Horsepower needs to be harnessed to maximize the impact it will make on your time slips, and a great way to make that happen is through your suspension. Project Red Dragon is about to make double the horsepower it once did, so we’re ditching the 21-year-old OEM shocks for some new VariShocks from Chris Alston’s Chassisworks.
Weight transfer is the key to making any car work at the track — if you’re building a street/strip car like we are you have to make some compromises that an all-out race car doesn’t. To get the most out of Project Red Dragon’s suspension, we’re using a front coil-over conversion from Chis Alston’s that includes a set of double-adjustable shocks; we’re also installing double-adjustable shocks in the rear. Today we’re going to cover the reasons you would want to convert to a coil-over front suspension, why double-adjustable shocks are the way to go, and the basics of tuning a street/strip car’s suspension.
Coil-Over Conversion And Springs
Project Red Dragon came stock from GM with an SLA, or Short Long Arm style front suspension, with a very basic coil-over type of shock setup. There are a lot of cars that don’t come with a coil-over style front suspension, or might have the non-adjustable style that the fourth-gen F-body comes with from the factory.
The VariShock coil-over conversion from Chis Alston’s is an attractive upgrade for many different reasons and that’s why we decided to use it for Project Red Dragon. This kit gives you the ability to use better shocks and springs versus the OEM units, and you can also use single- or double-adjustable shocks with the kit. That means you have more shock travel, you can adjust the front ride height, and can make spring preload adjustments on the car. All of these are important when you’re trying to fine-tune your suspension at the track.
A coil-over conversion for the fourth-gen F-body has another huge advantage: you have a larger library of spring rates to choose from. The front springs are there to support the weight of the car; the spring rate dictates the amount of suspension compression or extension you’ll see. If the spring is stiff, it won’t allow the shock to compress while you’re at static ride height, and in turn you won’t have full extension before the shock will top out. If your spring is too soft, it will allow the shock to compress too much and it will remain outside the optimal level of shock travel.
Lino Chestang from Chris Alston’s Chassisworks explains how spring rates translate for a street/strip car.
“When tuning more toward strip use, the car should run the lightest front and rear spring rates possible, without letting the shocks bottom out when making a pass. Lighter springs allow the car to easily transfer weight and settle faster down track.”
When your car launches there’s a lot going on; chief among those is weight transfer to the rear wheels. Shocks facilitate this action and they also help to control the movement — they’re what ensures your car will stick to the track and transfer power. That said, non-adjustable shocks will only do so much for you; the valve adjustments that adjustable shocks provide allow you to tune the shocks to work with your vehicle.
As we’ve already alluded to, there are two main adjustable shock options on the market for street/strip applications: the single-adjustable and the double-adjustable.
“Single-adjustable shocks generally allow adjustment of only one characteristic…normally shock rebound. This leaves you with the ‘best guess’ from the shock manufacturer at the compression valving. To remove this limitation, VariShock single-adjustables controls the overall stiffness of the shock — both compression and rebound. We find this much more useful as it results in a noticeable change in performance and makes our single-adjustable shocks very effective on cars serving multiple performance roles as street-driver, dragstrip, autocross, or track day machine,” Chestang explains.
The most common mistake is adjusting the shocks to maximize performance at the track and using the same settings on the street, or vice versa. – Lino Chestang, Chris Alston’s Chassisworks
Double-adjustable shocks have a pair of knobs on the shock body, hence the name. One of the knobs will adjust the compression stroke of the shock, while the other is in charge of adjusting the rebound of the shock. Unlike the single-adjustable shock, these adjustments are independent of each other, so it provides you with more tuning options.
You’ll see more of a benefit from using double-adjustable shocks under the rear of your car, as they will provide you with a much larger window for fine-tuning how well the car will deal with varying track conditions. For a street/strip application, double-adjustable shocks will allow a vehicle to have a smoother ride when you’re not at the track, but then let you get the weight transfer dialed-in for racing.
So, is the single-adjustable or double-adjustable shock better for a street/strip car? According to Chestang, it depends on how you plan on using your vehicle.
“If it’s mostly street, you could run either one. If you’re kind of on the fence over which to choose, or if performance leans more towards the strip, definitely go with the double-adjustables. The cost difference isn’t that much and you’ll be glad to have the adding tuning options.”
Tuning For Street/Strip Action
So, you’ve just bolted some adjustable shocks to your car and you’re ready to hit the track. Before you start turning knobs, the first thing you’ll need to do is ensure the car is tracking straight so it will launch straight. After that, you will want to start making your adjustments with the front shocks and then move to the rear. VariShock has very detailed guides on its website to help you, but for this article, we’re just going to hit the high-level basics to get you going.
When you’re starting the process of tuning the front shocks, the goal is to get the front end as free as possible so it will transfer weight to the rear tires.
“For the front, you want to lighten up the rebound valving to let the front of the car rise. If it rises too fast and yanks the tires off the ground, stiffen up the rebound to keep the movements controlled. Smoothing out the weight transfer will help with managing available traction. Compression stiffness is used to control the front end as it settles. Again, we’re looking for smooth and controlled movements. Too soft and it may bounce off the bump stop; too stiff and it may bounce off the tire. The car should settle in one motion without extra oscillations,” Chestang explains.
Now, you want to make these adjustments in small increments and only one at a time. If you’re making too many changes you won’t know what’s actually working. As well, the size of the adjustments should be small so you can have an accurate idea of how they’re performing. While you’re making all of these changes it’s very important to take notes: record the track conditions, weather conditions, how the car felt, and how it performed. This is critical to track and evaluate how the changes are affecting performance so you know if you’re going in the right direction.
After the front end has been sorted out it’s time to move to the rear of the vehicle. This is where tracking your progress will really come in handy so you can analyze how the changes are working.
“At the rear of the car there are other variables, such as suspension geometry and tire pressure, that will affect getting the shocks dialed in. In short, we’re looking to slow the suspension compression as it takes on transferred weight by stiffening the shock. You’ll want to run the shock as stiff as the tires can handle. If you start to lose traction and spin the tires, soften the shocks a couple of clicks and see if that helps. Rebound setting can be a little on the light side initially but can be stiffened to help with stability downtrack, if needed,” Chestang explains.
Jumping into the world of adjustable shocks and suspension adjustments isn’t something you should do without a plan. There are numerous mistakes you can make on the tuning side of things that will lead to less-than-desirable results on the track and on the street.
“The most common mistake is adjusting the shocks to maximize performance at the track and using the same settings on the street, or vice versa. Its best for both performance and safety to develop settings specific for each use. Another mistake that people make is not tracking what changes they’ve made or trying to change too many things at once. Both of those will hamper your performance at the track,” Chestang states.
Now that we’ve got some good shocks under Project Red Dragon we’ll be able to optimize the suspension so we can apply every bit of the turbo LS power we’re going to have on tap. Make sure you follow Project Red Dragon right here to track our progress, both past and present, as we transition to boosted power in 2021.