In our case here, we have 0.625” of packers/shims on top of the bump spring, and the shock deflection is 3.45”, meaning it has compressed 3.45” from full length. For a quick refresher, the Packer value is how tall the shim stack is on top of the bump spring Shock Deflection is how much the shock has traveled from full length. We’ll start with these values highlighted in the above picture: Packer and Shock Deflection. This can be tedious, but it is invaluable, in my opinion. This consistency means it can be measured and traced to a fairly reliable amount, but the drawback is that it requires a bit of work and patience to get it working properly. Since the bump spring is mounted on the shock shaft and the height of the entire spring/packer stack is constant while on track, this means it will engage the bump spring at a specific deflection every single time.
I have exactly zero experience with Atlas, so if you have experience with it and know how to convert this method for use with Atlas, please let me know and I’ll add it into this article!įirst we need to know when the shock is going to contact the bump spring. I use MoTeC i2 Pro v1.1 and a custom Maths channel that isn’t very hard to configure at all, just follow the steps I have outlined here. This is the method I’ve used for a few years to determine the bump spring engagement point. Now, with two 500 lb/in springs being the minimum, most of your gains will be from tuning the bump spring rates and packer amounts, but the hurdle for this is determining when you have contacted the bump spring and when you have not.
The 420 lb/in had enough travel to hit the splitter prior to binding, but the 380 lb/in would bind just prior to the splitter contacting the track, but after engaging the bump spring. In my Class B car prior to the update, I ran a 420 lb/in left-front spring and a 380 lb/in right-front spring.
For many setups that utilized springs in the 300-400 lb/in range on the front, the bump spring was never engaged at all, leaving the drivers and setup builders to believe they were using the bump springs when, in fact, they were not ever touching them at all. While the abandonment of coil-binding in the Gen 6 Class A series was largely a non-issue since coil-binding seemed to be limited to a small number of cars and teams, this has produced a big problem with the Class B series due to the low-rate springs of the past (less than 430 lb/in) all having the ability to bind before ever engaging either front bump spring.
This update is just on the heels of the Gen 6 update which did the same thing to eliminate both the coil-binding and pre-binding setups that were used, meaning both of the NASCAR cars are limited to bump spring front end setups, with the NASCAR Truck being the sole remnant of an abandoned setup era. Eliminating all front springs below 500 lb/in took us away from binding by simply eliminating the springs that could bind under normal conditions, placing everyone firmly into the bump spring setup world and leveling the playing field across the series. Last week’s build release put a stop to the coil-binding trend in the Class B series that had become widespread across the front-running cars. World of Outlaws ButtKicker Late Model SeriesĬommodore’s Garage #25 – Bumpstop Contact in Telemetry.World of Outlaws CARQUEST Auto Parts Sprint Car Series.Force Dynamics Dallara iRacing Grand Prix Championship.Keyboard Shortcuts: Replay / Camera Controls.