Putting The Diablosport SRT Suspension Controller To Work

05/18/2021
10 min read

Putting The Diablosport SRT Suspension Controller To Work

05/18/2021
10 min read

OEM suspension tuning has always been an exercise in compromises. Automakers are tasked with establishing a balance between ride quality and capability based largely on the application and the intended buyer. Back in the days before adaptive suspension systems were commonplace, this was a particularly tricky proposition for enthusiast vehicles – models which must deliver performance but also be easy to live with in the real world, where surfaces vary in quality and an overly-stiff ride can result in a bad experience for the driver.


Adaptive dampers like the three-mode Bilsteins that Dodge installs on SRT, Hellcat, and Scat Pack Widebody Challengers and Chargers have improved this situation dramatically, as their damping adjustability allows engineers to use a softer spring rate to deliver better ride quality in every day driving and then stiffen those dampers during sporty driving situations to corral body roll in the corners and nose dive under hard braking. (Or, as with the SRT Demon’s shock tuning, soften the rear dampers to improve weight transfer for better launches.)


As a result, those tuning compromises are significantly reduced in vehicles equipped with adjustable dampers. But as Diablosport’s lead calibration engineer Brian McMahan points out, they aren’t entirely eliminated.


“The dampers are designed for it, so it’s hard to say why the factory is not using the available valving in these dampers to a greater extent than they are. The factory just has such an immense amount of considerations to make from a multitude of different angles. I think it may just come down to trying to balance out the needs of the many, rather than the needs of the few.”


And that’s where Diablosport comes in. The first offering of its kind for the company, Diablosport’s new suspension controller is the result of a collaboration with DSC Sport, a company that has developed similar units for sports cars like the Corvette, Porsche 911, and Dodge Viper for drivers who’re looking to get the most out of their adaptive performance suspension systems both on-track and off.


SRT Suspension Controller Hellcat And Friends

When comes to chasing down Lamborghini Huracán Evos and Porsche Cayman GT4s in our Challenger, we’ll take all of the handling gains we can get.


“The factory suspension controller tends to look at the valving in kind of a binary way,” McMahan explains. “It’s almost like flipping a switch – instead of getting linear response from the dampers. They work in very specific, defined ranges where they’re either blocking the fluid or letting it pass. We worked extensively with Michael Levitas, who is DSC Sport’s chief suspension engineer and also a multi-time IMSA GT3 Cup champion. Michael is a shock dyno guru and developed most of the calibration that we’re using here in terms of the G-meter and shock-absorption-sensing-versus-acceleration parameters.”


The upshot is that Diablosport and DSC’s approach to suspension calibration blends the shock tuning strategies across a wider range of the damper’s capabilities rather than working within a very strictly-defined range of suspension mode settings, as the factory unit does. “It also takes advantage of the shock absorber’s total performance potential,” McMahan says. “That provides ride quality benefits in everyday driving, reduces understeer in road course handling, and makes the car a lot more predictable during launches. In our Challenger Hellcat Redeye test car we not only gained five hundredths on the 60-foot time, it was also much more consistent.”


And all that sounds pretty good to us, so we decided to give Diablosport’s new controller a try in our manually-shifted 2017 Challenger SRT Hellcat. Your author’s performance interests tend to lean more toward road course handling than drag racing, but both are exercised on a fairly regular basis in this machine. Below we’ll walk you through the installation of the controller, provide some driving impressions of our own, and check back in with McMahan to see what’s next for this new tech.

Installation


SRT Suspension Controller compared to stock

The new controller uses a similar form factor to the factory unit and mounts using the existing hardware – no drilling required.


The installation is very straight-forward; we were able to do it with nothing more than a socket wrench with a 10mm socket, push pin puller tool, and about 30 minutes of our time.


The factory suspension controller is mounted inside the trunk on the driver’s side, so to gain access to it we first removed the trunk carpet, which is form-fitted to its location but not mounted. All you really need to do is pull off the Velcro strips that are attached to the seat backs and the carpet will pull free.


From there we disconnected the battery and covered the terminals to prevent any accidental contact. Next, we unscrewed the wingnut-style fastener located just above the driver’s side tail light and removed the two push pins that secure the trunk liner down (save those, you’ll need them to secure the liner again when you’re done).


After that the trunk liner can be pulled back to reveal the factory suspension controller. The controller is mounted to the side of the trunk with three 10mm bolts. Once those bolts have been removed, the controller’s data cables can be disconnected. These cables are secured with two side-locking connectors, so for each you’ll need to slide the connector toward the outside edges of the controller unit while also pulling the connector away from the port to get it to come out. It’s a little fiddly, but you’ll get it.


Once the cables are disconnected, installing the Diablosport controller is simply a matter of reversing the process – plug in the new controller, mount it in the factory location with the factory bolts, secure the trunk liner, re-connect the battery and re-install the trunk carpet.


After buttoning everything back up, we hopped in the car to check our work and make sure everything functioned as normal. We noted that the drive mode settings remain the same, and as McMahan explained during our conversation, installing this controller doesn’t affect the accuracy of the telemetry data in Performance Pages, either.

Behind The Wheel

SRT Performance Pages

After the installation we fired up the drive mode settings menu and the Performance Pages, both of which continue to function just as they did with the factory controller. “This unit sits on the CAN bus like it has always lived there,” McMahan says.



Once behind the wheel, the damping in Street mode is actually a bit softer than stock controller here as a general rule, and that means less head toss and jostling over pockmarked pavement. The dampers do noticeably firm up during larger suspension events, though – like when you’re going over a bridge connector on the freeway – which keeps the car stable and minimizes body motion.


In the corners, it’s the Track setting that impressed us the most. With the factory controller, this setting is normally too stiff for these less-than-perfect surfaces – the car tends to bounce off of mid-corner bumps rather than absorbing them, which reduces grip and makes the car less stable. We normally drive in Sport mode for that reason, but with the Diablosport controller installed, Track mode now feels totally usable – and preferable. The wider dynamic range of the valving strategies is obvious here, as the car is now stable both at the higher speeds where the factory Sport mode setting felt too soft, and also at lower speeds in more technical sections, where the factory Track setting often felt too stiff.


Setting up for corners under hard braking, we noticed that the nose of the car now feels noticeably more pinned down, both in terms of dive and turn-in response, which encourages confidence and provides a better sense of where the tires’ limit of grip is. Diablosport touts faster road course times with this controller, and based on our experience hustling our test car, we see no reason to doubt that claim.


Also of particular note to drag racers is Diablosport’s launch mode damping strategy, which is triggered by pressing the clutch all the way in from a standstill and blipping the loud pedal past 20% throttle on manually-shifted cars like this one. “It’s done by brake pressure on the automatic cars,” McMahan says. “The traditional launch control mode works great as well, but I personally prefer to foot-brake it. Either way you get the advantages of this new damping strategy.”

What's Next?


Diablosport SCM USB Ports

The Diablosport controller has a mini-USB port that will allow users to connect the unit up to a PC or Mac and make changes to various shock parameters when the Diablosport software launches later this year.


As Diablosport continues its rollout of this new SRT and Hellcat suspension controller, McMahan says that more functionality is on the way for these units. Currently the controller’s mini-USB port can be used with DSC Sport’s tuning software to program in custom parameters, but the unit will lock the user out of making changes after three updates, as this feature is unsupported for the time being.


“The Diablosport unit is designed to be a plug-and-play kind of thing – set it and forget it. DSC’s unit is designed more for hardcore road racers who’re changing settings for specific tracks and things like that. We weren’t really intending for users to modify these parameters – you really need to know what you’re doing with this in order to make changes that will help rather than hurt performance. With that said, we’re currently in the midst of developing Diablosport software for these units that will allow users to make changes based on their preferences, but with certain parameters removed that could potentially get someone into trouble.”


McMahan says that we should see that software by late summer, if not sooner.


In the meantime, Diablosport’s new suspension controller for Challengers and Chargers with factory adaptive suspension systems (Hellcat, SRT 392, and Scat Pack Widebody) is ready to elevate your suspension game right now, right out of the box.


SRT Suspension Controller Hellcat

Currently, the Diablosport unit is a set-and-forget system, but Diablosport is in the process of developing software that will allow for more changes, which is expected to be released later in 2021.

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