26. "My fuel-injected Ducati seems to pop a lot when I'm accelerating; nosmoke, just noise. Is it too lean? What is the equivalent of rejetting thecarburetors for highly-evolved steed?"
Description
This article is from the Ducatis Motorcycles FAQ, by Duke Robillard duke@io.com with numerous contributions by others.
26. "My fuel-injected Ducati seems to pop a lot when I'm accelerating; nosmoke, just noise. Is it too lean? What is the equivalent of rejetting thecarburetors for highly-evolved steed?"
Thanks to Brad Turner (mbt@mkt.3com.com), Godfrey DiGiorgi
(ramarren@apple.com), and Michael Nelson, (nelson@seahunt.imat.com) or
research.
Why yes, it is. If you have a fuel-injected Duc, fear not because you can
achieve similar results to rejetting with a better chip. Again, Cagiva
leans the mixture out to pass emissions in the States, but the European
chip corrects this situation. Even better, posters report the best
improvements by using the enhanced chip by Fuel Injected Motorcycles
(available from PI Motorsports, (formerly Pro Italia) of Glendale, CA),
which removes some mapping anomalies (you know, bugs) from the factory
chips. Combined with the aforementioned K & N air filter mods a 907ie owner
reports roughly 12 hp. more in the midrange and possibly 6 to 8 hp. at the
top end, as an example. Regardless, it's worth it just for the full 9000
rpm redline instead of the factory 8700 limit. Fast By Ferracci also makes
a chip that some posters have used, but many have since switched to the FIM
version.
Apparently FBF uses the "some is good, more is better" approach to
engineering (if you call it that) their EPROMS. On the Duc EFI systems the
CPU basically does a series of table lookups. On the 907's 6801 based
processor these table lookups produce an injector values from 0-255 to
indicate how long to open the injector -- for a richer mixture, they just
spray for a longer time, for leaner, a shorter time. According to Duane at
Fuel Injected Motorcycles, all that FBF did was to do an across-the-board
bump of all of the values in the table. He claims that if you look at the
table lookup outputs a lot of the time under acceleration you'll see 0xff
[maximum value] outputs when that is really not appropriate based on an
exhaust gas analyzer. The upshot of this is that the bike tends to run
richer and mileage suffers. According to him he does his EPROM tables with
a brake dyno and EG analyzer setup. When running with the FBF chip, too
rich is what seemed to be happening. It wasn't uselessly too rich but it
was noticeable. Side effects of the too-rich settings, however, are carbon
build up in the exhaust and crappy mileage.
Note: some fuel-injection units use dual-capacity EPROMS to independently
map the two cylinders, combined with a faster CPU for more precise
metering. These can be found in the 888 series Ducatis. Make sure you
specify which model (SP1, SP2, SP3, etc.) when you order.
Fuel Injected Motorcycles
P.O. Box 851
Apollo Bay, Victoria 3233
AUSTRALIA
61 52 379 222 phone/fax
(sold by Pro Italia in
the States, 818.249.5707,
www.pimotorsports.com)
Fast by Ferracci
1641 Easton Rd.
Willow Grove, PA 19090 215.657.1276 phone
www.ferraci.com
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