Quote:
Originally Posted by slicer
I don't agree. The e46 design is significantly different and that bushing design on the e46 makes it more susceptible to NVH. I have had both, ran Delrin on e46 and monoball on e92. I immediately detected more NVH with e46. Immediately detected nothing with the e92 monoball.
Try it out and report back. It's certainly possible that you are more sensitive and will disagree with me. I'm surprised you have a strong opinion considering you have never experimented with the monoball bushing change. I should clarify that changing that one single bushing did not increase NVH. I did detect an increase in NVH when I went to full monoball on the entire front and rear suspension. In other words I agree that rubber bushings are more compliant in general. However, converting that one bushing to monoball did not cause a detectable increase in NVH in my experience.
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Again, the designs may be different but the two bushings share the same single purpose in life - to control 100% of the fore/aft movement of the front wheels. When you hit a bump the wheel gets thrust backwards with immense force - this force is absorbed by the FTAB/FCAB bushing.
To be clear, I'm not saying you're wrong but I think we have different definitions of what NV
H is. Are you really saying that there was "zero" difference over sharp edges, lane dots, etc.? I'm not talking about noise, I'm talking about energy transfer to the cabin over sharp hits.
My angle is simply that any time you replace rubber with a solid bushing where the bushing is in the direct load path of impacts, there will be a comfort tradeoff.
Even changing tires affects NVH. I just replaced worn RE71s with new PS4S' and noticed a dramatic decrease in harshness over sharp edges. Both the tires and the FTABs are 'front line' items - nothing else takes the initial hit. The dampers are secondary and come after the initial spike.
All that said, I am open to the idea that I'm wrong in this case (hoping, actually)... it's just that experience has taught me that there's no free lunch with hard bushings. The problem here is that harshness is very subjective - some people hate it and others call it "more responsive" and the truth is always somewhere in the middle. My only goal in conversations like these is to get at the real truth.