[TitaniumTT]

Not really all that complicated really, and not the most accurate but at least now I definately know what the fuck is going on with the ole' FC. Here's what I did yesterday

I started off by permanently mounting all the relays in the trunk and building a brace that fills the void behind the drivers side wheel where the harness travels. In here I installed two SPDT switches underneath some safety covers. The idea being that the common terminal runs to terminal 86 on the fuel pump relays. The top terminal (which is contacted when the covers are closed) is connected to the turn-on from the MoTeC and the bottom terminal is connected to an ign hot source. The thought being that the pumps can be completely manipulated with the engine off and the engine not running. Or the engine running to de-pressurize the lines, drain the surge tank etc etc etc...... So after that was done and all tidy I moved on to actually testing the pumps.

While I admit this isn't the most effective way to do this, it did give some pretty valuable insight as to what was actually going on. When I wired up the fuel pumps I added an extra hot/grnd that ran outside the cell so that I can see exactely what voltage the pumps where seeing when running. Pretty trick I thought. So I went to RS and bought a second set of test leads that I added some metri-pack connectors to so everything plugged in and I didn't have to tape shit together or hold test leads. So with that in place I moved onto th reconfiging the fuel cell.

The first thought that Dave had outside bad voltage was that the surge tank wasn't getting enough fuel into the surge tank. I was pretty convinced when the thing lean surged on me and pressure went to almost nothing on the drive home. On the return from the surge tank to the main cell I put in a length of clear hose so I could visually see the fuel moving around. It took a while as I'm pretty sure the surge tank was dry but within a few seconds the clear line purged a few bubbles and then was solid fuel with the engine running. Cool, so the surge tank is getting filled, cross that off.



Next I disconnected the feed into the surge tank off the Denso and ran it to an external reg set for ~43psi and dumping right into my 5 gal Jerry can.



I turned on the denso pump and timed how long it took to fill the 5 gallon jerry. ou can see in one of the pics the amount of V it's getting and the voltage drop. About 12.5 on the dash (VERY close to what the battery sees) and 12.34 on the multimeter. Bryan from BNR confirmed my numbers @ 292lph.... fucking sweet! Ok, so lets cross that off becuase that pump will never really see any pressure so the flow will be more than enough. Alright, now lets test the bosch pump.

I reconnected the feed from the Denso to the surge tank, but left the clear hose installed. I did this becuase there is only 5 qt's in the surge tank, and I'm looking to fill 5 gallons, so the Denso needs to be running as well. The fuel from the regulator on the back of the engine will be dumped into the 5 gallon jerry just so this is basically 100% flow out of the surge tank, with no return, so I wanted to make sure that the Denso would definately keep up.




I disconnected the return from the regulator and hooked that line up to the dump into the 5 gal jerry and capped the return line on the firewall. The reason for capping it was becuase the Denso would fill the surge tank, and then I'm sure there will be a little pressure and that will push up the return line and spew all over the bay, so that fucker got capped. I fired up both pumps and started the clock.. Voltage at the Bosch pump was less, around 11.7 and the dash saw 12.2 12.3V Sadly the mighty 044 put out a lathargic 165 lph at 59psi rail pressure..... FAIL. A far cry from the 300lph it claims and 200 lph @ 70 psi and 12V.



Just to satisfy everything that needed to be satisfied I stuffed a mechanical gauge in before the filter and turned the pumps back on. I saw over 70psi before the filter and some pretty nasty fluctuations, as in betweel 60 and 80 psi. The gauge was boucing all over the place. I swapped the filter for a BRAND new one adn repeated the test. The time dropped by a whopping 3 seconds and the psi dropped a few psi as well Average seemed to be about high 60's now maybe around 70. So the filter isn't really to blame for all of this... I think the pump really is shit. It's probably just this pump though, not all Boschs.

So, thoughts opinions on what the next step is? I'm not convinced that the Bosch pump is going to be the best for me. I'm really leaning towards a second Denso pump in the surge tank. 292lph is defintately going to be enough especially if I drop the base pressure.

If it's still not enough I could bump the voltage. Something that I'm not opposed to doing via a Kenne Bell BAP but without the boost sensor. I would rather the voltage be constant and not varying all over the place becuase there will be a time delay, or so I'm convinced of. I'd rather set it to 14V and just leave it there at all times.

So, what is hands down the best intank QUIET fuel pump out there. People sweat by the A'pexi BNR32 but that sells for about $400, I could buy the BAP and a Denso pump for that price.