Sunday, May 31, 2020

Mustang BXR Manifold

In the early 2000s I had a website dedicated to my car (naturalaspiration.com) and over the years the most popular part about it was the information I had on it about the intake manifold. I decided to keep some of the information around as a blog post.
BXR Intake Manifold without covers

My car was a 1989 Mustang and the intake manifold was a BXR, which stands for balanced cross ram. The concept was a balanced intake where the air had straight shots to the cylinders. The first advertisement I saw for it had yard sticks hanging out of it to show how straight the paths were. Steve Turner wrote in How To Tune & Modify Your Ford 5.0 Liter Mustang, "taking the tuned runner length, optimized port line of sight, and big airflow capacity to the nth degree, the BXR ... intake ignores most all factory packaging considerations to provide stunning performance."

The BXR is no longer manufactured and I am not a representative of that company. If you need information beyond what you see here, you may find it on this mirror of their old website. If you want to purchase a BXR look on used auto part sites or ebay.

There were three different plenum covers you could choose for the BXR manifold. I choose the hi-torque plenum covers for my Mustang because it was a daily driver and I thought I'd buy the other kinds later. It's interesting being able to inspect the inside of the manifold with just the removal of a three bolts, but the real utility is in the easy of switching covers and transforming the characteristics of the engine. Also, porting and polishing is much easier with removable covers. One thing about the  hi-torque covers and the manifold was it seemed to produce more power at slightly higher RPMs than stock. If you babied the throttle it felt less powerful than stock, but if you got on it, you felt the difference.

Some general advice on installing a BXR.

  • Check the engine's computer for error codes (or trouble codes) before you begin.
  • If you have aftermarket fuel injectors get the special rails. The fuel rails that came with the manifold kit worked best with stock injectors. There were larger o-rings in the special kit which I needed for my 30 lb. hr. fuel injectors.
  • Plan for the extra forward height of the manifold. You'll need more room in the front, so if you have a hood mounted functional ram air kit, it will be in the way. The manifold fits under a stock hood, but there's no extra room.
  • Have a crows foot wrench and lots of patience for installing the temperature sensor on the manifold. There's not enough room to work and the manifold is alluminum. You might want to consider a temperature sensor relocation kit. I didn't and I had a difficult time getting it seated so that it was sealed but didn't interfear with the fuel rails.
  • Get diagrams of hoses and wires or make sketches before you take it apart.
  • Use the fan relocator kit if you have a stock fan and radiator. The clearance looks fine at low RPM, but when you rev the engine, it'll jump forward and the fan will attack the raditor.
  • The throttle linkage on the BXR isn't clearly explained in the instructions, so I've taken a picture of how it looks installed.