Speed Density vs MAF

[Brian Warburton, c/o Turbo Systems Ltd]

Sorry, wasn't intending to offend or insult anybody or their
beliefs ....

My experience of speed-density stems from time at Ford Motor Co.
writing production speed density code for the EEC-iv and attempting
to calibrate speed density systems. My experience showed that there
was no way we could get a speed density system to reliably emit
and meet 50k and 100k emissions durability tests.

>From getting involved in strip downs on competitor cars, it became
obvious that the Japs in particular seemed to have little trouble
meeting the emissions requirements with speed-density systems.
The main difference we determined was that their engines were built
with much tighter (better !) production tolerences and gave better
initial feed-gas. i.e. their speed-density systems didn't have
anywhere near as much work to to as ours did to achieve the same
result. Hence my comment that you need good initial feed-gas to make
speed-density a viable proposition. 

That's just what I'd found from experience, speed density has a
future with a good base engine design, it must have, it's cheaper
than most other methods and the Japs use it and have made it work.

Doesn't stop it being a real sh*t to calibrate tho' .......

                         Brian Warburton