The method for modifying the E30 subframe to allow for camber and toe adjustment is nothing new, we’ve been doing this for years since the E30 has been raced for so many years now. However we noticed that we get lots of E30’s on our alignment rack that haven’t had this modification done properly so we wanted to document and make some notes on the latest car we did and share that information with others. If you plan to tackle this job at home there’s definitely some things you need to be aware of.
Our methods may take a bit longer but they are worth it in the long run. The first thing we do when we get a car in for this modification is make sure the car is sitting at its desired ride height. If the car is ride height adjustable we try to put it at the median ride height it is likely to see in the forseeable future. That allows us to put the car up on our alignment rack and measure the alignment. Based on the current measurements we can pretty well estimate what location we need to weld the adjustable plates in. We also make sure that the position of the plates will give us adequate adjustability for toe and camber even if the ride height is changed in the future.
Typically cars will have some extreme camber angles and some cars will have too much toe in or too much toe out. We take a printout of the rear end alignment and sit down with it at our welding table to make sure we weld the adjustment plates up in the correct place. At this point I want to point out that all alignment kits are not created equal. The kit we use in house consists of milled steel plates that are strong and precise. We have, however, had customers bring us some inferior kits consisting of bent sheet metal tabs that are flimsy and inferior. The fitment is poor on the eccentric bolt which increases the likelihood your car will go out of alignment when you start driving it aggressively.
Once the plates are located in the place we want them we tack weld them on using our eccentric bolt to hold them in place. Once tacked we remove the bolt and complete the weld using our TIG welder. We always prefer to TIG weld these plates on as it allows more precise control over the weld bead and prevents us from getting any material onto the area the bolt needs to rotate and pass through. This takes a bit more time than MIG welding but on a job that requires so much labor to remove and reinstall the subframe we feel taking the time to do it right is worth it.
Once all the welding is out of the way we have to take some time to carefully grind out the slotted holes. We like to use our electric dremel but we also use a die grinder with a carbide bit or a grinding bit depending on the position. This is a very time consuming task but precision and patience will pay off and result in a subframe that can be used for many years.
Once the holes are properly slotted the trailing arms can be reinstalled with the eccentric bolts and the entire rear end can be reinstalled into the car. From there we will put the car back on the alignment rack and finalize the alignment using our new and improved subframe.
If you’re in the Orange County area and need to have the BMW E30 rear subframe modified for camber and toe adjustment consider giving us a call. Not all facilities have welding and alignment equipment in house to accomplish this job properly. We do it all here in our facility in Irvine.