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Solid vs poly rear subframe bushing.


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The performance difference between rubber and solid or poly is like using a condom to running bareback.


45 year old rubber.....

No rubber in my rear! tight and solid.
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I'll take the bait.


No verifiable increase in 'performance'? That's easy to say when you know none of us have data to prove one way or the other, but people who have that data run solid connectors. You know, people like the Nissan factory racing R&D folks, Peter Brock, Bob Sharp, and Troy Ermish who holds lap records in his vintage B sedan 510 on tracks all through the West. Now you could say that "on the street" you will likely never experience any difference other than hearing and feeling more "vibration". That argument totally overlooks the fact that some of us Datsun owners are lucky enough to have license plates on our race cars. We aren't talking about daily drivers or even secondary transportation. For impractical race/performance minded people, our expectation is the antithesis of quiet comfort. Wether you can tolerate it or not, there are tangible performance benefits to direct tactile chassis feedback and minimizing any vagueness that comes from play and or cushioning in the stock chassis. The softness and give of rubber bushings is designed specifically for comfort, not performance. 


For the sake of argument lets say you had a 510 with 330hp SR swap, stupid grippy tires riding on stiff springs and fat sway bars. Even your motor mounts would need to be poly, because if they were rubber the motor would torque rotate and the fuel rail would pumch a hole through the hood. Do you really think you wouldn't see difference in performance between cushy stock rubber bushings, and solid? Maybe you should quantify what you mean by performance, because you are comparing Fuji apples to prunes here. 


I was replying to wiltz in the post above about 620 cab mounts.


Handling performance because solid mounts won't make the car accelerate faster.


People with this 'data' are running race cars not street cars. 'Some' race cars have license plates. Yes one in 500, probably less, so lets stick to non race prepared 510s on the street which is my point about polly bushings and mounts. I realize 'race cars' use poly for the reasons given and they replace them and inspect them regularly. So what about street 510s or others? What exactly will they get for all the negative aspects of solid mounting? Most drivers wouldn't know or feel the difference anyway. Hell they wouldn't know what to look for in the first place. They would accept stiffness, vibration and noise as an improvement.... even though they don't drive, or extremely rarely drive, in conditions where any improvements can be experienced. Monkey see.... monkey do. Like an engine catch can on a street car.

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Got the aluminum bushing installed!  Got a race day tomorrow!  Can't wait to try them out. 




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