Anybody tried running the 380cc P2 injectors in the P1 position ?
03-03-2010, 01:48 PM
#26
Regardless of what pump you use, the target rail pressure is about the same (58 - 65 PSI).
The difference is that on the vast majority of OE pumps (if not ALL of them), the target fuel pressure is not met at high demand.
I've see fuel pressures drop to as low as 40 PSI on a known "good" OE pump at 6000 RPM on a 300 HP FI application. I've seen lower than that on my own system and actually lost an engine to it.
Since upgrading the OE assembly with the Walbro pump, I've never seen the fuel pressure drop below 60 PSI, even as I ran on "fumes".
The net fuel pressure is exactly the same on the primary and secondary rails, which have enough flow to supply a little over 4000 cc at 65 PSI each. You wont exceed that on the secondary rail and you definitely wont exceed it on the primary rail.
Retuning will have to be done, but only because the tuning was already "wrong" to compensate for sagging fuel pressures.
The difference is that on the vast majority of OE pumps (if not ALL of them), the target fuel pressure is not met at high demand.
I've see fuel pressures drop to as low as 40 PSI on a known "good" OE pump at 6000 RPM on a 300 HP FI application. I've seen lower than that on my own system and actually lost an engine to it.
Since upgrading the OE assembly with the Walbro pump, I've never seen the fuel pressure drop below 60 PSI, even as I ran on "fumes".
The net fuel pressure is exactly the same on the primary and secondary rails, which have enough flow to supply a little over 4000 cc at 65 PSI each. You wont exceed that on the secondary rail and you definitely wont exceed it on the primary rail.
Retuning will have to be done, but only because the tuning was already "wrong" to compensate for sagging fuel pressures.
Last edited by MazdaManiac; 03-03-2010 at 02:09 PM.
03-04-2010, 08:57 AM
#34
Need to clarify--when i agreed with Team I was reponding to his bypass statement and I was wondering if that changed with the new designed pump assembly in the 09 models.
I have had differences in the fuel rail pressures----when i blew the line connector spacer out!
OD
I have had differences in the fuel rail pressures----when i blew the line connector spacer out!
OD
03-04-2010, 08:32 PM
#40
If you were just going to add blues, you would have 380/380/480.
The blues go in P2.
Then, you have enough fuel for 350, but you are right at the edge (MAX of 380 or so crank HP).
290/380/700 Gets you over 420 at the crank.
03-04-2010, 08:40 PM
#41
which is it ?
My reference point is I ran 350whp with only 290/380/480 and saw afrs starting to lean out due to under capacity .
Add another 200cc by changing out the reds( 9% ) + whatever you get from upgrading the pump and you should be sweet at 350 .
Add another 200cc by changing out the reds( 9% ) + whatever you get from upgrading the pump and you should be sweet at 350 .
Last edited by Brettus; 03-04-2010 at 08:47 PM.
03-05-2010, 01:11 PM
#45
Which is why I made the above statement about 380/480/380 working to 350 - you would have about 9% spare capacity not counting whatever you got from upgrading the pump .
I guess that is still below the recommended 75% max duty cycle so not ideal .
Nevertheless a lot of people have done the swap to AT blues and i'm sure they would like to know how far they can push that combo without going to aftermarket injectors.
03-24-2010, 10:45 PM
#49
Turns out the rich 'accelerator pump' effect I was getting was more to do with maf scaling than anything else .
Compare previous log to this one and there is no rich condition this time . Injectors still the same as before 380/380/480
Now can conclude that there don't seem to be any issues with running this setup.
Compare previous log to this one and there is no rich condition this time . Injectors still the same as before 380/380/480
Now can conclude that there don't seem to be any issues with running this setup.