While building the Sprint Car I kept
noticing that the car wouldn’t set properly from day to day. The
mismatched shocks weren’t technically the correct correct length for the
application and the two rear shocks were some threaded body, no-name
units that were internally limited on the left side and had slotted
pistons coupled with 5,000cst diff oil for shock fluid. The fronts
weren’t much better; the right one was a limited Rustler rear Ultra
shock that was still not the correct length and the left side was a
Bandit front shock that didn’t really have enough travel to match any of
the other three shocks. In the interest of actually having the car
handle it was time to put some quality dampers on the car.
After measuring the lengths of the shocks on the car currently and comparing those measurements with the chart on Pro-Line’s website (https://blog.prolineracing.com/2016/…-download-now/) I settled on a pair of 6308-31 rear SC shocks for the right side of the car and 6308-30 fronts for the left side. I also ordered the tuning springs sets for the front and rear to have some options to set the corner balance of the car as well as a hardware mounting kit just to be safe. The mounting kit wasn’t absolutely required but it was helpful in getting everything 100% dialed.
Out of the box the shocks only require being filled with oil and installed on the car. I filled the shocks with 35wt shock oil all around which seems to be a good match for the included medium rate springs. Straight out of the package the ride height was a little low in the right rear as well as both sides of the front while the left rear was just about perfect. Winding in a little preload on those three corners got the chassis sitting level with no fuss. I did notice that the preload collars are a little stiff at first and take some effort to turn. I would rather see them be a little firmer than spin freely and possibly change the preload setting during a run.
Cycling the shocks through their travel, even without oil, rewards you with the smoothest action with no shaft play or stiction. These shocks are even smoother than the units included with the Pro Fusion SC 4×4, which I previously thought had the smoothest shocks I’d ever used. The included white delrin pistons and shaft guides attribute to the smoothness but it is the attention to detail in the assembly that makes the difference and Pro-Line definitely got it right with these.
My first run with the new shocks was on freshly laid Ozite. My neighbor offered his recently renovated storefront to try the car out; he had never tried RC before and was intrigued by what I had going on when I was setting the trims in the driveway. The store didn’t have its fixtures installed yet and measured around 800 square feet. We set up an oval on the carpet using some shoe boxes and took turns putting around with the car for the first pack. He was having a blast and I was taking note of how the car was turning in and checking for any odd motion in the chassis while accelerating and braking. The car looked composed but at such a low speed that wasn’t too surprising.
After dropping in a freshly charged battery it was time to drop the hammer. The car has a ton of forward traction, carrying the left front from corner exit to corner entry. I may try a slightly firmer right rear spring or a few more millimeters of preload to calm down the amount of tweak that the current setup has. Once the throttle is released on corner entry the car takes a set without any drama and stays planted through the corner with no need to chop the throttle or stab the brakes to put more weight on the nose. There was no chatter from the front tires even when I over-cooked it on corner entry. At no point did the rear become unsettled to the point of causing a spin. The car is easy to drive and easy to drive fast. The run was cut short due to a grenaded transmission but it did show promise that the setup was going to work.
Overall, the Pro-Spec shocks really impressed me with their smoothness and how well they performed on the car. They look great with their anodized blue accents and polished finish. The inclusion of delrin pistons (both installed and optional tuning pistons) as well as delrin shaft guides are a standout feature for SC shocks and the firm feel of the preload collars was a pleasant surprise. I highly recommend these dampers to anyone looking to take their SC truck to the next level of performance.
The whole package:
The rear 6308-31 units:
The 6308-30 front dampers:
The tuning springs and mounting hardware:
The finished installation:
The “rear” length shocks on the right front:
The “rear” length shocks on the right rear:
The “front” length shocks on the left front:
The “front” length shocks on the left rear:
Rear Tuning Springs https://www.prolineracing.com/perfor…rings-rear.asp
Front Tuning Springs https://www.prolineracing.com/perfor…ings-front.asp
Universal Mounting Hardware Kit https://www.prolineracing.com/perfor…rdware-kit.asp