Soft or hard springs?

Okay so I recently made a discovery in my car tunes. What I have always been told is to keep a certain fraction of my cars weight to determine the softness of my springs, but in my ZL1, ZR1, CTS-V, and 1M I all tried to have extra soft springs and it seems to be working. In my ZR1 for instance the car weighs 3,200 lbs and my springs are 420 up front and 390 to the rear. Damping and rebound are also rather low with rebound being 3.4f 3.6r and bump being 2.6f and 2.8 rear. With this I chance my time at Sebring from a 2:10:7 to a 2:09:9 the car feels real responsive and seems to turn good. It seems to be upset by bumps a little so I’m trying to raise the rebound and bump stiffness a little.

My question is if everyone is telling me to go with a stiffer spring rate than what I’m using on my tunes right now. Why is having my springs soft enough to be right on the edge of bottoming out working out so good. Did I discover the secret behind all those top LB tunes?

I need your input to help me get the most out of this new base tune I’m starting to use and be able to fine tune it to be umbeatable, because this is a whole new feeling for me I feel like I’m starting over with everything I once new about tuning.

It all depends on your preference and how you drive. Personally I’m a lot quicker with softer springs my only problem is I tend to make them a little soft and bottom out occasionally on some of the hillier tracks.

To answer your question I think softer springs are able to absorb more of the energy that’s created in a turn when the body of your car wants to keep going straight and the tires want to turn. With a stiffer spring that energy is transferred to your tires (instead of being stored in the softer springs) which increases the demand on the tires and you wont be able to hold as much speed in the corner.

Hope this helps

I also agree the softer springs seem to be the better way to go. Worm said once before that he tunes with the springs on the softer side and just try and keep the car from bottoming out. Rebound setting on my cars vary from as low as 5.5 to 10 depending on the spring rate and weight of the car. I’m not really sure the best way of setting them but I just keep adjusting until the car feels stable and controlled. Bump settings are stranger to understand for me. My settings always seem to be a little higher than most of the top tuners and I don’t know why theirs are so low. I just adjust them until the car is stable over the bumps and curbs.

Thanks and yeah it does help I’m working on my 1M right now actually so I’m going to try the damping like you said and see how it works. I’m much happier with my times now that I dropped my springs 300 pounds.

Yes and no. Softer is faster, to certain extent

Generally when you lower your car, you want to make it softer, and stiffen the damping settings, it other words. if there would be no rumble strips and the track is flat you want the car really low to the ground, on very soft suspension, and bump set up so that the car couldn’t bottom out when you brake, accelerate or turn.

How ever there is always some bumps on the track, rumblestrips which you drive over, which either forces you to raise the car, and stiffen the suspension, or stiffen the bump settings. cause bottoming out might cause sudden peak of grip (lasting 0.01 seconds, follower by very weak grip and if the car was turning when this happens, it might make the driver lose control.

If there is lot of elevation changes, like on alps you need bit stiffer suspension, and bump, so that when downhill turns to uphill, wouldn’t cause bottoming out, and that would cause loss of control.

The more you have sudden small elevation changes (running over rumblestrips) the higher and stiffer you want the suspension, and the softer you want the bump to be. (generally) and the softer you want the rebound setting so be, so that the dampers wouldn’t disturb springs work to much.

Although. The lower and softer you can get it to be without bottoming out, the better it will be.

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I’ve been using real world spring rates that different companies offer and my times have gone down drastically. I’m not sure how the top timers are using softer rates. Like my 95 Cobra is 3200lbs and I use 1000f/850r and I shot up the leaderboards on my favorite tracks. That coupled with knowledge of how suspension works on the track. You want to eliminate body roll and bottoming out. I use a race from ARB and set it to 1 and a Sport rear ARB. I also bump the front bumper stiffness up a few notches from the standard race setting and leave the rear alone. Increasing your from bump stiffness will keep your car from dipping when braking and transfer grip to the rear wheels. The way I see it, if you use softer springs you have to rely on ARB’s. If you use stiffer springs, you don’t need ARB’s at all. Most of my autocross friends remove their front ARB because they’re using 550lb+ springs.