brucejoanne

Tom,

I just received my shipments from you on Friday. My coilovers have the gold flat springs sitting on top of the main blue/grey springs just like your 3rd picture. In the next picture of the installed coilovers, the gold flat springs are missing. Would you explain? Thanks. Bruce Matthews in Arizona.

ShatterPoints

They are two different coilovers, count the coils on the blue spring. In the case of the picture with the gold spring that is a "helper" spring and on some applications is used to keep the spring seated against the suspension under full droop.(Droop is how far above the designed/natural ride height the car and suspension can move)

Here is my coilover for comparison, the helper spring I have at the top is black, it's sorta hard to see but it's there:

brucejoanne

ShatterPoints,

You are correct, I didn't think to count the coils on the shock. My understanding is the helper springs are for the street and deal with small rebound. Is the set without the helper springs for the track? Thanks.

Bruce

ShatterPoints

Helper springs are used for a lot of applications, offroading, track, and street. They are used to provide a variable spring rate, or more commonly keep the spring from resting loosely when the wheel is extending away from the chassis. Which can happen if the spring is small enough and the geometry can allow for travel beyond the springs natural height.

Tom@TPC Racing

Hi Bruce. Glad to know your coilovers arrived. ShatterPoints is correct that the item in your question is the helper spring. Helper springs are used on for both street and race cars to take up any "slack" when the suspension is fully extended for situations such as when the car is lifted by floor jack. Helpers springs are typically fully compressed by the weight of the car when the suspension is loaded. The reason why the one photo doesn't have helper spring is because on that particular installation we did at our shop the local customer wanted a very specific ride height with a specific spring rate and we were able to achieve this ride height using a longer spring without any slack on full extension so I made the decision to use a longer main springs and deleted the helper springs. The main springs typically are available in length of one-inch increment. If the targeted ride height is not exactly "to the inch" then there will be slack when the suspension is fully extended. Helper springs are typically less than 200 in-lbs of spring rate which is easily fully compressed by the weight of the car making helpers springs good for taking up the slack between the main spring length increments. Having helper springs gives the installer more flexibility for ride height adjustment(without spring slack or loose fitting spring on full extension).

brucejoanne

Such a great experience being part of Rennlist. So much valuable information and people willing to share their knowledge. Thanks to all. Tom, the Tractive System and Sway Bars are being installed by Parts Score in Scottsdale, AZ tomorrow. Today, Monday is removal of my worn out suspension. I have high expectation and will absolutely review the feel and performance of the change over. I am unsure if my installer calls TPC Racing to get a link for the down load of the new program for the DSC Controller or if something is shipped with the new system? Thanks Tom! Bruce

IMI A

So Tom for fast road use (no track) DDA Tractive or B16 Damptronics in comfort spec? Cars a 997.1 turbo with circa 680bhp. Running DSC box, with lowering springs and OEM shocks. Its fine but at speeds above 140mph can all get very bouncy. Do the Tractive and B16 display this tendency to bounce at high speeds on less than average road surface? Ironically driving around in an air cooled has reminded me how bad the body control on the 997 is with current set up. Also run Cup 2 on 19 inch wheels in 245/325 set up

ShatterPoints

The behavior at speed is spring related more than it is shock related. In general terms springs determine how much weight is transferred and by what bias, shocks control how fast that weight is transferred. With regard to damping / shock forces, you want less damping at higher velocities (think total oscillation, both a low amplitude high frequency and a high amplitude low frequency bump or set of bumps (rumble strip/curbing/twinkies)). In addition to correct damping you want to match the damper with the spring and you need to decide which component you want to control body roll with. There are many ways to do this, Big roll bars, soft springs, stiff dampers or stiffer springs, moderate stiffness dampers, and dealer's choice of roll bar, and any mix in between. Off the top of my head I cannot think of many places you're going to be at or above 140mph but you will be leaving performance on the table if you are not including those speeds in your setup's performance envelope.

Tom@TPC Racing

Sorry, I can't/won't tell you what to buy. Only you can decide. I can inform you that between the two ,Tractive DDA coilover kit is superior in damping performance and in build quality, includes monoball front & rear top plates, custom spring rate selection, and direct car setup support from a race team that knows these cars very well. To some, the car setup support alone is well worth the price. B16 is a good value in its own price range.


It depends on the spring rate selection and how bad the roads are. Typically 330/720 or 400/720 in-lb springs are very stable with Tractive at high speeds. Also with DSC Tuning software users can set stiffness % to vehicle speed.

ShatterPoints

My setup 50nm front 90nm rear is planted at speed. I finally have my car back with the custom dampers I had made and have been enjoying it greatly. Now my limitation is the cheapo hankook tires I have on the car. I would caution people, or at least like to make them aware that they would want an appreciable amount of aero if you are going to use the dampers for body control in a straight line at speed.