Testing and development began when we ran the car at Willow Springs Raceway prior to the Red Line Time Attack event at Buttonwillow. During that first run several shortcomings of the car reappeared. The first was stock axles that we had improved enough to be reliable previously in Grand Am GS proved immediately unreliable. Secondly, the new Pirelli tires which we had never run before were definitely different than the Hoosiers the car ran before in Grand Am. The car went well in the test but we decided to change tire sizes to the larger Pirellis that are now allowed in Grand Am.
We arrived at Buttonwillow full of confidence but as soon as we started running we knew things were not quite right. All of Saturday was spent chasing the handling. At the end of the day we found a broken shock. With the shock fixed things were better on Sunday but still not quite right and then the engine blew.
After the weekend we identified the following areas that needed to be improved prior to the next event.
- Build new engine / fix oiling problem
- Change seat position for better driver comfort
- Install new JRZ shocks
- Decrease roll
- Increase front compression travel
- Remove all compliance from suspension
- Improve half shafts
We then went to work developing solutions for the known problems.
1. We took a carefull look at the entire oil system. Aviaid built new pumps and we worked with Goodridge to improve the oil plumbing throughout the chassis. Cosworth came on board as a sponsor / technology partner so we built a new 3.8 liter variant of the VQ35 using a Cosworth crank, rods, pistons, bearings, and head gaskets.
2. Moving the seat is fairly straight foward but does require a bit of fabrication as the seat is very solidly mounted.
3. Working with JRZ is easy and they built a custom set of shocks right to our specifications.
4. A thorough study of the suspension revealed a need for stiffer springs. We ordered new Hypercoils front and rear. Additionally the JRZ shocks provide an increase in support from rod pressure. The front anti roll bar diameter was also increased. The bar is driver adjustable over a wide range but we needed more control in the upper end of adjustment.
5. With the new larger tires we had some rubbing issues and not quite enough compression travel. We cut away all the material that rubbed or limited travel and seam welded the newly trimmed areas.
6. Since building the car we knew we needed to remove all rubber from the suspension. We acquired new links for the rear from Megan Racing. We reworked the Megan Racing parts to improve their reliability and we made custom monoball bushing replacements. The front lower control arms were modified to use rod ends to allow additional adjustment to the front suspension.
7. We worked with The Drive Shaft Shop to build custom axles using Lobro 108mm CV joints and 36 spline axles. Nobody else had really addressed the requirements that an endurance car has for drive axles so we had to go down a new path to come up with an acceptable solution.
After spending a few hundred hours in the shop and several days on the dyno we believe we have now completed this phase of development. This weekends testing and Sunday's Red Line Time Attack event will prove our efforts and probably create a new list of things to further develop before the next event.
Check out the Gallery page of the website to view photos of the changes that were made.
Posts
