Pics: X5 lowered ~2in (~50mm)

[HaroldC]

So I finally had some time today to install the custom springs and custom rear links for the air suspension ecu. The total lowering was ~2in (50mm)m which was more than I previously calculated. I calculated ~43mm drop, which was a bit too conservative of an estimate.

The custom springs are H&R springs in the front with one (1) dead coil cut off. On the front of H&R springs, there usually are a few 'dead' coils which act as spacers while the other 'active' coils are supplying the spring force. In this application, there were 4 'dead' coils. H&R claimed a ~1.2in (~30mm) drop on the front. Each coil is 0.5in (12.5mm) think, so removing one would theoretically yield me an overall drop of ~1.7in (~42.5mm). Well that didn't work, and I ended up with a 2.125in (52mm) drop in front.

On the 4.8i there are air springs in the rear, which obviously can't be replaced. But there are these links that connect to the lower control arm and a sensor that tells the ecu what height the corner is at. Using a bit of high school algebra and geometry, I calculated that in order to have a 1.7in (43mm) drop in the rear, I would have to shorten the link ~0.39in (~9.9mm). I sourced some endlinks that I could adjust for length that would fit and set their length center-to-center about 16.4mm which is about 10mm shorter than stock. But there was barely enough thread overlap so I needed to shorten it a bit more to 16.2mm center-to-center. In the end I did end up with a 1.875in (~47mm) drop in the rear.

I totally forgot to take some pictures of the springs, especially to describe the 'dead' and 'active' coils. But here are the custom endlinks that I made:



Due to the lighting and lateness of the day I was only able to take a few shots of the current setup.






Impressions: It's definitely more bumpy of a ride. The stock shocks seem to be not be able to deal with the severly reduced travel that the springs resulted in. It's not harsh, but bouncy. Having had a few street cars with various different aftermarket (street and track oriented) suspensions, I understand the tradeoffs, and will use the weekend to judge the severity of the reduction in ride comfort.

I understand that my choice to shorten the springs has much to do with the ride quality. Now that I cut the spring, my choices to raise it in the front will be the but the H&Rs again and not modify them, or get the Eibachs. I can always raise the rear, as it's a simple process that involves romoving the rear links and turning the ends to lengthen them.

For now, I do love the way it looks. It is so much more aggressive and meaner looking. But the ride quality, since this is a daily driver, might require that I raise the car.