Adrianvh wrote:I picked up a pair of RX8 front and rear sway bars for $50 from RX8club.com.au. They are huge compared to the factory, especially the rear.
Direct bolt in, all you will need are $25 worth of urethane chassis mount bushes.
Cheap, yes, but I hope they were out of an automatic RX-8
The auto RX-8 front bar is smaller than the one from the manual and more suited to the NC.
Bar diameter sizes are:
NC standard: Front 21.1mm, Rear 12.0mm
Whiteline: Front 24mm, Rear 16mm
Eibach/Mazdaspeed: Front 25mm, Rear 16mm
RX-8: Front 26.8mm for the manual or 25.4mm for the auto, Rear 15.9mm
Both RX-8 front bars will give you more understeer that the other bars, with the manual RX-8 bar the worst.
As per the comments to Jim MX5 above, if all you want to do is reduce body roll and aren't particularly worried about understeer, then a non adjustable bar might suit you but if you want to retain the handling characteristics of the NC, especially cornering at 8/10ths and up, then adjustable sways are a must.
The Whiteline bars have two positions for the front bar and three for the rear. I’m running the soft position on the front and the hardest position on the rear for the track and the middle position for the road. At the track I tried the full stiff position on the front once and found the understeer to excessive for good times.
The NC, like all MX-5s out of the factory is slightly biased towards understeer. It’s safer that way for Joe Average. What we try to do with aftermarket bars is to get as near to neutral as possible. That makes it easier to control the car with the throttle when you're on the limit.
On the softest setting front and rear the Whiteline bars are 71% / 215% stiffer than standard. I haven’t done the maths on the middle and firm holes for the rear.
The RX-8 auto front / rear bars are 112% / 208% and the manual 158% / 208%, so you can easily see how the NC becomes more biased to understeer as the bar size goes up.