[urq] EFI + MAC-14 maxing ataround 5k RPM
QSHIPQ at aol.com
QSHIPQ at aol.com
Wed Oct 24 16:40:15 PDT 2007
IIRC Cody, the older EFI designed systems defined Alpha-N for the changeover
from MAP to TPS to accomodate big lumpy cams, ala race car, because the MAP
signal was unstable. The newer EFI systems use MAP/TPS/RPM 3D tables for tip
in transient response and fueling. As I haven't had the pleasure of playing
extensively with MS, I will assume it uses the standard MAP v RPM tabling
you describe. Unless Ben is running a 272 cam, this shouldn't be an Alpha-N
Not having the same tables to stare at, I'd take a swag that the injector DC
should be 50% or less with 'just' a run to 5k without load. Maybe I misread
what Ben put forth, but I swear I saw 100% DC mentioned.
If it's MAP vs RPM, and MAP is programmable, maybe a rescale is in order.
Also, IMS, Ben if this is an automatic MAC 14 computer/harness, there is a
jumper wire that needs to be cut off the plug (pin 7 comes to mind off the top
of my head) that was a reduced power for first gear launches in the slushbox.
I also recall that being a boost only intercept on the WGFV, not a timing
retard. But worthy of a looksee.
Getting a bit far out for a audifans discussion, but Ben, I'd go back to
seeing what happens to the FPR return flow at 5krpm. If there is none, you have
a more basic problem.
In a message dated 10/24/2007 12:47:54 P.M. Central Daylight Time,
cody at 5000tq.com writes:
It's MAP vs. RPM, for true speed density. MAP vs. TPS (called alpha-N) is
only used on race cars. TPS is only there for accel enrichment, where it gives
an extra shot of fuel as you open the throttle (like an accel pump on a carb).
It's all in the programming.
At any point if injectors are going 100% duty with no load then it's a
problem with how the tables are tuned or a basic setting issue. The thing is that
based on the log file that Ben sent me his injectores are not going over 70%
duty cycle under full load at the boost level he is currently running. I
haven't gotten the chance to look at the most recent log file he sent nor the
settings, but I'll get to that this evening.
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