REW Sequential Dyno - very uncommon results

dudemaaan · 10-10-2009, 01:06 PM

Does the cosmo pump have good wiring? You're sure it's the filter clogged and not a sticking check valve or something right? You have a fuel filter sock on the pump right? Check to make sure it has the plastic things to keep it from collapsing on itself. I remember one guy's thread he was having trouble with fuel pressure dropping off, and it turned out the aftermarket sock he installed didn't have anything to prevent the sock from collapsing on itself, once he replaced it, his fuel pressure was back to normal.

Curious, where are you measuring back pressure for the twins? It's hitting 33 psi of back pressure at that point on the graph and it hasn't even peaked yet. That's pretty terrible.

The boost dropping off doesn't look like it's falling off a lot, maybe you need to adjust the solenoid gain, not sure what the motec has for adjusting boost, but most boost controllers need some kind of tweaking to keep it from creeping or falling. You could pressurize the intake system and check for leaks. I'm more inclined to think your engine is just breathing too well for the turbos, they can't supply the air that the engine wants. Based on the amount of power it's making at low boost pressures, it's requiring a lot of air. Twins usually start running out of breath around 14 psi or so, well you're using the same amount of air at 9 lbs of boost. You might just need larger compressors, just throwing it out there. It might be something else going on.

10-10-2009, 01:06 PM	#21
dudemaaan Rotary Fanatic Join Date: Mar 2008 Location: Brenham, TX Posts: 335 Rep Power: 18	Does the cosmo pump have good wiring? You're sure it's the filter clogged and not a sticking check valve or something right? You have a fuel filter sock on the pump right? Check to make sure it has the plastic things to keep it from collapsing on itself. I remember one guy's thread he was having trouble with fuel pressure dropping off, and it turned out the aftermarket sock he installed didn't have anything to prevent the sock from collapsing on itself, once he replaced it, his fuel pressure was back to normal. Curious, where are you measuring back pressure for the twins? It's hitting 33 psi of back pressure at that point on the graph and it hasn't even peaked yet. That's pretty terrible. The boost dropping off doesn't look like it's falling off a lot, maybe you need to adjust the solenoid gain, not sure what the motec has for adjusting boost, but most boost controllers need some kind of tweaking to keep it from creeping or falling. You could pressurize the intake system and check for leaks. I'm more inclined to think your engine is just breathing too well for the turbos, they can't supply the air that the engine wants. Based on the amount of power it's making at low boost pressures, it's requiring a lot of air. Twins usually start running out of breath around 14 psi or so, well you're using the same amount of air at 9 lbs of boost. You might just need larger compressors, just throwing it out there. It might be something else going on. __________________ 500+ HP thanks to: Fast reacting IAT sensor thread! Mechanical Pre-turbo Water Injection Thread Dual Stock fuel pumps Thread T2 differential swap!