[travislambert]

I had a DSX aux pump kit on my ZL1 until I figured out you can't rely on it below 1/2 tank of fuel. Our cars have a saddle tank and there isn't any baffling to prevent the fuel from completely transferring from one side to the other. When you have 1/2 tank of fuel or less, a hard right turn will transfer every drop of fuel to the left side of the saddle leaving the right side completely dry. So an aux pump that only taps the right side of the tank won't do anything at all on a hard pull after a hard right turn (common on a road course).

Honestly, in addition to this major design flaw, the DSX aux kit has many problems that make it an engineering joke. This kit isn't controlled by PWM... it's completely on or completely off. This creates a tuning nightmare which is why DSX offers absolutely no guidance on how to tune around their kit. They hide behind statements like take it to a "competent tuner" implying if you don't know how then you're incompetent. The truth is, these kits are impossible to make work correctly. If it were possible, they could tell you how to do it. Making adjustments to the tables they recommend will have negative consequences.

They have a very similar story for the tapered tank fitting. They act like if your fitting leaks then you've done the install incorrectly. The truth is it'd be nothing short of a miracle to get this fitting to seal considering how thin our fuel tanks are. I ended up having to drop my tank and put a bulkhead fitting to get it to seal up. Oh, when I dropped the tank, I found it was full of plastic shavings where I drilled the hole. I was EXTREMELY careful while drilling. I backflushed the hole with gas and everything. I thought I had every last plastic shaving out of the tank. I was blown away with how much debris was still trapped in the tank. If you have the DSX kit, check your fuel filter on the aux pump. I bet it's full of plastic shavings sucked in from the tank.

I spent around $1,000 in dyno time just trying to get my kit working. I finally hacked something together that resembled working, but compromises had to be made. I also spent hours dropping the tank to get a reliable tap.

In spite of all of the effort, the car would occasionally drop fuel pressure and run lean. I eventually figured out what was going on when realized it only happened with 1/2 tank or less of fuel and I logged both in-tank fuel level sensors. I pulled this kit from my car immediately before it cost me an engine.

If anyone is putting together a museum of poorly engineered aftermarket accessories and would like to buy my DSX aux pump kit, I have one with very little use for sale.