BMW 135I ProjectYou may recall last month that Turner Motorsport (www.turnermotorsport.com) sent us the first pair of H&R sway bars in the country for our E82 135i project. Unfortunately, we hadn't anticipated the need to drop the rear subframe in order to fit them (et 7/08). So we visited the experts at BMS in Santa Ana, CA (www.bmsracecars.com) where owner Chris Welch handed us off to Chris "Junior" Chapman, who'd be doing the wrenching on our car. Although they estimated five hours for the job, he was confident of doing it in less if we weren't slowing him down for photos.
While the front anti-roll bar is simple to install, the rear isn't. Junior contradicted us by stating, "It's easy. The setup is just like the 335i. We've done loads of them and you drop the rear subframe about 4" to squeeze it in." However, there's no way you could tackle this on a DIY basis. You need a full workshop and experience, so expect to pay a company like BMS around $500 for the installation.
H&R sway bars from Turner Motorsport
TMS discounts the H&R sway bars to $233 front and $147 rear if you mention eurotuner when you order. At only 12mm in diameter, the stock rear bar certainly appeared to need upgrading, and so we were expecting great things of the 20mm H&R replacement. However, the stock and aftermarket front bars are both 27mm, so we were curious if this would have any effect.
An exclusive step-by-step installation guide is on the Tech pages at www.eurotuner.com However, the front simply requires the bellypan to be removed, and the bar to be unbolted from the end links and the bushing brackets - very simple.
Changing rear bar involves dropping rear subframe, supported by axle jack
On the rear, the end links are easily accessible but the bushings are bolted to the top of the axle. This means you have to drop the rear subframe to attack the brackets.
The job involves disconnecting the rear brake lines, removing the 18mm bolt from the upper suspension link and loosening the 16mm bolts on the subframe supports. The rear muffler also needs to be taken off its hangers so it hangs lower. Then remove the cross-brace under the car, unclip the ABS cables, and use 16mm wrenches to undo the sway bar end links. Finally, Junior loosened the four E18 subframe bolts before positioning a jack to support the axle before undoing all the loose bolts and dropping the subframe 4". It's then finally possible to access the sway bar bushing brackets before installing the thicker H&R bar.
Once in place, the jack needs to be raised to reposition the subframe. Then everything should be reassembled and tightened.
Geometry alignment is essential after major suspension surgery
Having previously fitted H&R Street coilovers (et 6/08 or the Tech pages at eurotuner.com) and now sway bars, Chris at BMS offered to align our geometry with his laser-guided four-wheel alignment system, discovering the rear camber and toe angles needed adjustment.
On the road, the alignment was instantly noticeable. The car tracked and turned better. The steering was also less twitchy. As for the sway bars, there's an improvement but it wasn't as pronounced as we were hoping. 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 grips harder when powering out of a turn. However, the stock E82 135i isn't exactly a wobble-butt.
Check the difference skinny 12mm stock rear bar and 20mm H&R replacement
To be honest, we masked the contribution of the sway bars with the H&R Street coilovers, which have significantly tightened the handling and reduced body roll themselves. So while the sway bars don't seem to have made a huge difference on the street, we know our TMS/H&R-equipped 135i will be significantly quicker on the track and aim to prove that in the future.
If you live in SoCal and need work done on your BMW, we recommend you pay BMS a visit. The team is extremely helpful and very knowledgeable. Its Santa Ana premises features a showroom, waiting area, service/tuning shop and a race/fabrication shop.
During our visit we witnessed everything from a software upgrade on a 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. According to Chris at BMS, his team is equipped, skilled and prepared to tackle any form of custom work on your BMW, or any other car for that matter. So visit the website or give them a call. See www.eurotuner.com for the full story. Greg
Front bar is easy to swap once bellypan is removed | 
Dropping axle 4" allows access to bushing brackets | 
fitting the new H&R rear bar isn't a DIY job |