Shortly after finishing
the dashboard upgrade I
decided that I would upgrade the Emerald
ECU to the latest firmware version, called the K3.
To do this the ECU was sent back to Emerald and they performed
the upgrade and returned the unit with 3 days!
All the connections remained the same, so it was simply
a case of plugging the unit back into the car but I wanted
to make use of one of the new features that required a bit
of extra hardware to be fitted to the car.
Switchable maps appealed for a couple of reasons. The first
was that I could have one map for normal driving on short
blats, another slightly more economical map for cruising
and one spare map, which I could use for guest drivers/MOT
with a lower rev limit imposed. To fit the switch I was
able to reuse the old heater control cable hole and you
simply add a single cable to the ECU connector. This is
taken to the switch, with 3 positions of the switch being
taken a) to earth (0v), b) to earth via a resistor (2.5v)
and c) to nothing (5v). You then configure
the different voltages in the Emerald software. Very simple
and works very well and it is happy to switch whilst you
are driving along with no discernible signal.
The main reason for the upgrade, however, was the introduction
of self mapping, or as Emerald call it, Adaptive mapping.
I used something similar on the Megasquirt
ECU and it worked quite well, but it's major drawback
was the fact that due to the limited number of 'writes'
that the EPROM could handle, you could let it self learn,
else you'd end up with a half mapped engine with an EPROM
that wouldn't allow any more updates. To get around this,
you had to run the car with the laptop on the passenger
seat and then only do a single 'burn to ECU' at the end
of a run. It wasn't a major problem, but it was a pain to
have to fire the PC up everytime you wanted to go for a
mapping run. The great thing about the Emerald system is
that you get 4 maps:
||The normal fuel injection map
||A map for each load site where you enter
the AFR (or lambda) target - e.g. at light throttle
and low rev you could use a figure in the low 14's or
high 13's, but at higher throttle and revs you would
want to run something in the lower 13's.
||This is where the ECU stores the values
that it has corrected so far - so each load site has
a +/- figure representing fuel added or removed from
the main map. This is read in conjuction with the main
map so when returning to a load site, the corrected
value is used and corrections are then added or removed
from the new starting point.
You can select correction values in the map and right
click and apply them to the main map, but you only need
to do this every now and again, just to keep the main
||This is where you can select, on a per
load site basis, how you want the ECU to act. It can
run in open loop where it ignores the lambda sensor
completely, closed loop where it targets according to
the AFR target map but doesn't record anything in the
Correction map or Adaptive, which is the same as closed
loop, but it stores the correction made for next time.
I found this worked very well, once I figured out, with
the help from some Blatchat members, how to set the various
settings, like response speed, etc.
One of the other new features of the K3 is the fact that
you can change the load site values to what you like, so
the rpm and throttle positions can be changed to 200rpm
gaps, or whatever you like. I did this when I got my ECU
back as the 500rpm gaps of the old version meant that I
was only using half the map. The ECU then interpolated the
new spacing and gave me a map based on the old one. When
I first drove the car with the K3 it was running very lean
up to around 3000rpm and I initially thought my AFR sensor
was playing up as it wasn't like that before the upgrade,
and I had fitted the dashboard in-between, so may have altered
something. After some trials I found it wasn't this and
it must be the map. I added some fuel in the problem areas
and switched on the adaptive mapping and went back out -
hey presto, which it as a bit rich to start with, you could
feel the engine getting stronger if you held the throttle
still and it simply got better and better. Great!
However great adaptive mapping may be, I still felt that
I should get the car on a rolling road - there are parts
of the map that you enter so rarely that it doesn't have
chance to correct (like high rpm, or high load but slow
rpm) and I had no way of knowing if my ignition was anywhere
near close. I booked a session at Emerald and then waited
the 8 weeks for it to come around - that's how busy they
are. I set off early in the morning for a gentle drive around
the M25 and up the A11 and I arrived 3hrs later, just after
9am. Dave Walker was there and moved a project car out of
the way so I could back my car into the torture chamber
and then made me a cup of tea. Things got under way around
10am and Dave worked his way through the lower rpm sites,
checking the fueling, adjusting it further up if you spotted
a potential problem, etc. He was very methodical, I suspect
from having done so many car now, but it was very interesting
to watch, and you just can't expect to be able to hold load
sites in the same way on the road whilst trying to drive
at the same time. He worked his way up to 5000rpm and then
went for the first power run. This was the moment I had
been dreading for two reasons: a) it might blow up and b)
what if it made some abysmal figure, far less than expected
- Id be gutted. I kept telling myself that I would be happy
if it made 190bhp and really happy if it made 200bhp - but
really I wanted the magic 200bhp - it just sounds so much
better doesn't it.
On the first run it made 196.4bhp - great, that isn't bad
for a first attempt and fear number 2 was crossed off my
list. Dave went back and added some advance and tried again
- 198.6bhp. Getting there, so a bit more was added and he
took it a bit higher on the revs this time and got 201.4bhp.
One happy bunny and the car was intact, which was a bonus.
Dave proceeded to check the fueling out from his data read-outs
and make some more adjustments and at around 1pm he declared
On the trip home the car felt a lot nicer to drive. Whilst
I was, again, only on the motorway, I could feel that the
engine had loads more power at light throttle due to all
the added advance and I was maintaining my speed with a
noticeably lighter throttle. I brimmed the tank shortly
after leaving Emerald and again when I got home and recorded
33.5mpg - which wasn't bad as I hit some traffic on the
M4 and had a play with a Ferrari F355 as we were both bored.