The Photography of Dr. Jeffrey P. Harper

Well . . . the new motor combination finally got to see its day on the dyno . . . actually two days.  There were a couple of issues that first delayed the dyno pull, and another that stopped it.  of course the water pump chose this moment to start leaking.  A  runner was sent to fetch a new one . . .  and it was installed four hours later. I had the opportunity to use the AVO Turbo development dyno for the day:

Then, when we got it up and running and a map was gradually being put into the ECU, the dyno computer would shut down for no reason as soon as we started to make real noise.  It was determined that the combination of RF interference and too much noise from the open headers was playing hell with the  computer.  We devised  some shields and, because we were at the AVO Turbo (Yeah Subaru!) manufacturing facility, they made up some large 3" pipes with nice stainless steel mufflers for the dyno.  This worked up to a point, but the dyno computer still died.  More shielding was added around the dyno computer, and a human shield was added (me!). This worked . . . . but then the car would not, absolutely not, run up above 4800rpm. All the usual suspects were checked (fuel pressure, spark, etc., etc.). It was like the throttle was being held at that rpm (it wasn't).  The fuel pressure and AFR were right, and it was not missing, popping or banging. We were all mystified.  Then we tested a "free rev" with the trans in Park . .  it sounded like it was up against a soft rev limiter. Oh well.  Time to go back to the shop and move the CDI the hell away from everything else, shield it, and separate all high RF wires from anything.  Theory number two was that perhaps one, or both, of the intake cams were put in too far in advance . . . a telltale sign being the 663 ft. lbs. of (delivered) torque it generated at 4200rpm.  Not too bad, really, from a 242 cu.in. (4.0L) motor on race gas. We'll sort it out and be back on the dyno in a couple of weeks.  I am disappointed . . . but we learned a thing or two.

The Dyno Day Debacle started with a water pump replacement.

The AVO guys made a nice pipe and muffler set-up to keep the open headers from vibrating the dyno computer into the "OFF" position.

I complained to the AVO Turbo Mangaing Director, Terry Wilson, that this exhaust system would make my car very difficult to park at the shopping mall.

El race truck con twice pipes.