z4 won't go to redline. Is it supposed to?

I just purchased a 06 z4 3.0si manual. I finally got the chance to take it up in the rpms. I don't know if this is normal or not but in 1st gear at about 6200rpm it barely builds rpms. feels like I go from full throttle to half. then in 2nd it has good power and builds rpms until around 6500rpm and it does the same thing. I don't think it could even build enough rpms to get to redline. Is this normal and just a fuel cut? the car doesn't misfire or jump or anything. accelerates good....hit 6200rpm...then feels like I let up on the gas to like half. then I shift and it's all good but then repeats. I've searched here a lot and all I could find is someone asked if there is a floating rev limiter so it doesn't rev too fast in 1st. Is this true, am I supposed to shift at 6200rpm in 1st and 2nd, or can you guys with si's go up to 7000? thanks

Steve

congrats..same one I have...mine is white... sorry I can't answer your question, I don't run mine hard at all...planning on being buried in mine so I'm taking it easy on the engine, for the most part

these are great engines but consistently high rpm will kill any engine. your engine has so much torque it probably isn't necessary to rev it that high unless you're tracking it. i've never taken mine that high and i used to race motorcycles.

as far as being normal to run out of rpm at that level, i'm not sure but the problem, if it is a problem, is usually related to "breathing." the engine runs out of air. so, check that your air filter is new and there are no restrictions in the air intake system. there are also sensors related to breathing but, if these are bad, they should throw a code.

Originally Posted by tohbi

these are great engines but consistently high rpm will kill any engine. your engine has so much torque it probably isn't necessary to rev it that high unless you're tracking it. i've never taken mine that high and i used to race motorcycles.

as far as being normal to run out of rpm at that level, i'm not sure but the problem, if it is a problem, is usually related to "breathing." the engine runs out of air. so, check that your air filter is new and there are no restrictions in the air intake system. there are also sensors related to breathing but, if these are bad, they should throw a code.

+1 ... or a cat converter which has become plugged, or partially so. Generally there is a bung just upstream of the cats where one can measure the back pressure - there is a normal range - and if you find it above, then time to replace. [the other pathological situation we've seen was for a car which has sat for a year, and mud wasps had built a nest in the muffler (or somewhere in the exhaust system), making for a very quiet running car, but one with no gusto - took the cat back part of the exhaust system off, banged it about a bit and retrieved maybe a quart of wasp nest parts, including quite a few unhappy wasps :-( ... ran a whole lot better afterwards.]

It's common for a lower rev limiter to be in place in low gears. Can you reach closer to the 7k rev limiter in later gears?

Ahh, isn't this covered in the owner's manual?

Hey mitty36, I own a 2004 Z4 3.0i smg.Mine will rev to the redline in no time flat. I have only reved it that high a few times. I also run a k/n airfilter.

I have read the owners manual twice now and did not come across anything about when to shift in 1st gear or it saying it will slow down before you get to redline(7000). Thanks for the replies guys. It sounds like I have a problem. Any suggestions since the closest bmw dealer is 450 miles away. I am in north Dakota.

also I have no codes. I will try spark plugs and fuel filter soon. thanks

Steve

mitty36, I think you have a rev limiter on your car. This controls how high you can rev your engine. You can have the rev limiter reset to raise your rev limit or lower your rev limit.I would have that checked out first to see where your rev limiter is set. This is suppose to be a protection for your engine to keep you from over reving the engine. It can easily be reset.

I am fine with if the car can't go to 7000 which is the redline in the dash, I just want to know if it has a problem or not. anyone try this in their car? thanks

Steve

From the Tachometer section of the 2006 Owner's Manual (downloaded from http://www.bmwsections.com/docs/z4/)

Never allow the engine to operate with the needle in the red overspeed sector of the gauge.
To protect the engine, the fuel supply is interrupted when speed reaches this sector.

There is also a picture showing the red sector starting at 7,000 rpm.

Sounds like you should be able to hit redline in every gear. I can't find any reference to the car having a rev limiter.

The maximum power output for the 3.0si is produced at 6,600 rpm (in the Technical Data: Engine Data), so 6,200 does seem a little short.

I would change the spark plugs, air filter, and fuel filter. If the problem persists, perhaps, a coil is marginal. Bimmerworld recommends "Coils should be replaced in complete sets to eliminate risk of engine computer damage". A complete set would cost $198.

Will transport mode cause this?

Have you had a dead battery in a while?

Steve

The manual says: "Never allow the engine to operate with the needle in the red overspeed sector of the gauge. To protect the engine, the fuel supply is interrupted when speed reaches this sector."

Originally Posted by dougmcintyre

... There is also a picture showing the red sector starting at 7,000 rpm. Sounds like you should be able to hit redline in every gear. I can't find any reference to the car having a rev limiter...

I would think the manual is referring to a rev limiter that shuts off the fuel at 7,000 rpm.

what is "transport mode"? actually before I bought the car the guy had to take it in because there was a check engine light on. He claimed they replaced some light bulb that was out and also charged his battery. thanks

Steve

See http://www.bimmerfest.com/forums/sho...transport+mode especially post no 3.