28 Sept 2014

A bumpy week, car-wise.

The water/meth controller was returned as “no problem found.” Of course it still didn’t work so I had to figure it out or drop it in the trash. I specifically asked the AEM tech on the phone if the self-test function would work with ONLY 12V connected – yes. The real answer turned out to be No.

The controller requires a direct connection straight to the car battery, the reason not explained. It turns out that this connection powers only the pump and not the controller, which of course isn’t explained either. Through trial and error I found that to power up the controller, the so-called “Enable” line must be set high. In electrical engineering, the term “enable” describes a very low power input which enables a circuit but doesn’t power it directly. What AEM doesn’t document is that their “enable” pin is actually the power pin for the controller, requiring far more power than any enable pin.

With that figured out, the circuit has to be redesigned since I took their word for what “enable” means – to the rest of the world. Worst case a relay will have to be added since the ECU was attempting to drive this “enable pin” with a signal appropriate for the task, but is incapable of powering the unit directly. Minus one point to AEM for mislabeling and misleading people on the meaning of this pin.

In other news:

– With ignition timing now corrected, boost could be increased up to about 16 psi without knocking, but I know I’m pushing my luck. The water/meth will help that situation as soon as the above is resolved.

– When I disassembled the intake to mount the water/meth injectors, a very thin film of oil was found throughout the intake tract – even into the wastegates. This was very disappointing because it means that the nearly-new turbo has an oil leak (which also effectively drives down fuel octane). If this happened to someone else I’d tell them to check that they have the appropriate oil restrictor in place, and a well-routed oil drain-back line. The thing is, the same parts from the previous turbo were transferred over to this one, so neither the restrictor (0.040″) or the drain-back is any different. Sigh… well, it is what it is, so out it came. It’s already boxed up and ready to go. Being only 3 months old I don’t expect major issues getting it repaired or exchanged but that’ll be dealt with tomorrow.

– With the turbo removed, the wastegates were also removed and 5 psi springs installed; with boost control there’s no reason to have high spring pressure. It allows using boost-by-gear which is sort of a poor-man’s traction control, but obviously that’s for later.

– With the turbo on its way out the door, that pretty much answers the question: Midlana’s not going to the runoffs in two weeks. Even if the turbo retailer sends a replacement within a week, I don’t like rushing major engine alterations. Along the same lines, my brother is having issues with the charging system in his LS-3 Stalker. In the name of science he disassembled the alternator to see why it worked for about an hour and then didn’t, finding that a piece of rock-hard insulation broke free and got jammed in the armature, effectively turning into a fly cutter and slicing a number of stater wires. This was the second alternator; the first one was dead out of the box. For the same reasons he’s decided to not drive his car to the runoffs either. Shrug, oh well, we’ll share the gas expense and talk on the way up and back.