Electric Steering Questions

[Efthreeoh]

Hey guys, this is my second post on the ZPOST Forum. I'm a long-time, 26-year BMW owner from our 1st E30 in 1988 to my current '06 E90, with a '97 Z3 thrown in to boot.

So I recently pulled the trigger on a 2008 Z4 3.0si Coupe and expect to have it in two weeks. While researching the car I curiously found out that the E85/E86 non-M chassis has electric steering. Not being a fan of the current F30 electric steering, I went searching on RealOEM to see the parts make up for the E86 steering gear. There is not much information on RealOEM. One schematic I saw looks like the electric drive for the steering system resides in the dash and applies assist to the steering column near the steering wheel and not at the rack like most EPS systems do. I searched this Forum too for "Electric Steering" and didn't find much info either.

The car I'm getting has the sport package. I've not yet driven the E86, how does the steering feel? Comparable to other hydraulic BMWs? How has the reliability of the E86 EPS been doing?

Any info is greatly appreciated. Thanks.

[3002 tii]

No objective data here but here's my thoughts. I've owned my 3.0si for about 7 years and the EPS has held up fine. No real maintenance/replacement needed thus far.

I just picked up a 135i last year and I was surprised how heavy the hydraulic steering is in that car. My other daily at the time was an Infiniti and it felt marginaly heavier than the Z. But even just parking the 135i on a daily basis was an adjustment because I couldn't effortless reverse/maneuver with 1 hand like I did on the Z.

I don't think all electric & hydraulic steering systems are the same though. I recently had a F30 328i as a loaner and that steering felt noticeably lighter than my Z. I've also driven a Z4 M coupe and my 135i steering feels noticeably heavier than the M coupe.

To sum up, it doesn't feel nearly as light as the new generation of BMW's. For daily driving I don't mind it and in certain ways it's a benefit. For performance driving I much prefer hydraulic steering since it's easier to make quick adjustments/corrections.

[Efthreeoh]

Originally Posted by 3002 tii

No objective data here but here's my thoughts. I've owned my 3.0si for about 7 years and the EPS has held up fine. No real maintenance/replacement needed thus far.

I just picked up a 135i last year and I was surprised how heavy the hydraulic steering is in that car. My other daily at the time was an Infiniti and it felt marginaly heavier than the Z. But even just parking the 135i on a daily basis was an adjustment because I couldn't effortless reverse/maneuver with 1 hand like I did on the Z.

I don't think all electric & hydraulic steering systems are the same though. I recently had a F30 328i as a loaner and that steering felt noticeably lighter than my Z. I've also driven a Z4 M coupe and my 135i steering feels noticeably heavier than the M coupe.

To sum up, it doesn't feel nearly as light as the new generation of BMW's. For daily driving I don't mind it and in certain ways it's a benefit. For performance driving I much prefer hydraulic steering since it's easier to make quick adjustments/corrections.

Thanks for the info and review. My concern was the E85/86 seems to be BMWs early foray into EPS and I was concerned with the then-new implementation of it. I'm looking to take the Z4 to 200,000 miles, so part longevity is a priority. The best steering BMW I ever drove was the E21 back in 1977, but that car was manual in everyway. Love your car BTW; looks great.

[The HACK]

The E85/86 Z4 has the first generation electronic power steering boost and feels dramatically different from even just the 2nd generation electronic power steering boost in the E9x. I had a Z4 3.0i and an E92 328i, and the E92 328i's EPS feels much different...Heavier, but ARTIFICIALLY heavier.

The big difference was the electronic boost on the Z4 isn't as linear, and at lower speeds seems over-boosted, while the E92 feels more natural, but the boost levels were "artificial" compared to say, a true hydraulic steering like my MZ4 Coupe.

Then you throw in the "active" steering that was on our E60 545i...Now that thing was trip. But once you get used to it it's actually really cool.

At the end of the day though...NOTHING BMW makes now beats the hydraulic rack on the MZ4 IMO.

p.s.: The 135i has hydraulic assisted steering? I thought pretty much everything BMW made after 2006 (except the MZ4 Coupe) had electric power assisted steering.

[3002 tii]

Originally Posted by The HACK

The E85/86 Z4 has the first generation electronic power steering boost and feels dramatically different from even just the 2nd generation electronic power steering boost in the E9x. I had a Z4 3.0i and an E92 328i, and the E92 328i's EPS feels much different...Heavier, but ARTIFICIALLY heavier.

The big difference was the electronic boost on the Z4 isn't as linear, and at lower speeds seems over-boosted, while the E92 feels more natural, but the boost levels were "artificial" compared to say, a true hydraulic steering like my MZ4 Coupe.

Then you throw in the "active" steering that was on our E60 545i...Now that thing was trip. But once you get used to it it's actually really cool.

At the end of the day though...NOTHING BMW makes now beats the hydraulic rack on the MZ4 IMO.

p.s.: The 135i has hydraulic assisted steering? I thought pretty much everything BMW made after 2006 (except the MZ4 Coupe) had electric power assisted steering.

I'm pretty sure the E90 had hydraulic steering as well. I remember the same year I picked up my 07 3.0si, I also test drove an e90 330i. The first thing I noticed between the 2 was the major difference in steering feel. Only the Euro models oddly enough (1 and 3 series from the E generation) had electric steering?

Realoem pull for my VIN:
http://www.realoem.com/bmw/showparts...09&hg=32&fg=10

PS: I'm assuming we're not even talking Active Steering

[Efthreeoh]

Originally Posted by The HACK

The E85/86 Z4 has the first generation electronic power steering boost and feels dramatically different from even just the 2nd generation electronic power steering boost in the E9x. I had a Z4 3.0i and an E92 328i, and the E92 328i's EPS feels much different...Heavier, but ARTIFICIALLY heavier.

The big difference was the electronic boost on the Z4 isn't as linear, and at lower speeds seems over-boosted, while the E92 feels more natural, but the boost levels were "artificial" compared to say, a true hydraulic steering like my MZ4 Coupe.

Then you throw in the "active" steering that was on our E60 545i...Now that thing was trip. But once you get used to it it's actually really cool.

At the end of the day though...NOTHING BMW makes now beats the hydraulic rack on the MZ4 IMO.

p.s.: The 135i has hydraulic assisted steering? I thought pretty much everything BMW made after 2006 (except the MZ4 Coupe) had electric power assisted steering.

The E9X has hydraulic power steering. It was available with Active Steering, which changed the ratio dependent upon speed.

[dc_wright]

Originally Posted by The HACK

The E85/86 Z4 has the first generation electronic power steering boost and feels dramatically different from even just the 2nd generation electronic power steering boost in the E9x. I had a Z4 3.0i and an E92 328i, and the E92 328i's EPS feels much different...Heavier, but ARTIFICIALLY heavier.

The big difference was the electronic boost on the Z4 isn't as linear, and at lower speeds seems over-boosted, while the E92 feels more natural, but the boost levels were "artificial" compared to say, a true hydraulic steering like my MZ4 Coupe.

Then you throw in the "active" steering that was on our E60 545i...Now that thing was trip. But once you get used to it it's actually really cool.

At the end of the day though...NOTHING BMW makes now beats the hydraulic rack on the MZ4 IMO.

p.s.: The 135i has hydraulic assisted steering? I thought pretty much everything BMW made after 2006 (except the MZ4 Coupe) had electric power assisted steering.

Nope! Our '11 E88 has active steering which is traditional hydraulic with on demand variable boost.