Ready for 2007?

By the time you read this we will have completed our shakedown of the car and possibly the first race weekend of the 2007 season.  Testing will happen May 4th and 5th at Mosport.  Hopefully it will have gone well because the race weekend is the very next weekend which does not leave alot of time for changes.  We are picking away at the remaining items on the to do list.  Material is ordered to rework the exhaust, a long outstanding item required as a result of trying a new line through one of the back corners at Shannonville while chasing the leader.  The fuel injectors are out for rebuilding, flowing and balancing.  Heating elements have been added to the windshield defogging system.  An attempt to use a simple blower to move air over the windshield slowed fogging in wet weather but not enough to allow good visibility in wet weather. The rear spring rate and front sway bar have been increased slightly.  A front splitter has also been added to try improve front traction in some of the faster corners.

This year we have added a wide band oxygen sensor and a 5 channel datalogger.  Initially we will be using it to monitor and adjust engine performance.  Rpm, manifold pressure, injector useage, knock indication, exhaust O2 and linear acceleration parameters will be measured. With these we want to optimize injector size, fuel pressure, fuel octane, fuel and ignition mapping while ensuring we do not encounter knock.  Currently we are running the fuel system that came with the car.  The only modifications over the OEM system is increased injector size and modified ignition map.  We don't have a lot of information how well the combination works together and have been very conservative picking fuel octane levels to compensate for this.  Higher octane is only beneficial if it is being used to allow increased compression or more advanced ignition timing.  Increasing Octane in itself does not increase performance.  It can actually reduce performance.  Octane is effectively a measure of the gasolines resistance to combust.  The higher the octane rating the more resistive the fuel is to combustion.  The octane rating of a fuel should only be high enough, with a small margin, to prevent knock. Any more than this you are wasting your money and slowing combustion. We are currently running 102 Octane by mixing 94 and 110 Octane fuel.  We have found this to be the most economical way to run intermediate octanes.  Once we have completed this driver performance will be the next target.

For 2007 we are trying Hoosiers.  It is a constant battle trying to find improved traction in suitable tire sizes.  We had previously been using Toyo RA 1s but the sizing staggers what should be ideal for the 968. Picking the width above ideal made it difficult to get the tires up to operating temperature on days that track temperature was under 28 C.  Tires narrower then ideal meant that they would start to overheat on hotter days towards the end of a 20 minute session.  On the plus side the cost of the Toyos was more reasonable and they wore well.  The Toyos delivered good grip right to the point of cording if kept in their best operating temperature range.  Hoosiers improved traction should contribute to lower lap times but it remains to be seen if it is enough to offset the higher cost and wear rates.  They are offered in widths that should suit our car but the aspect ratio is less that desirable.  There will be a significant diameter difference between front and rear. The ride height of the car will be set up specifically for these tires.  Using other tires will affect ride height. We use Yokaham A048 for our rain tires as they have reasonable wet traction and impressive dry traction if you are very careful not to overheat them.

There are a few other odds and ends on our list to complete before racing starts including some improvements to the trailer.  The rear ramp needs to be extended to reduce the angle to clear the new splitter.  We have also added a workbench and shelves to improve storage.  Eventually a 120 and 12 V electrical system will be installed. One of the additions we are most excited about is the addition of a video camera to the car.  This will be both entertaining and helpfull.  We will use the footage to help analyze performance and consistancy on the track.  The speed and line can be monitored on the video to assess each corner based on visual ques and time between corner markers.

I have included a schedule for the CASC Ontario GT Challenge Cup.  There are several St. LAC members actively participating in CASC racing either in the regional sprints, G70 or vintage.  Come out and see them in action, get involved.