BMW 135i Coupe Sway Bar Fitting - BMW 135i Project update

slowly lower the jack to drop the subframe. We can't begin to tell you how critical this stage is. You don't want to get it wrong or it will end in tears.

With the subframe lowered about 4" it's finally possible to access the sway bar bushing brackets (pic 14). There are two 10mm nuts on each bracket that must be undone before the bar can be removed.

With the stock and aftermarket rear bars placed together, it's possible to see the significant difference in diameter (pic 15). We're hoping this will have a dramatic affect on the handling.

Lube and push the H&R bushings over the H&R bar. Then push the stock brackets over the bushings (pic 16).

Junior jiggled the bar through the suspension and back into place over the axle; a task made more difficult by the thicker, heavier bar (pic 17). You need to align the brackets and bolt it down again using the original 10mm nuts.

Once in place, the jack needs to be raised to reposition the subframe. Then everything should be reassembled and tightened.

Align time
Having previously fitted H&R Street coilovers (see the Tech or Blog pages of www.eurotuner.com) and now anti-roll bars to our BMW 135i project, Chris at BMS offered to align our suspension geometry. This is always important after such procedures since misalignment can adversely affect the handling and rapidly increase tire wear.

The workshop has a dedicated lift for its Hofmann Geoliner 650 laser-guided four-wheel alignment system (pic 18). Its operation is dependant on the reflectors mounted to all four wheels (pic 19). By accessing the factory geometry settings from its database, the machine is able to measure the alignment very precisely (pic 20).

While most of the numbers were within acceptable tolerance, the negative rear camber needed adjustment. At -2.2˚, it was going to cause us long term problems with tire wear, so it was reset to -1.6˚ (-1.8 to 1.3 is recommended).They also adjusted the rear toe angles. There was excessive toe-in, so they brought this back to factory spec as well.

Road Test
On the road, the alignment was instantly noticeable. The car tracked and turned better. The steering was also less twitchy. It was time and money well spent.As for the sway bars, there's an improvement but it wasn't as pronounced as we were expecting. Perhaps the huge size difference on the rear bar led us to believe the impact would be greater.

That said, the car turns in more crisply and body roll is almost non-existent. It also seems to grip harder when powering out of a turn. However, the stock 135i isn't exactly a wobble-butt.

The BMW engineers did an incredible job on the 1-Series Coupe's suspension, making it harder for H&R to improve it. We further masked the contribution of the new sway bars with the previous addition of H&R Street coilovers, which have significantly tightened the handling and reduced body roll themselves.

While the sway bars don't seem to have made a huge difference to how the 135i handles on the street, we know our TMS/H&R-equipped car will be significantly quicker on the track and aim to prove that in the future, once we've made a few more modifications. Stay tuned for the next update at www.eurotuner.com or in eurotuner magazine.

BMS
This was our first visit to BMS, but it certainly won't be our last. The team is extremely helpful and very knowledgeable about all manner of BMW related issues.

The Santa Ana premises (pic 22) features a showroom, waiting area, service/tuning shop (pic 23) and a race/fabrication shop.

During our visit we witnessed all manner of cars being worked on, from a software upgrade on a BMW 335i, rollcage fabrication for an E30 M3 racer to custom work on a E39 BMW 540i. The latter was receiving a genuine quad exhaust system, so the rear floor had been cut and new sheet metal welded to create a void for a second rear muffler. The standard of work looked as if it had left the factory floor that way - it was far more involved than it needed to be considering few will ever see it. However, the BMS team is dedicated to doing the job right (pic 21).

If you drive a BMW, live in the SoCal area and need work done to your car, we highly recommend you pay them a visit (www.bmsracecars.com).