Quote:
Originally Posted by FaRKle!
Quote:
Originally Posted by kern417
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Kern's linked my thread for the camber bushings.
For the tension strut/caster bushings I've only mentioned some initial things here and there on the 2-series forums, and am still feeling them out. Here's my initial impressions:
Quote:
Originally Posted by FaRKle!
The camber bushing doesn't significantly improve steering feel, but the caster bushing significantly adds to the feel and responsiveness. You can feel the road more through the wheel and it also feels like you're more connected with the car. The latency between turning the wheel and the car responding also feels reduced. The downside is that NVH is also increased due to the more solid bushing vs the rubber and fluid-filled OE bushing. The noise increase is mostly low frequency, no clunking or ticking noises.
Increasing the negative camber on xDrive cars also increases the caster. When I maxed out my camber with the K-Mac bushings, my caster went to 8.55deg and 7.95deg. at 8.55deg I was slightly rubbing at full steering lock. After I installed the tension strut caster bushings I set both sides to 8deg.
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Since the above post I've taken the vehicle on twisty back roads and some trail/dirt/gravel roads. The NVH on non-paved roads wasn't as bad as I was expecting. I would say the area where NVH has degraded the most are bumps (such as the steel plates they put over the road during construction or expansion joints) at lower speed. At higher speed these bumps aren't much worse than with the OE bushings. The type of noise increase you get is mostly a low pressure boom, which blends into the background better than a higher frequency clunk/thunk type noise.
One thing I noticed the week after my off-roading was I started to get some creaking when braking and accelerating from a stop. This past weekend I put the car up on my quickjack and found that was due to the bolts that hold the tension strut bushing to the subframe weren't properly tightened (100 Nm, 74 ft-lbs). They each had about a quarter turn to go before being fully tightened. I'm not sure whether this was due to the alignment shop not fully tightening them, or the vibration of the harder bushing making them loosen up. I'm going to be hitting the dirt trails again this weekend and will see if the noise returns.
Thus far I'd say if you're prepping your car for HPDEs or just weekend sportiness the tension strut caster bushings can give you what you're looking for, for better steering response, feel, and caster adjustment. If you want your car to be a comfy cruiser, I'd probably skip them due to the added NVH. I'm on the fence whether I'll keep these or not (I might try the powerflex "street" non-adjustable tension strut bushings for more road comfort). |
Any developments since you wrote this back in March? I'm looking for the monoball steering improvement in daily driving (no tracking). Would like to get less of the numb center feel and more steering precision. But don't want to introduce/increase NVH.
'15 335ix, KoniSA's, Eibachs, H&R Sways, strut brace, 245/40-18 MPS4S tires
It's a street performance sleeper car that we also drive on trips so I don't want to lose the comfort that we've put in with some of the suspension choices like KoniSA's and tires.
Any advice is appreciated.