Project S2000 – Part 14 – Phase 2, More Grip



Here is the BlackTrax modified pan next to the pan that came off my car.  In taking the bolts out of the stock pan, I placed them in the corresponding location on the new pan as some of the bolts are different lengths.  There are two dowel pins in opposite corners of the pan that need to be transferred from the old pan to the new one (or you can buy new pins I suppose).  One of the dowel pins was a little stuck, so I used a small butane torch to get it loose.   One other little tip, there’s a rubber bumper thing sitting between the front of the pan and the subframe.  It comes off easily and gives you easy straight access to the two bolts sitting behind it.

With the extra grip NT01 tires installed along with the baffled BlackTrax oil pan to prevent oil starvation from the extra grip, it was time to see what these tires could do.  But before doing so, I wanted to tweak the rear alignment a bit.  After my last alignment and following track day, the car was biased towards understeer.  At the time, I did a spring rate change and I wasn’t sure how much that would change the handling bias.  So, I went with the typical 3/16″ toe-in used by many track driven S2000s.  The result was a slight push at the limit which made the car very easy to drive with little fear of spinning off the track backwards.  However, now that I’m more comfortable with the car, I decided to shift the balance back towards neutral.  Plus, it would help with my tire wear situation.

To measure the toe, I had some old desk shelves and two tape measures.  As I was by myself, I used some duct tape to tape the ends of the tape measures to one board and used my toolkit to keep weight on the board against the tire.  


I took a base measurement before making any adjustments and it was indeed at 3/16″; it’s always a good idea to take a base measurement on whatever you’re checking, like tire pressure or engine power.  Knowing the board has a width of approximately 17″ (it was basically the same as the diameter of the wheel) and using a little trig, each wheel has a toe-in of ~0.316 degrees, or a total of 0.632 degrees between the two.


To adjust the rear toe, I turned the front eccentric bolt on the toe arm/tie rod.  The eccentric bolt has marks on it to help determine how far you have adjusted it.  It took me three tries to get the rear alignment to 1/16″ toe-in (0.105 degrees each, 0.210 total).  After each adjustment, I bounced up and down on the back of the car to help the suspension settle to ensure an accurate measurement.

I had the NT01s mounted at America’s Tire Co located at 2026 Torrance Blvd in Torrance, CA.  This is the only location I go to for getting wheels and tires mounted as they actually take the time to do things properly; they are careful with your wheels, put the tire pressures to your specs, and torque every lug nut properly.  I know the guys at Hondata and DG-Spec Scion Racing use them too.  I had the tires set to 32psi and off I went.  My initial impressions were unexpected.

The steering effort feels significantly lighter compared to the RE-11s.  Also, while the tire widths are virtually the same, the NT01 does have a shorter sidewall.  However, despite the shorter sidewall, the tire actually rides softer than the RE-11 which rode softer than the stock RE050s.  I’m guessing the difference in tire construction which allows for the softer ride also reduced the steering effort.  So what compromises were introduced by going to the NT01?  Just looking at the tread pattern, you can probably guess the tire is not designed to handle much rain.  Huge tread blocks are great for traction, but bad for evacuating standing water.  The second compromise is that these tires hum a bit while driving, so there’s added noise.  I’m guessing the big tread blocks generate the noise.  Well, I suppose a third compromise is tire life, but I didn’t get these tires for daily driving duties.  I got them for a lot of grip.  It was time for a test.

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