Just ordered my BC coilovers

[240Z-Fan]

On 6/24/2016 at 7:01 PM, madkaw said:

Ride quality is so subjective- but I am always looking for a bit of refinement in my ride. I noticed the OP had solid mounted tension rods(basically). Don't know if that was done at the same time or not, but that transmits a LOT of roughness to the chassis . Add urethane and hard springs and wow. I run urethane with suspension technique springs and KYB Struts. I believe my spring rates are less- though my car is lower than stock considerably. 

This subject has been on my mind lately with respect of how mixing rubber bushings with a firmer suspension would work out. Could a person go fairly rigid on the suspension for handling and not defeat that with rubber bushings? Would the suspension just wear out the rubber twice as fast- or not fast enough to worry about. This is assuming NEW rubber all the way around. 

This is where I really miss the wisdom of John Coffey

 

I believe polyurethane bushings are overrated. They do make sense for a race car in the right locations (not the TC rod). They might make sense in a track car that sees light street use. But they are not inappropriate for a street car if you want to maintain any amount of civility. While they do add stiffness, I don't see that the performance/NVH tradeoff is worth it in anything but a track or race car.

I run open track days in a Miata that I setup specifically for the track. Spring rates are 504/448 lb/in F/R. (363/394 wheel rates) I also run a street Miata with 375/275 lb/in springs (270/242 wheel rates). In both cases I run stock rubber bushings. 

The street car will never go to poly. I love the way it drives and I absolutely do not want the NVH that comes from Poly bushings.

The track car has been running the higher rate suspension for 15,000 miles, with roughly 4500 of those miles on the track. To date, I have not had to replace a single bushing. Would the car handle better with Poly bushings? Probably, but it has been a great car without it and I have no plans to switch anytime soon. (In part because it takes a lot of work to rebush a Miata suspension, and I haven't needed to rebush it, yet)

I am currently working on getting my '73 Z back on the road. The car is nice but way too soft for me. Part of it surely due to the tall sidewalls (225/60/14 Michelin Pilot XGT all season performance tires). So I will go to 15 inch wheels and better tires.  I just ordered the Vogtland springs and will pair them with a NOS set of Bilstein dampers. Spring rates will go from 83/104 to155/175 lb/in. If that isn't enough I might go to a GC coil over setup with stiffer springs. But regardless, the suspension bushings will be replaced with stock rubber, due to the age. 

Al