N1 Racing parts on a street driven Civic Si Sedan

Mike of Evasive Motorsports has successfully been using our Mono FLEX coilovers on his street/ track Civic Si Sedan. The car has finished well in the last few events (class win at Super Lap Battle Finals 2009 and class win at Redline TA 2010 Rd.1) and Mike wants to keep it that way. Mike already added a larger diameter sway bar and a revalve but still wanted more vehicle rotation. So Mike and our engineer agreed the next step was to try some parts from our N1 race kit.

The parts arrived last Friday and Mike brought the car in a few days ago for us to install the parts and perform the needed revalve to make it all work.

The N1 kit is used on many cars competing in Japan’s Civic One-Make race series. Normally these cars use spring rates of 20kg front and 26kg rear. Modifications are very limited to keep the racing tight.

We ONLY used a few of the parts from an N1 kit:

N1 pillowball rear spring seat, Special 20kg rears springs, N1 HAS (Height Adjustment System)

The N1 pillowball rear spring seats are NICE (you can see that the top section can pivot). The spring can now better match the travel radius of the lower control arm and allows the use of a straight spring which are readily available in various sizes and rates. Normally a barrel shaped spring is used for more spring stroke but alternate spring rates are not available.

To make this all work we needed to change the stroke and damping force of the rears dampers. Then in order to balance the car front to rear we increased the front spring rate to 16kg, shortened the stroke, and increased the damping force.

The end result is very aggressive spring rates, short suspension travel and race car like handling. When we took the car out for a test drive on local roads and highways the ride was surprisingly smooth. A passenger would never guess that the car has such high spring rates. The car is firm but not bouncy. It absorbs the bumps well and settles quickly for optimal grip.

A few more pics of the Civic Type-Rs TEIN sponsors in Japan. These cars look so good with just livery and being slammed.