Coilover adjustment - how much spring perch adjustment is too much?

Hi all,

I have a Honda Civic MB2 which is a European Civic model but shares the same basic double wishbone / multi link platform as other 90s hondas (EG, DC2, etc)

My car has a set of Meister R ZetaCRD coilovers with a 8kg spring in the front and 6kg in the rear

I've been watching HP Academy's suspension setup course and they teach to use the bottom mount to set the suspension stroke so that the wheel or suspension components don't contact the chassis. I've started at the front of the car and set this nearly at the bottom (lengthening the shock body) and this means that the suspension hits the bump stop just before the upper A arm makes contact which is good.

The next step is to calculate an ideal ride height based on this with a 66/33 compression to rebound ratio. This means I have to raise the ride height significantly. According to the calculations they teach on the course I have to compress the spring by 29mm which is a huge amount (232kg of force) to get to the "target" ride height. Other sources online are telling me this is far too much and this coilover is not suitable for this method of setup (which is entirely possible)

I think I could reach 50/50 ratio by compressing the spring by around 15mm - is this still too much?

Hi, sorry this has taken a while to get to! I don't normally answer forum questions, but suspension is my jam, so I'll jump in here.

You have done everything right already. There is no point shortening the shock body any further since the bump stop is already at the right engagement point.

While the course is great, I believe it is too constrictive on the "ideal" bump/rebound ratios. The reality is that 1/3 droop travel should be the minimum you want to run in almost any scenario - for a lot of cars, a 66/33 bump/droop ratio will sit the car really high (OK for a road car, not so great for racing). For most production based saloon cars, you will often end up with as much as 60% droop travel, 40% rebound to reach your ideal ride height targets.

The reason for this is because production cars are usually very limited on compression travel due to bodywork and packaging constraints (and the fact their engineers designed them to be high for normal highway use). This means most cars can't get "enough" compression travel without the suspension arms binding or tyres hitting the bodywork.

Andre did a podcast with Thomas from KW Suspension and near the end of the interview he asked for a target bump/droop ratio that most people should target. Thomas's answer was that droop travel is more important than most people think and that 45% bump, 55% rebound would be a good starting point.

Head to 1hour 34 minutes in this podcast to hear Thomas's comments: https://www.hpacademy.com/blog/079-suspension-setup-secrets-from-kws-head-of-motorsport-podcast/

Here's my quick recommendations:

1. Leave you shock body lengths as they are. You've done this well already.

2. Set your desired ride height and go test the car. Go over some big bumps and load it up in higher G corners. Take notes on how it handles.

3. Play with your ride height using the spring perches. Repeat similar tests to before. Take more notes.

4. Repeat steps 2 and 3 at the racetrack if you can and pay attention to lap times - the stopwatch doesn't lie

Your ideal ride height should make itself fairly obvious to you. If it's too low, it'll bottom out and bounce around, or it will roll weirdly because of the drop in roll centre. My double wishbone experience comes from Mazda MX5 racing, which is quite different to your application but still relevant... In those cars, the lower you go, the faster the car will be, right up until you're spending too much time in the bump stops. In that case, smoother track = run lower, rougher track or road events = run higher.

Hope this helps!