3.0 si vs M suspension

[Kim Schwartz]

Does anyone know what the difference is between the 3.0si with the performance package and the M suspension? I know that the tires and the engine are different but what about the suspension?

[dubsesd]

Z4 non-M sports suspension is based on the E46 non-M design. Struts, springs, shocks, control arms...etc are all interchangeable between them. The Z4 M suspension is a hybrid between E36 M3 and E46 M3, with the front suspension parts being re-designed E36 M3 parts, and the rear suspension parts being redesigned E46 M3 parts. The swaybars are from E46 M3 as well (rears are E46 M3 CSL bars).

As for comparison, the non-M Z4 will hold its own, but the MZ4s have stiffer springs and higher damper rates, plus the MZ4s have more camber up front. The lower control arm is from the E46 330i with Performance Package (ZHP). The major difference will be the fact that the MZ4 has a tuned limited slip differential while the Z4 3.0Si has an open diff, and the M has servotronic rack-and-pinion steering instead of the non-M's electronically assisted rack-and-pinion steering. The M also has a quicker steering ratio.

End result, is that on the track the M has a much higher threshold, with quicker turn-in feel. But you will not be disappointed with the 3.0Si coupe, it'll likely hang at most tracks with the best of them. 265HP on a 2,9xx lbs frame is going to make a very capable car on track.


http://forums.bimmerforums.com/forum...d.php?t=844305

[Kim Schwartz]

Originally Posted by dubsesd

Z4 non-M sports suspension is based on the E46 non-M design. Struts, springs, shocks, control arms...etc are all interchangeable between them. The Z4 M suspension is a hybrid between E36 M3 and E46 M3, with the front suspension parts being re-designed E36 M3 parts, and the rear suspension parts being redesigned E46 M3 parts. The swaybars are from E46 M3 as well (rears are E46 M3 CSL bars).

As for comparison, the non-M Z4 will hold its own, but the MZ4s have stiffer springs and higher damper rates, plus the MZ4s have more camber up front. The lower control arm is from the E46 330i with Performance Package (ZHP). The major difference will be the fact that the MZ4 has a tuned limited slip differential while the Z4 3.0Si has an open diff, and the M has servotronic rack-and-pinion steering instead of the non-M's electronically assisted rack-and-pinion steering. The M also has a quicker steering ratio.

End result, is that on the track the M has a much higher threshold, with quicker turn-in feel. But you will not be disappointed with the 3.0Si coupe, it'll likely hang at most tracks with the best of them. 265HP on a 2,9xx lbs frame is going to make a very capable car on track.


http://forums.bimmerforums.com/forum...d.php?t=844305

Thank you. Great description. We have a Z4 3.0si and a 128i both with the sport package. The Z4 is noticably stiffer than the 128 of course. The Z4 is better on a track. On the street sometimes I think that I notice the stiffness of the Z4 more than I notice the improvement in handling and I was wondering how much stiffer the M was than the 3.0si and what it might be like on the street. Would one want to take a road trip in the M for example? I drive the Z4 most of the time and have taken it for raod trips and occasionally think that the 128 would have been the better choice.

[Mirko]

Originally Posted by Kim Schwartz

Thank you. Great description. We have a Z4 3.0si and a 128i both with the sport package. The Z4 is noticably stiffer than the 128 of course. The Z4 is better on a track. On the street sometimes I think that I notice the stiffness of the Z4 more than I notice the improvement in handling and I was wondering how much stiffer the M was than the 3.0si and what it might be like on the street. Would one want to take a road trip in the M for example? I drive the Z4 most of the time and have taken it for raod trips and occasionally think that the 128 would have been the better choice.

I've taken a 300-400km road trip in my M and it was fine. On the highway the stiffness isn't bad. Bumpy roads you will toss around a little bit but I think its fairly comfortable. Going slower speeds in residential areas on crappy roads you get tossed around a bit.

[3002 tii]

I did a 10hr drive from NJ to VIR in my 3.0si. It wasn't too bad, discomfort in the lumbar but I think that'd happen with any car. You just have to remember to sit further back, straight up.

[The HACK]

Both the MZ4 and regular non-M Z4 use the "performance package" E46 330i front lower control arms if I'm not mistaken. Otherwise all other info are correct as far as I know.

I had an '03 Z4 3.0 prior to the MZ4 Coupe, and frankly both cars are too stiff for daily use, especially if the road is rough. Neither are super comfortable for long drives, but the non-M can be comfortable enough with traditional tires (non-run-flats), where as the MZ4 already comes with traditional tires so there's not much to "soften the blow" unless you replace the shocks and springs.

[Kim Schwartz]

Originally Posted by The HACK

Both the MZ4 and regular non-M Z4 use the "performance package" E46 330i front lower control arms if I'm not mistaken. Otherwise all other info are correct as far as I know.

I had an '03 Z4 3.0 prior to the MZ4 Coupe, and frankly both cars are too stiff for daily use, especially if the road is rough. Neither are super comfortable for long drives, but the non-M can be comfortable enough with traditional tires (non-run-flats), where as the MZ4 already comes with traditional tires so there's not much to "soften the blow" unless you replace the shocks and springs.

Now that you mention it, switching to Continental DW's made a noticable improvment in ride comfort. The run flats were great on the track but did feel like wood on the street.

[Stromtech]

So my BMW build sheet specifying code 0704 M Sport Suspension is not really M sport suspension on my 2004 3.0i? Seems strange they claim it is.

[3002 tii]

Originally Posted by strom

So my BMW build sheet specifying code 0704 M Sport Suspension is not really M sport suspension on my 2004 3.0i? Seems strange they claim it is.

M sport is just a marketing term that has no set definition. On certain cars it can mean a trim, others can mean sport option, etc. But it is not to be confused with actual M components. For example I have M sport seats, but they are still not the same as the actual seats in the M coupe / roadster.

That's why wheels for M fitment won't fit on non-m cars even with sport or m-sport suspensions. The offset is way too aggressive.

[Stromtech]

Originally Posted by Dubbedown

M sport is just a marketing term that has no set definition. On certain cars it can mean a trim, others can mean sport option, etc. But it is not to be confused with actual M components. For example I have M sport seats, but they are still not the same as the actual seats in the M coupe / roadster.

That's why wheels for M fitment won't fit on non-m cars even with sport or m-sport suspensions. The offset is way too aggressive.

Thank you for the explanation...seems BMW marketing is playing with the facts

[v3.0si]

Originally Posted by strom

...seems BMW marketing is playing with the facts

why are you down on this?

the fact is that BMW didn't have an ///m variant of your car when it was new. people wanted a sportier version of the car, so BMW gave it to the fine folk of ///m to tune the suspension. now you have an ///m approved product.

so was your car built by ///m? ... no.
were some of the components tuned by ///m? ... yes.

be proud of your car. you worked hard for it.

[Ivesy]

Guys, noone seems to be touching on the fact that the Z coupe Si came in two variants. SE and Sport. I beleive there is further differences between there two sets of suspension, I know for a fact that the sway bars are thicker on the Sport, Autodoc also has different shock absorbers and spring listed as "for cars with sports suspension".