New Hahn/QA1 Bolt-In Spherical Coilovers!

Quote from Speedr117

Posted earlier, but since you asked:

These are with Bill's spring rates (250 front, 350 rear) set at stock height:

Front: 8 Compression, 6 Rebound
Rear: 6 Compression, 6 Rebound

I try and keep the rebound at low as I can to make sure the shocks don't pack down over multiple bumps or ripples.

It's amazing what a difference 1 click can make (at least on these shocks). Going from 7 to 8 on the front compression really made the Slingshot handle and stay composed in the corners! Most cars (or bikes for that matter), the chassis gets really out of shape when you try to brake and turn, especially if done together (obviously not optimal). With the front end set up tight like this, it was great, even when braking mid-corner (again, not optimal, but back roads, following others, and of course, bad judgement). The only other non-race vehicle I've ever felt like this was my Lotus Elise.

The only downside is, it's a little jarring in straight lines (at 8 compression). I'm looking into the DDM Sway Bar, which I hope will give me the stable chassis with slightly lower front compression settings.

BTW, at first I tried them at the mid point (9/9) on all ends, and I thought my Dentist could here the cash registry ringing with the cost of my dental work falling out. 4/4 felt like a Cadillac (of course these days, more like a Lexus).

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Hahn RaceCraft installing their Hahn/QA1 Spherical Coilovers at Slingshots in the Rockies!

Quote from MACAWS

Hey Bill how about a little direction from the master.

For those of us who are pushing the envelope for HP. I am running (and absolutely love) my Hahn RaceCraft QA1 coil overs
I chose your dual adjustable an would love to know what you would recommend to help get the best bite out of the rear wheel.
Maybe a little explanation as to why.

Thanks

Thanks for the kudos!

This is an absolutely great question. On high-powered machines, what we want to do is encourage weight transfer to the rear wheel(s) so as to enhance traction. The idea is to leverage traction by making vehicle weight shift rearward. The physics involved are rather interesting, for acceleration G-force literally moves the center of gravity rearward on an angled vector, the angle of which changes as the G-force subsides.

What? It's actually an area of much theory and conjecture as to how these forces interact. Back down to earth, let's discuss some practical aspects of how we can assist this phenomenon.

The best way to get more weight rearward is to encourage the rear to "squat", or compress the suspension. So we'll run the compression damping as soft as we can without losing the ability to withstand bumps via over-compressing the suspension in spirited driving. Stay at the soft end of the range and experiment to taste. Go over some decent bumps. You'll be able to tell what is too soft for your liking. If it's too soft, the suspension will over-compress and "bang" or feel rough.

So we are now squatted under acceleration. What's next? Well, we want to keep it squatted. So we set the rebound hard...again, as hard as we can stand. In full-blown drag race applications, we'll set it full hard, but that's impractical for a street-driven machine. So, again, we'll set it as hard as our stiffness preference and butt-o-meter dictate. Excessive rebound damping can make the suspension uncooperative over rough pavement.

But wait. What about the front? Precisely the opposite. Let it rise easily (less rebound) and settle slowly (more compression). Again, season to taste. Always check the settings you optimize for these behaviors over some rough pavement to make sure the effect isn't too severe.

Back in the day, we used drag-style shock absorbers on our muscle cars that were 90/10 (rear) and 10/90 (front). You may recall those. Same intentions, but much more limited as they typically were not adjustable.

Now, for a street-driven machine, we also like to retain some good handling settings too, and unfortunately, great handling settings don't jibe with great drag race settings. So a compromise must be found that best suits both handling and straight line acceleration. The nice thing about having adjustable coilovers is that you can still devise two different setting strategies, one that optimizes handling, and another that works best at the drag strip, or when you are in a dragging mood on the street.

So now you have the strategy. Time to take it out and play with it!

Another substantial change that we've noticed with the Hahn/QA1 Coilovers is greatly improved braking performance. The machine will stop in a shorter distance, with a much more solid feel. This is owing primarily to the greater resistance to the substantial front end dive and rear end lift to which the stock coilovers are prone. Since the machine stays in a more level position during braking, the center of gravity also isn't shifting forward so dramatically, which not only keeps the weight more evenly distributed and allows the rear wheel to brake harder, it also improves the feel and feedback to the driver. A machine that is diving the nose down and raising the rear when you brake hard feels vague and strange as this CG is flopping about. It's as it you had a movable weight in the machine that is moving around while you try to stop hard! The effect can feel very unsettling.

Users of these coilovers will know to what I am referring. The machine just feels more composed and easy to control under hard braking, and will undoubtedly slow in a shorter distance as a result. Coilovers as safety enhancement!

Hahaha, you guys! Loving it