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Walker’s
World January 05
Autosport
05
Many
thanks to all our customers/readers who came to the Autosport show
at the NEC. We had teamed up with racing shock company Nitron to
allow us a bigger stand. This is where we first released details
of the new K2 ECU. You can read the technical spec elsewhere on
the web site but basically it’s a tiny miniaturised ECU with
fuel and ignition capability. Everyone I showed kept saying: “but
what is it?” they couldn’t believe that it did all the
same fuel and ignition functions of the larger ECU.
Obviously to get it that small we had to leave out a lot of the
larger box’s functions like boost control, idle stepper motor
control and so on – but if you just want fuel and sparks it’s
every bit as good as the original and even takes the same maps and
uses the same, albeit abbreviated, software. The larger ECU got
a whole host of new functions and a new name: “K3”.
The feeling I got from the show was that there were less people
there than last year and possibly less stands – the isles
were apparently wider than previous years. All the same the level
of enthusiasm were as high as ever and I came away with a sore throat
from talking too much – I always talk too much but I listen
as well. Thanks for all the feed-back and we will be acting on some
of your suggestions to improve the Emerald products.
Rotary
While
I was racing in Sweden recently I also had the chance to check out
an RX7 racer with the original rotary engine. This twin rotor unit
had been fitted with a carburettor but this has now been replaced
with a slide throttle injection system. The Emerald ECU has modified
software so that the twin spark plugs in the combustion chamber
can be fired at different intervals.
T.S. Motorsport’s mapping expert Svalle did the setting up
on their 4WD Dyno Dynamics rolling road. The car now starts from
cold on the hard race plugs and idles cleanly until warm. Peak power
increased from 265 bhp to 280 bhp but the biggest gain is in the
fuel consumption. During a race the car now uses 30% less fuel!
You would think that a result like that would keep the driver happy
– not so. He now wants to install the three rotor engine that
he has been preparing for a winter rebuild.
Vauxhall
head porting
I did
a feature for PPC magazine on porting the Vauxhall XE head. Briefly
we wanted more top end power and I wanted to test out a flow bench
modification to measure inlet mixture tumble. The tumble device
works and I now have my first set of figures for the stock head
and two different port shapes – both with larger valves. Interestingly
the tumble increased with the increased air flow but what I don’t
know is if this is a good thing or a bad thing.
When we re-mapped the engine on the rollers we increased maximum
power from 112 bhp to 235 bhp – but lost out in the lower
rpm range on torque. A lot of the torque was regained by playing
with the inlet trumpet lengths but we couldn’t run like that
because the bonnet didn’t have enough clearance. That is being
sorted and we also plan to make the exhaust somewhat adjustable
so we can tune in the lengths on the next rolling road session.
The plan was to try some Piper cams with solid followers to see
if we can’t gain from increased lift over the soft hydraulic
profiles currently fitted.
The Piper cams were their “Hot Rod” profile which were
claimed to give excellent torque spread. Hot Rods run in one gear
so a good spread of power is essential for passing and not being
passed. It worked like magic. We recovered all the low speed torque
lost with the big valve head and went on to take the new maximum
to 257bhp with masses more power where it counts – from 5000rpm
to 8500rpm.
If Team Silman does not go Duratec for this year then the plan is
to try some exhaust changes and try double injectors with a modified
air box/bonnet to gain even more torque. The XE may be a dated engine
but it’s still a powerful option if you have to stick to a
2.0 litre class limit.
New
Record
My favourite
Piper cam for the K-Series is the 285H hydraulic profile. No shims,
no modified tappets, just bolt them in and start her up. We have
just done a Caterham 7 with a DVA ported VHPD head and 285H cams.
The engine is pretty much full-on spec but the cams are normal Piper
Blueprint 285H profiles. The owner was expecting over 190bhp, it
actually made 210 bhp at 7900rpm and 152 ft lbs at 5900rpm. That’s
a new all time record for a 285H on our rollers. Andy Perry, who
owns the car, was just a little bit pleased with himself.
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