Yet Another E30 Project Car---Unlike Any Other E30 Project Car---The M-Touring. Part 3: Brakes
We started this project with a 1989 3-series Touring, one of only three known E30 Tourings in the United States. We are converting it from a suburban grocery getter station wagon to a serious performance MACHINE. Nothing novel or new is needed for this change since the BMW Motorsports Division made all the pieces we need and assembled them in the form of the E30 M3. We have simply been analyzing the E30M3 to see what makes it great and then we've been taking the best of the M3 for our Touring. In Part 1 and Part 2 we talked about making our car handle and steer like an M3. Here in Part 3 we will talk about making it stop like one.
3 -Series BMWs do not have bad brakes. For normal use there is no need to do anything exotic to the braking system. But for a track car, a serious driver school car, or a race car, bigger brakes are not only appropriate but are necessary. And there aren't any simple options. Sure, there are big brake kits---but get out your checkbook. Two thousand and up [dollars].
What we have done on a more reasonable budget, is to transfer the stock E30 M3 brakes from a parts car to our Touring project. We're talking about a big change here---both front and rear M3 rotors are about an inch and a half bigger in diameter---and that's a lot. The M3 also has bigger calipers which use bigger pads-the same size as is used by big BMWs. When we transferred the M3 suspension to our project car [in Part 1 of this project] the brakes were transferred at the same time. We installed new PBR/Repco pads during the transfer. We had already replaced the stock rubber flex hoses at each wheel with stainless steel braided brake lines--the stock rubber lines flex slightly under heavy brake pressure and the braided lines give a firmer feeling pedal. The master cylinder has to have a fluid capacity to match the rest of the system, both for proper volume as well as to create the required hydraulic pressure. We could have used a M3 master cylinder to match the rest of the system, but we chose the larger cylinder from a BMW 750 as an experimental upgrade. We have heard that some E30 M3 owners are using the 750 cylinder as an upgrade, but we were unable to tell any difference from other M3s. Finally, we pressure bled the system, flushing completely with ATE Racing Blue Brake Fluid.
Results: How is the project so far? Confused. Now it feels like a real car except that it looks like a stock station wagon and it doesn't have any power. What can we do?