The stock upper shock holes...
The stock upper shock holes in the frame were positioned well outside of the center of the spring. This put the shocks into the spacer that was mounted on top of the spring and caused significant damage to the shock body on both sides of the car. We had to relocate the hole to be more inline with the spring center. We welded a washer over this new hole to permanently position the shock away from the spacer and spring.
Because the front shocks were hitting the spring height adjuster, we needed to make a correction. We noticed that the stock hole where the top of the shock was anchored was positioned at the factory well towards the outside edge of the inside of the spring on both sides of the car. With stock shocks and springs, this would be okay for clearance, but with our setup and equipment it was not.
The fix was to create a new "stock" hole farther inward and closer to the center of the spring. We reinforced this new hole by welding a washer on top of the frame. This provided a good bit of spacing between the spring spacer and the shock body.
To make sure we were good with the rules against using front weight jackers, we welded the height adjuster so it wouldn't turn. This made it a spacer rather than a weight jacking device. We also installed a new set of shocks provided by the team that were more inline with what should be used on this type of car.
I reviewed the existing tire sizes versus the tire pressures they had been running. The sizes were LF = 83.75, RF = 83.75, LR = 84.5 and RR = 85.0. This only allowed a 1/2-inch of stagger in the rear, not nearly enough for this track. This would also facilitate a tight car.
Once we had made all of our...
Once we had made all of our changes, we weighed the car, set the cross weight and lowered the rear ride height. The car previously had 53 percent cross, which was too much. We changed that to 48.5 percent to go along with the 48.2 percent rear weight. This ended up being about 75 pounds of LR, more acceptable than the original 216 pounds of LR.
The tire pressures were: LF = 17psi, RF = 23psi, LR = 15psi and RR = 14psi. The RF was high and the RR was low on pressures. The fix was to try to change the tires around while repressuring the tires so that we could get front and rear stagger.
I traded the RF tire and the LR tires. This put a larger tire at the RF and a smaller tire on the LR. We re-pressured the tires to: LF = 18psi, LR = 16psi, RF = 22psi and RR = 16psi. With those pressures, we now had a front stagger of 1.00 inch and a rear stagger of 1.50 inches.
When we weighed the car before making any changes, the cross weight was at 53 percent. After installing the new springs, changing the front cambers, moving tires around and adjusting tire pressures, we re-set the cross weight at 48.5 percent, or about 75 pounds of left rear weight.
With only 48.2 percent rear weight, the car did not need the 53 percent cross which represented 216 pounds of LR weight. This was yet another reason why this car was way too tight. It was cross weight tight and was driving off the LR tire under acceleration.
Note the placement of lead....
Note the placement of lead. I don't like lead placed this far behind the rear end. It causes a cantilever effect. It might make a tight car more neutral, but there are other ways to make a car turn better, as we are demonstrating. We moved this lead to the front of the rear axle and high in the car.
Another thing I noticed and corrected was the placement of lead in the rear of the car. The car builder had placed a considerable amount of lead well behind the rear end on the rear hoop that protects the fuel cell. Although fairly common, this tends to act with a cantilever effect and increases the polar moment. Polar moment is defined as a force trying to rotate or swing the rear end to the outside wall during cornering.
Some teams will experience a more neutral car by placing lead behind the rear end, but this is more likely a crutch for a tight car and although it helps the car into and through the turn, it will make the car loose off. It is much better to set up the car correctly and get the front to turn with a balanced spring setup and proper moment center and cambers. That way, you get into and through the turns better and still have more bite off.
It is always a good practice to keep all lead mounted inside the axles. We may decide later on to move it out, but for now we remounted the lead in front of the rear end and high in the car. A higher center of gravity is desirable on dirt cars for dry and slick tracks.
Our lead ended up mounted...
Our lead ended up mounted to a cross bar in front of the fuel cell and high up in the car. This reduces the cantilever effect and promotes roll over which is good for maintaining grip on slick surfaces.
Once we got the springs installed, the tires mounted, the cambers set, the air pressures set and the ride heights and weight distributed like we wanted, we stood back and took a look at the car. It just looked better right away. I've seen lots of hobby stocks, and this one looked like it was ready for the track.
We had to wait until after Speedweeks at VSP was over as the Hobby Stock division races were put on hold. The first chance we got to run the car, Joe noted that this car was now even better than his original Hobby Stock. The difference was that it turned better, which allowed him to maneuver past guys that were hanging it out trying to point the car to get off the corners. And it had much more forward bite than before due to the more straight ahead attitude.
With his smooth and relentless style, this car was just what he wanted. If you prefer to sling the car in sideways, fight to get control and then hope for some semblance of bite off, then you might not want to copy us. Good luck and good racing, now back to the Late Models.