the fuel cut off was closer to around 6,700 oem programing. However, the noise I get going off throttle (past 6,000 rpms) is like a loud air sucking sound (maybe metallic in some ways). I don't think that is a normal sound.
I have literally replaced the entire fuel system components barring the fuel tank and gas fill tube and I still get this sound.
I have literally replaced the entire fuel system components barring the fuel tank and gas fill tube and I still get this sound.
Don’t really know what to say as I don’t go past 6K for reasons above.
6000 rpm is plenty. 6500 is where they break, like a rod bolt letting go.
But, it's your car.
Crank pulleys are still available new but they're BMW only and £498. They fail when the bonding between the inner and outer sections delaminate.
But, it's your car.
Crank pulleys are still available new but they're BMW only and £498. They fail when the bonding between the inner and outer sections delaminate.
Thanks for the replies, I did DM a user that does AutoX and he stated there is a soft limit at 6,500 and hard cutoff at 6,700. I do plan to have the crank pulley replaced. Now I have to take another look at the fuel pump again (old and new pump-not OEM made the same noise).
Please, the hp peak is 6000rpm.
Going beyond peak power is completely and utterly pointless, the engine is then making LESS power.
Save the money from buying a pulley and balance the bottom end. If you can find a pulley, my dealer can’t get one.
Going beyond peak power is completely and utterly pointless, the engine is then making LESS power.
Save the money from buying a pulley and balance the bottom end. If you can find a pulley, my dealer can’t get one.
I'm with you Iain. I can't bear the sound of an engine screaming its nuts off.
But, I suppose, If I really was in an m44 drag race I'd hold 2nd till around 6200 or a tiny bit higher because even though power is dropping the lower gear is still a tiny advantage. Changing up at 6200/6300 into 3rd it'd be in the torque sweet spot.
But then I'd be spending my evenings rebuilding my engine between races and not putting my hat on backwards to scream round mcD's car park with the focus crowd.