E89 Steering and brake pedal feel

[Vetracr]

The 2010 E89 N52 Sdrive 3.0i 6 speed that I currently own is my first BMW. The suspension has been upgraded to beyond current M3 specs. and the car handles great on the track, very neutral and predictable. I've always tracked Corvettes so the comparison is natural. I have camber plates, run 2+ degrees of negative camber and run 235/18 200 tread wear Falken Azeni tires. I almost forgot to mention all the rubber bushings have been replaced with monoball bearings so there is no suspension deflection. On my Corvettes this set up would produce instant response to steering wheel input. The BMW responds but is much slower to react to inputs. I think its the electric steering rack. It may reduce weight but it kills the road feel BMW was famous for. I'm underwhelmed with the way the car feels. Does anyone know if the E90 M3 rack is faster and has better feel? Also will it fit on the E89?

Another peeve I have is the brake pedal travel. My DD is a Honda Accord. The BMW pedal has to travel twice as far as the Honda's before the brakes start to grab. I power bleed the brakes on the BMW so there is no air in the lines and there is no fade at the track. Its just very disconcerting to have a brake pedal have to travel so far before it starts to work. With the engine off the brake pedal is rock solid. As soon as the engine is turned on and the power brake assist comes into play the pedal travel is extended. Has anyone tried to address this problem with a smaller or different brake booster?

 

[NoQuarter]

Sport mode steering "should" be able to be modified via ncsexpert but I think this is one of the elusive settings. I don't recall seeing it done anywhere and I took a brief look at it once and wasn't able to connect to the steering module.

 

[Vetracr]

Sport mode steering "should" be able to be modified via ncsexpert but I think this is one of the elusive settings. I don't recall seeing it done anywhere and I took a brief look at it once and wasn't able to connect to the steering module.

While at the track I disable the DTC. With the BMW nannie controls on the car is undrivable. The DSC would have me understeer off course in tight corners. Been there, tried that. With DTC off the steering is in comfort mode. You can't be in sport steering mode without also having DSC active.

 

[fmorelli]

First off no E9x has EPS. And of course most BMW guys don't know that the E89 Z4 came with it. Another oddity of the Z4. I've asked around a few times about the programmability of it, but no one has cracked that nut - I suspect because ... Z4.

I'm actually pretty pleased with my steering response. My suspension has all spherical bearings/ball joints/Ohlins/Vorshlag plates. Only rubber is the E46 M3 RTABs with limiters. Rear subframe mounts are stock still. I've owned a ton of BMWs over the years, and I can't say I'm disappointed with my Z4's steering response. We are doing a bunch of setup work this Wed (ride height, corner weighting, alignment) - I'll share numbers with you. Maybe we can compare notes ...

@NoQuarter any thoughts on programming the rack control?

Filippo

 

[Asbjorn]

While at the track I disable the DTC. With the BMW nannie controls on the car is undrivable. The DSC would have me understeer off course in tight corners. Been there, tried that. With DTC off the steering is in comfort mode. You can't be in sport steering mode without also having DSC active.

This is incorrect. When dsc is fully off (long press) the steering is the same as sport+. In traction mode the feel is similar to sport I believe, but I never use those modes.

You can feel it easily by zig zagging and turning dsc on and off while doing so.

 

[Vetracr]

This is incorrect. When dsc is fully off (long press) the steering is the same as sport+. In traction mode the feel is similar to sport I believe, but I never use those modes.

You can feel it easily by zig zagging and turning dsc on and off while doing so.

I don't know about your car but I can feel the difference immediately when I switch to sport mode. The steering effort increases. With DTC off its back to less effort steering. I also have a chart I read indicating this is the case as designed by BMW.

 

[Asbjorn]

I don't know about your car but I can feel the difference immediately when I switch to sport mode. The steering effort increases. With DTC off its back to less effort steering. I also have a chart I read indicating this is the case as designed by BMW.

I know the chart. It was made by bmw, and it is simply wrong. At least for 35i eur. Try it next time and let me know.

 

[Vetracr]

I know the chart. It was made by bmw, and it is simply wrong. At least for 35i eur. Try it next time and let me know.

It wouldn't surprise me if Euro versions are different from American versions. American drivers are used to cars with on center dead spot while driving straight. European drivers are much more aware especially in Germany where you have autobahns.

 

[Asbjorn]

It wouldn't surprise me if Euro versions are different from American versions. American drivers are used to cars with on center dead spot while driving straight. European drivers are much more aware especially in Germany where you have autobahns.

Could be haha. Personally I didn't realize this at first, but it slowly became evident as I used dsc off more and more for drifting.

But getting back to the slow response problem. Sway bars and stiffer dampers/coils may help. But in general you also need to remember you are basically sitting on the rear wheels, so you will never really get to feel what the front end is doing. On the positive side drifting can be felt very very nicely hahaha.

 

[fmorelli]

Actually this would not surprise me - different programming for different markets.

There are a number of benefits to electronic steering. One should be the ability for us to programming the steering behavior - but I've not found anyone that has cracked that nut. Less parts, no load on the engine, better space packaging, the ability to run non-linear profiles, etc...

Filippo