Had a conversation about an ideal fuel management system for TB ( Is there one?)

[norbs]

Just to note the processor speed on the XFI is 3x as a stock ECU or classic fast.........and has better emi resistance. I could not run a stock ecu with my msd box and maf, the signals were unpredictable.

 

[ravege]

"...the processor speed on the XFI is 3x as a stock ECU or classic fast..."
my dad got a 6MHz PC in 87, hard to imagine a computer in 2014 only running 18MHz.

 

[Lance]

The 3x faster thing is marketing's attempt at quantifying a performance improvement. The reality is that comparing processor clock speeds means very little today...especially with embedded systems (like EFI). Same is true for PC clock speeds. It's not the clock frequency that's important but how efficient the processor is at processing instructions. Because embedded systems are usually dedicated to a specific task, the question should be "is it fast enough?" The XFI recalculates all the important parameters (timing/fuel) every time a cylinder fires. Most of the time in between cylinders. it spends just waiting. In the case of the classic vs. the XFI, the architecture is significantly different and dramatically more efficient. The XFI is way faster.

 

[norbs]

Thanks for explaining that lance. The XFI is 24 MHZ speed and the classic fast, accel dfi, and I think the stock buick ecu is 8 Mhz. I could be wrong I lost the specs of the processors..

 

[TurboBob]

Because embedded systems are usually dedicated to a specific task, the question should be "is it fast enough?"

the stock ECM is 4mhz, but the fuel injector pulse and timing control are handled by dedicated chips, so the CPU does not need to handle them, just calculate the values.

the PowerLogger CPU which performs the Speed Density calculations for the SD2 system is also "fast enough" (24 Mhz) for the tasks it is responsible for.

Bob

 

[TurboDave]

Thanks for the tech input Bob! I knew the Powerlogger/SD2 system was much faster for the speed density side of the house, but didn't know the specs.

 

[norbs]

On another note, I run a distributor and MSD box, which puts out more output than coilpack or COP system. This was impossible to use on the stock ecu and MAF due to EMF/RF noise issues, the SD chip also failed giving into the interference. Some how with the fast XFI its not a problem....